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Ruthenium(II) Complexes of 2-Pyridylphosphines: Coordination Modes, Reactivity with Small Molecules,… Schutte, Richard Peter 1995

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Ruthenium(II) Complexes of 2-Pyridylphosphines: Coordination Modes, Reactivity with Small Molecules, and Aqueous Chemistry By RICHARD PETER SCHUTTE B.Sc. Queen's University, 1990 A THESIS SUBMITTED IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF DOCTOR OF PHILOSOPHY in THE FACULTY OF GRADUATE STUDIES (Department of Chemistry) We accept this thesis as conforming to the required standard THE UNIVERSITY OF BRITISH COLUMBIA September, 1995 © RICHARD P. SCHUTTE, 1995 In presenting this thesis in partial fulfilment of the requirements for an advanced degree at the University of British Columbia, I agree that the Library shall make it freely available for reference and study. I further agree that permission for extensive copying of this thesis for scholarly purposes may be granted by the head of my department or by his or her representatives. It is understood that copying or publication of this thesis for financial gain shall not be allowed without my written permission. Department of ' The University of British Columbia Vancouver, Canada DE-6 (2/88) ABSTRACT Several ruthenium(II) 2-pyridylphosphine PPh3- xpy x (PNX, where x = 1, 2, 3 and Ph = phenyl group, py = 2-pyridyl group) complexes were synthesized and characterized. The use of the 2-pyridylphosphines was prompted by the potential of forming water soluble complexes, for use in olefin hydration catalysis (i.e., adding H 2 O across a carbon-carbon double bond). With ruthenium, the PN X ligands exhibited a variety of coordination modes, including coordination through the phosphorus only (P), the phosphorus and one pyridyl group (P,N), the phosphorus and two pyridyl groups (P,N,N'; PN2 and PN3 only), and through three pyridyl groups (N,N',N"; PN3 only). Complexes synthesized were characterized in general by a combination of 3 1P{1H} NMR, !H NMR, IR, and UV-visible spectroscopies, as well as conductivity and elemental analysis, while four complexes were also characterized by X-ray crystallography. The water-soluble complexes [RuCl(PNx)3]Cl (x = 2, (3); 3, (1)) and [RuCl(PPh3)(PN3)2]Cl (2b) were obtained by ligand substitution of RuCl2(PPh3)3 with excess PNX in C6H6. With six equivalents of PN3, complexes 1 and 2b are obtained as a mixture. Complex 1 was synthesized independently by reaction of [RuCl2(CsHi2)]n (C8H12 = COD = 1,5-cyclooctadiene) with three equivalents of P N 3 in refluxing methanol, while 2b was obtained by reaction of RuCl2(PPh3)3 with two equivalents of PN3 in CH2CI2 at room temperature. Fifteen equivalents of PN2 were used to produce 3 via ligand substitution of RuCl2(PPh3)3 in C6H6- All three complexes contain two PjiV-coordinated PNX ligands with the other phosphine P-coordinated. Complex 2b was also isolated as the PF6" (2c) and BPh4" (2d) salts. An X-ray crystal structure of 2c confirmed the coordination geometry. In water, 1 and 3 dissociate chloride to form [Ru(PNX)3] 2 + cations with all three PN X ligands as P,N chelates. The cations were isolated as the PF6" (x = 2, 3) and BPI14" ii (x = 3) salts. The chloride in 2b does not dissociate in water. The complexes were tested as hydration catalysts for hydrating maleic acid in water. No hydration to malic acid was observed, but some catalytic isomerization to fumaric acid (4-6%) occurred after 24 h at 100 °C. The in situ reaction of RuCl2(PPh3)3 with one. equivalent of PN3 in C D C I 3 produced [RuCl(PPh3)2(PN3)]Cl (6a) after 7 d. The complexes [RuCl(PPh3)2(PNx)]PF6 (x = 2, (6b); 3, (6c)) were isolated from the reaction of RuCl2(PPh3)3 with one equivalent of PN X and NH4PF6 in acetone. X-ray crystal structures revealed a distorted octahedral structure for 6b and 6c with a strained PNX ligand coordinated via the phosphorus and two pyridyl groups (.P.Af.AO. Complexes 6b and 6c are the first examples of complexes displaying the P,N,N' coordination mode. The P,^/-coordinated complexes c/s-RuCl2(DPPB)(PNx) (x = 1, (8a); 2, (8b); 3, (8c); DPPB = Ph2P(CH2)4PPh2) were made by isomerization of the corresponding trans chloro isomers, by refluxing in C^W^. The trans isomers were synthesized by ligand substitution of RuCl2(DPPB)(PPh3), with one equivalent of PNX in benzene at room temperature. The cis complexes, 8a, 8 b, and 8c undergo equilibria in chlorinated solvents (i.e., C H C I 3 and CH2CI2) involving dissociation of a chloride. In the case of 8b and 8c, cationic complexes with P,N,N -coordinated PN X ligands are formed. The cationic complexes were isolated as the PF6' salts, [RuCl(DPPB)(PNx)]PF6 (x = 2, (9a); 3, (9b)), and are analogues of 6b and 6c. Reactivity of the strained P.N,iV'-coordination mode with small molecules (i.e., H2, O2, N2, CO; 1 atm , room temperature) was investigated. Complexes 6b, 6c, 9a, and 9b react with CO only, displacing one coordinated pyridyl group from the metal centre and forming the ^//-coordinated PN X complexes: [RuCl(CO)(PP)(PNx)]PF6 (PP = (PPh3)2, x = 2 (10a), 3 (10b); and PP = DPPB, x = 2 (lib), 3 (11c)). Solution structures of these carbonyl complexes were determined and are discussed. Heating solutions of iii l i b and 11c partially reversed the CO reactions with formation of the respective starting materials; however, isomerization also occurred. The N,AT,JV"-coordinated PN3 complex, RuCl2(PPh3)(PN3) (13) was synthesized by ligand substitution of RuCl2(PPh3)3 with one equivalent of PN3 in refluxing C6H6. This complex was also produced by heating (65 °C, 2 d) the in situ complex 6a. An X-ray crystal structure of 13 revealed an octahedral coordination with cis chlorides and the PN3 ligand bound facially via the three pyridyl groups only. In methanol, 13 dissociates chloride to form a coordinated methanol complex which was isolated as [RuCl(MeOH)(PPh3)(PN3)]BPh4. The dissociation in methanol allowed chloride substitution reactions with neutral two-electron donors, and the complexes [RuCl(L)(PPh3)(PN3)]PF6 (L = CO, MeCN, PhCN) were isolated. In benzene the triphenylphosphine of 13 can be replaced to form RuCl2(L)(PN3) (L = CO, MeCN, PhCN). The non-coordinated phosphorus of the PN3 in 13 is slowly oxidized by O2 to give RuCl2(PPh3)(OPN3) which was synthesized also by reaction of 13 with m-ClC6H4C(0)OOH. The stereochemistry of the various complexes is described, particularly for PN2 where the phosphorus is chiral for bidentate P,N-coordinated complexes. iv TABLE OF CONTENTS Abstract 1 1 Table of Contents v List of Tables xii List of Figures x v Abbreviations and Symbols xxii List of Complexes xxv Acknowledgements xxvii CHAPTER 1 Introduction 1 1.1 Homogeneous Catalysis in Aqueous Media 1 1.2 Catalytic Hydration of Olefins Using Transition Metal Complexes 2 1.2.1 Non-Phosphine Complexes 2 1.2.2 Phosphine Complexes 3 1.3 2-Pyridylphosphine Chemistry 7 1.3.1 Synthesis of 2-Pyridylphosphines 7 1.3.2 Coordination Chemistry of 2-Pyridylphosphines 7 1.3.3 Ruthenium Complexes with 2-Pyridylphosphines 9 , 1.3.4 Catalysis with 2-Pyridylphosphine Complexes 9 1.4 Scope of this Thesis 11 1.5 References 13 CHAPTER 2 Experimental Procedure 16 2.1 General Materials 16 2.1.1 Solvents 16 2.1.2 Gases...: 16 v 2.1.3 General Reagents 17 2.2 General Instrumentation 17 2.3 Phosphines 18 2.3.1 2-Pyridylphosphines 18 2.3.1.1 Diphenyl(2-pyridyl)phosphine, PNi 18 2.3.1.2 Phenylbis(2-pyridyl)phosphine, PN2 19 2.3.1.3 Tris(2-pyridyl)phosphine, PN3 19 2.3.1.4 Separation of PNi from OPNi 20 2.3.2.5 Preparation of the 2-Pyridylphosphine Oxides, OPNi, OPN 2, and OPN3 20 2.4 Ruthenium Precursor Compounds 21 2.4.1 Preparation of RuCl2(PPh3)3 21 2.4.2 Preparation of RuCl2(DPPB)(PPh3) 21 2.4.3 Preparation of [RuCl2(C 8 Hi 2 )]n 22 2.5 General Experimental Procedure for Chapter 3 22 2.5.1 Reaction of RuCl2(PPh3)3 with Excess PN3 22 2.5.2 Preparation of [RuCl(PN3)3]Cl (1) 23 2.5.3 Preparation of [RuCl(PPh3)(PN3)2]Cl (2b) 24 2.5.4 Preparation of [RuCl(PPh3)(PN3)2]PF6 (2c) 24 2.5.5 Preparation of [RuCl(PPh3)(PN3)2]BPh4 (2d) 25 2.5.6 Preparation of [RuCl(PN2)3]Cl (3) 25 2.5.7 Preparation of [Ru(PN3)3][BPh4]2 (4a) 26 2.5.8 Preparation of [Ru(PN3)3][PF6]2 (4b) 26 2.5.9 Preparation of [Ru(PN2)3] [PF6]2 (5) 27 2.5.10 Attempted Hydration of Maleic Acid 27 2.6 General Experimental Procedure for Chapter 4 28 2.6.1 In Situ Reaction of RuCl2(PPh3)3 with One Equivalent of PN3 29 vi 2.6.2 Preparation of [RuCl(PPh3)2(PNx)]PF6 (x = 2, 3) 29 2.6.2.1 [RuCl(PPh3)2(PN2)]PF6 (6b) 29 2.6.2.2 [RuCl(PPh3)2(PN3)]PF6 (6c) 30 2.6.3 Preparation of Jrans-RuCl2(DPPB)(PNx) (x = 1, 2, 3) 30 2.6.3.1 rrans-RuCl2(DPPB)(PNi) (7a) 30 2.6.3.2 frans-RuCl2(DPPB)(PN2) (7b) 31 2.6.3.3 *rans-RuCl2(DPPB)(PN3) (7c) 31 2.6.4 Preparation of m-RuCl2(DPPB)(PNx) (x = 1, 2, 3) 31 2.6.4.1 cw-RuCl2(DPPB)(PNi) (8a) 31 2.6.4.2 d5-RuCl2(DPPB)(PN2) (8b) 32 2.6.4.3 cw-RuCl2(DPPB)(PN3) (8c) 32 2.6.5 Preparation of [RuCl(DPPB)(PNx)]PF6 (x = 2, 3) 32 2.6.5.1 [RuCl(DPPB)(PN2)]PF6 (9a) 32 2.6.5.2 [RuCl(DPPB)(PN3)]PF6 (9b) 33 2.6.6 Reactivity of P,N,N'-TiN2 and -PN 3 Ruthenium Compounds 33 2.6.6.1 NMR-Scale Reactions 33 2.6.6.2 Catalytic Hydrogenation of N-benzylidenebenzylamine 34 2.6.6.3 Preparation of [m-RuCl(CO)(PPh3)2(PN2)]PF6 (10a) 35 2.6.6.4 Preparation of [cw-RuCl(CO)(PPh3)2(PN3)]PF6 (10b) 35 2.6.6.5 Preparation of [ris-RuCl(CO)(DPPB)(PNx)]PF6 (x = 2 (ds-llb), 3 (ds-llc)) 36 2.6.6.6 Preparation of [RuCl(CO)(DPPB)(PNi)]PF6 (11a) 36 2.6.6.7 Isomerization of [ds-RuCl(CO)(DPPB)(PNx)]PF6 (x = 2, 3) and CO Loss 37 2.6.6.8 Isomerization of [ds-RuCl(CO)(DPPB)(PNx)]PF6 (x = 2, 3) 37 2.7 General Experimental Procedure for Chapter 5 37 vii 2.7.1 Preparation of RuCl2(PPh3)(PN3) (13) 38 2.7.2 Attempted Preparation of [RuCl(MeOH)(PPh3)(PN3)]BPh4 38 2.7.3 Chloride Substitution Reactions of RuCl2(PPh3)(PN3) 38 2.7.3.1 Preparation of [RuCl(CO)(PPh3)(PN3)]PF6 (14a) 38 2.7.3.2 Attempted Preparation of [RuCl(CO)(PPh3)(PN3)]PF6 in Acetone 39 2.7.3.3 Preparation of [RuCl(MeCN)(PPh3)(PN3)]PF6 (14b) 39 2.7.3.4 Attempted Preparation of [RuCl(MeCN)(PPh3)(PN3)]PF6 in MeCN 40 2.7.3.5 Preparation of [RuCl(PhCN)(PPh3)(PN3)]PF6 (14c) 40 2.7.3.6 Attempted Preparation of [RuCl(PhCN)(PPh3)(PN3)]PF6 in PhCN 41 2.7.3.7 Reaction of RuCl2(PhCN)(PN3) with PhCN and NH4PF6 in MeOH 41 2.7.4 Triphenylphosphine Substitution Reactions of RuCl2(PPh3)(PN3) 42 2.7.4.1 Preparation of RuCl2(CO)(PN3) (15a) 42 2.7.4.2 Preparation of RuCl2(MeCN)(PN3) (15b) .42 2.7.4.3 Preparation of RuCl2(PhCN)(PN3) (15c) 42 2.7.4.4 Reaction of RuCl2(PPh3)(PN3) in PhCN 43 2.7.5 Reaction of RuCl2(PPh3)(PN3) with O2 43 2.7.5.1 Preparation of RuCl2(PPh3)(OPN3) (16) 43 2.7.5.2 Attempted Preparation of RuCl2(PPh3)(OPN3) from RuCl2(PPh3)3 and OPN3 44 2.7.6 Reaction of RuCl2(PPh3)(PN3) with H 2 45 2.7.6.1 Reaction of RuCl2(PPh3)(PN3) with H 2 in DMA 45 2.7.6.2 Reaction of RuCl2(PPh3)(PN3) with H 2 in MeOH 45 2.8 References 47 viii CHAPTER 3 Water-Soluble Ruthenium 2-Pyridylphosphine Complexes 49 3.1 Introduction 49 3.2 Reaction of RuCl2(PPh3)3 with excess PN3 49 3.3 Synthesis and Characterization of [RuCl(PN3)3]Cl 53 3.3.1 Synthesis of [RuCl(PN3)3]Cl 53 3.3.2 Characterization of [RuCl(PN3)3]Cl 54 3.4 Synthesis and Characterization of [RuCl(PPh3)(PN3)2]X (X = Cl, PF 6, BPh4) 60 3.4.1 Synthesis of [RuCl(PPh3)(PN3)2]X (X = Cl, PF 6, BPh4) 60 3.4.2 Solution Structure of [RuCl(PPh3)(PN3)2]X (X = Cl, PF 6 , BPh4) 62 3.4.3 X-ray Crystal Structure of [RuCl(PPh3)(PN3)2]PF6 69 3.5 Reaction of RuCl2(PPh3)3 with Excess PN2, Synthesis of [RuCl(PN2)3]Cl 73 3.6 Aqueous Solution Chemistry of [RuCl(PPh3)(PN3)2]Cl and [RuCl(PNx)3]Cl (x = 2, 3) 75 3.7 Attempted Hydration of Maleic Acid 85 3.8 Conclusions 89 3.9 References 90 CHAPTER 4 P,iV,JV'-Coordination Mode of 2-Pyridylphosphines 92 4.1 Introduction 92 4.2 Reaction of RuCl2(PPh3)3 with One Equivalent of PN3 93 4.3 Synthesis and Characterization of [RuCl(PPh3)2(PNx)]PF6 (x = 2, 3) 96 4.4 Synthesis and Characterization of ?rans-RuCl2(DPPB)(PNx) (x=l,2, 3) 109 ix 4.5 Synthesis and Characterization of RuCl2(DPPB)(PNx) (x = 1, 2, 3) and [RuCl(DPPB)(PNx)]X (x = 2, 3 and X = Cl, PF6) 111 4.6 Reactivity of the P,N,/^'-Coordination Mode 119 4.6.1 Reactivity with H2, O2, and N2 120 4.6.2 Catalytic Hydrogenation of Imines using Ruthenium 2-Pyridylphosphine Complexes 121 4.6.3 Reactivity with CO 123 4.6.3.1 Reactions of [RuCl(PPh3)2(PNx)]PF6 (x = 2 , 3) with CO. Synthesis of [RuCl(CO)(PPh3)2(PNx)]PF6 (x = 2 , 3) 123 4.6.3.2 Reactions of [RuCl(DPPB)(PNx)]PF6 (x = 2, 3) with CO. Preparation of [c/s-RuCl(CO)(DPPB)(PNx)]PF6 (x = l,2, 3) 130 4.6.3.3 Isomerization of [m-RuCl(CO)(DPPB)(PNx)]PF6 (x = 2, 3) and Reversibility of the CO Reactions 138 4.6.3.4 n-Acceptor Abilities of the PNX (x = 1, 2, 3) Ligands 141 4.7 Conclusions 142 4.8 References 143 CHAPTER 5 Ar,Ar,AT-Tris(2-pyridyl)phosphine Complexes 145 5.1 Introduction 145 5.2 Synthesis and Characterization of RuCl2(PPh3)(PN3) 145 5.3 Dissociation of a Chloride from RuCl2(PPh3)(PN3) in Methanol 156 5.4 Chloride Substitution Reactions of RuCl2(PPh3)(PN3) 163 5.5 Triphenylphosphine Substitution Reactions of RuCl2(PPh3)(PN3) 166 5.6 Comparison of Substitution Products of RuCl2(PPh3)(PN3) with Those of Analogous Cp Complexes 169 5.7 Reaction of RuCl2(PPh3)(PN3) with O2 171 5.8 Reactions of RuCl2(PPh 3)(PN3) with H 2 175 5.9 Conclusions 178 5.10 References 179 CHAPTER 6 181 6.1 Conclusions and Recommendations for Future Work 181 6.2 References 186 APPENDICES 187 APPENDIX A 188 A.1 3 1 P { lU) and ! H N M R Data for 2-Pyridylphosphines and 2-Pyridylphosphine Oxides 188 A.2 References 192 APPENDIX B Crystallographic Data for [RuCl(PPh3)(PN3)2]PF6 (2c) 193 APPENDIX C Crystallographic Data for [RuCl(PPh3) 2(PN 2)]PF 6 (6b) 202 APPENDIX D Crystallographic Data for [RuCl(PPh3) 2(PN 3)]PF 6 (6c) 211 APPENDIX E Crystallographic Data for RuCl 2(PPh 3)(PN3>2CH 2Cl 2 (13) 219 xi LIST OF TABLES Table 3.1 lU NMR Chemical Shifts for Ruthenium PNX (x = 2, 3) Complexes 56 Table 3.2 31P{ !H} NMR Chemical Shifts for Ruthenium PNX (x = 2, 3) Complexes 57 Table 3.3 Conductivity Data for Ruthenium PNX (x = 2, 3) Complexes at 25 °C 59 Table 3.4 Selected Bond Lengths and Angles for [RuCl(PPh3)(PN3)2]PF6 2c 71 Table 3.5 Comparison of the Four-Membered Ring Bond Angles (°) in 2c, cis-RuCl2(PNi)2 and m-RuCl2(CO)2(PNi) 72 Table 3.6 31P{ XH} NMR Chemical Shifts for Water-Soluble and Related Ruthenium PNX (x = 2, 3) Complexes .77 Table 3.7 *H NMR Chemical Shifts for Water-Soluble and Related Ruthenium PNX (x = 2, 3) Complexes .78 Table 3.8 Composition of Reaction Mixtures in the Attempted Catalytic Hydration of Maleic Acid 88 Table 4.1 31P{ lH} NMR Chemical Shifts for Neutral and Cationic Ruthenium PNX (x = 1, 2, 3) Complexes 91 Table 4.2 lU NMR Chemical Shifts for Ruthenium PNX (x = 1, 2, 3) Complexes 98 Table 4.3 Selected Bond Lengths (A) for [RuCl(PPh3)2(PN2)]PF6 6b and [RuCl(PPh3)2(PN3)]PF6 6c 104 Table 4.4 Selected Bond Angles (°) for [RuCl(PPh3)2(PN2)]PF6 6b and [RuCl(PPh3)2(PN3)]PF6 6c 105 Table 4.5 Comparison of the Four-Membered Ring Bond Angles (°) in [RuCl(PPh3)(PN3)2]PF6 2c, [RuCl(PPh3)2(PN2)]PF6 6b, and [RuCl(PPh3)2(PN3)]PF6 6c 106 xii Table 4.6 UV-visible and Molar Conductivity Data for Ruthenium PNX (x = 1, 2, 3) Complexes 108 Table 4.7 Results for the Catalytic Hydrogenation of N-Benzylidenebenzylamine to Dibenzylamine 121 Table 4.8 31P{ !H} NMR (CDCI3) Chemical Shifts and Carbonyl Stretching Frequencies for Ruthenium PNX (x = 1, 2, 3) Carbonyl Complexes 127 Table 4.9 lU NMR Chemical Shifts for Ruthenium PN X (x = 1, 2, 3) Carbonyl Complexes 128 Table 5.1 Selected Bond Lengths (A) for RuCl2(PPh3)(PN3) 13, and [Ru(PN3)2][C7H7S03]2 147 Table 5.2 Selected Bond Angles (°) for RuCl2(PPh3)(PN3) 13 148 Table 5.3 31P{ !H} NMR Chemical Shifts for N,N',<V'-Coordinated Tris(2-pyridyl)phosphine Complexes 151 Table 5.4 ! H NMR Chemical Shifts for MJV',iV"-Coordinated Tris(2-pyridyl)phosphine Complexes 152 Table 5.5 Infrared and Conductivity Data for A^iV'-Coordinated Tris(2-pyridyl)phosphine Complexes 157 Table 5.6 Calculated C, H, and N Percentages for Possible Impurities in the Isolated [RuCl(MeOH)(PPh3)(PN3)]BPh4 complex, as well as the Found Percentages 158 Table 5.7 UV-visible Data for N,W,iV"-Coordinated Tris(2-pyridyl)phosphine Complexes 161 Table 5.8 Comparison of Colours and Infrared Stretching Frequencies for Analogous Cp and N,N',N"-PN^ Ruthenium Complexes 170 Table 5.9 Characterization Data for RuCl2(PPh3)(OPN3) 16 173 Table A. 1 31P{ !H} and !H NMR Chemical Shifts for 2-Pyridylphosphines and 2-Pyridylphosphine Oxides 189 xiii Tables B.1-E.4 list crystallographic data. Table B. 1 Experimental Details for [RuCl(PPh3)(PN3)2]PF6 197 Table B.2 Atomic Coordinates and Beq for [RuCl(PPh3)(PN3)2]PF6 199 Table B.3 Bond Lengths (A) for [RuCl(PPh3)(PN3)2]PF6 200 Table B.4 Bond Angles (°) for [RuCl(PPh3)(PN3)2]PF6 201 Table C. 1 Experimental Details for [RuCl(PPh3)2(PN2)]PF6 206 Table C.2 Atomic Coordinates and Beq for [RuCl(PPh3)2(PN2)]PF6 208 Table C.3 Bond Lengths (A) for [RuCl(PPh3)2(PN2)]PF6 209 Table C.4 Bond Angles (°) for [RuCl(PPh3)2(PN2)]PF6 210 Table D. 1 Experimental Details for [RuCl(PPh3)2(PN3)]PF6 214 Table D.2 Atomic Coordinates and Beq for [RuCl(PPh3)2(PN3)]PF6 216 Table D.3 Bond Lengths (A) for [RuCl(PPh3)2(PN3)]PF6 217 Table D.4 Bond Angles (°) for [RuCl(PPh3)2(PN3)]PF6 218 Table E. 1 Experimental Details for RuCl2(PPh3)(PN3) 221 Table E.2 Atomic Coordinates and Beq for RuCl2(PPh3)(PN3) 223 Table E.3 Bond Lengths (A) for RuCl2(PPh3)(PN3) 224 Table E.4 Bond Angles (°) for RuCl2(PPh3)(PN3) 225 xiv LIST OF FIGURES Figure 1.1 Sulphonated phosphines used in the Ruhrchemie/Rhone-Poulenc Oxo process 2 Figure 1.2 Hydration of olefins to produce alcohols 2 Figure 1.3 Reactions of the some palladium PN3 complexes in water. "Activation" of DM AD by a palladium dimer 6 Figure 1.4 Possible coordination modes of 2-pyridylphosphines with transition metals 8 Figure 2.1 Newman projection of malic acid showing J H NMR assignments 28 Figure 2.2 NMR tube with J. Young Valve and 'gas reservoir' 34 Figure 3.1 Summary of syntheses of compounds described in Chapter 3 50 Figure 3.2 31P{ 1H} NMR (121.4 MHz) spectra in CD2CI2 (a) and CDCI3 (b) for the mixture isolated from the reaction of RuCl2(PPh3)3 with six equivalents of PN3 52 Figure 3.3 Structures of [RuCl(PNx)3]Cl (x = 1, 2, 3) 53 Figure 3.4 31P{ lH] (CDCI3, 121.4 MHz) and *H NMR (CDCI3, 300 MHz, RT) spectra of [RuCl(PN3)3]Cl 1 58 Figure 3.5 31P{ ^ U) NMR (CDCI3, 121.4 MHz) spectra of the in situ reaction of RuCl 2(PPh3)3 with two equivalents of P N 3 61 Figure 3.6a 31P{ !H} NMR (121.4 MHz) spectra of [RuCl(PPh3)(PN3)2]Cl 2b 63 Figure 3.6b 31P{!H} NMR (121.4 MHz) spectra of [RuCl(PPh3)(PN3)2]PF6 2c 64 Figure 3.6c 31P{ iH} NMR (121.4 MHz) spectra of [RuCl(PPh3)(PN3)2]BPh4 2d .65 Figure 3.7 *H NMR (CDCI3, 300 MHz) spectra showing the phenyl region for [RuCl(PPh3)(PN3)2]X (X = Cl, PF 6 , BPh4) .66 xv Figure 3.8 Possible structures for [RuCl(PPh3)(PN3)2]+ along with expected 31P{1H} NMR patterns, type of 2Jpp coupling, and maximum number of observable H6 signals in the *H NMR 67 Figure 3.9 ORTEP plot (33% probability) of the molecular structure of the cation in [RuCl(PPh3)(PN3)2]PF6 2c 70 Figure 3.10 Stereoisomers of [RuCl(PN2)3]Cl 3. Four diastereomers with their corresponding enantiomers are shown 74 Figure 3.11 3 1 P {lH] NMR (CDC13, 121.4 MHz) spectrum of the mixture of diastereomers for [RuCl(PN2)3]Cl 3 75 Figure 3.12 Chloride loss from [RuCl(PNx)3]Cl (x = 2, 3) in H 2 0 .76 Figure 3.13 *H NMR (300 MHz) spectra showing the phenyl region for Cl", BPh4", and PF6" salts of the [Ru(PN3)3]2+ cation 79 Figure 3.14 Stereoisomers of [Ru(PN2)3]2+ 81 Figure 3.15 3 1 P {lH} NMR (CD2C12, 121.4 MHz) spectrum of [Ru(PN2)3][PF6]2 5 82 Figure 3.16 Variable temperature 31P{ !H} NMR (D20, 121.4 MHz) spectra of [RuCl(PN2)3]Cl 3.. 83 Figure 3.17 Hydration of maleic acid to malic acid 86 Figure 4.1 Binding modes for 2-pyridylphosphines 92 Figure 4.2 Summary of syntheses of compounds 93 Figure 4.3 31P{ lH} NMR (CDC13; 121.4 MHz) spectra for the in situ reaction of RuCl^PPh^ and PN 3 95 Figure 4.4 31p{ 1H} NMR ( C D C I 3 , 121.4 MHz) spectra of [RuCl(PPh3)2(PNx)]PF6 (x = 2 (6b), 3 (6c)) 100 Figure 4.5 Possible structures for 6b and 6c based on the 3 1P{ *H} and *H NMR spectra 101 xvi Figure 4.6a ORTEP plot of the cation in [RuCl(PPh3)2(PN2)]PF6 6b (33% probability). Phenyl groups have been eliminated for clarity 102 Figure 4.6b ORTEP plot of the cation in [RuCl(PPh3)2(PN3)]PF6 6c (33% probability) 103 Figure 4.7 Diagram illustrating the strain around the phosphorus atom of PN 3 in 6c 107 Figure 4.8 UV-visible spectra of [RuCl(PPh3)2(PNx)]PF6 (x = 2 (6b), 3 (6c)) in CH 2C1 2 107 Figure 4.9 Structures of frans-RuCl2(DPPB)(PNx) (x = 1 (7a), 2 (7b), 3 (7c)) 109 Figure 4.10 UV-visible spectra of frans-RuCl2(DPPB)(PNx) (x = 1 (7a), 2 (7b), 3 (7c)) in CH 2C1 2 I l l Figure 4.11 Dissociation.of a chloride from cw-RuCl2(DPPB)(PNx) (x = 1 (8a), 2 (8b), 3 (8c)) 112 Figure 4.12 3 1P{ lU) NMR (CDCI3, 121.4 MHz, room temperature) spectra of ds-RuCl2(DPPB)(PNx) (x = 1 (8a), 2 (8b), 3 (8c)) 114 Figure 4.13 UV-visible spectra of complexes 8b, 8c, 9a, and 9b in MeOH and CHCI3 116 Figure 4.14 31P{ !H} NMR (CD2C12, 121:4MHz) spectrum of cw-RuCl2(DPPB)(PN2) 8b. 117 Figure 4.15 Stereoisomers for cw-RuCl2(DPPB)(PN2) 8b 117 Figure 4.16 Possible mechanisms for the heterolytic cleavage of H2 by (a) the P,N-coordination mode and (b) the P,iV,N'-coordination mode of 2-pyridylphosphines 120 Figure 4.17 Summary of syntheses and reactivity of carbonyl compounds 124 xvii Figure 4.18 31P{!H} NMR (CDCI3, 121.4 MHz) of [RuCl(CO)(PPh3)2(PNx)]PF6 (x = 2 (10a), 3 (10b)) 126 Figure 4.19a 31P{ !H} NMR (CDCI3, 121.4 MHz) spectra of [cw-RuCl(CO)(DPPB)(PN2)]PF60.5Et2O, cis-Ub, and [m-RuCl(CO)(DPPB)(PN3)]PF60.25Et2O, m-l lc 131 Figure 4.19b lH NMR (CDCI3, 300 MHz) spectra of [cw-RuCl(CO)(DPPB)(PN2)]PF60.5Et2O, cis-llb, and [cw-RuCl(CO)(DPPB)(PN3)]PF60.25Et2O, cis-Uc 132 Figure 4.20 Possible structures for [c/s-RuCl(CO)(DPPB)(PNx)]PF6 (x = 2, cis-Ub; 3, cis-Uc) 134 Figure 4.21 Structures of [cw-RuCl(CO)(DPPB)(PNx)]PF6 (x = 1, m-lla; 2, cis-Ub; 3, cis-Uc) 135 Figure 4.22 31P{ lR} NMR (CDCI3, 121.4 MHz) spectra of (a) isolated [c/5/fran^-RuCl(CO)(DPPB)(PNi)]PF6 11a, and (b) after heating at 50 °C for 24 h 137 Figure 4.23 Possible structures for |>rans-RuCl(CO)(DPPB)(PNx)]PF6 (x = 1, trans-Ua; 2, trans-Ub; 3, trans-Uc) 139 Figure 4.24 31P{ lU} NMR ( C D C I 3 , 121.4 MHz) spectra after refluxing [cw-RuCl(CO)(DPPB)(PNx)]PF6 (x = 2, cis-llb; 3, cw-llc) in CHCI3 under Ar, (x = 2,16 h; x = 3, 24 h) 140 Figure 5.1 Synthesis of compounds described in Sections 5.2 to 5.5 146 Figure 5.2 ORTEP plot of RuCl2(PPh3)(PN3) 13 (33% probability) 149 Figure 5.3 31P{ !H} ( C D C I 3 , 121.4 MHz) and *H NMR ( C D C I 3 , 300 MHz) spectra of RuCl2(PPh3)(PN3) 13 154 Figure 5.4 Structures of some ruthenium(II) complexes containing a six-electron donor ligand 155 xviii Figure 5.5 IR spectra (KBr pellets) of (a) RuCl2(PPh3)(PN3) 13, (b) "[RuCl(MeOH)(PPh3)(PN3)]BPh4n, and (c) N a B P t n 159 Figure 5.6 UV-visible spectra of (a) RuCl2(PPh3)(PN3) 13 in MeOH, (b) 13 in MeOH with 1.33 M LiCl, (c) 13 in CH2CI2, and (d) [RuCl(MeOH)(PPh3)(PN3)]BPh4 in CH 2C1 2 162 Figure 5.7 Structures of compounds isolated from chloride-substitution reactions: [RuCl(L)(PPh3)(PN3)]PF6 where L = CO 14a, L = MeCN 14b, or L = PhCN 14c 164 Figure 5.8 Structure of compounds isolated from triphenylphosphine-substitution reactions of RuCl2(PPh3)(PN3): RuCl2(L)(PN3) where L = CO 15a, L = MeCN 15b, or L = PhCN 15c 167 Figure 5.9 *H NMR ( C D C I 3 , 300 MHz) spectrum of RuCl2(MeCN)(PN3) 15b 168 Figure 5.10 31P{ 2H} NMR (CDC13, 121.4 MHz) spectra for the in situ reaction of RuCl2(PPh3)(PN3) 13 with O2 172 Figure 5.11 Structure of RuCl2(PPh3)(OPN3) 16 174 Figure 5.12 Proposed reaction between RuCl2(PPh3)(PN3) 13 and H 2 in DMA 175 Figure 5.13 UV-visible spectra for the in situ reaction of RuCl2(PPh3)(PN3) 13 in MeOH with H2 (1 atm) at room temperature 177 Figure 5.14 Proposed reaction between RuCl2(PPh3)(PN3) 13 and H2 in MeOH 177 Figure 6.1 Illustration of the correlation between the coordination mode of a 2-pyridylphosphine and its 31P{ lH} NMR chemical shift in ruthenium complexes. 182 xix Figure 6.2 A complex for the selective and reversible coordination of CO, containing a P,N,AT-coordinated PN X (x = 2, 3) and a tripodal ligand 183 Figure 6.3 Proposed synthesis for a complex containing a P,iV,Af'-coordinated P N X (x = 2, 3) ligand as well as a tripodal PN3 ligand 184 Figure 6.4 Proposed synthesis and structure of the hydride complexes: [RuH(PPh3)2(PNx)]PF6 (x = 2, 3) 185 Figure A. 1 Numbering scheme for 2-pyridylphosphines and 2-pyridylphosphine oxides 189 Figure A.2 lU NMR (300 MHz) spectra of 2-pyridylphosphines in CDCI3 and C 6 D 6 190 Figure A.3 *H NMR (300 MHz) spectra of 2-pyridylphosphine oxides in CDCI3 and C 6 D 6 191 Figure B. 1 Molecular structure of cation in [RuCl(PPh3)(PN3)2]PF6 (PLUTO plot) 193 Figure B.2 Molecular structure of cation in [RuCl(PPh3)(PN3)2]PF6 (ORTEP plot) 194 Figure B.3 Molecular structure of cation in [RuCl(PPh3)(PN3)2]PF6 (Stereoview) 195 Figure B.4 Unit cell for [RuCl(PPh3)(PN3)2]PF6 196 Figure C. 1 Molecular structure of cation in [RuCl(PPh3)2(PN2)]PF6 (PLUTO plot) 202 Figure C.2 Molecular structure of cation in [RuCl(PPh3)2(PN2)]PF6 (ORTEP plot) 203 Figure C.3 Molecular structure of cation in [RuCl(PPh3)2(PN2)]PFg (Stereoview) 204 Figure C.4 Unit cell for [RuCl(PPh3)2(PN2)]PF6 205 xx Figure D. 1 Molecular structure of [RuCl(PPh3)2(PN3)]PF6 (PLUTO plot) 211 Figure D.2 Molecular structure of cation in [RuCl(PPh3)2(PN3)]PF6 (Stereo view) 212 Figure D.3 Unit cell for [RuCl(PPh3)2(PN3)]PF6 212 Figure E. 1 Molecular structure of RuCl2(PPh3)(PN3>2CH2Cl2 (PLUTO plot) 219 Figure E.2 Molecular structure of RuCl2(PPh3)(PN3) (Stereoview) 220 xxi ABBREVIATIONS AND SYMBOLS The following list of abbreviations and symbols was used in this thesis. aq aqueous atm atmosphere (1 atm = 760 mm Hg) br broad * chiral centre COD 1,5-cyclooctadiene Cp r]5-cyclopentadienyl A coordination chemical shift A delta isomer for chiral metal centres A refluxing d days d doublet (NMR spectra) dd doublet of doublets (NMR spectra) DMA N,N'- dimethylacetamide DMAD dimethylacetylenedicarboxylate DN donor number DPPB 1,4-bis(diphenylphosphino)butane DPPE 1,2-bis(diphenylphosphino)ethane A R ring contribution to coordination chemical shift e dielectric constant Emax extinction coefficient at maximum absorbance Et CH3CH2-, ethyl group FID flame ionization detector FTIR fourier transform infra red xxii G C gas chromatography hapticity proton ( N M R sepctroscopy) h hour(s) H z Hertz (cycles per second) IR Infrared A lamda isomer for chiral metal centres L Ligand wavelength (nm) A M molar conductivity (ohm^mol^cm 2 ) ^max wavelength at maximum absorbance M molar (mol L" 1 ) bridging coordination mode m medium (IR spectra) m multiplet ( N M R spectra) m's more than one multiplet ( N M R spectra) M e C H 3 - , methyl group min minute(s) N M R nuclear magnetic resonance p-d pseudo doublet ( N M R spectra) Ph C 6 H 5 - , phenyl group P N i diphenyl(2-pyridyl)phosphine P N 2 phenylbis(2-pyridyl)phosphine P N 3 tris(2-pyridyl)phosphine ppm parts per million psi pounds per square inch py 2-pyridyl group xxiii 3 1P{ ifi} proton broad band decoupled phosphorus (NMR spectroscopy) o" conductivity (ohm^cm"1) s singlet (NMR spectra) s strong (IR spectra) sep septet (NMR spectra) sh shoulder (UV-visible spectra) t triplet (NMR spectra) THF tetrahydrofuran TMS tetramethylsilane tR retention time v stretching frequency (IR) UV Ultra Violet w weak (IR spectra) [ ] concentration degrees °C degrees Celsius xxiv LIST OF COMPLEXES Complex Number [RuCl(PN3)3]Cl 1 [RuCl(PPh3)(PN3)2]Cl 2a [RuCl(PPh3)(PN3)2]Cl 2b [RuCl(PPh3)(PN3)2]PF6 2c [RuCl(PPh3)(PN3)2]BPh4 2d [RuCl(PN2)3]Cl 3 [Ru(PN3)3][BPh4]2 4a [Ru(PN3)3][PF6]2 4b [Ru(PN2)3][PF6]2 5 [RuCl(PPh3)2(PN3)]Cl (in situ) 6a [RuCl(PPh3)2(PN2)]PF6 6b [RuCl(PPh3)2(PN3)]PF6 6c frow-RuCl2(DPPB)(PNi) 7a rra/«-RuCl2(DPPB)(PN2) 7b rrans-RuCl2(DPPB)(PN3) 7c cw-RuCl2(DPPB)(PNi) 8a cw-RuCl2(DPPB)(PN2) 8b cw-RuCl2(DPPB)(PN3) 8c [RuCl(DPPB)(PN2)]PF6 9a [RuCl(DPPB)(PN3)]PF6 9b [RuCl(CO)(PPh3)2(PN2)]PF6 10a [RuCl(CO)(PPh3)2(PN2)]PF6 10b [RuCl(CO)(DPPB)(PNi)]PF6 11a [RuCl(CO)(DPPB)(PN2)]PF6 lib X X V Complex Number [RuCl(CO)(DPPB)(PN3)]PF6 11c RuCl2(PPh3)(PN3) 13 [RuCl(CO)(PPh3)(PN3)]PF6 14a [RuCl(MeCN)(PPh3)(PN3)]PF6 14b [RuCl(PhCN)(PPh3)(PN3)]PF6 14c RuCl2(CO)(PN3) 15a RuCl2(MeCN)(PN3) 15b RuCl2(PhCN)(PN3) 15c RuCl2(PPh3)(OPN3) 16 xxvi ACKNOWLEDGEMENTS I wish to thank Dr. Brian James for his guidance and support throughout the preparation of this thesis. I would also like to thank past and present members of the 'James Group', particularly Ken MacFarlane, Chris Alexander, and Dr. Deryn Fogg, for their help with experiments and useful discussions. As well, discussions with Dr. Murguesapilai Mylvaganum (Myl) were always interesting and appreciated. I would also like to express my appreciation to Mr. P. Borda and Dr. S. J. Rettig, as well as the NMR room staff. An NSERC postgraduate scholarship (1990-1994) and a Charles A. McDowell Fellowship (1990) are gratefully acknowledged. Finally, I would like to thank my family and Chris Avery for their encouragement throughout this work. As well, a special thanks goes to Katja Macura. xxvii CHAPTER 1 Introduction 1.1 Homogeneous Catalysis in Aqueous Media Homogeneous catalysis using transition metal complexes in aqueous media offers one main advantage over catalysis in organic solvents. A common problem with homogeneous catalysis is separating the product from the catalyst. The use of biphasic systems where the catalyst operates in an aqueous phase and products are extracted into an organic phase offers a solution, often with decreased need for further downstream product purification. One system operating on an industrial scale since 1984 is the Ruhrchemie/Rhone-Poulenc Oxo process.1 The process converts propylene to butyraldehyde via hydroformylation. The original catalyst was based on the activity of RhH(CO)(P(m-C6H4S03Na)3)3. Since 1984, the phosphine has been changed twice, once in 1990 (to bisbis, Figure 1.1) and again in 1992 (to norbos, Figure 1.1), with a 2 3 resulting 100-fold increase in activity over the original catalyst. ' The success of this process illustrates the potential of homogeneous catalysis in water. Thus the major impetus for research in this area is the development of aqueous organometallic chemistry, with a large part being the synthesis of water-soluble phosphines and transition metal complexes.2'4'5 So far, in terms of catalysis, most efforts have centred around hydroformylation and hydrogenation (including asymmetric hydrogenation). Another catalytic process well suited for aqueous media is the hydration of olefins to produce alcohols (Figure 1.2). The direct hydration of olefins offers an alternative to current industrial processes to alcohols, from olefins, and the possibility of producing chiral alcohols through the use of a prochiral olefin and a chiral metal complex (Figure 1.2). A review of current industrial processes, methods for making chiral alcohols, and the feasibility of direct hydration in terms of specific catalytic steps has been presented by Xie. 6 A brief history of catalytic olefin hydration is given here. 1 references on page 13 Chapter 1 Figure 1.1 Sulphonated phosphines used in the Ruhrchemie/Rhone-Poulenc Oxo process. R R' H 2 ° R R >^ / catalyst* / \ H * H H HO H Figure 1.2 Hydration of olefins to produce alcohols. 1.2 Catalytic Hydration of Olefins Using Transition Metal Complexes Very few systems exist for catalytic olefin hydration. Those systems considered below are divided into two parts, catalysts that contain phosphines and those that do not. 1.2.1 Non-Phosphine Complexes The earliest reports on metal complexes catalyzing hydration reactions appeared in the 1960s. Halpern and co-workers were investigating the H2-hydrogenation of maleic, fumaric and acrylic acids in aqueous acid solutions of ruthenium(II) chlorides.7 They confirmed the formation of a 1:1 olefin complex, and determined through isotope 2 references on page 13 Chapter 1 studies,8 that the source of hydrogen adding to the carbon-carbon double bond came from water rather than hydrogen gas (via exchange of a Ru-H intermediate with water), but hydration was not observed. However, using ruthenium(III) chloride species in aqueous acid (HCI), acetylenic compounds were hydrated catalytically,^ acetylene, methylacetylene, and ethylacetylene being converted to acetaldehyde, acetone, and methyl ethyl ketone, respectively. The proposed mechanism involved net insertion of the acetylene into a coordinated hydroxide, followed by cleavage of the ruthenium-carbon bond by a proton to produce a vinyl alcohol which rearranged to the aldehyde. Aqueous acid solutions of some rhodium(III) chloro complexes were then found by James and Rempel to be active for the hydration of acetylene.10 Then James and Louie, while studying catalytic hydrogenation reactions, demonstrated that hydrochloric acid solutions of chlororuthenate(II) were capable of hydrating 1,1-difluoroethylene and 1-fluoroethylene to acetic acid and acetaldehyde, respectively, even under hydrogen.11 The proposed mechanism was similar to that proposed for the acetylenic compounds, except the fluorohydroxy intermediate formed rearranges, with loss of HF, to give acetic acid or the acetaldehyde product. Around this time (1967), Bzahasso and Pyatnitskii found that CrCl3-6H20 catalyzed the hydration of maleic acid to malic acid at 170 ° C . 1 2 This system was studied by Xie as well,6 and some isomerization of the maleic acid to fumaric acid also occurs. 1.2.2 Phosphine Complexes In 1979 Yoshida et al. reported on the use of platinum(O) complexes for the hydration of nitriles to amides.13 Using acrylonitrile, as well as the nitrile functionality being hydrated, the olefinic moiety was hydrated to produce B-cyanoethanol. The catalysts used were Pt(PR3)2 or 3 (R = alkyl), which react with water to form complexes of the type [PtH(PR3)3]OH, m*ns-[PtH(S)(PR3)2]OH (S = solvent) or trans-3 references on page 13 Chapter 1 PtH(OH)(PR3)2, depending on the phosphine. The proposed mechanism for olefin hydration involves nucleophilic attack of hydroxide on a coordinated olefin with subsequent protonolysis of the Pt-C bond to release the alcohol. Arnold and Bennett around the same time (1980) were investigating Pt(OH)(R)(PR'3)2 (R = Me or Ph and R' = alkyl) complexes for nitrile hydration.14 The complexes showed lower activity compared to those of the platinum(O) precursor complexes used by Yoshida et al. In the hydration of acrylonitrile, Arnold and Bennett had difficulty reproducing the yields of the 6-cyanoethanol produced. Purification of the nitrile prior to catalysis increased the amount of 8-cyanoethanol. Further work in the area was done by Jensen and Trogler (1986).15 Again nitriles were the subject under investigation and the catalyst used was the platinum(II) hydrido complex [PtH(H20)(PMe3)2]OH formed by metathesis of frans-PtH(Cl)(PMe3)2 with aqueous NaOH. In the same year, Jensen and Trogler reported that the trans-PtH(Cl)(PMe3)2 complex used for the nitrile hydrations, selectively catalyzed the hydration of 1-hexene and 1-dodecene to n-hexanol and n-dodecanol.16 For n-hexene, the reaction was carried out at 60 °C in aqueous NaOH in the presence of a phase transfer 1 H agent, benzyltriethylammonium chloride. However, careful work by Ramprasad et al. failed to reproduce the catalytic hydration of olefins to primary alcohols reported by Jensen and Trogler. This later group found that the 7t-olefin complex [PtH(l-hexene)(PMe3)2]+, a key intermediate in the proposed hydration mechanism, was stable at low temperature, but at room temperature the 1-hexene isomerized to internal olefins. As well, reactions of the rc-olefin complex with the base NMe4+0H_-5H20 did not produce any n-hexanol. It was around this time that Xie from our laboratory began investigating the use of 2-pyridylphosphines, PPh3_xpyx (where x = 1, 2, 3), in platinum and palladium complexes as possible olefin hydration catalysts.6 These phosphines have been given the abbreviations PNi, PN2, and PN 3 throughout this thesis, the subscript designating the 4 references on page 13 Chapter 1 number of 2-pyridyl groups incorporated. As well, these three phosphines are generally referred to as '2-pyridylphosphines' in this work. These phosphines were employed by Xie in the platinum and palladium work because of the potential for forming water-soluble complexes. The platinum complexes Pt(PN3)4, Pt(PNi)3, Pt(PNi)2(CH2CHCN), and fran5-PtH(Cl)(PNi)2 were tested for the catalytic hydration of acrylonitrile to 1 8 8-cyanoethanol in the presence of aqueous sodium hydroxide. Although the complexes were similar to those reported above, no hydration to 6-cyanoethanol, greater than the base (NaOH)-catalyzed reaction, was observed. With palladium, the complex ds-PdCl^PN^ dissolves in water with the liberation of both chlorides, and the resulting solution undergoes the equilibrium reactions shown in Figure 1.3(a), forming a bridged-hydroxy dimer.19 Similarly, the neutral palladium dimer Pd 2Cl 2(PN 3) 2 dissolves in water.19 However, in this case the resulting complex is cationic, Figure 1.3(b). The palladium dimers Pd 2Cl 2(PN x) 2 (x = 1, 2, 3), as well as the platinum analogues Pt2I2(PNx)2 (x = 1,2, 3), are also capable of "activating" DMAD (dimethylacetenedicarboxylate), forming the A-framed alkene complex, Figure 1.3(c).6'19'20 Thus, these palladium complexes are capable of "activating" water and presumably olefins, which are most likely important features for a hydration catalyst. Ganguly and Roundhill have shown subsequently that the palladium dimer, [Pd(p>OH)(DPPE)]2[BF4]2 (DPPE = l,2-bis(diphenylphosphino)ethane) can hydrate diethylmaleate to diethylmalate, albeit with a low turnover number of 14, in 30 h at 140 °C 2 1 The majority of work in the area of olefin hydration with transition metal phosphine complexes has centred around platinum and palladium complexes. Thus the objective of this thesis work was to synthesize ruthenium complexes, incorporating the 2-pyridylphosphine ligands as a means of forming water-soluble complexes, and to test these complexes as possible hydration catalysts. Prior to this work, no ruthenium 5 references on page 13 Chapter 1 complexes containing the PN 2 ligand, and only three with PN3, were known. Thus a large portion of this work involves the synthesis and characterization of 2-pyridylphosphine complexes, which proved to have a rich coordination chemistry with ruthenium. Before the scope of this thesis is discussed, a short review of chemistry with 2-pyridylphosphines is presented, including the reported ruthenium complexes. H 2 0 (a) cw-PdCl2(PN3)2 • cw-Pd(H 20) 2(PN 3) 2 2 + + 2 CT 11 -Pd(OH)(H20)(PN3)2+ 1/2 [Pd(u.-OH)(PN3)2]2' (b) Pd 2Cl 2(p-PN 3) 2 (HT) - • Pd 2(H 20) 2(p-PN 3) 2 2 + + 2C1" (HT) (c) Pd 2Cl 2(p-PN x) 2 (HT) (x=l,2,3) DMAD N C1", I ^C1 P d v Pd" MeOOC^T* ^ C O O M e Figure 1.3 Reactions of the some palladium P N 3 complexes in water, (a) and (b). "Activation" of DMAD by a palladium dimer, (c). (HT = head-to-tail isomer, see Figure 1.4). 6 references on page 13 Chapter 1 1.3 2-Pyridylphosphine Chemistry 1.3.1 Synthesis of 2-Pyridylphosphines The 2-pyridylphosphines as a class of compounds and as ligands in transition metal complexes have recently been reviewed by Newkome. The 2-pyridylphosphines used in this work, namely PNi, PN2, and PN3, were first made by Mann and Watson (PNi and P N 2 ) 2 3 and Davies and Mann ( P N 3 ) . 2 4 Over the years the procedure has been modified 2 5 - 2 8 and the general synthetic strategy involves reaction of 2-lithiopyridine, formed at low temperature (-65 to -100 °C), with the appropriate chlorophosphine (PClPh2, (PNi); PCl2Ph (PN2); PCI3 (PN3)), in a one pot synthesis. The 2-lithiopyridine itself is produce by reaction of 2-bromo- or 2-chloropyridine with n-butyllithium. A slight modification of the procedure reported by Kurtev et al. was used in the present work for the synthesis of PN 2 and P N 3 . 2 7 An alternative high yield method for the synthesis of P N 1 has been reported by Balch and co-workers. Reaction of 2-chloropyridine with LiPPh 2 in THF at room temperature produced PNi in high yields (94%). The lithium diphenylphosphide is made by reaction of n-butyllithium with diphenylphosphine. A similar method was employed for PNi in this work. The X-ray crystal structures of PNi and P N 3 have been determined. 1.3.2 Coordination Chemistry of 2-Pyridylphosphines The opportunity for a diverse coordination chemistry with transition metals exists for 2-pyridylphosphines. Their heteropolydentate nature, particularly for PN 2 and PN3, allows a variety of possible binding modes, shown in Figure 1.4. 7 references on page 13 Chapter 1 HH HT head-to-head head-to-tail Common Isomers with HI (above) Figure 1.4 Possible coordination modes of 2-pyridylphosphines with transition metals. Typical isomers for type in coordination are shown. Examples of the different coordination modes have been seen with a variety of transition metals. Complexes with ruthenium are considered in the next section. Type I in Figure 1.4 is by far the most common coordination mode among the second and third row transition metals. Only the phosphorus coordinates the metal centre in PdX2(PNx)2 (X = halide, x = 1, 2, 3),19 PtX2(PNx)2 (X = halide, x = 1, 2, 3), 6' 3 2' 3 3 Mo(CO)5(PN2) 3 4 RhCl(CO)(PNi)2, 3 5 and AuCl(PNx) (x = 1, 3). 3 6' 3 7 The P,W-chelating mode, type n, 8 references on page 13 Chapter 1 has been observed in [PtI(PNi)2]PF632 and RhCl(PN3)2-27 For the complexes RhCl(CO)(PNx)2 (x = 2, 3) an equilbrium exists between types I and II in solution. The bridging coordination mode, type i n , offers substantial possibilities and a lot of work has been done in the synthesis of bimetallic complexes. The different isomers for some of these complexes are shown in Figure 1.4. For example, the complexes Pd2X2(p-PNx)2 and Pt2X2(p-PNx)2 (X = halide and x = 1, 2, 3) (HT, head-to-tail isomer, Figure 1.4),6'19 Pt2i2(!t-PNX)2 (x = 1, 2, 3) (HH, head-to-head isomer, Figure 1.4),6 [Re2Cl2(M--PNi)4][PF6]2,39 and Rh2Cl2(p-CO)(p-PNi)2 (HT) 4 0 all contain bridging PNX ligands. The range of complexes is not restricted to homobimetallic species. Several heterobimetallic complexes have also been synthesized, represenative examples being PtPdX2(u-PN3)2 (X = halide) (HT), 6 RhPtCl3(CO)(p-PNi)2 (HT), 3 3 PdMoCl2(p-CO)(CO)2(p-PNi)2 (HT) 4 1 and RhPdCl3(CO)(u-PNi)2 (HT). 3 5 For type IV, there is a limited number of examples including, Mol2(CO)3(PN2) and Mo(CO)4(PN2),34 and the structurally characterized complex, CoCl 2(PN2) 4 2 Type V is a common coordination mode among the first row transition metals. The salts with the general formula [M(PN3)2][C104]2 (M = Mn, Co, Ni, Cu, Z n ) 2 6 ' 4 3 and Zn(PN3)(N03)243 all contain PN 3 ligands coordinated via the three pyridyl nitrogens only. Prior to this work, the final coordination mode, type VI, was unobserved (see Chapter 4), although it had been predicted using electronic arguments.26 1.3.3 Ruthenium Complexes with 2-Pyridylphosphines The majority of work with ruthenium has centred around the use of PNi. In Ru3(CO)9(PNi)3, Ru(CO)3(PNi)2, and RuCl2(CO)2(PNi)2 the phosphine coordinates to the metal via the phosphorus only, type I, Figure 1.4.29 The related complex RuCl2(CO)2(PNi) contains a P,iV-coordinated PNi ligand, type II, and has been structurally characterized 4 4 In [RuCl(PNi)3]Cl, a mixture of coordination modes is observed, the complex containing one type I and two type II coordinated ligands.45 This 9 references on page 13 Chapter 1 complex slowly dissociates a PNi ligand in chlorinated solvents forming the neutral type II complex cw-RuCl2(PNi)2 which has been structurally characterized.45 As for the bridging coordination mode, type III, RuPdCl2(CO)2(p>PNi)2 (HT) is an example. Prior to this thesis work, no ruthenium complexes containing the PN2 ligand have been 27 2R reported, and only two papers reporting PN3 complexes have appeared. ' One paper, by Kurtev et al. reported the complexes RuH(Cl)(PN3)3 and 27 RuCl2(PN3)2. The latter complex was incorrectly formulated, and the correct stoichiometry and solution structure have now been determined (Chapter 3). For RuH(Cl)(PN3)3, the complex contains a P- and two P,Af-coordinated PN3 ligands. The only other PN3 complex known (prior to this thesis work) was [Ru(PN3)2][C7H7S03]2, which is of type V, with two AT,./V"-coordinated PN3 ligands, as confirmed by X-ray crystallography. 1.3.4 Catalysis with 2-Pyridylphosphine Complexes The 2-pyridylphosphines have been used within catalysts for a few different catalytic reactions. The complexes, [Rh2(Cp)(p:-CO)(p:-PNi)(CO)Ci]46 RhH(C0)(PPh3)(PN3)2,27 and [RuCl(PNi)3][Rh(CO)2Cl2] 4 5 have all been used in hydroformylation reactions. Interestingly, with the ruthenium/rhodium salt, neither the cation (as [RuCl(PNi)3]Cl) nor the anion (as [Rh(CO)2Cl2]AsPh4) gave good conversions (1.1% and 12% respectively) for styrene to 2- and 3-phenylpropanal. However, together (as [RuCl(PNi)3][Rh(CO)2Cl2]), the conversion was 94% at 75 °C after 6 hours under H2/CO (1:1) at 60 atm in benzene, with a branched to linear aldehyde ratio of 4.1, the results revealing a cooperative effect between the ruthenium cation and the rhodium anion. Formation of ion pairs in benzene (based on conductivity), and an interaction between an uncoordinated pyridyl group in [RuCl(PNi)3]+ and the rhodium centre, are evident. However, the "activation mechanism" for the styrene, CO, and H2 is not understood. One other hydroformylation catalyst is the in situ one formed by reaction 10 references on page 13 Chapter 1 of [RhCl(COD)]2 (COD = 1,5-cyclooctadiene) with two equivalents of P N 1 4 7 With this catalyst and styrene as the substrate, a high branched to linear ratio of 49 was obtained for the aldehyde products, with 66% conversion after 1.5 hours at 80 °C under H2/CO (1:1) at 600 psi (40.8 atm) in CHCI3. This is compared to a branched to linear ratio of 5.6 and a conversion of 43% in 5 hours for the corresponding PPI13 system under the same conditions. The chelating ability of the P N i ligand is believed to enhance the rate and selectivity by accelerating the reductive elimination of aldehydes from the intermediate hydrido(acyl)rhodium complex. Another catalytic system generated in situ uses Pd(CH3COO)2, PN 2 , and /?-MeC6H4S03H in N-methylpyrrolidone and MeOH for the conversion of propyne and CO to methylmethacrylate with 98.3% selectivity. A similar system using P N 1 gave a 99% conversion with a high turnover (20, 000 h - 1 ). 4 9 Finally, a rhodium complex containing PN3 generated in situ from Rh2(CH3C00)4 catalyzes the Water Gas Shift (WGS) reaction.50 Thus the 2-pyridylphosphine complexes have been used mainly in hydroformylation reactions, and demonstrate some interesting catalytic abilities. 1.4 Scope of this Thesis As was noted near the end of Section 1.2.2, the initial aim of this work was to synthesize some water-soluble 2-pyridylphosphine ruthenium complexes to be used as catalysts for olefin hydration. However, during the course of the work the emphasis changed because of the diverse coordination chemistry observed, mainly with the PN2 and PN3 ligands. The general experimental procedures including the syntheses of all compounds are described in Chapter 2. Chapter 3 reports on some water-soluble ruthenium 2-pyridylphosphine complexes. The complexes, [RuCl(PNx)3]Cl (x = 2, 3) and [RuCl(PPh3)(PN3)2]Cl, were synthesized and well characterized. As the complexes 11 references on page 13 Chapter 1 were water-soluble, their aqueous solution chemistry was investigated and they were tested as hydration catalysts for maleic acid; however, no hydration was observed. In Chapter 4, the synthesis and characterization of [RuCl(PPh3)2(PNx)]PF6 (x = 2, 3) are described. Both complexes were structurally characterized (X-ray crystallography) and exhibit the previously unseen P,Af,N-coordination mode, (type VI, Figure 1.4). Similar complexes containing DPPB (l,4-bis(diphenylphosphino)butane) instead of PPh3 were also made. The reactivity of the P,Af,iV'-coordination mode with small molecules (i.e., H2, 0 2 , and CO), as well as in the catalytic hydrogenation of imines, was investigated. The complexes isolated from reaction with CO allowed the establishment of a 7t-acceptor ability trend for the PNX ligands. Another complex isolated during the course of this work was RuCl2(PPh3)(PN3) where the PN3 is N,N',N"-coordinated (type V, Figure 1.4). This complex is described in Chapter 5 and undergoes ligand substitution reactions of a chloride or the triphenylphosphine, similar to those reported for RuCl(PPh3)2(Cp) (Cp = cyclopentadienyl ligand).51 As well, the free phosphorus of the PN3 ligand in RuCl2(PPh3)(PN3) can be oxidized. Finally, a preliminary reaction of RuCl2(PPh3)(PN3) with H2 is described. 12 references on page 13 Chapter 1 1.5 References (1) Kuntz, E. G. Chemtech 1987, 570. (2) Herrmann, W. A.; Kohlpainter, C. W. Angew. Chem., Int. Ed. Engl. 1993, 32, 1524. (3) Haggin, J. Chem. Eng. News. 1994, 72, 28. (4) Sinou, D. Bull. Soc. Chim. Fr. 1987, 480. (5) Kalck, P.; Monteil, F. Adv. Organomet. Chem. 1992, 34, 219. (6) Xie, Y. Ph.D. Thesis, The University of British Columbia, 1990. (7) Halpern, J.; Harrod, J. F.; James, B. R. J. Am. Chem. Soc. 1961, 83, 753. (8) Halpern, J.; Harrod, J. F.; James, B.R.J. Am. Chem. Soc. 1966, 88, 5150. (9) Halpern, J.; James, B. R; Kemp, A. L. W. J. Am. Chem. Soc. 1961, 83, 4097. (10) James, B. R.; Rempel, G. L. J. Am. Chem. Soc. 1969, 91, 863. (11) James, B. R.; Louie, J. Inorg. Chim. Acta 1969, 3, 568. (12) Bzahasso, N. A.; Pyatnitskii, M. P. Izv. Vyssh. Ucheb. Zaved., Pishch. Tehch. Tekhnol. 1967 5, 207, through C.A., 1968, 68, 39013k. (13) Yoshida, T.; Matsuda, T.; Okano, T.; Kitani, K.; Otsuka, S. J. Am. Chem. Soc. 1979,101, 2027. (14) Arnold, D. P.; Bennett, M. A. J. Organomet. Chem. 1980,199, 119. (15) Jensen, C. M.; Trogler, W. C. J. Am. Chem. Soc. 1986,108,723. (16) Jensen, C. M.; Trogler, W. C. Science 1986,233, 1069. (17) Ramprasad, D.; Hue, H. J.; Marsella, J. A. Inorg. Chem. 1988, 27, 3151. (18) Xie, Y.; James, B. R. J. Organomet. Chem. 1991, 417, 277. (19) Xie, Y.; Lee, C.-L.; Yang, Y.; Rettig, S. J.; James, B. R. Can. J. Chem. 1992, 70, 751. (20) Xie, Y.; James, B. R. Inorg. Chim. Acta 1994,217, 209. (21) Ganguly, S.; Roundhill, D. M. J. Chem. Soc, Chem. Commun. 1991, 639. (22) Newkome, G. R. Chem. Rev. 1993, 93, 2067. 13 Chapter 1 (23) Mann, F. G.; Watson, J. J. Org. Chem. 1948,13, 502. (24) Davies, W. C ; Mann, F. G. J. Chem Soc. 1944, 276. (25) Plazek, E.; Tyka, R. Zesz. Nauk. Politech. Wroclaw. Chem. 1957,4, 79, through C.A., 1958, 52, 20156c. (26) Boggess, R. K.; Zatko, D. A. J. Coord. Chem. 1975, 4, 217. (27) Kurtev, K.; Ribola, D.; Jones, R. A.; Cole-Hamilton, D. J.; Wilkinson, G. J. Chem. Soc, Dalton Trans. 1980, 55. (28) Keene, F. R.; Snow, M. R.; Stephenson, P. J.; Tiekink, E. R. T. Inorg. Chem. 1988,27, 2040. (29) Maisonnet, A.; Farr, J. P.; Olmstead, M. M.; Hunt, C. T.; Balch, A. L. Inorg. Chem. 1982,21, 3961. (30) Charland, J. P.; Roustan, J. L.; Ansari, N. Acta Crystallogr., Sect. C 1989, 45, 680. (31) Keene, F. R.; Snow, M. R.; Tiekink, E. R. T. Acta Crystallogr., Sect. C 1988, 44, 757. (32) Farr, J. P.; Wood, F. E.; Balch, A. L. Inorg. Chem. 1983,22, 3387. (33) Farr, J. P.; Olmstead, M. M.; Wood, F. E.; Balch, A. L. / . Am. Chem. Soc. 1983, 105, 792. (34) Espinet, P.; Gomez-Elipe, P.; Villafane, F. J. Organomet. Chem. 1993,450, 145. (35) Farr, J. P.; Olmstead, M. M.; Balch, A. L. /. Am. Chem. Soc. 1980,102, 6654. (36) Lock, C. J. L.; Turner, M. A. Acta Crystallogr., Sect. C 1987,43, 2096. (37) Alcock, N. W.; Moore, P.; Lampe, P. A.; Mok, K. F. J. Chem. Soc, Dalton Trans. 1982, 207. (38) Wajda-Hermanowicz, K.; Pruchnik, F. P. Transition Met. Chem. 1988,13, 101. (39) Barder, T. J.; Cotton, F. A.; Powell, G. L.; Tetrick, S. M.; Walton, R. A. / . Am. Chem. Soc 1984,106, 1323. 14 Chapter 1 (40) Farr, J. P.; Olmstead, M. M.; Hunt, C. H.; Balch, A. L. Inorg. Chem. 1981,20, 1182. (41) Zhang, Z.; Wang, H.; Wang, H.; Wang, R. J. Organomet. Chem. 1986, 314, 357. (42) Ehrlich, M. G.; Fronczek, F. R.; Watkins, S. F.; Newkome, G. R.; Hager, D. C. Acta Crystallogr., Sect. C 1984,40, 78. (43) Gregorzik, R.; Wirbser, J.; Vahrenkamp, H. Chem. Ber. 1992,125, 1575. (44) Olmstead, M. M.; Maisonnat, A.; Farr, J. P.; Balch, A. L. Inorg. Chem. 1981, 20, 4060. (45) Drommi, D.; Nicolo, F.; Arena, C. G.; Bruno, G.; Faraone, F. Inorg. Chim. Acta 1994, 221, 109. (46) Gladiali, S.; Pinna, L.; Arena, C. G.; Rotondo, E.; Faraone, F. J. Mol. Catal. 1991, 66,183. (47) Abu-Gnim, C ; Amer, I. J. Mol. Catal. 1993, 85, L275. (48) Drent, E.; Budzelaat, P. H. M. Eur. Pat. Appl. EP 386833, through C.A., 1991, 114, 142679z. (49) Drent, E. Eur. Pat. Appl. EP 271144 A2, through C.A., 1989,110, 232239c. (50) Pruchnick, F. P.; Kuczewska-Patrzalek, G.; Wajda-Hermanowicz, K. Pol. Patent, PI. 128190,1984, through C.A., 1986,104, 209509h. (51) Davies, S. G.; McNally, J. P.; Smallridge, A. J. Adv. Organomet. Chem. 1990, 30, 1. 15 CHAPTER 2 Experimental Procedure 2.1 General Materials 2.1.1 Solvents Solvents were purified by standard techniques.1 Obtained from Fisher or BDH, spectral or reagent grade solvents were dried and distilled under a nitrogen atmosphere prior to use. Benzene, toluene, hexanes, tetrahydrofuran, and diethyl ether were dried over sodium/benzophenone. Dichloromethane was passed through a neutral alumina column and distilled from calcium hydride or phosphorus pentoxide. Methanol and ethanol were dried over magnesium methoxide and magnesium ethoxide, respectively, formed by reaction of the appropriate alcohol with magnesium turnings and a trace amount of iodine. Chloroform and acetone were dried over potassium carbonate. Acetonitrile and benzonitrile were dried over calcium hydride for 24 h prior to fractional distillation, and stored under argon in the dark. Nitromethane was dried over calcium chloride, fractionally distilled, and stored under argon. Deuterated solvents (benzene-d6, chloroform-di, acetone-d6, medianol-d4, and dichloromethane-d2) were obtained from Merck Frosst, dried over molecular sieves (BDH 4A 1/16" pellets), degassed and/or stored under argon. For sealed NMR samples, C6D6 was dried over sodium/benzophenone and degassed. 2.1.2 Gases Argon (Linde), nitrogen (Linde), hydrogen (Research, extra dry), carbon monoxide (CP), and oxygen (USP) gases were supplied by Union Carbide. All gases except argon and hydrogen were used without further purification. Argon was passed through an anhydrous CaS04 column. To remove trace oxygen, hydrogen was passed through an Engelhard Deoxo catalytic hydrogen purifier. 16 refernces on page 47 Chapter 2 2.1.3 General Reagents The following compounds were used without further purification: cone. H2SO4 (Fisher); NaOH; cone HCI (Fisher); N H 4 P F 6 (Ozark-Mahoning); H2O2 30% (aq) (Fisher); Celite 545® (Fisher); m-ClC6H4C(0)OOH, meta-chloroperbenzoicacid (Aldrich, 80-85% Tech. grade); P h C H 2 N C H P h , N-benzylidenebenzylamine (Aldrich); c/s-HOOCCHCHCOOH, maleic acid (MCB Manufacturing Chemists Ltd.); n-butyllithium (1.6 M in hexanes, Aldrich). 2.2 General Instrumentation Nuclear magnetic resonance (NMR) spectra were recorded on a Varian XL-300 MHz (300 MHz for *H; 121.4 MHz for 3 1P) or a Bruker AC200 (200 MHz for !H; 81.0 MHz for 3 1P) spectrometer using 5 mm NMR tubes. *H chemical shifts were recorded relative to external TMS. All 3 1 P chemical shifts were referenced to external 85% H 3 P O 4 , by setting the chemical shift for P(OMe)3 (Aldrich) at 141.00 ppm (relative to 85% H3PO4) in the appropriate solvent. All spectra were recorded at room temperature (20 to 23 °C) unless otherwise stated. Chemical shifts reported are in parts per million, ppm. Infrared spectra were recorded on a Nicolet 5DX-FT spectrophotometer or a Mattson Genesis Series FTIR. Nujol mulls between KBr plates or KBr pellets were used for solid state spectra. UV-visible spectra were recorded on a Hewlett-Packard-8452A diode array spectrometer using quartz cells (1.0 cm or 0.1cm path length). For recording spectra under anaerobic conditions, a cell which has been described elsewhere was used.3 Solid state visible spectra were recorded by dissolving a small amount of complex in either MeOH or CH2CI2 and placing the solution on a glass plate (UV cutoff 300 nm) and allowing the solvent to evaporate so that a thin amorphous film was left behind. The thin film was then placed in the beam of the spectrometer and the spectrum recorded. 17 references on page 47 Chapter 2 Conductivity measurements were made using a Model RCM151B Serfass Conductance Bridge (A. H. Thomas Co. Ltd.) connected to a 3403 cell from the Yellow Springs Instrument Company. The cell constant was determined by measuring the resistance of an aqueous solution of KC1 (0.0100 M, a = 0.001413 o h m - W l at 25 °C). 4 The temperature was controlled by the use of a water-bath thermostatted at 25 °C. Solutions of ~1 x 10~3 M in CH3NO2 or MeOH were made just prior to use. Elemental analyses were performed by Mr. P. Borda and X-ray crystal structures were solved by Dr. S. J. Rettig, both of this department. 2.3 Phosphines Diphenylphosphine (PPh2H) and triphenylphosphine (PPh3) purchased from Aldrich, as well as l,4-bis(diphenylphosphino)butane (DPPB) from Strem Chemicals, were used without further purification. Phosphorus trichloride (PCI3) from BDH, and dichlorophenylphosphine (PPhCl2) obtained from Aldrich were refluxed under nitrogen for 30 min and fractionally distilled. Also from Aldrich, 2-bromopyridine was stirred over NaOH pellets for 24 h at room temperature, then vacuum distilled from CaO. 2.3.1 2-Pyridylphosphines Preparations of PPh3_xpyx or PN X (x = 1, 2, 3) are described below. The phosphines are designated as P N i , PN2, and PN3, for convenience, the number referring to the number of pyridyl groups incorporated. Reactions in this section (except Section 2.3.2.5) were performed under an inert atmosphere. 2.3.1.1 Diphenyl(2-pyridyI)phosphine, PNi The title compound was prepared by a modified procedure reported by Balch and co-workers.5 To a solution of PPh2H (10 g, 54 mmol) in THF (200 mL) was added n-butyllithium (34 mL, 1.6 M in hexanes, 54 mmol) dropwise over 10 min. The resulting 18 references on page 47 Chapter 2 red solution was stirred for 30 min and then a solution of 2-bromopyridine (5.1 mL, 54 mmol) in THF (40 mL) was added dropwise over 45 min. The red solution turned black in colour and was stirred overnight. Ethanol (50 mL) was added resulting in a clear yellow solution which was stirred for an additional 30 min. The solvent was removed under vacuum, leaving a yellow oil. The oil was extracted with toluene (total volume of 500 mL) and filtered through activated charcoal. After removal of the toluene under vacuum, the resulting off-white precipitate was reprecipitated from acetone/hexanes. Yield: 12.3 g (86%). Calculated for C17H14NP: C, 77.56; H, 5.36; N, 5.32%. Found: C, 77.63; H, 5.33; N, 5.18%. 31P{1H} and ! H NMR data are reported in Appendix A. PNi can also be prepared according to the procedure for PN3 (Section 2.3.1.3) using PPh2Cl instead of PCI3. 2.3.1.2 Phenylbis(2-pyridyl)phosphine, PN2 The procedure for PN2 is identical to that for PN3, described in the next section, except PPhCl2 (11 mL, 80 mmol) is used in place of PCI3. Yield: 6.92 g (33%). Calculated for C i 6 H i 3 N 2 P : C, 72.72; H, 4.96; N, 10.60%. Found: C, 72.56; H, 4.94; N 10.63%. 3 1P{ lH] and lH NMR data are reported in Appendix A. 2.3.1.3 Tris(2-pyridyl)phosphine, PN3 The title compound was prepared by a modified literature procedure.6 To a solution of n-butyllithium (100 mL, 1.6 M in hexanes, 160 mmol) in ether (100 mL) cooled to -77°C (acetone/CC»2 (s) bath)7 was added dropwise 2-bromopyridine (16 mL, 160 mmol) over 10 min. The resulting mixture was stirred for 4 h in which time it turned a deep red colour. A solution of PCI3 (4.6 mL, 53 mmol) in ether (30 mL) was then added dropwise via a syringe. The beige slurry obtained was stirred for a further 2 h, then allowed to warm to room temperature. The mixture was extracted with H2SO4 (aq) (2M, 2 x 100 mL) and the aqueous solution made alkaline by adding saturated NaOH (aq) 19 references on page 47 Chapter 2 dropwise while cooling in an ice bath. The resulting yellow precipitate was collected by vacuum filtration, washed with H2O, and reprecipitated from acetone/hexanes. Yield: 2.74 g (20%). Calculated for C15H12N3P: C, 67.92; H, 4.56; N, 15.84%. Found: C 67.87; H, 4.58; N, 16.00%. 31P{!H} and ! H NMR data are reported in Appendix A. 2.3.1.4 Separation of PNi from OPNi Although the formation of phosphine oxides was not generally a problem in the above syntheses, a convenient method for removing PN1 oxide from PNi is described. The phosphine mixture was dissolved in a minimum amount of a 10% CH2Cl2/hexanes solution. This clear solution was then placed on a dry packed neutral alumina (Brockmann activity I (Fisher) converted to activity III) column of approximately 4 cm length. The column was then eluted with the same CH2Cl2/hexanes mixture and the solvent removed under vacuum resulting in PNi free of phosphine oxide. The oxide does not move on the column unless a more polar solvent mixture is used (i.e., increasing the amount of CH2CI2 in the eluting solvent). 2.3.2.5 Preparation of 2-Pyridylphosphine Oxides, OPNi, OPN2, and OPN3 The phosphine oxides were prepared by stirring the precursor phosphine in a mixture of CH2Cl2/30% H2O2 (aq) for 30 min. The reaction solvent mixture was removed under vacuum and the resulting white residue reprecipitated from acetone/hexanes. OPNi: IR (Nujol mull): v P 0 = 1191 cm-1 (strong). OPN 2: Calculated for OPN 20.5H 2O, C16H14N2O1.5P: C, 66.43; H, 4.87; N, 9.68%. Found: C, 66.37; H, 4.89; N, 9.69%. The 0.5 mole of H 2 0 was confirmed by 1H NMR (CDCI3) at 1.6 ppm. IR (Nujol mull): v P 0 = 1194 cm"1 (strong). O P N 3 : Calculated for O P N 3 , C15H12N3OP: C, 64.06; H, 4.30; N, 14.94%. Found: C, 64.21; H, 4.28; N, 15.23%. IR (Nujol mull): v p o = 1212 cm"1 (strong). 20 references on page 47 Chapter 2 3 1P{1H} and *H NMR for OPNi, OPN2, and OPN3 are reported in Appendix A. The OPN3 characterization data reported here, as well as in Appendix A, agree with the literature data.8'9 Data for O P N 2 could not be found in the literature, while for OPNi, only mass spectral, 1 3C{XH} NMR, and 3 1P{1H} NMR data have been reported.10 The 3 1P{ 1H} (CDCI3) chemical shift measured during this work (Appendix A) agrees with the reported value.10 2.4 Ruthenium Precursor Compounds Ruthenium was supplied on loan from Johnson Matthey Ltd. as RUCI3XH2O. The ruthenium content varied from 41.50% to 43.96% depending on the batch. Reactions were carried out under argon unless stated otherwise, using standard Schlenk techniques.11 2.4.1 Preparation of RuCl2(PPh3)3 The title complex was prepared by the reported literature procedure.12"14 A solution of R u C l 3 x H 2 0 (1.95 g, 8.23 mmol Ru) in MeOH (300 mL) was heated to reflux for 15 min. After the solution was cooled to room temperature, PPh3 (12.6 g, 48.2 mmol) was added and the mixture refluxed for 3 h in which time a brown precipitate formed. The product was collected by filtration and washed with MeOH (7 x 15 mL), ether (3 x 20 mL), and hexanes (5 x 20 mL), then dried under vacuum. Yield: 7.33 g (93%). Calculated for RuCl2(PPh 3) 3, C54H45CI2P3R11: C, 67.64; H, 4.73%. Found: C, 67.66; H, 4.73%. 2.4.2 Preparation of RuC.2(DPPB)(PPh3) The title complex was prepared according to the literature15"17 by addition of a CH2CI2 (20 mL) solution of DPPB (0.89 g, 2.09 mmol) to a CH 2C1 2 (15 mL) solution of RuCl2(PPh3)3 (2.0 g, 2.09 mmol) at room temperature. The dark orange solution of the 21 references on page 47 Chapter 2 starting ruthenium complex turned green immediately upon addition of the phosphine. The reaction mixture was stirred for 2 h, and then concentrated (to ~10 mL) by removal of the solvent under vacuum. Ethanol (80 mL) was added to precipitate the green product. The solid was collected by filtration, washed with ethanol (3 x 20 mL) and hexanes (3 x 20 mL) to remove PPI13, and dried under vacuum. Small amounts of the bridged-phosphine complex [RuCl2(DPPB)i.5]2 have sometimes been reported to be present in the product.15'16 However, this impurity was never observed in any of the preparations performed during these studies. In any case, this complex can easily be removed by filtration prior to the concentration step, as it is quite insoluble in CH2CI2. Yield: 1.8 g (97%). Calculated for RuCl2(DPPB)(PPh3), C46H43CI2P3R11: C, 64.19; H, 5.04%. Found: C, 64.34; H, 5.16%. 2.4.3 Preparation of [RuC^CgHn)],, The title complex was prepared by established procedures18'19 and was kindly provided by Mr. K. S. MacFarlane. 2.5 General Experimental Procedure for Chapter 3 2.5.1 Reaction of RuCl2(PPh3)3 with Excess PN3 According to Kurtev et al. the reaction of RuCl2(PPh3)3 with excess PN3 in benzene produced a mixture of isomers with the general formula RuCl2(PN3)2.6 However, when the reported synthesis was followed (described below), a mixture of two products was obtained: [RuCl(PPh3)(PN3)2]Cl and [RuCl(PN3)3]Cl. A solution of RuCl2(PPh3)3 (0.180 g, 0.188 mmol) and excess PN3 (0.300 g, I. 13 mmol) in C6H6 (10 mL) was stirred for 2 h at room temperature during which time a yellow precipitate deposited. The precipitate was filtered, washed with C6H6 (10 mL) followed by hexanes (10 mL), and dried under vacuum. Yield: 0.170 g (93%). The product is a mixture of two compounds, [RuCl(PPh3)(PN3)2]Cl (18%) and 22 references on page 47 Chapter 2 [RuCl(PN3)]Cl (82%) based on integration of the *H NMR (CD2CI2) spectra. Both compounds have been synthesized independently and their syntheses are described below. 2.5.2 Preparation of [RuCl(PN3)3]CI (1) The title complex was prepared by a procedure similar to that reported for [RuCl(PNi)3]Cl.20 A brown suspension of [RuCl2(C0Hi2)]n (0.048 g, 0.171 mmol) and PN3 (0.142 g, 0.535 mmol) in MeOH (15 mL) was refluxed for 6 h during which time the suspension changed to a yellow and finally an orange coloured solution. The reaction mixture was then pumped down to an orange, oily material which was dissolved in a minimum of CH2CI2 and chromatographed on a neutral alumina column, Brockmann Activity I (20 cm length x 2 cm diameter) saturated with CH2CI2. A thin red band was eluted with CH2C1 2 and discarded. With a 3% MeOH/CH2Cl2 solution an orange/yellow band was collected (FRACTIONS). The remainder of the yellow band was eluted with a 5% MeOH/CH 2Cl2 solution (FRACTION#2). Finally, the remainder of products on the column was eluted with MeOH (FRACTION#3). The solvent from each fraction was removed with a rotary evaporator. Note: some material permanently adheres to the column and is not recovered. Acetone (5 mL) was added to the residue of the yellow band (FRACTION#2), resulting in the formation of a yellow precipitate which was filtered off, washed with Et20 (3 x 10 mL), and dried under vacuum at 100 °C for 16 h. Yield: 0.030 g (17%). Calculated for [RuCl(PN3)3]Cl-3H20, C45H42N 9Cl 20 3P 3Ru: C, 52.89; H, 4.14; N, 12.33%. Found: C, 52.98; H, 4.17; N, 12.06%. The presence of the H2O solvate was confirmed by *H NMR (CDC13) spectroscopy with the H2O peak appearing as a broad signal at 1.8 ppm. *H and 3 1P{ 1H} NMR data are reported in Tables 3.1 and 3.2, 23 references on page 47 Chapter 2 respectively (Section 3.2.2). A M (CH3NO2, 25 °C) = 77.7 ohm-imoHcm2. A M (H20, 25 °C) = 179 ohm-imol-icm2. A portion of the residue isolated from the orange/yellow band (FRACTION#l) was dissolved in CDCI3 and the 3 1P{ 1H} NMR spectrum measured. The spectrum showed that the residue contained mainly a product which shows two singlets (4.81 ppm and 15.4 ppm), and [RuCl(PN3)3]Cl. The 3 1P{!H} NMR (CDCI3) spectrum of the residue isolated from the MeOH fraction (FRACTION#3), mainly consisted of two doublets (-12.3 ppm and -30.2 ppm, 2 7 P P = 24.2 Hz). 2.5.3 Preparation of [RuCl(PPh3)(PN3)2]Cl (2b) A CH 2 C1 2 (10 mL) solution of RuCl2(PPh3)3 (0.464 g, 0.484 mmol) and two equivalents of PN3 (0.259 g, 0.976 mmol) was stirred for 3 d in which time the solution changed from a red to an orange colour. After the solution was concentrated (~5 mL) under vacuum, Et20 (20 mL) was added rapidly (slow addition results in formation of an oil). The lemon yellow precipitate was filtered off, washed with a 10% CH2Cl2/Et20 mixture (10 mL) followed by Et20 (3 x 10 mL) and dried under vacuum. Yield: 0.450 g (96%). Calculated for [RuCl(PPh3)(PN3)2]Cl-2H20, C48H44N6Cl202P3Ru: C, 57.61; H, 4.33; N, 8.39%. Found: C, 57.51; H, 4.40; N, 8.34%. The presence of H 2 0 was confirmed by *H NMR (CDCI3) spectroscopy with the H2O peak appearing as a broad signal at 1.8 ppm. *H and 3 1P{ 1H} NMR data are reported in Tables 3.1 and 3.2, respectively (Section 3.2.2). A M (CH3NO2, 25 °C) = 73.6 ohm-imoHcm2. 2.5.4 Preparation of [RuCl(PPh3)(PN3)2]PF6 (2c) To a clear solution of [RuCl(PPh3)(PN3)2]Cl-2H20 (0.120 g, 0.120 mmol) in acetone (10 mL) was added NH4PF6 (0.021 g, 0.129 mmol), causing the solution to become turbid. After being stirred for 1 h, the solution was filtered through Celite 545® along with acetone washings (10 mL). The filtrate volume was reduced (5 mL) under 24 references on page 47 Chapter 2 vacuum and Et20 was added rapidly, causing formation of a yellow precipitate which was collected by filtration, washed with Et20 (3 x 10 mL), and dried under vacuum. Yield: 0.115 g (88%). Calculated for [RuCl(PPh3) (PN3)2]PF60.5H2O, C48H40N6ClF6Oo.5P4Ru: C, 53.22; H, 3.68; N, 7.76%. Found: C, 53.25; H, 3.63; N, 7.87%. The 0.5 mole of H2O was confirmed by integration of the *H NMR spectrum. *H and 3 1P{ 1H} NMR data are reported in Tables 3.1 and 3.2, respectively (Section 3.2.2). A M (CH3NO2, 25 °C) = 82.2 ohm-imoHcm 2. 2.5.5 Preparation of [RuCl(PPh3)(PN3)2]BPh4 (2d) To a clear solution of [RuCl(PPh3)(PN3)2]Cl-2H20 (0.185 g, 0.185 mmol) in EtOH (5 mL) was added dropwise a solution of NaBPh4 (0.067 g, 0.195 mmol) in EtOH (5 mL). The resulting yellow suspension was stirred for 30 min. The yellow precipitate was collected by filtration, washed with EtOH (2 x 10 mL) and dried under vacuum. Yield 0.193 g (84%). Calculated for [RuCl(PPh3)(PN3)2]BPh4, C72H59N6BCIP3RU: C, 69.26; H, 4.76; N, 6.73%. Found: C, 69.05; H, 4.70; N, 6.83%. *H and 31P{!H} NMR data are reported in Tables 3.1 and 3.2, respectively (Section 3.2.2). A M (CH3NO2, 25 °C) = 52.6 ohm-imoHcm 2 . 2.5.6 Preparation of [RuCI(PN2)3]Cl (3) A solution of RuCh(PPh3)3 (0.154 g, 0.161 mmol) and PN2 (0.633 g, 2.40 mmol) in C6H6 (10 mL) was stirred for 3 h at room temperature, during which time a yellow precipitate deposited. After filtration, the precipitate was washed with CtsHg (2 x 10 mL) followed by hexanes (3 x 10 mL) and dried under vacuum for 1 h. The precipitate was then dissolved in H 2 0 (~ 25 mL) to form a light yellow solution. The H2O was then removed on a rotary evaporator leaving behind a yellow crystalline product which was collected and dried under vacuum at 78 °C for 3 d. Yield: 0.117 g (75%). Calculated for [RuCl(PN2)3]C10.5H2O, C48H4oN6Cl20o.5P3Ru: C, 59.20; H, 4.14; N, 8.63%. Found: 25 references on page 47 Chapter 2 C, 59.18; H, 4.20; N, 8.58%. The presence of H 2 0 was confirmed by ! H NMR (CDCI3) spectroscopy with the H2O peak appearing as a broad signal at 1.8 ppm. J H and 3 1P{ ^H} NMR data are reported in Tables 3.1 and 3.2, respectively, (Section 3.2.2). A M (CH3NO2, 25 °C) = 78.4 ohm-imoHcm2. A M (H20, 25 °C) = 161 ohm-imoFcm2. 2.5.7 Preparation of [Ru(PN3)3][BPh4]2 (4a) The mixture of products (0.046 g, containing 0.039 mmol [RuCl(PN3)3]Cl) from the reaction of RuCl2(PPh3)3 with excess PN3 (Section 2.5.1) was dissolved in H2O (3 mL) and the resulting yellow solution was stirred for 1 h. A solution of NaBPh4 (0.068 g, 0.199 mmol) in H 2 O (10 mL) was then added dropwise causing formation of an off-white precipitate, which was collected by filtration and washed with H2O followed by EtOH. The product was reprecipitated by dissolving in CH2CI2 and reducing the volume (~1 mL) then adding MeOH (10 mL). After filtration the product was dried under vacuum. Yield: 0.049 g (82%), based on the starting material containing 82% [RuCl(PN3)3]Cl. Calculated for [Ru(PN3)3][BPh4]2, C93H76N9B2P2RU: C, 72.75; H, 4.99; N, 8.21%. Found: C, 72.69; H, 5.05; N, 7.93%. 31P{!H} and X H NMR data are reported in Tables 3.6 and 3.7, respectively (Section 3.6). A M (CH3NO2, 25 °C) = 94.7 ohm-1 mol"1 cm2. 2.5.8 Preparation of [Ru(PN3)3][PF6]2 (4b) The mixture of products (0.039 g, containing 0.033 mmol [RuCl(PN3)3]Cl) from the reaction of RuCl2(PPh3)3 with excess PN3 (Section 2.5.1) was dissolved in H2O (1 mL) and stirred for 1 h. A solution of N H 4 P F 6 (0.029 g, 0.178 mmol) in H 2 0 (1 mL) was added dropwise. The resulting yellow suspension was stirred for a further 15 min. The precipitate was filtered off, washed with H 2 O (3x5 mL), followed by MeOH (3 mL), and dried under vacuum. Yield: 0.024 g (61%), based on the starting material containing 82% [RuCl(PN3)3]Cl. Calculated for [Ru(PN3)3][PF6]2, C45H36N9F12P5RU: 26 references on page 47 Chapter 2 C, 45.54; H, 3.05; N, 10.62%. Found: C, 45.77; H, 3.08; N, 10.61%. 31P{!H} and X H N M R data are reported in Tables 3.6 and 3.7, respectively (Section 3.6). A M (CH3NO2,25 °C) = 152.3 ohm-WHcni2. 2.5.9 Preparation of [Ru(PN2)3][PF6l2 (5) A solution of NH4PF6 (0.035 g, 0.215 mmol) in H2O (1 mL) was added dropwise to a clear solution of [RuCl(PN2)3]C10.5H2O (0.040 g, 0.041 mmol) in H 2 0 (25 mL). A white precipitate formed immediately and the reaction mixture was stirred for 15 min prior to filtration. The white precipitate was washed with H 2 O (3x5 mL) and dried under vacuum at 78 °C for 24 h. Yield: 0.028 g (58%). Calculated for [Ru(PN2)3][PF6]2, C48H39N6F12P5RU: C, 48.70; H, 3.32; N, 7.10%. Found: C, 48.70; H, 3.30; N, 6.96%. ^Pf1!!} and lU NMR data are reported in Tables 3.6 and 3.7, respectively (Section 3.6). A M (CH3NO2, 25 °C) = 152 ohm-imoHcm2. 2.5.10 Attempted Hydration of Maleic Acid The three compounds used for the attempted catalytic hydration of maleic acid were [RuCl(PN3)3]Cl 1, [RuCl(PN2)3]Cl 3, and [RuCl(PPh3)(PN3)2]Cl 2b. The procedure used was similar to that reported. A typical reaction involved putting approximately 0.01 g of catalyst and 0.12 g of substrate (maleic acid) in a thick-walled glass bomb, along with a magnetic stir-bar. Deionized water (10 mL) was added with a pipette to give catalyst and substrate concentrations of 1.0 x 10~3 M and 1.0 x 10"1 M, respectively. A blank was setup identically, except without catalyst. The bomb was then sealed (Kontes valve) and submerged in an oil-bath heated at 100 °C. After the appropriate length of time, the Kontes valve was opened and the contents of the bomb sampled with a syringe (-1.5 mL). The H2O was then removed on a rotary evaporator and the flask containing the residue put on a vacuum line overnight. The residue was then dissolved in acetone-d6 27 references on page 47 Chapter 2 and the *H NMR spectrum measured. Relative concentrations of the starting material and products were determined from integration of peaks in the spectrum. 1 H NMR (8, acetone-d6): maleic acid: 6.40 (s, 2H, cw-HOOCCHCHCOOH); fumaric acid: 6.80 (s, 2H, frans-HOOCCHCHCOOH); malic acid (see Figure 2.1 below for assignments): 4.52 (dd, 1H, HOOCCHa(OH)CHb(Hc)COOH, 3 j H a H 5 = 7.2 Hz, 3 J H a Hc = 4.5 Hz), 2.75 (ddd, 2H, HOOCCHa(OH)Ca(Hc)COOH, 2JHbHc = 15.9 Hz).3 For runs containing NaOH (aq), the bomb was set up as previously, except only 8 mL of H2O was added, followed by 2 mL of 1 M NaOH (aq). The work-up procedure was also modified. After the sampling, the H2O was again removed on a rotary evaporator. The residue was then dissolved in HCI (aq) (~ 3 mL, ~ 0.2 M) and the organic products extracted with Et20 (5x5 mL). The ether fractions were dried over anhydrous magnesium sulphate and filtered. The solvent was removed on a rotary evaporator and the residue dissolved in acetone-d6 for NMR spectroscopic analysis as before. Results for the attempted hydration are shown in Table 3.8, Section 3.7. Figure 2.1 Newman projection of malic acid showing the *H NMR assignments. 2.6 General Experimental Procedure for Chapter 4 Characterization data for complexes synthesized in Sections 2.6.1 to 2.6.5 are reported in Chapter 4. 31P{ !H} and *H NMR data are reported in Section 4.3, Tables 4.1 and 4.2, respectively. UV-visible and conductivity data are given in Section 4.3, Table 4.6. Elemental analyses are reported below with each complex. COOH COOH 28 references on page 47 Chapter 2 2.6.1 In Situ Reaction of R u C ^PPhab with One Equivalent of PN3 RuCl2(PPh3)3 (0.017 g, 0.018 mmol) and P N 3 (0.005 g, 0.019 mmol) were put in a sealable 5 mm NMR tube. The tube was evacuated and C D C I 3 vacuum transferred into the tube which was immersed in liquid N 2 . The tube was then flame sealed and warmed to room temperature. The initially brown suspension formed a red solution after a few min. The 3 1 P { N M R spectrum was measured after 24 h and after 7 d. After 7 d the sample was orange in colour. The sample was then heated at 65 °C for 2 d and the 31P{lfI} NMR spectrum measured. 2.6.2 Preparation of [RuCI(PPh3)2(PNx)]PF6 ( x = 2, 3) 2.6.2.1 [RuCl(PPh 3 )2 (PN 2 ) ]PF6 (6b) A solution of RuCl2(PPh3)3 (0.31 g, 0.33 mmol), PN 2 (0.087 g, 0.33 mmol) and N H 4 P F 6 (0.054 g, 0.33 mmol) in acetone (20 mL) was stirred for 20 h at room temperature. The initially brown suspension became an orange turbid solution. The solution was filtered through Celite 545® along with acetone washings (10 mL). The filtrate volume was reduced (~5 mL), Et20 (10 mL) was added, and the resulting solution left undisturbed overnight, during which time red crystals deposited. The crystals were collected and washed with a 20% actone/ether mixture (3x1 mL) and dried in air. Yield: 0.16 g (45%). Calculated for [RuCl(PPh3)2(PN2)]PF6, C52H43N2ClF6P4Ru: C, 58.35; H, 4.05; N, 2.62%. Found: C, 58.15; H, 4.07; N, 2.55%. The acetone/ether filtrate (from above) was pumped down to dryness leaving behind a yellow oily residue. Et20 (10 mL) was added and the resulting yellow precipitate was stirred for 1 h. The precipitate was filtered off and washed with Et20 (2x5 mL), then dried under vacuum. Yield: 0.12 g. A 31P{1H} NMR ( C D C I 3 ) spectrum of the filtrate precipitate showed that it was a mixture of products. Included in the spectrum were peaks for the desired product, [RuCl(PPh3)2(PN2)]PF6, as well as several other signals: 57 to 63 ppm and -3 to -12 29 references on page 47 Chapter 2 ppm (36 peaks), major peaks; 28 to 41 ppm and -20 to -28 ppm (25 peaks), minor peaks. This material was not investigated further. 2.6.2.2 [RuCl(PPh3)2(PN3)]PF6 (6c) Acetone (40 mL) was added to a mixture of RuCl2(PPh3)3 (0.51 g, 0.53 mmol), P N 3 (0.14 g, 0.53 mmol), and N H 4 P F 6 (0.087 g, 0.53 mmol). The resulting red suspension was stirred for 20 h at room temperature. The final orange suspension was filtered through Celite 545® and the volume reduced (to -10 mL). Ether (40 mL) was added to form an orange precipitate which was filtered off, washed with Et20 (3 x 10 mL), followed by acetone (2x1 mL), and dried under vacuum. Yield: 0.22 g (39%). Calculated for [RuCl(PPh3)2(PN3)]PF6, C51H42N3CIF6P4RU: C, 57.18; H, 3.95; N, 3.92; Cl, 3.31%. Found: C, 57.28; H, 3.93; N, 3.89; Cl, 3.12%. A 3 1P{ !H} NMR (CDCI3) spectrum of the material isolated, prior to the acetone wash, showed peaks for [RuCl(PPh3)2(PN3)]PFg as well as a broad signal around 0 ppm and two doublets at 61.4 ppm and 2.64 ppm (2/pp = 34.5 Hz). These 'impurities' occurred in small amounts relative to the desired product and were removed by washing with acetone at the expense of the yield. Further improvements in the yields of the [RuCl2(PPh3)2(PNx)]PF6 (x = 2, 3) complexes should be attainable by altering the isolation procedures. Both isolations produced pure materials; however, the procedure for the PN2 complex gave a higher yield and could possibly be employed for the PN3 complex. 2.6.3 Preparation of trans-RuCl2(DPPB)(PNx) (x = 1, 2,3) 2.6.3.1 <ra/is-RuCl2(DPPB)(PNi) (7a) This compound was synthesized by a procedure similar to that reported by Joshi15 and is described below for the PN 2 analogue. Yield: 0.18 g (91%). Calculated for 30 references on page 47 Chapter 2 RuCl2(DPPB)(PNi),C45H42NCl2P3Ru: C, 62.72; H, 4.91; N,1.63; Cl, 8.23%. Found: C, 62.59; H, 4.96; N, 1.51; Cl, 8.39%. 2.6.3.2 fra/is-RuCl2(DPPB)(PN2) (7b) A solution of RuCl2(DPPB)(PPh3) (0.20 g 0.23 mmol) and PN 2 (0.06 g, 0.24 mmol) in benzene (15 mL) was stirred for 1.5 h. The initial green solution turns orange/brown in colour. After the solution was stirred, the volume was reduced (to ~5 mL) and hexanes (30 mL) added to form a light orange precipitate. After vacuum filtration the precipitate was washed with hexanes (3x5 mL) to remove any residual PPh3; and dried under vacuum. Yield: 0.19 g (93%). Calculated for RuCl2(DPPB)(PN2) C44H41N2CI2P3R11: C, 61.26; H, 4.79; N, 3.25; Cl, 8.22%. Found: C, 61.41; H, 5.03; N, 3.03; Cl, 8.07%. 2.6.3.3 /ra«s-RuCl2(DPPB)(PN3) (7c) The title complex was synthesized by the same procedure as the P N 2 analogue above. Yield: 0.17 g (83%). Calculated for RuCl2(DPPB)(PN3), C43H4oN 3 Cl 2 P3Ru: C, 59.79; H, 4.67; N, 4.86; Cl, 8.21%. Found: C, 60.03; H, 4.87; N, 4.82; Cl, 8.00%. 2.6.4 Preparation of cw-RuCl2(DPPB)(PNx) (x = 1, 2, 3) 2.6.4.1 cw-RuCl2(DPPB)(PNi) (8a) The prepartion was similar to that reported by Joshi.15 A solution of trans-RuCl2(DPPB)(PNi) (0.12 g, 0.14 mmol) in benzene (10 mL) was refluxed for 1.5 h over which time a yellow precipitate deposited from the initially brown solution. Hexanes (30 mL) were added and the precipitate filtered, and dried under vacuum. Yield: 0.11 g (91%). Calculated for RuCl2(DPPB)(PNi), C45H42NCl2P3Ru: C, 62.72; H, 4.91; N, 1.63; Cl, 8.23%. Found: C, 62.36; H, 4.95; N, 1.65; Cl ,8.11%. 31 references on page 47 Chapter 2 2.6.4.2 cw-RuCl2(DPPB)(PN2) (8b) A solution of ?rans-RuCl2(DPPB)(PN2) (0.18 g, 0.20 mmol) in benzene (10 mL) was refluxed for 2 h. After 1.5 h a yellow precipitate forms from the brown solution. The reaction mixture was concentrated (to ~7 mL) under vacuum and hexanes (30 mL) added to complete precipitation. The yellow product was filtered, washed with hexanes (2 x 10 mL), and dried under vacuum. Yield: 0.16 g (89%). Calculated for RuCl2(DPPB)(PN2),C44H4iN2Cl2P3Ru: C, 61.26; H, 4.79; N, 3.25%. Found: C, 61.30; H, 4.96; N, 3.08%. 2.6.4.3 cw-RuCl2(DPPB)(PN3) (8c) The title compound was prepared by the same procedure as the PN2 analogue above (Section 2.6.4.2) from fr<my-RuCl2(DPPB)(PN3). Yield: 0.16 g (93%). Calculated for RuCl2(DPPB)(PN3), C 4 3 H 4 oN 3 Cl2P 3 Ru: C, 59.79; H, 4.67; N, 4.86%. Found: C, 59.69; H, 4.69; N, 4.76%. 2.6.5 Preparation of [RuCl(DPPB)(PNx)]PF6 (x = 2,3) 2.6.5.1 [RuCl(DPPB)(PN2)]PF6 (9a) A suspension of cw-RuCl2(DPPB)(PN2) (0.06 g, 0.07 mmol) in acetone (45 mL) was stirred for 15 min. To the resulting clear solution was added NH4PF6 (0.01 g, 0.07 mmol) at which time the solution went immediately cloudy. The reaction mixture was stirred for a further 1 h, then filtered through Celite 545® to remove the NH4CI. The clear yellow filtrate was concentrated (to ~3 mL) and ether (20 mL) followed by hexanes (10 mL) added, causing formation of a yellow precipitate. The product was filtered, washed with hexanes (2 x 5 mL), and dried in vacuo. Yield: 0.05 g (82%). Calculated for [RuCl(DPPB)(PN2)]PF6, C44H41N2CIF0P4RU: C, 54.36; H, 4.25; N, 2.88; Cl 3.64%. Found: C, 54.26; H, 4.32; N, 2.80; Cl, 3.81%. 32 references on page 47 Chapter 2 2.6.5.2 [RuCl(DPPB)(PN3)]PF6 (9b) The title complex was synthesized by the same procedure as used for the P N 2 analogue above (Section 2.6.5.1) starting with ci's-RuCl2(DPPB)(PN3) (0.08 g, 0.093 mmol) Yield 0.07g (76%). Calculated for [RuCl(DPPB)(PN3)]PF6H20, C43H42N3CIF6OP4R1K C, 52.10; H, 4.27; N, 4.23%. Found: C, 52.22; H, 4.42; N, 3.90%. The presence of H 2 O was confirmed in the ipf NMR spectrum. 2.6.6 Reactivity of P,N,N'-PN2 and -PN3 Ruthenium Compounds Characterization data for complexes described in this Section are reported in Chapter 4, Section 4.6. 3 1P{1H} and X H NMR data are reported in Tables 4.8 and 4.9, respectively. Table 4.8 also contains IR data. All other characterization data are reported below with each complex. 2.6.6.1 NMR-Scale Reactions Initial studies of the reactions of small molecules with the P,N,N'-2-pyridylphosphine complexes were done in NMR tubes. In a typical experiment an NMR tube fitted with a J. Young valve (Figure 2.2) was loaded with the ruthenium complex of interest. The tube was evacuated and the NMR solvent ( C D C I 3 ) added under a flow of Ar. After the J. Young valve was closed, the tube was fitted with a 'gas reservoir' (Figure 2.2) which was evacuated and the gas under investigation added (1 atm). The J. Young valve was then opened and the apparatus was agitated periodically to ensure proper diffusion. After -24 h the J. Young valve was closed, the gas reservoir removed, and the 3 1P{1H} NMR spectrum measured, to determine if a reaction had occurred. Compounds 6b, 6c, 8a, 9a, and 9b were reacted with H2, O2, N2 (9b only) and CO gases in the manner described above. None of the complexes showed reaction with H2, O2, or N2 after 24 h in CDCI3 at room temperature. The 3 1 P NMR spectra contained 33 references on page 47 peaks for the starting materials only, in the hydride region (0 to -60 ppm). in the following sections. Chapter 2 For H 2 gas reactions, the *H spectra were checked Products from reactions with CO gas are described (10cm(l)xl.5cm(d)) Gas Reservoir Removable Kontes Valve gas TT O-ring J. Young Valve w 5 mm NMR tube Not to Scale \J Figure 2.2 NMR tube with J. Young Valve and 'gas reservoir'. 2.6.6.2 Catalytic Hydrogenation of N- benzylidenebenzylamine Several compounds (2b, 6b, 6c, 8a, 8b, 13,15c) were tested as catalysts for the hydrogenation of Af-benzylidenebenzylamine. The catalytic reactions were performed by Mr. K. S. MacFarlane (8a, 8b) and Dr. C. Abu-Gnim (2b, 6b, 6c, 13, 15c). The 91 procedure used by MacFarlane has been described elsewhere, while Abu-Gnim used the procedure which follows. To a 50 mL glass liner, under a flow of Ar, was added P h C H 2 N C H P h (2.04 mmol), catalyst (0.0150 mmol, or 0.0075 mmol), and MeOH (20 mL). The glass liner was placed in a stainless steel 4590 microreactor from the Parr Instrument Company 34 references on page 47 Chapter 2 which was sealed and charged with H2 (500 psi) at room temperature (21 to 22 °C). The reaction mixture was stirred and at appropriate times a sample was removed via a sampling valve. The sample was analyzed by GC: HP 5890A Gas Chromatograph fitted with a HP-20M (Carbowax 20M) column, FID, and an HP-integrator. Conditions: carrier gas = He (50 psi head pressure, -12 mL/min flow); injection volume = 2 pL; injector and detector temperature = 220 °C; temperature program = 140 °C (for 2 min) followed by an increase of 20 °C/min to a final temperature of 220 °C (for 5 min), giving the following retention times: tR = 2.24 min (MeOH), tR = 9.38 min (PhCH2NHCH2Ph), and tR = 10.16 min (PhCH2NCHPh). Relative amounts of imine and amine (identical response factors) were determined from the areas under the baseline resolved peaks in the chromatogram. The hydrogenation results are reported in Section 4.6.2, Table 4.7. 2.6.6.3 Preparation of [cw-RuCl(CO)(PPh3)2(PN2)]PF6 (10a) To a Schlenk tube fitted with a rubber septum, and containing an orange solution of [RuCl(PPh3)2(PN2)]PF6 (0.050 g, 0.047 mmol) in acetone (1 mL), was added one equivalent of CO gas (1.15 mL (1 atm), 0.047 mmol) via a gas tight syringe. Over 4 h the solution turned yellow and was stirred for a further 20 h to ensure the reaction was complete. Ether (25 mL) was added, causing formation of an off-white precipitate, which was collected by filtration and dried under vacuum. Yield: 0.041 g (80%). Calculated for [RuCl(CO)(PPh3)2(PN2)]PF6, C53H43N2CIF6OP4RU: C, 57.95; H, 3.94; N, 2.55%. Found: C, 57.95; H, 4.07; N, 2.52%. 2.6.6.4 Preparation of [m-RuCl(CO)(PPh3)2(PN3)]PF6 (10b) To a degassed solution of [RuCl(PPh3)2(PN3)]PF6 (0.16 g , 0.15 mmol) in CH2CI2 or acetone (3 mL) was added CO gas (1 atm). The initially orange solution turned yellow-orange after 5 min and was stirred for 1 h. The product was precipitated with ether (20 mL). The white precipitate was collected by filtration, and dried under 35 references on page 47 Chapter 2 vacuum. Yield: 0.15 g (91%). Calculated for [RuCl(CO)(PPh3)2(PN3)]PF6, C52H42N3CIF6OP4RU: C, 56.81; H, 3.85; N, 3.82%. Found: C, 56.47; H, 3.85; N, 3.74%. UV-vis (CH2C12): ^max (nm), e (M-icnr1): 268, 14200; 294, 14600. A M (CH3NO2, 25 °C) = 78.8 ohm-imoHcm2. 2.6.6.5 Preparation of [cw-RuCl(CO)(DPPB)(PNx)]PF6 (x = 2 (cis-1 lb), 3 (cis-1 lc)) To a degassed solution of [RuCl(DPPB)(PNx)]PF6 (x = 2: 0.06 g, 0.062 mmol; x = 3: 0.07 g, 0.072 mmol) in CH2CI2 (3 mL), CO (1 atm) was added. After the solution was stirred for 1 h, Et20 (30 mL) was added causing formation of a light yellow precipitate. The precipitate was collected by filtration and dried under vacuum. Yield: for x = 2: 0.05 g (78%); for x = 3: 0.07 g (94%). For complex l i b : Calculated for [cw-RuCl(CO)(DPPB)(PN2)]PF60.5Et2O C47H46N2CIF6O1.5P4R11: C, 54.42; H, 4.47; N, 2.70%. Found: C, 54.19; H, 4.36; N, 2.53%. The Et 2 0 solvate was confirmed in the !H NMR ( C D C I 3 ) spectrum (5: 1.20 (t) and 3.48 (q), 2 7 H H = 6.9 Hz), see Figure 4.19b. For complex 11c: Calculated for [ds-RuCl(CO)(DPPB)(PN3)]PF6<).25Et20 C45H42.5N3CIF6O1.25P4RU: C, 52.39 H, 4.15 N, 4.07%. Found: C, 52.37 H, 4.07; N, 4.06%. The Et20 solvate was confirmed in the lH NMR (CDCI3) spectrum (8: 1.20 (t) and 3.48 (q), 2 7 H H = 6.9 Hz), see Figure 4.19b. 2.6.6.6 Preparation of [RuCl(CO)(DPPB)(PNi)]PF6 (11a) To a degassed solution of ds-Rua 2(DPPB)(PNi) (0.077 g, 0.090 mmol) and NH4PF6 (0.015 g, 0.093 mmol) in acetone (5 mL) was added CO (1 atm). The resulting yellow suspension was stirred for 21 h over which time a light yellow, turbid solution developed. The reaction mixture was filtered through Celite 545® to remove NH4CI, and concentrated (~ 1 mL) under vacuum. Et20 was added (20 mL) and the resulting lemon yellow precipitate was filtered off and dried under vacuum at 78 °C. Yield: 0.064 g 36 references on page 47 Chapter 2 (71%). Calculated for [RuCl(CO)(DPPB)(PNi)]PF6, C46H42NClF6OP4Ru: C, 55.29; H, 4.23; N, 1.40%. Found: C, 55.64; H, 4.34; N, 1.40%. The product was a mixture of cis (20%) and trans (80%) complexes, based on integration of the DPPB methylene signals in the NMR spectrum (Table 4.9). 2.6.6.7 Isomerization of [cis-RuCl(CO)(DPPB)(PNx)]PF6 (x = 2,3) and CO Loss [ds-RuCl(CO)(DPPB)(PNx)]PF6 (x = 2, or 3) (~ 0.02 - 0.03 g) was placed in a 25 mL round-bottom flask fitted with a condenser and attached to a vacuum line. The system was evacuated and put under Ar. Chloroform (5 mL) was added, and the resulting yellow solution was refluxed in the dark and open to an atmosphere of Ar. After the refluxing procedure (x = 2, 16 h; x = 3, 24 h), the solvent was removed under vacuum, leaving behind a yellow-orange residue, which was analyzed by 3 1P{ ^H} NMR, lH NMR (CDCI3), and IR (Nujol mull/KBr plates) spectroscopies. Results for these experiments are reported in Section 4.6.3.3. 2.6.6.8 Isomerization of [cw-RuCl(CO)(DPPB)(PNx)]PF6 (x = 2,3) [czs-RuCl(CO)(DPPB)(PNx)]PF6 (x = 2, or 3) (~ 0.05 g) was stirred in CH 2 C1 2 (2 mL) under CO (1 atm) at room temperature. After 6 d, Et 2 0 (15 mL) was added and the resulting precipitate collected by filtration. The precipitate was analyzed by 31P{1H} NMR, lH NMR ( C D C I 3 ) , and IR (Nujol mull/KBr plates) spectroscopies. Results for these experiments are reported in Section 4.6.3.3. 2.7 General Experimental Procedure for Chapter 5 The characterization data for complexes prepared in Sections 2.7.1-2.7.4 are reported in Chapter 5, Sections 5.2 and 5.3. 3 1P{1H} and lU NMR data are reported in Tables 5.3 and 5.4, respectively. IR and conductivity data are reported in Table 5.5. UV-37 references on page 47 Chapter 2 visible data are reported in Table 5.7. Elemental analyses are reported below with each complex. 2.7.1 Preparation of RuCl2(PPh3)(PN3) (13) Benzene (30 mL) was added to a mixture of RuCl2(PPh3)3 (0.48 g, 0.50 mmol) and PN3 (0.13 g, 0.50 mmol). The resulting red solution was refluxed for 7 h in which time a dark red precipitate formed. After the volume was reduced in half, hexanes (40 mL) were added to complete precipitation. The red precipitate was filtered, washed with hexanes (3 x 10 mL) to remove any residual PPI13, and dried under vacuum. Yield: 0.32 g (92%). Calculated for RuCl2(PPh3)(PN3), C33H27N3CI2P2RU: C, 56.66; H, 3.89; N,6.01%. Found: C, 56.65; H, 3.89; N, 5.96%. 2.7.2 Attempted Preparation of [RuCI(MeOH)(PPh3)(PN3)]BPh4 NaBPh4 (0.022 g, 0.064 mmol) was added to a clear orange solution of RuCl2(PPh3)(PN3) (0.042 g, 0.060 mmol) in MeOH (30 mL). After being stirred for 0.5 h, the solution volume was reduced (to ~ 10 mL) under vacuum during which time an orange precipitate formed. The mixture was stirred for a further 0.5 h and then the precipitate was filtered off and washed with MeOH (2x1 mL) and dried under vacuum (24 h). Yield: 0.33 g. Calculated for [RuCl(MeOH)(PPh3)(PN3)]BPh4, C58H51N3BCIOP2R11: C, 68.61; H, 5.06; N, 4.14%. Found: C, 67.85; H, 4.94; N, 4.21%. The product isolated was not pure; possible impurities are discussed in Section 5.3. 2.7.3 Chloride Substitution Reactions of RuCl2(PPh3)(PN3) 2.7.3.1 Preparation of [RuCl(CO)(PPh3)(PN3)]PF6 (14a) To a degassed solution of RuCl2(PPh3)(PN3) (0.13 g, 0.19 mmol) and NH 4 PF 6 (0.032 g, 0.20 mmol) in MeOH (6 mL), CO gas (latm) was added. The mixture was 38 references on page 47 Chapter 2 heated in an oil-bath (65 °C) for 2 h. The initial red suspension forms a clear yellow solution which was pumped to dryness and the residue dissolved in acetone (5 mL). The resulting turbid, orange solution was filtered through Celite 545® along with acetone washings (15 mL). The clear filtrate was pumped to dryness and MeOH added (1 mL) to form a yellow precipitate which was filtered off and dried under vacuum. Yield: 0.12 g (75%). Calculated for [RuCl(CO)(PPh3)(PN3)]PF6, C 3 4 H 2 7N 3 ClF 6 OP 3 Ru: C, 48.79; H, 3.48; N, 5.02%. Found: C, 48.65; H, 3.38; N, 4.96%. 2.7.3.2 Attempted Preparation of [RuCl(CO)(PPh3)(PN3)]PF6 in Acetone To an evacuated suspension of RuCl2(PPh3)(PN3) (0.124 g, 0.177 mmol) and N H 4 P F 6 (0.029 g, 0.180 mmol) in acetone (30 mL) was added CO (1 atm). The red suspension was stirred for 11 d at room temperature over which time an orange-yellow suspension formed. The reaction mixture was filtered through Celite 545® along with acetone washings (~ 30 mL). The solvent was removed from the filtrate under vacuum and MeOH (5 mL) added to the residue. The yellow precipitate which formed was collected by filtration and dried under vacuum. Yield: 0.062 g. ^P^H} NMR (CDC13): 36.7 ppm (s, PPh3); -0.81 ppm (s, PN3); -144 ppm (sep, P F 6 , 1 / P F = 713 Hz) for [RuCl(CO)(PPh3)(PN3)]PF6 14a (major product) and 2.36 ppm (s, PN3) for RuCl2(CO)(PN3) 15a (minor product). 2.7.3.3 Preparation of [RuCl(MeCN)(PPh3)(PN3)]PF6 (14b) To a suspension of RuCl2(PPh3)(PN3) (0.085 g, 0.121 mmol) and NH4PF6 (0.020 g, 0.122 mmol) in MeOH (4 mL) was added a solution of MeCN in MeOH (1 mL, made by mixing 0.05 mL of MeCN in 5 mL of MeOH), and the resulting mixture refluxed for 10 min. The orange solution was pumped to dryness and the residue dissolved in acetone (5 mL) and filtered through Celite 545®. The volume was reduced (to ~3 mL) and ether (40 mL) added to form a yellow precipitate. The product was collected by filtration, 39 references on page 47 Chapter 2 washed with ether ( 3 x 5 mL), and dried under vacuum. Yield: 0.084g (82%). Calculated for [RuCl(MeCN)(PPh3)(PN3)]PF6, C 3 5H 3 0 N 4 ClF 6 P 3 Ru: C, 49.45; H, 3.56; N, 6.59%. Found: C, 49.58; H, 3.64; N, 6.73%. 2.7.3.4 Attempted Preparation of [RuCl(MeCN)(PPh3)(PN3)]PF6 in MeCN A solution of NH4PF6 (0.020 g, 0.12 mmol) in MeCN (5 mL) was added to a suspension of ds-RuCl2(PPh3)(PN3) (0.084 g, 0.12 mmol) in MeCN (10 mL). The resulting red suspension was refluxed for 1.5 h developing into an orange, turbid solution. The NH4CI was removed by filtering through Celite 545®. The filtrate solvent was removed under vacuum and the resulting residue dissolved in C H 2 C I 2 (1 mL). Ether (20 mL) was added causing formation of an orange precipitate, which was collected by filtration and dried under vacuum. Yield: 0.088 g. Calculated for [RuCl(MeCN)(PPh3)(PN3)]PF6, C 3 5H 3 oN 4 ClF 6 P 3 Ru: C, 49.45; H, 3.56; N, 6.59%. Found: C, 48.31; H, 3.38 N, 6.78%. 2.7.3.5 Preparation of [RuCl(PhCN)(PPh3)(PN3)]PF6 (14c) To a red suspension of RuCl2(PPh3)(PN3) (0.098 g, 0.14 mmol) and NH4PF6 (0.023 g, 0.14 mmol) in MeOH (10 mL) was added PhCN (0.05 mL) with a syringe. The resulting mixture was refluxed for 15 min during which time an orange solution formed. The MeOH was removed under vacuum and the residue dissolved in acetone (50 mL) and filtered through Celite 545®. The filtrate was concentrated (~5 mL) and Et 2 0 (30 mL) added. The yellow precipitate was filtered off and dried under vacuum. Yield: 0.091 g (71%). Calculated for [RuCl(PhCN)(PPh3)(PN3)]PF6, Q o H 3 2 N 4 C l F 6 P 3 R u : C, 52.67; H, 3.53; N, 6.14%. Found: C, 52.80; H, 3.55; N, 5.96%. 40 references on page 47 Chapter 2 2.7.3.6 Attempted Preparation of [RuCl(PhCN)(PPh3)(PN3)]PF6 in PhCN To a mixture of RuCl2(PPh3)(PN3) (0.096 g, 0.137 mmol) and N H 4 P F 6 (0.022 g, 0.137 mmol) was added C 6 H 5 C N (4 mL) and acetone (5 mL). The resulting red suspension was refluxed for 1 h, becoming a turbid, orange solution. The reaction mixture was filtered through Celite 545® with acetone washings (~ 10 mL). The acetone was removed from the filtrate under vacuum, and E t 2 0 (60 mL) added, causing formation of a yellow-orange precipitate. The precipitate was collected by filtration, washed with E t 2 0 (3 x 5 mL), and dried under vacuum. Yield: 0.104 g. The product is a mixture of two compounds: 3 1P{ 1H} NMR (8, acetone-dg): 42.8 (s, PPh3), 3.57 (s, PN3), -143 (sep, PF 6, ! 7 P F = 708 Hz) for [RuCl(PhCN)(PPh3> ( P N 3 ) ] P F 6 ; and 6.32 (s, PN 3), -143 (sep, P F 6 , 1 J P F = 708 Hz) for [RuCl(PhCN)2(PN3)]PF6. In CD 2C1 2: 41.7 (s, PPh3), 2.18 (s, PN3), -145 (sep, PF 6 , i / P F = 710 Hz) for [RuCl(PhCN)(PPh3)(PN3)]PF6; and 5.05 (s, PN3), -145 (sep, Pig, 1 J P F = 710 Hz) for [RuCl(PhCN)2(PN3)]PF6. 2.7.3.7 Reaction of RuCl2(PhCN)(PN3) with PhCN and NH 4PF 6 in MeOH To a red suspension of RuCl2(PhCN)(PN3) 15c (0.072 g, 0.133 mmol) and N H 4 P F 6 (0.022 g, 0.134 mmol) in MeOH (3 mL) was added PhCN (0.15 mL). The mixture was refluxed for 1.5 h over which time an orange-yellow suspension formed. The solvent was removed under vacuum and the residue was dissolved in acetone and filtered through Celite 545®. The filtrate volume was reduced (~ 10 mL) and E t 2 0 (40 mL) added to produce a yellow precipitate which was collected by filtration, washed with E t 2 0 (3x5 mL), and dried under vacuum. Yield: 0.076 g. 31p{lH} NMR (8, CD2C12): 5.05 (s, PN3); -145 (sep, PF 6, L J P F = 710 Hz). Also minor impurities gave signals at: 7.48 ppm (s), 6.63 ppm (s), and 5.22 ppm (s). The product is tentatively assigned the following stoichiometry, [RuCl(PhCN)2(PN3)]PF6-41 references on page 47 J Chapter 2 2.7.4 Triphenylphosphine Substitution Reactions of RuC.2(PPh3)(PN3) 2.7.4.1 Preparation of RuCl2(CO)(PN3) (15a) To a red suspension of RuCl2(PPh3)(PN3) (0.13 g, 0.19 mmol) in GoH6 (10 mL) was added CO (g) (1 atm). The suspension was refluxed for 42 h in which time an orange brown suspension developed. Hexanes (30 mL) were added to further precipitation and the precipitate collected by filtration. The product was reprecipitated from CH2CI2 (15 mL) by Et20 (20 mL), filtered, and dried in vacuo. Yield: 0.05 g (56%). Calculated for RuCl2(CO)(PN3), C1.6H12N3CI2OPRU: C, 41.31; H, 2.60; N, 9.03%. Found: C, 41.05; H, 2.64; N, 8.91%. 2.7.4.2 Preparation of RuCl2(MeCN)(PN3) (15b) To a red suspension of RuCl2(PPh3)(PN3) (0.13 g, 0.18 mmol) in Q H 6 (10 mL) was added MeCN (1 mL, 19 mmol). The suspension was refluxed for 17 h. After the mixture was cooled to room temperature, the red precipitate was filtered off, washed with C6H6 (4x5 mL), and dried in vacuo. Yield: 0.06 g (68%). Calculated for RuCl2(MeCN)(PN 3)l/6C 6H6,Ci8Hi6N 4Cl 2PRu: C, 44.00; H, 3.28; N, 11.40%. Found: C, 44.15; H, 3.46; N, 11.04%. The 1/6 C 6 H 6 solvate was confirmed in the lH NMR (CDC13) spectrum at 7.36 ppm (s). Attempts to remove the solvate by heating (78 °C) under vacuum caused decomposition of the product and the following analysis was obtained: C, 43.69; H, 3.57; N, 10.55%. 2.7.4.3 Preparation of RuCl2(PhCN)(PN3) (15c) To a red suspension of RuCl2(PPh3)(PN3) (0.18 g, 0.25 mmol) in C 6 H 6 was added PhCN (1 mL, 11 mmol). The suspension was refluxed for 4 h, then stirred for a further 16 h at room temperature. Hexanes (30 mL) were added and the red precipitate collected by filtration. This product was reprecipitated from C H 2 C I 2 (5 mL) withEt2O(50 mL) and dried under vacuum. Yield: 0.12 g (88%). Calculated 42 references on page 47 Chapter 2 for RuCl2(C 6H 5CN)(PN3), C22H17N4CI2PRU: C, 48.90; H, 3.17; N, 10.37%. Found: C, 48.87; H, 3.50; N, 10.09%. 2.7.4.4 Reaction of RuCl2(PPh3)(PN3) in PhCN A red suspension of RuCl2(PPh3)(PN3) (0.069 g, 0.099 mmol) in PhCN (4 mL) was refluxed for 0.5 h over which time a dark red solution formed. Ether (30 mL) was added followed by hexanes (20 mL) to produce a red precipitate which was filtered off, washed with hexanes ( 3 x 5 mL), and dried under vacuum. Yield: 0.042 g. ^POH} NMR ( C D C I 3 ) : 7.71 ppm (s, P N 3 ) for RuCl2(PhCN)(PN3). As well, minor impurities gave signals at: 1.52 ppm (s); 2.56 ppm (s); 41.3 ppm (s). Longer reaction times (e.g., 20 h) also gave impure product. 2.7.5 Reaction of RuCl2(PPh3)(PN3) with 0 2 Characterization data for complexes described in this section are reported in Section 5.7, Table 5.9, except for elemental analyses which are reported below. 2.7.5.1 Preparation of RuCl2(PPh3)(OPN3) (16) The title compound was synthesized by the following two procedures, of which the latter produced analytically pure material. Both procedures were done in air. a A solution of RuCl2(PPh 3)(PN3) (0.04 g, 0.057 mmol) in CH2CI2 (15 mL) was stirred for 12 d under O2 (1 atm), during which time an orange precipitate deposited. The precipitate was collected by filtration leaving a red-brown filtrate. Yield: 0.023 g. The orange precipitate was the desired product with non-stoichiometric amounts of CH2CI2 and H 2 0 solvates, RuCl2(PPh3)(OPN 3)-xCH 2Cl2-xH20 based on the 31P{!H} and iff (CDCI3) NMR spectra. To remove the solvates the product was heated under vacuum at 78 °C for 24 h over which time the colour changed from orange to red. Not all of the solvates were removed at this point. 43 references on page 47 Chapter 2 The filtrate solvent was removed under vacuum leaving a brown residue. The brown residue contains RuCl2(PPh3)(OPN3) and a small amount of an unidentified product with a 3 1P{ lH} NMR chemical shift at 1.5 ppm. b A solution of RuCl2(PPh3)(PN3) (0.21 g, 0.29 mmol) with excess m-ClC6H4C(0)OOH (0.11 g, 0.51 mmol based on 80% purity) in C H C I 3 (25 mL) was stirred for 24 h. Hexanes (160 mL) were added and the resulting brown precipitate filtered. The brown precipitate was redissolved in C H C I 3 (5 mL) and hexanes (10 mL) added to form a light brown precipitate which was removed by filtration and discarded. Hexanes (150 mL) were added to the red filtrate causing formation of an orange-red precipitate that was collected and dried under vacuum at 78 °C for 2 d. Yield: 0.15 g (52%). Calculated for RuCl2(PPh3)(OPN3), C33H27N3CI2OP2R11: C, 55.39; H, 3.80; N, 5.87%. Found: C, 55.14; H, 3.80; N, 6.06%. Note: Possibly, a better solvent combination for this reaction is MeOH, and Et 2 0 to precipitate; this would facilitate the removal of benzoic acid. 2.7.5.2 Attempted Preparation of RuCl2(PPh3)(OPN3) from RuCl 2(PPh 3) 3 and OPN 3 A reaction, similar to that used to prepare RuCl2(PPh3)(PN3) (Section 2.7.1), was attempted for the preparation of RuCl2(PPh3)(OPN3). A solution of RuCl2(PPh3)3 (0.466 g, 0.486 mmol) and OPN3 (0.137 g, 0.487 mmol) in C6Hg was refluxed for 7 h, turning dark red. The volume was reduced (~ 10 mL) under vacuum and hexanes (20 mL) were added to produce a red precipitate. The precipitate was collected by filtration, washed with hexanes (3 x 10 mL) and dried under vacuum. Yield: 0.335 g. The ^P^H} NMR (CDCI3) spectrum of the product showed several signals. Some of the desired product, RuCi2(PPh3)(OPN3) (40.4 ppm (s) and 3.56 ppm (s)) was obtained, however several other peaks were also present: 50.4 ppm (s), 39.8 ppm (s), 44 references on page 47 Chapter 2 10.4 ppm (s), 1.5 ppm (s), and 14.5 ppm (s, possibly OPN3). This reaction was not investigated further because of the number of products observed. 2.7.6 Reaction of RuCl2(PPh3)(PN3) with H 2 2.7.6.1 Reaction of RuCl2(PPh3)(PN3) with H 2 in DMA A red suspension of RuCl2(PPh3)(PN3) (0.107 g, 0.153 mmol) in DMA (10 mL) was heated at 50 °C under H2 (1 atm) for 2.5 h. Although no DMAH+C1" was observed, the reaction mixture was filtered through Celite 545® along with DMA washings (~ 5 mL) and the filtrate solvent was removed under vacuum. Benzene (10 mL) was added followed by Et20 (10 mL) and hexanes (40 mL). The red precipitate which formed was collected by filtration and dried under vacuum. The 3 1P{1H} and *H NMR (CDC13) spectra of the product indicated no reaction with H2 occurred, the starting material being recovered. A non-stoichiometric amount of DMA solvate was present in the ! H NMR spectrum: 2.91 ppm (s, CH3CON(Cfd3)2); 2.81 ppm (s, CH 3CON(CH 3) 2); 1.98 ppm (s, CFJ3CON(CH3)2). 2.7.6.2 Reaction of RuCl2(PPh3)(PN3) with H 2 in MeOH To a Schlenk tube containing RuCl2(PPh3)(PN3) (0.00222 g, 0.00317 mmol) was added MeOH (25 mL, pipette) which was previously degassed and put under Ar. Under a flow of Ar, this solution (1 mL, pipette) along with MeOH (5 mL, pipette) was transferred to an anaerobic UV-visible cell (1.0 cm path length) which has been described elsewhere3 giving a [Ru] = 2.12 x 10"5 M. The UV-visible spectrum of this solution was then measured. The solution was degassed by three freeze(N2(l))-pump-thaw cycles and H2 (1 atm) added. The spectrum was immediately measured (t = 0 min) and was identical to the spectrum obtained prior to H2 addition. The reaction with H2 was then followed over time (t = 52 min and t = 99 min), see Figure 5.13, Section 5.8. The spectrum of the reaction mixture did not change after t = 99 min. The sample was then 45 references on page 47 Chapter 2 frozen (N2(l)), the H2 gas evacuated, and the solution put under Ar. The spectrum was measured after removal of the H2 and again after 19 h, these last two spectra being identical to the spectrum obtained at the end of the reaction with H2 (t = 99 min). 46 references on page 47 Chapter 2 2.8 References (1) Perrin, D. D.; Armarego, W. L. F.; Perrin, D. R. Purification of Laboratory Chemicals; 2nded.; Pergamon: Oxford, 1980. (2) Dixon, K. R. In Multinuclear NMR, J. Mason, Ed.; Plenum: New York, 1987; Chapter 13. (3) Xie, Y. Ph.D. Thesis, The University of British Columbia, 1990. (4) Lind, J. E. J.; Zwolenik, J. J.; Fuoss, R. M. J. Am. Chem. Soc. 1959, 81, 1557. (5) Maisonnat, A.; Farr, J. P.; Olmstead, M. M.; Hunt, C. T.; Balch, A. L. Inorg. Chem. 1982, 21, 3961. (6) Kurtev, K.; Ribola, D.; Jones, R. A.; Cole-Hamilton, D. J.; Wilkinson, G. J. Chem. Soc, Dalton Trans. 1980, 55. (7) Gordon, A. J.; Ford, R. A. The Chemist's Companion; Wiley: New York, 1972. (8) Boggess, R. K.; Zatko, D. A. J. Coord. Chem. 1975, 4, 217. (9) Griffin, G. E.; Thomas, W. A. J. Chem. Soc. (B) 1970, 477. (10) McCabe, D. J.; Russell, A. A.; Karthikeyan, S.; Paine, R. T.; Ryan, R. R; Smith, B. Inorg. Chem. 1987,26,1230. (11) Shriver, D. F.; Drezdon, M. A. The Manipulation of Air-Sensitive Compounds; 2nd ed.; Wiley: New York, 1986. (12) Stephenson, T. A.; Wilkinson, G. J. Inorg. Nucl. Chem. 1966, 28, 945. (13) Hallman, P. S.; Stephenson, T. A.; Wilkinson, G. Inorg. Synth. 1970,12, 237. (14) Hoffman, P. R.; Caulton, K. G. J. Am. Chem. Soc. 1975, 97, 4221. (15) Joshi, A. M. Ph. D. Thesis, The University of British Columbia, 1990. (16) Jung, C. W.; Garrou, P. E.; Hoffman, P. R.; Caulton, K. G. Inorg. Chem. 1984, 23, 726. (17) Joshi, A. M.; Thorburn, I. S.; Rettig, S. J.; James, B. R. Inorg. Chim. Acta 1992, 198-200, 283. (18) Bennett, M. A.; Wilkinson, G. Chem. Ind. (London) 1959, 1516. 47 Chapter 2 (19) Genet, J. P.; Pinel, C ; Ratovelomanana-Vidal, V . ; Mallart, S.; Pfister, X . ; Caiio De Andrade, M . C ; Laffitte, J. A . Tetrahedron: Asymmetry 1994, 5, 665. (20) Drommi, D.; Nicolo, F.; Arena, C. G.; Bruno, G.; Faraone, F. Inorg. Chim. Acta 1994, 221, 109. (21) MacFarlane, K. S. Ph.D. Thesis, University of British Columbia, 1995. 48 CHAPTER 3 Water-Soluble Ruthenium 2-Pyridylphosphine Complexes 3.1 Introduction In 1980 Kurtev et al. reported on a series of water-soluble ruthenium and rhodium tris(2-pyridyl)phosphine complexes.1 They were interested in hydroformylation in aqueous media. Included in this paper was the ligand substitution reaction of RuCl2(PPh3)3 with excess tris(2-pyridyl)phosphine. The reaction product was reported to be a mixture of isomers of RuCl2(PN3)2, containing cis chlorides and two PN3 ligands coordinated in a bidentate mode via P and N. We were interested in this compound for two reasons. First, to use it as a possible starting material for making Ru(0) complexes and second, as RuCl2(PN3)2 is water soluble, to test it as a possible hydration catalyst. However, when the synthesis described in Kurtev's paper was repeated, a mixture of two different products was obtained: namely, [RuCl(PN3)3]Cl and [RuCl(PPh3)(PN3)2]Cl. This chapter describes the reaction of RuCi2(PPh3)3 with excess PN3 (Section 3.2), as well as the syntheses of the products [RuCl(PN3)3]Cl (Section 3.3) and [RuCl(PPh3)(PN3)2]Cl (Section 3.4). The reaction of RuCl2(PPh3)3 with excess PN2 was also investigated, the product being [RuCl(PN2)3]Cl, an analogue of the PN3 complex (Section 3.5). The aqueous solution chemistry of the products from the ligand substitution reactions was investigated (Section 3.6), and attempts to hydrate olefins reported (Section 3.7). The syntheses of the compounds described in this chapter are summarized in Figure 3.1. 3.2 Reaction of RuCl2(PPh3)3 with excess PN3 Experimental details for the reaction of RuCl2(PPh3)3 with excess PN3 are given in Section 2.5.1. The procedure was identical to that reported by Kurtev et al.1 When RuCl2(PPh3)3 was reacted with excess PN3 (6 equivalents) for 2 hours in C6H6, a yellow 49 references on page 90 Chapter 3 RuCl2(PPh3)3 I" , „C ,<„h , , „ , , , , x W W W M , c , , „ „ , 2cX = PF 6 X I,... — " " n 4 X I I M o t h e r products RuCl2(PPh3)3 -[RuCl(PN2)3]Cl 3 (v) - H 2 0 H,0 [Ru(PN2)3]Cl2 (vii) [Ru(PN2)3][PF6] 5 [RuCl(PPh3)(PN3)2]Cl + [RuCl(PN3)3]Cl 2b . 1 H 9 0 H,0 [RuCl(PPh3)(PN3)2]Cl + [Ru(PN3)3]Cl2 (viii) [Ru< Cl(PPh3)(PN3)2]X [Ru(PN3)3][X]: 4a X = BPh 4 4b X = PF, Figure 3.1 Summary of syntheses of compounds described in Chapter 3. Reaction conditions: (i) 2 PN 3 , CH2CI2; (ii) 3 d; (iii) 3 PN3, A MeOH, 6h; (iv) NH 4 PF 6 , acetone or; NaBPln, EtOH; (v) 6 PN3, C6H 6 , 2 h; (vi) 15 PN 2 , C 6 H 6 , 3 h; (vii) 5 N H 4 P F 6 ; (viii) 5 NaBPh4 or 5 NH4PF6. precipitate deposited. This precipitate was isolated and characterized by NMR spectroscopy. The 31P{1H} NMR spectra of the yellow precipitate are shown in Figure 3.2. The C D C I 3 spectra contained an AMX and an A X 2 pattern indicating the presence of two compounds. When the solvent was changed to CD2CI2 the A X 2 pattern became an ABX pattern, while the AMX pattern remained unchanged. The AMX pattern belonged to 50 references on page 90 Chapter 3 [RuCl(PN3)3]Cl 1 and the A X 2 or ABX patterns belonged to [RuCl(PPh3)(PN3)2]Cl 2b. This was confirmed by independent synthesis of the two compounds and is described below. For the 3 1P{ lU} NMR (CD2CI2) spectrum, Kurtev et al. reported a series of 12 lines around 0 ppm for the species isolated from the same preparation.1 The presence of the signals around 62 and 49 ppm in the spectrum (Figure 3.2) was the first indication that the product was different. From the *H NMR spectrum of the mixture it was possible to determine the relative amounts of the two species by integrating the signals for the H6 protons, adjacent to the nitrogens in the pyridyl rings (See Appendix A for the numbering scheme used). The H6 protons of the PN X (x = 1, 2, 3) ligands are quite distinctive and generally appear downfield from other proton signals in the phenyl region. They appear as pseudo-doublets (actually multiplets) and are useful for determining the number of equivalent pyridyl rings in a complex. Thus by integrating the C D 2 O 2 spectrum of the mixture (i.e., H6 of 2b (1H, 8.79 ppm) versus H6 of 1 (1H, 8.69 ppm)), the mixture contained 18% [RuCl(PPh3)(PN3)2]Cl and 82% [RuCl(PN3)3]Cl. Attempts to separate 1 and 2 b by selective precipitation and column chromatography were unsuccessful. Longer reaction times did not change the product ratio as the products came out of solution as they were formed. When the reactant ratio of PN 3 to RuCl2(PPh3)3 was changed the product ratio changed. Lowering the ratio to two produced 2b with a small amount of 1 when the reaction was done in C 6 H 6 (in CH2CI2 only 2b was isolated, Section 3.4). Below a reactant ratio of two, different products were obtained (see Chapters 4 and 5). Raising the reactant ratio beyond six, presumably favours formation of 1; however, this requires a significant amount of the PN 3 ligand and was not tried. For the analogous PN2 reaction, a fifteen-fold excess of ligand was required to isolate [RuCl(PN2) 3 ]Cl without formation of [RuCl(PPh3)(PN2)3]Cl (Section 3.5). 51 references on page 90 Chapter 3 Figure 3.2 3 l P { l H } NMR (121.4 MHz) spectra in CD 2C1 2 (a) and CDC13 (b) for the mixture isolated from the reaction of RuCl2(PPti3)3 with six equivalents of PN3. 52 references on page 90 Chapter 3 3.3 Synthesis and Characterization of [RuCl(PN3)3]Cl 3.3.1 Synthesis of [RuCl(PN3)3]Cl A recent report by Drommi et al. describes a high yield (95%) synthesis of [RuCl(PNi)3]Cl by reacting polymeric [RuCl2(CsHi2)]n with three equivalents of P N i in refluxing MeOH. 2 The product [RuCl(PNi)3]Cl, as suggested by spectroscopic data, contains two bidentate PNi ligands coordinated via P and N, as well as a monodentate PNi ligand coordinated via P only, as shown in Figure 3.3. A similar reaction was performed using P N 3 instead of P N 1 to make the P N 3 analogue of [RuCl(PNi)3]Cl. Figure 3.3 Structures of [RuCl(PNx)3]Cl (x = 1, 2, 3). Stereoisomers for x = 2 are shown in Figure 3.10. The reaction of [RuCl2(C8Hi2)]n with three equivalents of P N 3 in refluxing MeOH produced a mixture of products (Section 2.5.2). After six hours the MeOH was removed under vacuum leaving behind a red, oily material, which was a mixture of several products as determined by 3 1P{ 1H} NMR spectroscopy. Three main products were observed. The oily residue was chromatographed on a neutral alumina column and a yellow band was collected. After removal of the solvent under vacuum a yellow orange residue was obtained. Acetone was added to the residue and a yellow precipitate of [RuCl(PN3)3]Cl 1 was isolated in a 17% yield. Other products from the reaction remain unidentified. The reaction did not proceed as cleanly as the PN1 reaction 2 as evidenced by the low yield and the number of products obtained. The main reason was probably due to the 53 references on page 90 Chapter 3 nature of [RuCl2(C8Hi2)]n and the PN3 ligand. For PNi, three coordination modes are available for the ligand, while for PN3 there is the possibility of six coordination modes (Section 1.3.2, Figure 1.4) when forming a metal complex. The availability of these 'extra' coordination modes leads to the possibility of forming other products. Also, the [RuCl2(C8Hi2)]n starting material is polymeric and does not readily dissolve, making the control of stoichiometry difficult. When the reaction was repeated with double the concentration of PN 3 (6 equivalents) or for a longer reaction time (48 hours), no change in the product distribution was observed. Although a single product was not obtained, some of the desired complex 1 was isolated, and was characterized by elemental analysis, 3lP{!H} and lH NMR spectroscopy, and conductivity. 3.3.2 Characterization of [RuCl(PN3)3]Cl The stoichiometry of 1 isolated in the reaction of PN3 with [RuCl2(CgHi2)]n was confirmed by elemental analysis with the presence of 3 H 2 O solvates which were confirmed in the lH NMR (CDCI3) spectrum. The ifl NMR chemical shifts for 1 are reported in Table 3.1 and the spectrum in C D C 1 3 is shown in Figure 3.4. The spectrum shows multiple peaks in the phenyl region. An H6 proton of one of the PN 3 ligands is clearly visible at 8.67 ppm and integrates for 1H when compared to the rest of the phenyl region. This signal in the spectrum of 1 in CD2CI2 was used to determine the relative ratios of the two products discussed in Section 3.2. The presence of H2O as found in the elemental analysis was confirmed in the lH NMR spectrum. Free H2O in C D C 1 3 appears at 1.6 ppm.3 A broad peak at 1.8 ppm is observed in the NMR spectrum of 1 and was confirmed as H2O by spiking the sample with H 2 O . The broadness of the peak as well as its position suggests an exchange process is occurring with the complex. The water is most likely interacting with the coordinated chloride in the complex. When 1 is dissolved in water, the chloride dissociates; complexes without coordinated chlorides were isolated and these did not 54 references on page 90 Chapter 3 have H2O solvates, Section 3.6. Heating complex 1 at 100 °C for 16 hours under vacuum did not remove the H2O. The 3 1 P{ 1 H} N M R data for 1 are reported in Table 3.2 and the spectrum in CDCI3 shown in Figure 3.4. The N M R spectrum consisted of an A M X spin system or three sets of doublets of doublets indicating three phosphorus environments. The low field doublet of doublets (69.3 ppm) is not resolved and appears as a triplet. This low field signal is assigned to a PN3 ligand coordinated via P only. The two high field signals (0.35 ppm and -0.81 ppm) are each assigned to a bidentate PN3 ligand coordinated to the metal centre via P and N, forming a four-membered ring. These assignments are made based on the differences between the chemical shifts observed in the metal compound compared to those seen in the free ligand (i.e., on the coordination chemical shift, A ) . 4 " 6 Generally, when a monodentate phosphine binds a metal centre, A is positive and the observed chemical shift for the complex is downfield from that of the free ligand. (In complex 1, for the P-coordinated PN3, A = 70.0 ppm, and the P ^-coordinated PN3 ligands have A = 1.09 and -0.07 ppm, respectively.)* For bidentate phosphines however, there is a ring contribution A R to the coordination chemical shift.7 When four- or six-membered rings are formed, A R is negative and the observed chemical shift in the complex is upfield when compared to a similar complex with monodentate phosphines. For five-membered rings A R is positive. Thus four- and six-membered rings have a net shielding effect while five-membered rings have a deshielding effect. There is clearly a large, negative A R contribution to A for two of the phosphines in complex 1 and so the two PN3 ligands with the small coordination chemical shifts are considered to be P- and iV-coordinated. These ring shifts have been observed in ortho-metalated phosphine complexes, bidentate phosphine complexes,7 and in other ruthenium P N X (x = 1,3) * The 31P{ lH] NMR (CDCI3) chemical shift for the free ligand (PN3) is -0.74 ppm, (Appendix A). 55 references on page 90 Table 3.1 !H NMR Chemical Shifts for Ruthenium PNX (x = 2, 3) Complexes Complex Solvent ppm (# of H) (a) ppm (# of H) H6 of PNX x = 2, 3 0>) [RuCl(PPh3)(PN3)2]Cl 2a CDC13 6.25-8.63 (c) [RuCl(PPh3)(PN3)2]Cl 2b CDC13 6.80-8.10 (36) 8.15(1) 8.51 (1) 8.79 (1) CD 2 C1 2 6.87-8.09 (36) 8.16 (1). 8.56 (1) 8.79 (1) [RuCl(PPh3)(PN3)2]PF6 2c CDC13 6.82-8.00 (36) 8.07 (1) 8.51 (1) 8.79 (1) CD 2 C1 2 6.87-7.91 (36) 8.16(1) 8.56 (1) 8.79 (1) [RuCl(PPh3)(PN3)2]BPh4 2d CDC13 6.79-8.10(54) 7.83 (1) 7.96 (1) 8.07 (1) 8.53 (1) 8.64 (1) CD 2 C1 2 6.87-7.78 (54) 7.88 (1) 8.01 (1) 8.17 (1) 8.57 (1) 8.75 (1) [RuCl(PN3)3]Cl 1 CDC13 CD 2C1 2 6.86-8.63 (35) 6.85-8.60 (35) 8.67 (1) 8.69 (1): [RuCl(PN2)3]Cl 3 (d) CDC13 6.60-9.25 (c) 8.10 8.73 (a) Several phenyl and pyridyl peaks appearing as multiplets. (b) H6 protons appear as pseudo-doublets (multiplets). See Appendix A for numbering scheme, (c) Integrations are omitted where the spectrum contained a mixture of complexes, (d) Mixture of diastereomers. Table 3.2 31P{ lH} NMR Chemical Shifts for Ruthenium PNX (x = 2, 3) Complexes 3 Complex Spin System Solvent P A P B (ppm) P M Px 2/AB 2/AX 2JAM (Hz) 2JBX 2JMX [RuCl(PPh3)(PN3)2]Cl 2a AMX C D C 1 3 36.6 - -7.66 -21.4 - 27.0 27.0 - 304 [RuCl(PPh3)(PN3)2]Cl 2b A X 2 C D C 1 3 48.9 - - -1.36 - 30.8 - - -ABX C D 2 C 1 2 -2.03 -2.28 - 49.3 26.1 28.8 - 32.6 -[RuCl(PPh3)(PN3)2]PF6 2c (a) ABX C D C 1 3 -1.43 -1.97 - 49.1 26.1 28.9 - 32.8 -ABX C D 2 C 1 2 -2.16 -2.42 - 49.3 25.8 28.8 - 32.6 -[RuCl(PPh3)(PN3)2]BPh4 2d ABX C D C 1 3 -1.34 -1.48 - 48.9 26.0 28.3 - 33.7 -A X 2 C D C 1 3 * ) 48.8 - - -1.71 - 30.4 - - -A X 2 C D 2 C 1 2 49.2 - - -2.09 - 30.8 - - -[RuCl(PN3)3]Cl 1 AMX C D C 1 3 62.3 - 0.35 -0.81 - 29.9 30.8 - 26.4 AMX C D 2 C 1 2 62.6 - 0.88 -0.71 - 29.9 30.8 - 25.9 [RuCl(PN2)3]Cl 3 (c) AMX C D C 1 3 55.1 - -3.03 -6.22 - 29.8 32.2 28.4 AMX C D C 1 3 54.2 - -4.48 -7.68 - 30.7 30.0 26.5 AMX C D C I 3 53.1 - -2.69 -3.55 - 32.2 30.3 29.6 AMX C D C 1 3 51.8 - (d) -6.07 - 32.5 29.3 27.4 I (a) PF 6': C D C 1 3 , -144 ppm V P F = 713 Hz; CD2CI2, -145 ppm LJP¥ = 710 Hz. (b) 50 °C. (c) Mixture of diastereomers, see ^ Figure 3.11. (d) Not observed because of other signals. Chapter 3 P,N coordinated PN3 P coordinated PN3 I 1 l 11 1 1 1 1 1 1 111111 1111 1 1 1 111 11 1111111 1 1111 11111 1 1111 111111 I 111 1 10 8 6 4 2 0 PPM Figure 3.4 3 l P { l H } (CDCI3,121.4 MHz) and *H NMR (CDCI3, 300 MHz) spectra of [RuCl(PN3)3]Cl 1. Structure of 1 is shown in Figure 3.3. 58 references on page 90 Chapter 3 complexes when the PN X (x = 1, 3) ligand is bound via P and N, forming a four-membered ring. ' ' The 3 1P{ 1H} NMR spectrum of 1 is identical to that found in the mixture discussed in Section 3.2. The observed coupling constants (2/pp = 29.9, 30.8, and 26.4 Hz) are typical of mutually cis phosphines.9'10 Therefore 1 is assigned the structure shown in Figure 3.2, analogous to the structure of [RuCl(PNi)3]Cl reported by Drommi et al. Note the isolated compound is a racemate, because of the chirality at the metal centre. In line with the ionic nature of 1, the compound is a 1:1 conductor in C H 3 N O 2 (Table 3.3). Table 3.3 Conductivity Data for Ruthenium PNX (x = 2, 3) Complexes at 25 °C Complex Solvent A m Type of conductor (a> (ohm^moHcm2) [RuCl(PPh3)(PN3)2]Cl 2b C H 3 N 0 2 73.6 1:1 H 2 0 134 1:1 [RuCl(PPh3)(PN3)2]PF6 2c C H 3 N 0 2 82.2 1:1 [RuCl(PPh3)(PN3)2]BPh4 2d C H 3 N 0 2 52.6(b) 1:1 [RuCl(PN3)3]Cl 1 C H 3 N 0 2 77.7 1:1 H 2 0 179 1:1 -2:1 [Ru(PN3)3][BPh4]24a C H 3 N 0 2 94.7(b) 2:1 [Ru(PN3)3][PF6]2 4b C H 3 N 0 2 152 2:1 [RuCl(PN2)3]Cl 3 (c) C H 3 N 0 2 78.4 1:1 H 2 0 161 1:1-2:1 [Ru(PN2)3] [PF6]2 5 (c) CH 3 NQ 2 152 2:1 (a) Accepted ranges at ~ 10"3 M in C H 3 N 0 2 for 1:1, 75-90; 2:1, 150-180 ohm-imol" 1 c m 2 . 1 1 In H 2 0 for 1:1, 96-124; 2:1 228-281 ohm-lmoHcm2.12 (b) The BPh4- salts tend to give low conductivities because of the low anionic mobility of the anion, (c) Mixture of diastereomers. 59 references on page 90 Chapter 3 Finally, the complex is water-soluble and the aqueous solution chemistry is discussed in Section 3.6. 3.4 Synthesis and Characterization of [RuCl(PPh3)(PN3)2]X (X = Cl, PF 6, BPh4) 3.4.1 Synthesis of [RuCl(PPh3)(PN3)2]X (X = Cl, PF 6, BPh4) The syntheses of the title compounds are summarized in Figure 3.1. The in situ reaction of RuCl2(PPh3)3 with two equivalents of PN3 in CDCI3 was monitored by 31P{!H} NMR spectroscopy (Figure 3.5). After twenty four hours, two species were seen in the spectrum along with free PPI13. All of the PN3 was incorporated, as there was no signal for free PN3 (-0.74 ppm). The first species, 2a, showed an AMX pattern and the second species, 2b, an A X 2 pattern. After one week, only 2b was present, along with free PPI13. When the reaction was done on a synthetic scale (Section 2.5.3) in CH2CI2 at room temperature, 2b was isolated after three days. Shorter reaction times produced mixtures of 2a and 2b. Redissolving the mixtures in CH2CI2 and stirring for longer periods of time allowed isolation of only 2b. Elemental analysis of the product confirmed the stoichiometry as: [RuCl(PPh3)(PN3)2]Cl 2b. The two species are isomers: 2a the kinetic product and 2b the thermodynamic product. The thermodynamic product was the compound seen in the mixture of products obtained when RuCl2(PPh3)3 was reacted with excess PN3 in C6FJ.6 (Section 3.2). Attempts to convert 2b to [RuCl(PN3)3]Cl 1 by reaction with excess PN3 in CH2CI2 or refluxing CHCI3 failed. Conversion of the thermodynamic product 2 b to the PF6~ salt 2c was accomplished by reaction with one equivalent of NH4PF6 in acetone (Section 2.5.4). Similarly the BPh4" analogue, 2d, was made using one equivalent of NaBPln in EtOH (Section 2.5.5). These two salts were synthesized in order to study the solution NMR properties of the RuCl(PPh3)(PN3)2+ cation. 60 references on page 90 Chapter 3 (a) after 24 h 2a • 2b * PPh3 • l II I 11 l H I I III 111 H 11 111111 H 11 II H | II 11 60 50 40 30 20 10 0 -10 -20 PPM -30 (b) after 7 d 2a & 2b isomers of [RuCl(PPh3)(PN3)2]Cl PPh3 I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I | I I I I I I M I I M 11 I I I I I | I I M I I II I | I I I I I 11 I I | I I I II I M I | I I I II bo 50 40 30 20 10 0 -iO -20 PPM -30 Figure 3.5 3 1P{!H} NMR (CDC13, 121.4 MHz) spectra of the in situ reaction of RuCl2(PPh3)3 with two PN 3. 61 references on page 90 Chapter 3 3.4.2 Solution Structure of [RuCl(PPh 3)(PN 3 )2]X (X = Cl, P F 6 , B P h 4 ) The 3 1 P{!H} NMR spectra in C D C I 3 and C D 2 C I 2 of the isolated [RuCl(PPh3)(PN3)2]X (X = Cl 2b, PF 6 2c, BPh* 2d) are shown in Figure 3.6a-c and the data are reported in Table 3.2. The appearance of the spectra for the RuCl(PPh3)(PN3)2+ cation is dependent upon the solvent and associated anion. The room temperature spectrum of the chloride salt, 2b, appeared as an ABX pattern in CD2CI2 and an A X 2 pattern in C D C 1 3 , as observed in the mixture of 2b and 1 described in Section 3.2. When the C D C 1 3 solution was cooled to -50 °C the A X 2 pattern was maintained. When the CD2CI2 solution was cooled to -85 °C the chemical shifts did not change; however, the signals broadened. In order to explore the differences seen in the C D C 1 3 and CD2CI2 spectra of 2b and to rule out chloride exchange as a possible reason for the differences, the PF6' and B P I H " salts were made. For the PF6~ salt 2c, both the CD2CI2 and C D C 1 3 spectra appeared as ABX patterns at room temperature. The BPI14- salt 2d shows an opposite effect when compared to the chloride salt 2b. At room temperature in CD2CI2 the spectrum appeared as an A X 2 pattern while in C D C 1 3 it was an ABX pattern. Heating the C D C 1 3 solution to 50°C converted the ABX pattern to an A X 2 pattern. The *H NMR data are reported in Table 3.1 and the spectra for the three salts in C D C 1 3 are shown in Figure 3.7. There was no difference in the appearance of the spectra when the solvent was changed to C D 2 C 1 2 or when the temperature was changed. Thus the differences seen in the 3 1P{ 1H} spectra were caused by a process occurring on the 3 1 P NMR timescale and not on the *H NMR timescale. The most distinguishing feature of the ! H NMR spectra was the number of signals seen for the H6 protons of the PN 3 ligand. For 2b and 2c three H6 signals were clearly visible, each integrating for one proton. Five were seen for 2d. Figure 3.8 shows possible structures for the RuCl(PPh3)(PN3)2+ cation. Structures with a monodentate PN 3 coordinated via the P are not considered because of the chemical shifts seen in the 31P{ XH} NMR spectra (Figure 3.6), based on 62 references on page 90 Chapter 3 CDCI3 Figure 3.6a 3 1P{ 1H} NMR (121.4 MHz) spectra of [RuCl(PPh3)(PN3)2]Cl 2b, structure i n in Figure 3.8. 63 references on page 90 CDC13 .^^ -coordinated PN3 T I I I I I 1 I I I I I 1 I I I t' I I I I • I I I I I I I i I I • • ' i ' ' ' « I ' ' 1 ' 1 * ' ' ' I '-- — 40 30 20 10 I I I I I I I I I " " ! " " 1 " " ! " " 1 " " ! -10 PPM -20 60 50 Figure 3.6b 3 1P{!H} NMR (121.4 MHz) spectra of [RuCl(PPh3)(PN3)2]PF6 2c, structure in in Figure 3.8. (PF6" region not shown). 64 references on page 90 Chapter 3 CDCI3 PPh3 J P,N-coordinated PN 3 ' I'''' 11111 |l 1111 j 1111 j iri 11.11 ] 11 j 111111111 j 111 ij 11 11111 I*I [ 111,' I 11111111 60 50 40 30 20 10 CD2CI2 1 1 1 1 I 1 I 1 1 -10 PPM J PPh3 P,N-coordinated PN 3 m+#Mfi***)uitmfiiivm*)i >'MM»KIII»I n u l l u m t .LL«. .J I 1 1 1 1 I 1 " 1 I 1 1 1 1 I " ' ' I ' ' " I ' ' ' ' I I ' '-I I " I I I II I I I I II I I I I I I I I I I I I I I I I I ) I I I I I I I I I I I I M 60 50 40 30 2b 10 6 -10 PPM -20 Figure 3.6c 31P{lH} NMR (121.4 MHz) spectra of [RuCl(PPh3)(PN3)2]BPh4 2d, Structure HI in Figure 3.8. 65 references on page 90 Chapter 3 I I I I I j I I I I I I I I I I I I M I j I I I | b.O 8 . 5 8 . 0 7 . 5 7 . 0 PPM 6 . 5 Figure 3.7 J H NMR (300 MHz, CDCI3) spectra showing the phenyl region for [RuCl(PPh3)(PN3)2]X (X = Cl, PF 6, BPh4). 66 references on page 90 Chapter 3 arguments made in Section 3.3.2. Also included in Figure 3.8 for each structure, is the expected 3 1P{ 1H} NMR pattern, the expected type of 2/pp coupling constants (i.e., cis/trans), and the maximum number of H6 protons that could be observed (some signals may be obscured due to other resonances). Structures I-IV are chiral at the metal centre and only one enantiomer is shown. By considering the possible structures for RuCl(PPh3)(PN3)2+ shown in Figure 3.8, as well as the NMR spectroscopic evidence, the structure of the cation in solution can be determined. AMX or ABX trans/cis 2 / P P ^ 6 H6 signals P AMX or ABX cis «/P P 6 F16 signals Cl I P PPh, AMX or ABX trans/cis 2 / P P 6 H6 signals + AMX or ABX trans/cis 2 7 P P PPh3 6 H6 signals A X 2 cis Jpp 3 H6 signals IV PPha n + AX. ^ ^ c i s 2 / P P 3 H6 signals VI Figure 3.8 Possible structures for [RuCl(PPh3)(PN3)2]+ along with expected 3 1P{ AH} NMR patterns, type of 27pp coupling, and maximum number of observable H6 signals in the NMR spectra. 67 references on page 90 Chapter 3 The initial product formed when RuCl2(PPh3)3 reacts with two equivalents of PN3 is the [RuCl(PPh3)(PN3)2]Cl kinetic product 2a, with either structure I or II, which are the only ones consistent with the observed 3 1 P { 1 H } N M R spectra (Figure 3.5). The cation then isomerizes, presumably via Berry pseudo rotation 1 3 or a Bailar twist 1 4 to form the thermodynamic product 2b. Structure III is assigned to 2b, 2c, and 2d. Structures I, II, and IV can be ruled out since the observed spectra do not show trans phosphorus-phosphorus coupling constants. For 2c, structure III is the only possibility consistent with the observed 3 1 P { ! H } N M R spectra (i.e., A B X pattern in CD2CI2 and CDCI3). The 3 1 P { 1 H } N M R spectra for 2b and 2d suggest the cation may have different structures in CD2CI2 and CDCI3, either one of structures V or VI ( A X 2 ) , or III ( A B X ) . However the ! H N M R data rule out structures V and VI. For 2d, five H6 signals were observed, independent of the solvent used, and consistent with structure III only. Three is the maximum number of observable H6 signals for IV and V. Although only three H6 signals were seen for 2c (six are expected based on the 3 1 P { 1 H } N M R spectra), the remaining signals must be obscured by other resonances. Presumably, interaction of the phenyl groups of the BPh4 anion with the cation in 2d allows observation of five H6 signals. Peaks in the phenyl region are shifted and the H6 signals observed because of the influence of ring currents created by the phenyl rings. This effect has been noted for spectra obtained in C(D§ when compared with other solvents. 1 5 ' 1 6 Finally, 2b is assigned structure III, based on the similarity of its * H N M R spectrum with that of 2c and its 3 1 P { ! H } N M R spectrum with that of 2d. The differences in the 3 1 P { X H } N M R observed upon changing the solvent is attributed to subtle differences in the way the salts are solvated in CD2CI2 and CDCI3. Thus when the spectra appear as A X 2 patterns the phosphorus nuclei of the two PN3 ligands are accidentally equivalent. Structure III for the cations of the three salts is 68 references on page 90 Chapter 3 analogous to the structure assigned for [RuCl(PN3)3]Cl (Section 3.2.1, Figure 3.3) for which a similar solvent effect does not occur. The conductivities of the three salts were also measured. In CH3NO2 at 25 °C all the salts are 1:1 conductors (Table 3.3). [RuCl(PPh3)(PN3)2]Cl is water-soluble and its aqueous solution chemistry is discussed in Section 3.6. 3.4.3 X-ray Crystal Structure of [RuCl(PPh3)(PN3)2]PF6 The solid state structure of the title compound 2c was determined by single crystal X-ray diffraction and further confirms the structure in solution (Section 3.4.2). A single crystal was grown by allowing ether to diffuse into a MeOH solution of the compound. The molecular structure of the RuCl(PPh3)(PN3)2+ cation is shown in Figure 3.9. Selected bond lengths and angles are reported in Table 3.4. A complete list of crystallographic data is given in Appendix B. The Ru(II) metal centre has a distorted octahedral geometry, the distortion resulting from the two four-membered rings. Bond angles around the Ru centre and external to the four-membered rings range from 83.68(7)° to 96.39(9)°. The internal ring angles namely Pl-Ru-Nl and P2-Ru-N4 are equivalent (67.92(7)° and 67.98(7)°, respectively) and give rise to the octahedral distortion. These ring angles are discussed in more detail below. The metal ligand bond lengths are similar to those found in other ruthenium complexes. For example, the Ru-Cl bond of 2.4275(8) A falls between the Ru-Cl bonds found in ds-RuCl2(PNi)2 (2.473(4) and 2.420(3) A ) . 2 The Ru-P bonds fall within the range of those reported for other Ru(II) phosphine complexes (2.22 - 2.45A).17 The Ru-P bonds for the two PN3 ligands are different (Ru-Pl 2.3103(8) A trans to Cl and Ru-P2 2.3077(8) A trans to NI) and is probably a reflection of the different trans ligands. Similarly, the Ru-N bond lengths are unequal: 2.132(2) A for Ru-Nl versus 2.153(2) A 69 references on page 90 Chapter 3 Figure 3.9 ORTEP plot (33% probability) of the molecular structure for the cation in [RuCl(PPh3)(PN3)2]PF6 2c. 70 references on page 90 Table 3.4 Chapter 3 Selected Bond Lengths and Angles for [RuCl(PPh3)(PN3)2]PF6 2c Bond Lengths (A) Ru-Cl(l) 2.4275(8) P(2)-€(26) 1.845(3) Ru-P(l) 2.3103(8) P(2)-C(21) 1.829(3) Ru-P(2) 2.3077(8) P(2)-C(16) 1.834(3) Ru-P(3) 2.3252(8) C(l)-N(l) 1.355(4) Ru-N(l) 2.132(2) C(6)-N(2) 1.336(4) Ru-N(4) 2.153(3) C(ll)-N(3) 1.336(4) P(l)-C(l) 1.822(3) C(16)-N(4) 1.349(4) P(l)-C(ll) 1.841(3) C(21)-N(5) 1.333(4) P(l)-C(6) 1.829(3) C(26)-N(6) 1.336(4) Bond Angles (°) Cl(l)-Ru-P(l) 155.61(3) P(l)-Ru-P(3) 103.77(3) Ru-P(l)-CQl) 136.6(1) Cl(l)-Ru-P(2) 93.48(3) P(2)-Ru-N(l) 163.37(7) Ru-P(2)-C(16) 84.9(1) Cl(l)-Ru-P(3) 92.41(3) P(2)-Ru-N(4) 67.98(7) Ru-P(2)-C(21) 125.6(1) Cl(l)-Ru-N(l) 90.25(7) P(3)-Ru-N(l) 92.24(7) Ru-P(2)-C(26) 128.1(1) Cl(l)-Ru-N(4) 83.68(7) P(3)-Ru-N(4) 170.53(7) Ru-N(l)-C(l) 105.1(2) P(l)-Ru-P(2) 104.54(3) N(l)-Ru-N(4) 96.39(9) Ru-N(4)-C(16) 104.8(2) P(l)-Ru-P(3) 98.95(3) Ru-P(l)-C(l) 84.89(1) P(l)-C(l)-N(l) 102.0(2) P(l)-Ru-N(l) 67.92(7) Ru-P(l)-C(6) 115.6(1) P(2)-C(16)-N(4) 102.2(2) P(l)-Ru-N(4) 87.93(7) for Ru-N2. These bonds are similar to those found in c/s-RuCl2(PNi)2 (2.13(1) and 2.063(8) A ) . 2 The two four-membered rings are roughly orthogonal with a dihedral angle of 94.25° and are planar with mean deviations of 0.02 A for the Ru-Pl -Cl -Nl plane and 71 references on page 90 Chapter 3 0.0027 A for the Ru-P2-N4-C16 plane. The angles in the two four-membered rings are identical within experimental error (Table 3.5). The P-Ru-N angles are compressed to an average of 67.95° in comparison to an ideal value of 90° for octahedral coordination. The P-C-N angles are also compressed to an average of 102.1° from an average of 117.2° in the free PN3 ligand. The ring angles found in 2c are similar to those found in cis-RuCl2(PNi)2 2 and ds-RuCl2(CO)2(PNi) 8 as shown in Table 3.5. It is interesting to note that there is barely any difference between PNi and PN3 in terms of the angles found when four-membered rings are formed. In terms of bond lengths, a valid comparison between PNi and PN3 cannot be made. Although 2 c, c/.s-RuCl2(PNi)2, and cw-RuCl2(CO)2(PNi) all contain a Ru-P bond trans to Cl (Ru-P = 2.3103(8), 2.265(4), and 2.322(2) A , respectively) the bond lengths clearly depend on the other ligands present. The bond lengths in the PN3 ligand itself do not change upon coordination to the metal centre as compared to those of the free ligand. Table 3.5 Comparison of the Four-Membered Ring Bond Angles (°) in 2c, m-RuCl2(PNi)2 2 and cw-RuCl2(CO)2(PNi)8 <N'"-2c P2-1> PPh. Cl cis-RuCl2(PNi)2 ,N <N"-1 T> Cl Cl RuCl2(CO)2(PNi) oo,. N C 1 Cl Angle Ring 1 Ring 2 Ring 1 Ring 2 P-Ru-N 67.98(7) 67.92(7) 69.6(3) 68.7(3) 68.7(2) Ru-P-C 84.9(1) 84.8(1) 84.2(4) 86.1(4) 84.0(3) P-C-N 102.2(2) 102.0(2) 100.6(8) 100.7(8) 101.3(5) C-N-Ru 104.8(2) 105.1(2) 105.5(8) 104.5(7) 106.0(5) 72 references on page 90 Chapter 3 3.5 Reaction of R u C l 2 ( P P h 3 ) 3 with Excess P N 2 , Synthesis of [ R u C I ( P N 2 ) 3 ] C l The PN 2 analogue of [RuCl(PN3)3]Cl (Section 3.3) was synthesized by ligand substitution of RuCl2(PPh3)3 with excess PN2 in C6H6 (Section 2.5.6). A fifteen fold excess of PN2 was required to isolate solely [RuCl(PN2)3]Cl 3. When lower excesses of PN2 were used, the 31P{1H} NMR (CDCI3) of the product showed peaks which could be attributed to the partially substituted product: [RuCl(PPh3)(PN2)2]Cl. For example, a triplet and a doublet of doublets were seen at -48 ppm which could be for the PPI13 of [RuCl(PPh3)(PN2)2]Cl, analogous to 2b where the PPI13 signal appears as a triplet at 48.9 ppm (Section 3.4). No attempts were made to synthesize [RuCl(PPh3)(PN2)2]Cl independently. When PN2 coordinates a metal centre via P and N, the phosphorus becomes chiral. Thus 3 was isolated as a mixture of diastereomers. Three chiral centres are present in the complex, two from the bidentate PN2 ligands and one from the metal centre. The stereoisomers are shown in Figure 3.10. The 3 1P{ !H} NMR (CDCI3) of 3 is shown in Figure 3.11 and the data are reported in Table 3.1. The general features of the spectrum are similar to those observed for [RuCl(PN3)3]Cl (Section 3.3.2). The spectrum consists of four AMX patterns, one for each diastereomer present. Four triplets (unresolved doublets of doublets), for the monodentate P-coordinated PN2 ligand, are seen between ~ 51 to 55 ppm. The bidentate PN2 ligand signals appear between ~ -2 to -7 ppm. As in the PN3 analogue 1, the 2/pp couplings are typical of mutually cis phosphorus nuclei and hence the structures shown in Figure 3.10 are assigned to 3. More specific assignments cannot be made without separating the diastereomers. The mixture of diastereomers is a 1:1 conductor in CH3NO2 (Table 3.3). 73 references on page 90 Chapter 3 Ph X T py / ci A-R-R 'PN, P R , N P h Cl py A-S-S P > ' - P ^ P ^ + N P / Cl A-R-S 'PN, P h ^ p ^ P y ~ l + N PN, py Cl S P h A-S-R Ph/ ^, ~ ~ " T ^ p ^ y py PN, Cl A-S-R p y - f & p . N P h < > P N , ^ | ^ P ^ Cl py A-R-S •Piq.py Ph / ci PN, A-S-S py , p h T V PR Y Cl Ph A-R-R Figure 3.10 Stereoisomers of [RuCl(PN2)3]Cl 3. Four diastereomers with their corresponding enantiomers are shown. The stereochemical assignments are made in the order Metal-Pa-Pb 74 references on page 90 Chapter 3 # Four Diastereomer Pairs: # • j.' I! I ] III 1 ] 111 I ]7TI ITlllI{1IIl|lllip7111]I111]1MIJ1!11|I1M J1IH|IIIIII1II|1IIIJMII| 70 60 5b 40 3ft 20 10 o' -10 PPM Figure 3.11 3 1 P {lH} NMR ( C D C I 3 , 121.4 MHz) spectrum of the mixture of diastereomers for [RuCl(PN2)3]Cl 3. Structures for 3 are shown in Figure 3.10 3.6 Aqueous Solution Chemistry of [RuCl(PPh3)(PN3)2]CI and [RuCl(PNx)3]Cl (x = 2,3) All three complexes [RuCl(PNx)3]Cl (x = 2 (3), 3 (1)) and [RuCl(PPh3)(PN3)2]Cl 2b are water-soluble. Qualitatively, the PN 3 complexes are more soluble than the PN2 complex. The three complexes are considered in order below. The 3 1P{ 1H} and lU NMR data for compounds in this section are reported in Tables 3.6 and 3.7, respectively. 75 references on page 90 Chapter 3 Complex 1 dissociates the chloro ligand when dissolved in H2O. For 1 in D2O, the 3 1P{ 1 H) spectrum contains a singlet at 2.92 ppm, indicating three equivalent PN3 ligands. In H2O the monodentate (P-coordinated) PN3 ligand becomes bidentate (P- and //-coordinated), and displaces the coordinated chloride forming a four-membered ring (Figure 3.12). This dissociation reaction is reversible. When the water is removed and the compound dissolved in CDCI3 the spectrum is that of [RuCl(PN3)3]Cl. + c r Figure 3.12 Chloride loss from [RuCl(PNx)3]Cl (x = 2, 3) in H 2 O . Stereoisomers for the x = 2 product are shown in Figure 3.14. The [Ru(PN3)3] 2 + cation was isolated as BPh 4 _ 4a and PF6" 4b salts (Section 2.5.7 and 2.5.8, respectively) by dissolving the mixture of [RuCl(PPh3)(PN3)2]Cl and [RuCl(PN3)3]Cl (Section 3.2) in H2O and adding either excess NH4PF6 or NaBPln. The two products 4a and [RuCl(PPh3)(PN3)2]BPh4 (or 4b and [RuCl(PPh3)(PN3)2]PF6) were then separated by selective precipitation. Compounds 4a and 4b are not water-soluble, but their 3 1P{ lH} NMR spectra were obtained in CD2CI2 and showed singlets at 3.08 and 2.78 ppm, respectively. The difference seen in the chemical shift for the two salts is believed to be caused by solubility differences. The BPh4 salt is not as soluble as the PF^ salt in CD2CI2 and may be forming ion-pairs. The structure of the Ru(PN3)32 + cation is shown in Figure 3.12. This structure is assigned based on the 31P{1H} chemical shifts (i.e., three PN3 ligands coordinated via P 76 references on page 90 Chapter 3 Table 3.6 31P{ *H} NMR Chemical Shifts for Water-Soluble and Related Ruthenium PNX (x = 2, 3) Complexes Complex Spin System Solvent PA P M ppm Px 2JAM Hz 2JMX [RuCl(PPh3)(PN3)2]Cl 2b AMX D20(a) 50.5 -2.50 -4.00 - - -[RuCl(PPh3)(PN3)2]Cl 2b AMX D20(b> 50.5 -2.60 -4.17 32.1 29.0 26.9 [RuCl(PN3)3]Cl 1 A 3 D 2 0 2.92 - - - - -[Ru(PN3)3][BPh4]24a A 3 CD 2C1 2 3.08 - - - - -[Ru(PN3)3][PF6]2 4b (c) . A 3 CD 2C1 2 2.78 •- • - - - -[RuCl(PN2)3]Cl 3 (d) A 3 D 2 0 2.01 - - - - -A 3 D 2 0 -2.68 - - - - -ABX D 2 0 -0.16 -0.68 -2.98 29.2 27.9 26.2 A X 2 D 2 0 4.28 - 0.61 27.8 - -[Ru(PN2)3][PF6]25fed) A 3 CD 2C1 2 4.24 - - - - -A 3 CD 2C1 2 -4.22 - - - - -AMX CD 2C1 2 7.31 2.78 -3.10 30.6 25.7 25.0 AMX CD 2C1 2 2.77 1.08 -3.81 26.3 29.2 29.3 (a) broad signals, coupling not resolved (b) 50 °C. (c) PF6 - : -145 ppm (sep) ijpp = 710 Hz. (d) Mixture of diastereomers. and AO and is further supported by *H NMR data and the white colour of the complex. Based on the 31P{!H} NMR alone, a structure with the three PN 3 ligands coordinated via two pyridyl rings with a 'free' P atom could be assigned: 77 references on page 90 Chapter 3 The X H NMR spectra of the Cl", PF6", and BPI14- salts are shown in Figure 3.13. The Cl" salt in D2O shows at least 11 signals for the 36 protons in the complex. Three H6 signals are seen indicating that the PN3 ligands are all equivalent (as expected from the 3 1P{1H} NMR), and that the three pyridyl groups in each PN3 are inequivalent. The structure shown above would have two equivalent and one inequivalent pyridyl ring for each PN3 and hence two H6 signals integrating in a 2:1 ratio. Furthermore the salts are white in colour. If the PN3 ligands were coordinated via two pyridyl groups an orange colour would perhaps be expected as seen for complexes such as [Ru(2,2'-bipyridine)3]2+.19 Table 3.7 lU NMR Chemical Shifts for Water-Soluble and Related Ruthenium PN X (x = 2, 3) Complexes Complex Solvent ppm (# of H) (a) ppm (# of H) H6, PNX x = 2, 3 (b) [RuCl(PPh3)(PN3)]Cl 2b D 2 0 (c) 6.60-8.33 (37) 8.38 (1) 8.90 (1) [RuCl(PN3)3]Cl 1 D 2 0 6.89-8.13 (27) 8.12 (3) 8.28 (3) 8.53 (3) [Ru(PN3)3][BPh4]2 4a CD2CI2 6.89-8.15 (33) 8.33 (3) [Ru(PN3)3][PF6]2 4b CD2CI2 6.80-7.72 (67) 7.77 (3) 8.16 (3) 8.23 (3) [RuCl(PN2)3]Cl 3 W) D 2 0 6.46-8.56 8.38 8.60 8.76 [Ru(PN3)3][PF6]2 5(d) CD2CI2 6.30-8.37 8.39 8.45 8.64 (a) Phenyl and pyridyl peaks appearing as multiplets. (b) H6 protons appear as pseudo-doublets (multiplets). See Appendix A for numbering scheme, (c) 50 °C. (d) Mixture of diastereomers, therefore integrations not reported. 78 references on page 90 Chapter 3 c; i i i—i—]—i—i—i—i—1 i i i — i — 1 — i — i — i — i — I — i — i — i — r 0 8.S B.O 7 . 5 7 .0 PPH Figure 3.13 *H NMR (300 MHz) spectra showing the phenyl region for Cl", BPI14-, and PF6" salts of the [Ru(PN3)3]2+ cation. 79 references on page 90 Chapter 3 For the PN 2 complex 3 in water, a similar dissociation of chloride occurs. Four chiral centres are present in the [Ru(PN2)3]2+ cation, three from the ligands caused by the chirality of the PN 2 ligand when coordinated in a bidentate mode, and one from the metal centre. Eight diastereomeric pairs would be expected, but because the three PN 2 ligands in the complex are indistinguishable, a mixture of four diastereomeric pairs is seen, the other possible diastereomeric pairs being identical structures. The isomers are shown in Figure 3.14 along with their expected 3 1P{1H} NMR patterns. The PF6" salt, 5, of the dication [Ru(PN2)3]2+ was isolated (Section 2.5.9). The 3 1P{1H} NMR spectrum of the PF6- salt in CD 2 C1 2 is shown in Figure 3.14. Signals for the four diastereomeric pairs expected for the [Ru(PN2)3]2+ cation were observed. Structures I and II (Figure 3.14) are assigned to the two singlets (A3). The remaining two sets of three doublets of doublets (AMX) are assigned to structures III and IV. No attempts were made to separate the diastereomers, making more specific assignments impossible. Peaks for the four diastereomers of the dication are also seen in the D 2 0 spectrum of 3. The spectrum of 3 in D 2 0 (Figure 3.16) is different from its spectrum in CDCI3 but similar to that of 5 in CD 2C1 2 . The E^O spectrum contains two singlets (A3), a triplet and doublet (AX2), and three triplets, which are unresolved doublets of doublets (ABX). In comparison to 5 in CD 2C1 2 , the AMX patterns have changed into an A X 2 and ABX pattern in D 2 0. The slight difference in the appearance of the peaks, when compared to 5 in C D 2 C 1 2 , is attributed to a solvation effect on the dication as seen for [RuCl(PPh3)(PN3)2]Cl in CDCI3 and CD 2 C1 2 (Section 3.4.2), and is based on the variable temperature NMR spectral data. The variable temperature 3 1P{1H} NMR spectra of 3 in D 2 0 are shown in Figure 3.16. In comparison to the room temperature spectra, the appearance of the singlets (A3) for structures I and II (Figure 3.14) remained constant at higher temperatures. For structures III and IV (Figure 3.14), the X signal in the A X 2 pattern splits into a complex multiplet, while the A and X signals of the ABX pattern shifted downfield slightly, as the 80 references on page 90 Chapter 3 A-R-R-R A 3 A-S-S-S A 3 A-R-R-S [A-R-S-R] [A-S-R-R] AMX A-S-S-R [A-S-R-S] [A-R-S-S] AMX py/, Ph 2+ py N \ | v ^Ph Ph, 12+ .Ph Ph N. \ py N .Ph x N * " . y py N \ | \ py p h * ^ l 2 + '••p^(py 1 py N/, ^p n i n .py iv Ph ^Ph Ph py^ p" N Ph py N Ph 2+ N py Ph ~ l 2+ 3SL Ph, py N j>y Ph Ph P" ^ " 1 Ph N "... r py N Ph <2> N py py Ph py/, r Ph ^ N_py N Ph A-S-S-S A 3 A-R-R-R A 3 2 + A-S-S-R [A-S-R-S] [A-R-S-S] AMX | 2 + A-R-R-S [A-R-S-R] [A-S-R-R] AMX Figure 3.14 Stereoisomers of [Ru(PN2)3]2+. The stereochemical assignments are made in the order Metal-Pa-Pb-Pc- The three PN 2 ligands are indistinguishable (related by a C3 axis), therefore the chirality assignments made in brackets are for identical complexes . The expected 3 1 P pH} NMR pattern is also given. 81 references on page 90 Chapicr 3 Four Diastereomer Pairs: # • * • I, XILmi.n,,, Figure 3.15 3 1 P {JH} NMR (CD2CI2, 121.4 MHz) spectrum of [Ru(PN2)3][PF6l2 5. (PF6" region not shown). See Figure 3.14 for structures. temperature was increased. The relative intensities of the peaks were unaffected by the change in temperature. When the sample was cooled back to room temperature, the spectrum appeared the same as it did prior to heating. The slight differences in the appearance of the peaks when compared to those of 5 in CD2CI2 are attributed to a solvation effect, because only two of the diastereiomers are affected by the temperature change and the relative intensities of the peaks do not change. If the diastereomers were interconverting, or chloride exchange were occurring, it is more likely that all of the signals would be affected by the temperature change either in appearance or relative intensities. Furthermore, if chloride exchange were occurring, a more dramatic change in the chemical shifts of the signals would be expected, since the 82 references on page 90 Chapter 3 Four Diastereomer Pairs # • * • 23°C MJ -jiiii|iiiijiiii|iiiijiiii|[iiijiiii|iiiijiiii|iii)jiiii|iiiiyiii|iiii|iiii|iii^iiii|iin iiii|inij Figure 3.16 Variable temperature 3 1P{ 1H} NMR (D2O, 121.4 MHz) spectra of [RuCl(PN2)3]Cl 3. 83 references on page 90 Chapter 3 PN 2 ligand would be changing from being P^-coordinated to only P-coordinated. The phosphorus signal would shift downfield dramatically as seen for the P-coordinated PN2 in 3 in CDCI3 (Figure 3.11). As in the PN3 case, the chloride dissociation is reversible. When the H 2 O is removed and the compound dissolved in CDCI3, the spectrum is that of [RuCl(PN2)3]Cl. If excess NaCl is added to an aqueous solution of the compound a yellow precipitate forms and is presumably the monocationic complex. Finally, the conductivities of 1 and 3 in H2O were measured (Table 3.4). The observed conductivities fall between the ranges for 1:1 and 2:1 conductors (i.e., below the expected 2:1 range). This could result from three possibilities. The first is that an equilibrium between the monocation and dication exists, resulting in the low conductivity. The second and third possibilities are that the dications have low mobilities in H 2 O or ion-pairs are forming. The last two possibilities are more likely than the first because the NMR evidence suggests that the compounds are completely ionized. The spectra of the chloride salts in D2O are similar to the spectra of the PF6" or BPI14" salts in CD2CI2 . If in fact there are equilibria (as written in Figure 3.12), the equilibrium constants are large and favour the dications. Therefore the low conductivities are attributed to either ion-pair formation or low mobilities of the cations in H2O. In contrast to 1 and 3, 2b does not dissociate chloride in H 2 O and its structure remains unchanged. The 3 1P{1H} spectrum in D2O contains three broad signals at 50.5 ppm (PPh3), -2.50 ppm (PN3) and -4.50 ppm (PN3) at room temperature. When the solution is heated to 50 °C, the coupling can be resolved and the spectrum appears as three triplets (unresolved doublets of doublets), similar to the spectrum seen in CD2CI2 (Section 3.4.2). The room temperature broadness could be caused by chloride exchange between the coordinated and free chlorides or by inefficient tumbling of the complex. Molar conductivity data for 2b, however, confirms the complex as a 1:1 conductor in H 2 0 (Table 3.3). 84 references on page 90 Chapter 3 As mentioned at the beginning of this section, the PN 2 complex 3 is less soluble in water than the PN3 complexes 1 and 2b . Three properties of the complexes contribute to the solubility: charges on the ions formed, the number of uncoordinated pyridyl groups, and the overall polarity of the complexes. A direct comparison of complexes 1 and 3 can be made because they have the same structure and are both dications in H2O. Therefore the solubility difference between the two complexes is determined by the number of uncoordinated pyridyl groups, six for 1 and three for 3. The larger number of uncoordinated pyridyl groups leads to greater solubility. In contrast, comparisons with 2b are more difficult because the properties mentioned above cannot be considered independently. Although 2b is a monocation and has one more uncoordinated pyridyl group than 3, it is more soluble than 3. The polarity (caused by the distribution of the ligands around the metal center) of the complex probably plays an important role in determining the solubility difference between these two complexes. In summary, 1 and 3 ionize (i.e., lose the chloride) reversibly to form dications in H 2 O . The mixed phosphine complex, 2b, remains a monocationic species in H2O indicating the need for a coordinating group (e.g., py group of a PN2 or PN3) to promote formation of the dications. 3.7 Attempted Hydration of Maleic Acid The complexes discussed in the previous section were tested as catalysts for the hydration of maleic acid to malic acid (Figure 3.17). 85 references on page 90 Chapter 3 HOOC COOH 1 0 i v"1 rnnw Malic Acic * \ / L U U H A, H 2 0 Owtototi HO H HOOC COOH M a l i c A d Maleic Acid cat. + COOH HOOC Fumaric Acid (isomerization) Figure 3.17 Hydration of maleic acid to malic acid. The choice of maleic acid as substrate was prompted by its use in a previous study which used C r 3 + as catalyst20 and would allow for a comparison of catalytic activity. For the three complexes tested, it was thought that a substrate could bind to the metal center, which is probably important for hydration to occur. For example, one of the strained four-membered rings in 1 or 3 could be displaced by a substrate, or more likely, the coordinated chloride in 2b could be displaced to form a dication with coordinated substrate. The experimental details for the catalytic runs are given in Section 2.5.10. The catalyst, substrate, and H2O were put in a thick-walled glass bomb and heated at 100 °C. After 24 and 48 hours a sample was taken from the bomb, the H 2 0 removed, and the composition of the sample determined by lH NMR spectroscopy. In the runs with added NaOH, the isolation procedure was slightly different. The base was neutralized and the products extracted with E t 2 0 which was subsequently removed under vacuum (see Section 2.5.10). The results for the catalytic runs are shown in Table 3.8. The results show that there is no catalytic hydration of maleic acid under the conditions tested. The amount of malic acid in the reaction mixtures was the same as the amount found in the blank under acidic conditions (maleic acid is a weak acid with pK a 86 references on page 90 Chapter 3 values of 1.91 and 6.33).21 Under basic conditions no malic acid is produced (entries 7 to 9, Table 3.8). Some of the maleic acid isomerizes to fumaric acid. With 2b (entries 3 & 4, Table 3.8), approximately twice as much fumaric acid is produced when compared to the blank. With the other complexes (entries 1 & 2, Table 3.8) the amount of fumaric acid produced is equal to that produced in the blank. Under basic conditions (entry 7) as compared to acidic conditions (entry 3), the amount of fumaric acid produced is doubled. These results suggest there is some interaction between 2b and the maleic acid, for the fumaric acid to be produced: coordination at the double bond would decrease its bond order and facilitate the rotation process required for the isomerization. Silver nitrate was added (entry 4, Table 3.8) with the hope that the coordinated chloride in 2b could be removed as AgCl to produce a vacant site where catalysis could occur. Although a small amount of gray/brown precipitate was observed in the reaction solution after 16 h, no improvement in conversion was observed. To determine if AgNC<3 was removing the coordinated chloride in 2b, the complex and two equivalents of AgN03 were dissolved in D 2 0 in an NMR tube. Immediately, a yellow precipitate deposited and slowly turned brown. The 3 1P{ 1H} NMR spectrum showed very weak signals attributable to 2b, but clearly most of the phosphine content of the complex was lost in the yellow/brown precipitate. Silver nitrate is therefore not a suitable dehalogenating agent for 2 b. This brown precipitate was not investigated further, but presumably 99 93 contains Ag-phosphine species which are known. ' The results indicate that the three complexes are not suitable for hydrating maleic acid. For complexes 1 and 3, the coordinated pyridyl groups in the dications (Section 3.6) are probably stable to displacement by an olefin, which is perhaps not surprising as olefins are likely poor donors when compared to a pyridyl group. The more likely candidate for catalysis, 2b, also gave poor results. That the compound is sterically crowded and six-coordinate, and that the coordinated chloride could not be removed, are the most likely reasons for the inactivity. Further testing of these complexes with other 87 references on page 90 Chapter 3 substrates was not done because of the observed properties of the complexes in aqueous solution. Table 3.8 Composition of Reaction Mixtures in the Attempted Catalytic Hydration of Maleic Acid^) Catalyst Time % Maleic^) %Fumaric %Malic 1. [RuCl(PN3)3]Cl 1 24 h 95 4 1 48 h 92 6 2 2. [RuCl(PN2)3]Cl 3 24 h 93 5 2 48 h 94 4 2 3. [RuCl(PPh3)(PN3)2]Cl 2b 24 h 92 6 2 48 h 89 8 3 4. [RuCl(PPh3)(PN3)2]Cl 2b 24 h 91 7 2 + 2AgN03 48 h 89 8 3 5. Blank (c> 24 h 95 3 2 48 h 93 4 3 6. [RuCl(PN3)3]Cl 1(d) 48 h 95 5 0 7. [RuCl(PPh3)(PN3)2]Cl 2b (d) 48 h 84 16 0 8. Blank (d) 48 h 95 5 0 (a) Ratio: [catalyst]:[substrate] = 1:100; 100 °C. (b) mole %; absolute error estimated to be ± 1%. (c) No catalyst present. Average of two determinations, (d) With added NaOH, [NaOH] = 2 x [maleic]. 88 references on page 90 Chapter 3 3.8 Conclusions The products from the ligand substitution reactions of RuCl2(PPh3)3 with excess PN3 or PN2 have been identified and properly formulated. The favoured coordination mode for the PNX (x = 2, 3) ligand in these ruthenium(II) complexes is the bidentate P,N-mode. Depending on the ability of the solvent to support ions, this mode is favoured over coordination of chloride, as seen with [RuCl(PNx)3]Cl (x = 2, 3) in H2O. The water-solubility of the complexes increases with increasing number of uncoordinated pyridyl groups, although factors such as the charge on ions formed and overall polarity do play a role. Although the 2-pyridylphosphines promoted water-solubility, the formation of the four-membered rings making coordinatively saturated complexes (i.e., six-coordinate octahedral complexes in the case of Ru(II)) is the most likely reason hydration catalysis was not observed. 89 references on page 90 Chapter 3 3.9 References (1) Kurtev, K.; Ribola, D.; Jones, R. A.; Cole-Hamilton, D. J.; Wilkinson, G. J. Chem. Soc, Dalton Trans. 1980, 55. (2) Drommi, D.; Nicolo, F.; Arena, C. G ; Bruno, G.; Faraone, F. Inorg. Chim. Acta 1994,227,109. (3) Derome, A. E. Modern NMR Techniques for Chemistry Research; Pergamon Press: New York, 1991, p 34. (4) Pergosin, P. W.; Kunz, R. W. NMR: Basic Princ. Prog. 1979,16, 49. (5) Mann, B. E.; Masters, C ; Shaw, B. L. J. Chem. Soc. (A) 1971, 1104. (6) Mann, B. E.; Masters, C ; Shaw, B. L. J. Chem. Soc, Dalton Trans. 1972, 704. (7) Garrou, P. E. Chem. Rev. 1991, 81, 229. (8) Olmstead, M. M.; Maisonnat, A.; Farr, J. P.; Balch, A. L. Inorg. Chem. 1981,20, 4060. (9) Verkade, J. G. Coord. Chem. Rev. W12I13, 9, 1. (10) Pergosin, P. W.; Kunz, R. W. NMR: Basic Princ. Prog. 1979,16, 28. (11) Geary, W. J. Coord. Chem. Rev. 1971, 7, 81. (12) Huheey, J. E.; Keiter, E. A.; Keiter, R. L. Inorganic Chemistry: Principles of Structure and Reactivity; 4th ed.; Harper Collins: New York, 1993, p 389. (13) Berry, R. S. J. Chem. Phys. 1960, 32, 933. (14) Bailar, J. C. J. Inorg. Nucl. Chem. 1958, 8, 165. (15) Moore, D. S.; Robinson, S. D. Inorg. Chim. Acta 1981, 53, L171. (16) Keat, R. Chem. andlnd. (London) 1968, 1362. (17) Jessop, P. G.; Rettig, S. J.; Lee, C.-L.; James, B. R. Inorg. Chem. 1991, 30, 4617. (18) Keene, F. R.; Snow, M. R.; Tiekink, E. R. T. Acta Crystallogr., Sect. C 1988, 44, 757. (19) DeSimone, R. E.; Drago, R. S. J. Am. Chem. Soc 1970, 92, 2343. (20) Xie, Y. Ph.D. Thesis, The University of British Columbia, 1990. 90 Chapter 3 (21) Harris, D. C. Quantitative Chemical Analysis; 2 nd ed.; W.H. Freeman & Co.: New York, 1987, p 729. (22) Alcock, N. W.; Moore, P.; Lampe, P. A.; Mok, K. F. J. Chem. Soc, Dalton Trans. 1982, 207; and references therein. (23) Teo, B.-K.; Calabrese, J. C. Inorg. Chem. 1976,15, 2467. 91 CHAPTER 4 P,A/,A/'-Coordination Mode of 2-Pyridylphosphines 4.1 Introduction As discussed in Chapter 1 (Section 1.3.2), 2-pyridylphosphines can bind to metal centres with a variety of coordination modes. For the six coordination modes shown in Figure 4.1 examples of types I to V have appeared in the literature (See Section 1.3.2 for specific examples). Type VI was predicted in 1975 by Boggess and Zatko based on electronic arguments.1 / P *'- / \ M—P-... ^ / ^ - P N v / / l i * M — N M M i, p n, P,N ni, [i-p,N N ' M" / M' N IV, N,N' V, N,N',N" VI, P,N,N' Figure 4.1 Binding modes for 2-pyridylphosphines. This chapter describes a series of ruthenium (II) complexes which exhibit type VI coordination (Sections 4.2 to 4.5). The reactivity of these complexes with small molecules was also investigated to determine the stability and properties of this type of coordination (Section 4.6). The syntheses for compounds described in this chapter (except for Section 4.6) are summarized in Figure 4.2. 92 references on page 143 Chapter 4 RuCl2(PPh3)3 (iii) (i) T PPh [RuCl(PPh3)2(PN3)]Cl 6a (ii) PPha NH 4Cl+PPh 3 [RuCl(PPh3)2(PNx)]PF6 x = 2, 6b x = 3, 6c RuCl2(DPPB)(PPh3) (iv) PPh, frans-RuCl2(DPPB)(PNx) RuCl2(PPh3)(PN3) 13 (v) [RuCl(DPPB)(PNx)]PF6 NH4C1 ds-RuCl2(DPPB)(PNx) x = 1, 8a x = 2, 8b x = 3, 8c (vii) [RuCl(DPPB)(PNx)]Cl x = 2, 9a x = 3, 9b Figure 4.2 Summary of synthesis of compounds. Reaction conditions: (i) in situ: PN3, CDCI3, 7 d. (ii) 65 °C, 2 d. (iii) PNX, NH4PF6, acetone, 20 h. (iv) PNX, C 6 H 6 , 2 h. (v) A, C 6 H 6 , 2 h. (vi) N H 4 P F 6 , acetone, 1 h.(vii) CDCI3 orCD 2 Cl 2 4.2 Reaction of RuCl2(PPh3)3 with One Equivalent of PN3 The observation of the P.iV.iV'-coordination mode stems from the in situ reaction of RuCl2(PPh3)3 with one equivalent of PN3 (Section 2.6.1). This reaction was undertaken while trying to determine the products of the reaction of RuCl2(PPh3)3 with excess PN3 in C6H.6 (Section 3.2). Figure 4.3 shows the 31P{ !H} NMR spectra of the in situ reaction mixture of one equivalent of RuCl2(PPh3)3 and PN3 in CDCI3. After 24 h, several species were present (Figure 4.3(a)). However, after the solution was at room temperature for 7 d the spectrum simplified to an A 2 X pattern (cis 2 /AX ) and contained a 93 references on page 143 Chapter 4 singlet for free PPI13 (-5.42 ppm) (Figure 4.3(b)). This compound is formulated as [RuCl(PPh3)2(PN3)]Cl 6a for reasons which will become apparent. When the sample was then heated for 2 d at 65 °C, the spectrum changed again, showing two singlets as well as the singlet for free PPI13 (Figure 4.3(c)). This complex is RuCl2(PPh3)(PN3) 13 (type V, Figure 4.1) and is the subject of Chapter 5. When the reaction was repeated on a synthetic scale in CH2CI2 or CHCI3, after one week at room temperature the same A 2 X pattern for 6a was observed in the spectrum of the reaction mixture. However, after isolation, by precipitation with ether or hexanes, the material obtained showed several different peaks in the 3 1P{ 1H} NMR spectrum, leading to the conclusion that 6a is only stable when formed in situ. When the isolated material was refluxed in C6H6,13 was isolated. In order to improve the stability of compounds such as 6a so they could be isolated, two approaches were taken. The first was to do the reaction in the presence of a large anion which would add stability if chloride dissociation was occurring. The reaction of RuCl2(PPh3)3 with one equivalent of PN3 and NH4PF6 in acetone was carried out (Section 4.3). The compound isolated (6c) allowed assignment of the product observed in the in situ reaction as: [RuCl(PPh3)2(PN3)]Cl 6a. The second approach used to increase the stability was to use a different starting material; namely, RuCl2(DPPB)(PPh3), where DPPB is l,4-bis(diphenylphosphino)-butane. The mixed phosphine complex, RuCl2(DPPB)(PPh3),2"4 is very similar to s 7 RuCl2(PPh3)3 in its structure and chemistry. Thus, the chelating DPPB ligand could add stability with formation of a seven-membered ring. The reaction of RuCl2(DPPB)(PPh3) with PNi has been previously investigated by Joshi.2 This work was expanded here to include PN2 and PN3 (Sections 4.4 and 4.5). The next three sections describe the two approaches for isolating complexes with PjA^Af'-coordinated 2-pyridylphosphines. 94 references on page 143 Chapter 4 (a) [RuCl(PPh3)2(PN3)]Cl 6a * c/5-RuCl2(PPh3)(PN3) 13 # J PPh3 JL (b) (c) PPh3 # # PPh3 •a i " • "T—i—i i i—i—i i i—r—;—r-\m>iiitA«i|» i IHHIII^IMWXIIWW • J * 1 T 1 "f r 1 1 r-^ 1 'i 1 i 1 1 1 r Figure 4.3 3 1P{ 1H} NMR (CDC13, 121.4 MHz) spectra for the in situ reaction of RuCl2(PPh3)3 and PN 3 , (a) after 24 h, (b) after 7 d, (c) after heating at 65 °C for 2d. 95 references on page 143 Chapter 4 4.3 Synthesis and Characterization of [RuCI(PPh3)2(PNx)]PF6 (x = 2,3) As mentioned above, one possible reason for the instability of the in situ product formed when one equivalent of RuCl2(PPh3)3 reacts with PN3 was the possibility of chloride dissociation. The reaction of RuCl2(PPh3)3 with one equivalent of PN2 or PN3 was done in acetone in the presence of one equivalent of NH4PF6 (Sections 2.6.2.1 and 2.6.2.2). The products, [RuCl(PPh3)2(PNx)]PF6 (x = 2 (6b), 3 (6c)), were isolated in 45% and 39% yields, respectively. Elemental analysis of the compounds was consistent with the formulations. These reactions do not proceed to give a single complex, and other products remain unidentified (see Sections 2.6.2.1 and 2.6.2.2). The 3 1 P { ! H } NMR spectra in CDCI3 of 6b and 6c are reported in Table 4.1, shown in Figure 4.4, and consist of A 2 X patterns with cis 2 / A X coupling constants. The spectrum of 6c is identical to that seen in the in situ reaction (Section 4.2), hence, 6a was formulated as the chloride salt of 6c. Based on the observed chemical shifts, the high field triplets (Px) are assigned to the PNX ligands. These signals appear at high field because of the formation of four-membered chelate rings (Section 3.2.2), but are further upfield of the signals seen for the P.N-coordinated 2-pyridylphosphine complexes discussed in Chapter 3. The lowfield doublets (PA ) are assigned to the two triphenylphosphines in each complex. The ! H NMR (CDCI3) spectra (Table 4.2) showed multiple peaks in the phenyl region. The PN2 complex showed one H 6 signal (see Appendix A) integrating for two protons, while the PN3 complex showed two H 6 signals integrating in a 1:2 ratio, indicating the complexes contain two equivalent pyridyl groups. 96 references on page 143 Chapter 4 Table 4.1 3 1P{ !H} NMR Chemical Shifts for Neutral and Cationic Ruthenium PNX (x = 1, 2, 3) Complexes Neutral Complexes Solvent Spin System P A P M (ppm) Px 2JAM 2/AX (Hz) 2JMX frans-RuChCDPPBXPNO 7a CDC13 AMX 43.3 25.2 -22.5 36.7 27.1 324 ?ran^-RuCl2(DPPB)(PN2) 7b CDC13 . AMX 42.5 26.5 -20.5 36.1 26.4 321 rra/M-RuCl2(DPPB)(PN3) 7c CDC13 AMX 42.0 26.8 -18.4 36.3 26.3 316 cw-RuCl2(DPPB)(PNi) 8a CDC13 AMX 47.8 36.5 -20.9 34.6 26.3 27.4 ds-RuCl2(DPPB)(PN2) 8b (a) CD 2C1 2 AMX 47.5 37.1 -13.8 34.9 26.2 25.9 CD 2C1 2 AMX 48.9 39.3 -14.3 32.9 (b) 27.6 ds-RuCl2(DPPB)(PN3) 8c CDC13 AMX 49.5 39.4 -7.97 33.8 25.3 26.4 Cationic Complexes P A Px (c)PF6- 2 / A X Ijpp [RuCl(PPh3)2(PN3)]Cl 6a W) CDC13 A 2 X 44.0 -46.7 - 25.5 -[RuCl(PPh3)2(PN2)]PF6 6b CDC13 A 2 X 43.6 -45.6 -144 25.6 713 [RuCl(PPh3)2(PN3)]PF6 6c CDC13 A 2 X 43.9 -46.5 -144 25.5 713 [RuCl(DPPB)(PN2)]Cl (e) CDC13 A 2 X 47.0 -36.6 - 24.6 -CD 2C1 2 A 2 X 47.4 -36.6 - 24.4 CD 3 OD A 2 X 47.2 -35.1 - 24.5 -[RuCl(DPPB)(PN2)]PF6 9a CDC13 A 2 X 46.8 -36.8 -144 24.3 713 [RuCl(DPPB)(PN3)]Cl (0 CDC13 A 2 X 46.7 -41.2 - 23.6 -CD 3OD A 2 X 47.1 -38.7 - 23.9 -[RuCl(DPPB)(PN3)]PF6 9b CDC13 A 2 X 46.7 -40.9 -144 23.9 713 (a) Mixture of two diastereomers. (b) P A and Px signals are broad, coupling not resolved, (c) Septet, (d) In situ, (e) In equilbrium with 8b (CD2C12). (f) In equilbrium with 8c (CDCI3). 97 references on page 143 Table 4.2 *H NMR Chemical Shifts for Ruthenium PN X (x = 1, 2, 3) Complexes Complex Solvent (a)CH2-DPPB (b)Ph & py (c)H6-•py ppm (#ofH) ppm(#ofH) ppm(#ofH) frww-RuCl2(DPPB)(PNi) 7a CDC13 1.72(4) 2.76(2) 3.06(2) 6.46-7.82(34) ?rans-RuCl2(DPPB)(PN2) 7b CDC13 1.77(4) 2.64(1) 2.89(2) 3.14(1) 6.80-7.86(32) 8.50(1) mms-RuCl2(DPPB)(PN3) 7c CDC13 1.82(4) 2.75(2) 3.01(2) 6.65-7.85(30) 8.46(2) cw-RuCl2(DPPB)(PNi) 8a CDC13 0.81(1) 2.25(1) 1.46(1) 2.64(1) 1.83(2) 4.35(1) 2.13(1) 6.70-8.35(33) 8.34(1) cw-RuCl2(DPPB)(PN2) 8b <d> CD 2C1 2 4.08 2.75 2.20 (e) 6.75-8.35 8.05 8.12 m-RuCl2(DPPB)(PN3) 8c (d> CDC13 0.74(1) 2.75(1) 1.67(3) 4.21(1) 2.22(1) 2.34(1) 6.70-8.25(32) [RuCl(PPh3)2(PN2)]PF6 6b CDC13 - - - - 6.82-7.86(41) 8.12(2) [RuCl(PPh3)2(PN3)]PF6 6c CDC13 - - - - 6.79-8.03(39) 8.07(2) 9.02(1) [RuCl(DPPB)(PN2)]Cl CDC13 1.44(2) 1.89(2) 2.41(2) 3.23(2) 6.89-8.02(31) 8.20(2) CD 2C1 2 1.49(2) 1.94(2) 2.45(2) 3.28(2) 6.75-8.35(31) 8.20(2) CD 3OD 1.40(2) 1.86(2) 2.44(2) 3.22(2) 6.86-7.82(31) 8.20(2) continued on next page. Table 4.2 continued.. Complex Solvent (a>CH2-DPPB (b)Ph & py (c>H6-py ppm (#ofH) ppm (#ofH) ppm (# of H) [RuCl(DPPB)(PN2)]PF6 9a CDC13 1.45(2) 1.91(2) 2.41(2) 3.23(2) 6.88-7.77(31) 8.22(2) [RuCl(DPPB)(PN3)]Cl CDC13 1.43(2) 1.91(2) 2.49(2) 3.34(2) 6.70-8.25(29) 8.03(2) 8.82(1) CD 3 OD 1.39(2) 1.86(2) 2.48(2) 3.28(2) 6.93-7.92(29) 8.04(2) 8.83(1) [RuCl(DPPB)(PN3)]PF6 9b CDC13 1.43(2) 1.92(2) 2.47(2) 3.30(2) 6.70-7.95(29) 8.06(2) 8.81(1) (a) Broad signals, coupling not resolved, (b) Several peaks appearing as multiplets. (c) Pseudo-doublets (multiplets), see Appendix A for numbering scheme, (d) Seen as mixture with corresponding cationic species below. The neutral-PN2 complex is a mixture of two diastereomers. (e) Not all signals are observed, presumably due to masking by resonances for methylenes of the corresponding cationic complex. Integrations omitted. Chapter 4 6b PPh3 P.W-coordinated PN 2 111) i [111111111111111111111) 11; 111111111! 111111111111111111111111111II| 80 60 40 20 6 -20 -iO PPM -60 6c P,A/,N'-coordinated PN3 PPh3 3V | i i i i | i i i i i i i i i | i i i i | i i i i | i i i i | i i i i | i i i i | i i i i | i i i i i i i i i | i i i i | i i i i | i i n i bO Bb 40 20 0 -20 -40 PPM -60 Figure 4.4 3*P{lH} NMR (CDCI3, 121.4 MHz) spectra of [RuCl(PPh3)2(PNx)]PF6 (x = 2 (6b), 3 (6c)). (PF^-region not shown). 100 references on page 143 Chapter 4 Two structures (Figure 4.5) can be drawn based on the 3 1P{ 1H} and lU NMR data. In order to differentiate between dimer I and monomer II for 6b and 6c, the X-ray crystal structures of both compounds were determined. Ph,P Ph3PA/,., Ph3PA-X V A1 N Cl n Figure 4.5 Possible structures for 6b and 6c based on the 3 1P{ 1H} and lH NMR spectra. Phosphorus labels correspond to chemical shifts given in Table 4.1. Compound 6b was isolated as single red crystals, while single crystals of 6c were grown by ether diffusion into a CH2CI2 solution of 6c . The ORTEP plots of 6b and 6c are shown in Figure 4.6, and confirm structure II in Figure 4.5. Selected bond lengths are reported in Table 4.3 and bond angles are reported in Tables 4.4 and 4.5. Complete crystallographic data are reported in Appendix C (6b) and D (6 c). Complexes 6b and 6c have the "same" structures. The 2-pyridylphosphine ligands bind to the ruthenium via the phosphorus and nitrogens of two pyridyl groups, forming two four-membered rings. This arrangement causes a distorted octahedral geometry around the metal centre. For example, the Cl(l)-Ru-P(l) angles (151.48(3)° 6b; 151.59(3)° 6c) are less than 180° and the N(l)-Ru-N(2) angles (80.29(3)° 6b; 80.07(7)° 6c) are less than 90°. In terms of bond lengths there is a minimal difference between the two complexes. The Ru-P bond lengths fall within the range typical of ruthenium(II) complexes (2.22-2.45A)8. The Ru-Cl bond lengths, like the Ru-N bonds, are identical 101 references on page 143 Chapter 4 within experimental error between 6b and 6c. Within either 6b or 6c, the Ru-N bond lengths are slightly different, one bond being slightly longer than the other. Thus, the PNX (x = 2, 3) ligands are not bound symmetrically in the solid state. Figure 4.6a ORTEP plot of the cation in [RuCl(PPh3)2(PN2)]PF6 6b (33% probability). Phenyl groups have been eliminated for clarity. 102 references on page 143 Chapter 4 Chapter 4 Table 4.3 Selected Bond Lengths (A) for [RuCl(PPh3)2(PN2)]PF6 6b and [RuCl(PPh3)2(PN3)]PF6 c Bond [RuCl(PPh3)2(PN2)]PF6 6b [RuCl(PPh3)2(PN3)]PF6 6c Ru(l)-Cl(l) 2.4096(8) 2.4066(7) Ru(l)-P(l) 2.2925(8) 2.2854(7) Ru(l)-P(2) 2.3472(8) 2.3478(7) Ru(l)-P(3) 2.3539(8) 2.3452(7) Ru(l)-N(l) 2.161(2) 2.180(2) Ru(l)-N(2) 2.180(2) 2.166(2) P(D-C(D 1.821(3) 1.818(3) P(D-C(6) 1.825(3) 1.825(3) P(l)-C(ll) 1.797(3) 1.814(3) N(l)-C(l) 1.359(4) 1.359(3) N(2)-C(6) 1.361(4) 1.357(3) Table 4.5 contains the four-membered ring bond angles for the P,N,N'-coordinated complexes 6b and 6c, as well as those for the P,Af-coordinated complex [RuCl(PPh3)2(PN3)]PF6 2c (Section 3.4.3). Several trends are apparent. The ring angles for the two rings in any one complex are identical. As well, the ring angles found in complexes 6b and 6c are the same. A comparison of the P,-/V,iV-coordinated complexes versus the P,N -coordinated complex shows the Ru-P-C angle is larger (-2°) in the P,A/,A/'-coordinated complexes. This is compensated for by an equal compression of the P-C-N angle (-2°) in the P,A/,A/'-coordinated complexes versus the P.iV-coordinated complex. The P-C-N angles in 6c are much smaller than those found in the free PN3 ligand where the average angle is 117.2°.9 Therefore, there appears to be slightly more 104 references on page 143 Chapter 4 Table 4.4 Selected Bond Angles (°) for [RuCl(PPh3)2(PN2)]PF6 6b and [RuCl(PPh3)2(PN3)]PF6 6c Angle [RuCl(PPh3)2(PN2)]PF6 6b [RuCl(PPh3)2(PN3)]PF66c Cl(l)-Ru-P(l) 151.48(3) 151.59(3) Cl(l)-Ru-P(2) 95.63(3) 94.16(3) Cl(l)-Ru-P(3) 93.72(3) 96.20(3) Cl(l)-Ru-N(l) 90.71(7) 92.43(6) Cl(l)-Ru-N(2) 92.40(7) 90.75(6) P(l)-Ru-P(2) 103.19(3) 103.16(3) P(l)-Ru-P(3) 103.61(3) 102.47(2) P(l)-Ru-N(l) 67.24(7) 66.95(6) P(l)-Ru-N(2) 67.05(7) 67.35(6) P(2)-Ru-P(3) 100.30(3) 100.46(3) P(2)-Ru-N(l) 167.74(7) 167.81(6) P(2)-Ru-N(2) 88.95(7) 89.59(6) P(3)-Ru-N(l) 89.72(7) 89.00(6) P(3)-Ru-N(2) 168.35(7) 167.30(6) N(l)-Ru-N(2) 80.29(9) 80.07(7) strain in the P-C-N angle in the N'-coordination mode versus the P,./V-coordination mode. The P^iV'-coordination mode also shows strain around the phosphorus atom in the PN 3 ligand in 6c. The two coordinated pyridyl groups are pulled closer towards each other (around the phosphorus) in comparison to the situation in the free ligand (Figure 4.7). This is manifested in the angles between the pyridyl rings. The C(l)-P(l)-C(6) angle (96.6(1)°) is compressed, while the C(6)-P(l)-C(ll) (111.6(1)°) and C(l)-P(l)-105 references on page 143 Chapter 4 C(ll) (110.9(1)°) angles have expanded, compared to an average of 101.9° in the free ligand.9 Although the crystal structure of the PN 2 ligand has not been solved, it is expected that a similar strain exists in the PN 2 complex 6b. Table 4.5 Comparison of the Four-Membered Ring Bond Angles (°) in [RuCl(PPh3)(PN3)2]PF6 2c (Section 3.4.3), [RuCl(PPh3)2(PN2)]PF6 6b, and [RuCl(PPh3)2(PN3)]PF6 6c 2c 6b 6c Ph 3Pi„ > \ N V 1 \ N O 1 l ^ P P h „ P h 3 P * > N P h a P ^ Cl Cl Cl Angle Ring 1 Ring 2 Ring 1 Ring 2 Ring 1 Ring 2 P-Ru-N 67.98(7) 67.92(7) 67.24(7) 67.05(7) 66.95(6) 67.35(6) Ru-P-C 84.9(1) 84.8(1) 86.4(1) 86.86(10) 87.02(9) 86.45(9) P - C - N 102.2(2) 102.0(2) 100.8(2) 100.7(2) 100.8(2) 100.8(2) C-N-Ru 104.8(2) 105.1(2) 105.1(2) 104.9(2) 104.6(2) 104.9(2) The presence of the strain caused by the two pyridyl groups being pulled closer together should lead to reactivity in order to relieve the strain. This was explored and is reported in Section 4.6. Finally, 6 b and 6 c were characterized by UV-visible spectroscopy and conductivity. The UV-visible spectra, shown in Figure 4.8 and reported in Table 4.6, are similar. As expected, both compounds are 1:1 conductors in nitromethane. To close this section, compounds 6b and 6c represent the first isolated and structurally characterized examples of the P,N, N'-coordination mode for 2-pyridylphosphines. 106 references on page 143 Chapter 4 Average angle 101.9° _ 96.6° P. Free Ligand P, N, N' coordinated Figure 4.7 Diagram illustrating the strain around the phosphorus atom of PN3 in 6c. Figure 4.8 UV-visible spectra of [RuCl(PPh3)2(PNx)]PF6 (x = 2 (6b), 3 (6c)) in CH 2C1 2. 107 references on page 143 Table 4.6 Chapter 4 UV-visible and Molar Conductivity Data for Ruthenium PN X (x = 1, 2, 3) Complexes Complex (a)Solvent m^ax £max <b>AM (nm) ( M - W 1 ) (ohm^moHcm2) rran5-RuCl2(DPPB)(PNi) 7a CH 2 C1 2 346 2570 fran5-RuCl2(DPPB)(PN2) 7b CH 2 C1 2 342 2610 *rans-RuCl2(DPPB)(PN3) 7c CH2CI2 336 2710 cw-RuCl2(DPPB)(PNi) 8a CH2CI2 338 2960 66.7 cw-RuCl2(DPPB)(PN2) 8b C H C 1 3 320 4160 69.1 MeOH 320 4970 cw-RuCl2(DPPB)(PN3) 8c C H C 1 3 320 4010 70.2 MeOH 320 4370 [RuCl(DPPB)(PN2)]PF6 9a C H C 1 3 320 5100 79.4 MeOH 320 5050 [RuCl(DPPB)(PN3)]PF6 9b C H C 1 3 320 5050 81.2 MeOH 320 5010 [RuCl(PPh3)2(PN2)]PF6 6b CH2CI2 318(sh)(c) 5390 79.4 410 1710 460(sh) 1160 [RuCl(PPh3)2(PN3)]PF6 6c CH2CI2 410(sh) 1520 78.2 460(sh) 1110 (a) For UV-visible spectra, (b) Measured at ~ 10"3 M in CH 3N02 at 25 °C. All complexes are 1:1 conductors (accepted range: 75-90 ohm-imoHcm2).10 (c) sh = shoulder. 108 references on page 143 Chapter 4 4.4 Synthesis and Characterization of fra/is-RuCl2(DPPB)(PNx) (x = 1,2, 3) The reaction of RuCl2(DPPB)(PPh3) with PN X (x = 1, 2, 3) produced fr-a/2s-RuCl2(DPPB)(PNx) species. These compounds isomerized to produce cis complexes, which with loss of a coordinated chloride formed P,Af,A/'-coordinated 2-pyridylphosphine complexes (Section 4.5). This section describes the synthesis and characterization of the fr-ans-RuCl2(DPPB)(PNx) complexes. When equivalent amounts of RuCl2(DPPB)(PPh3) and PNX (x = 1, 2, 3) were stirred in C6H6 at room temperature for 2 h (Sections 2.6.3.1, 2.6.3.2, and 2.6.3.3), trans-RuCl2(DPPB)(PNx) (x = 1 (7a), 2 (7b), 3 (7c)) complexes were isolated, by precipitation with hexanes, as orange-brown solids in 83 to 93% yields. The complexes were characterized by elemental analysis, 31P{1H} and lH NMR spectroscopy, and UV-visible spectroscopy. The 31P{1H} and NMR data for the three complexes are reported in Tables 4.1 and 4.2, respectively. The 31P{!H} NMR spectra of the complexes consist of AMX patterns with cis and trans coupling constants. The structures, including assignments for the 31P{ if!} NMR signals, are shown in Figure 4.9. Cl Cl 7a , 7c R 7 b S Figure 4.9 Structures of frans-RuCl2(DPPB)(PNx) (x = 1 (7a), 2 (7b), 3 (7c)). Phosphorus labels correspond to chemical shifts given in Table 4.1. 109 references on page 143 Chapter 4 The high field phosphorus signal (Px) is assigned to the PNX ligand, the chemical shift being typical of a P,/V-coordinated 2-pyridylphosphine (for the reasons discussed in Section 3.3.2). The low field signal (PA) is assigned to the DPPB phosphorus trans to the N of the PNX ligand. The DPPB phosphorus trans to the P of the PN X ligand is assigned to the midfield signal ( P M ) -The iH NMR spectra of the three complexes (Table 4.2) contain multiple peaks in the phenyl region, as well as signals in the methylene region for the DPPB backbone. The number of signals seen in the methylene region for the three complexes reflects the planar symmetry. Thus, for the PNi (7a) and PN3 (7c) complexes three signals are seen for the methylenes of the DPPB ligand in a 1:1:2 integration ratio. For the PN2 complex (7b) the planar symmetry of the complex is interrupted because of the chirality of the PN2 ligand when it is P,Af-coordinated. While one pyridyl group is coordinated, the second pyridyl group projects to one side of the plane with the phenyl group projecting to the other. This is seen in the DPPB methylene signals, giving four signals in a 1:2:1:4 integration ratio. Complex 7b is thus isolated as a mixture of enantiomers as shown in Figure 4.9. The distinctive features of the phenyl regions for the three compounds are the H6 signals of the PNX ligands. For the P N i complex 7a, the H6 signal is not observed and is presumably hidden by other resonances. The spectra for 7b and 7c each contain one H6 signal, integrating for one and two protons, respectively. Based on these integrations, and because the H6 signal in 7a is not observed, the resonances are assigned to the uncoordinated pyridyl groups in the complexes. The H6 signals of the coordinated pyridyl groups must be obscured by other signals in the phenyl region and occur upfield from the signals for the uncoordinated pyridyl groups. Finally, the UV-visible spectra of 7a, 7b, and 7c were measured and are shown in Figure 4.10 and reported in Table 4.6. The spectra show an absorbance maximum 110 references on page 143 Chapter 4 decreasing in wavelength and increasing in intensity as the ligand is changed from P N i to P N 3 . 4000 3000-; 0 _ | , , _ , , | T - I 1 300 350 400 450 500 550 600 650 700 Wavelength (nm) Figure 4.10 UV-visible spectra of frons-RuCl2(DPPB)(PNx) (x = 1 (7a), 2 (7b), 3 (7c)) in CH 2C1 2. 4.5 Synthesis and Characterization of cw-RuCl2(DPPB)(PNx) (x = 1, 2, 3) and [RuCl(DPPB)(PNx)]X (x = 2,3 and X = Cl, PF 6) The rra/w-RuCl2(DPPB)(PNx) (x = 1 (7a), 2 (7b), 3 (7c)) complexes isomerize to cw-RuCl2(DPPB)(PNx) (x = 1 (8a), 2 (8b), 3 (8c)) when heated in solution. These cis complexes were isolated as yellow solids (89 to 93% yield) from refluxing C^H^ solutions of the trans precursors (Sections 2.6.4.1, 2.6.4.2, and 2.6.4.3). Elemental analysis revealed that formulations of the three compounds were identical to those of their 111 references on page 143 Chapter 4 their respective precursors. The three complexes were further characterized by 3 1P{1H} NMR and NMR spectroscopy, UV-visible spectroscopy, and conductivity (see below). The neutral cis complexes lose chloride in solution (Figure 4.11), the extent of dissociation being solvent dependent. In the case of the PN2 and PN3 complexes, P,N,N'-coordinated cationic complexes (Figure 4.11(b)) are formed, and these were isolated as their PF6" salts by reaction of 8b or 8c with one equivalent of NH4PF6 in acetone (Sections 2.6.5.1 and 2.6.5.2) which forms [RuCl(DPPB)(PN2)]PF6 9a and [RuCl(DPPB)(PN3)]PF6 9b, respectively. Before discussing the equilibria shown in Figure 4.11 and the characterization of the cis neutral species, complexes 9a and 9b are considered. Cl 8b, 8c Figure 4.11 Dissociation of a chloride in cis-RuCi2(DPPB)(PNx) (x = 1 (8a), 2 (8b), 3 (8c)). Phosphorus labels correspond to chemical shifts reported in Table 4.1. Complexes 8a and 8c are chiral at the metal centre and only the A isomer is shown. Stereoisomers for 8b are shown in Figure 4.15. 112 references on page 143 Chapter 4 Complexes 9a and 9b are DPPB analogues of [RuCl(PPh3)2(PNx)]PF6 (x = 2 (6b), 3 (6c)). The 3 1P{1H} NMR (Table 4.1) spectra are similar to those of 6b and 6c, and consist of A 2 X patterns (cis 2JAX), as well as a septet for the PF6" anion. The *H NMR (Table 4.2) spectra are also similar to the spectra seen for 6b and 6c. From integration of the H6 signals of the 2-pyridylphosphine ligands, versus the methylenes of the DPPB ligand, the two pyridyl groups of 9a are equivalent (coordinated), while 9b contains two equivalent (coordinated) and one inequivalent (uncoordinated) pyridyl group. Four signals, each integrating for two protons, are seen for the eight methylene protons of the DPPB backbone. Based on the similarity of the observed 3 1P{ LH} and LH NMR spectra to the spectra of 6b and 6c, complexes 9a and 9b are assigned structures with the 2-pyridylphosphines coordinated in a P,Af AT-fashion. Finally, 9a and 9b are 1:1 conductors in nitromethane (Table 4.5). Evidence for the equilbria shown in Figure 4.11 and the formulation of 8a, 8b, and 8c as neutral cis complexes comes from 3 1P{ !H} and 1 H NMR data, UV-visible data, and conductivity data. The complexes 8a, 8b, and 8c are considered in order. The 31P{ JH} and if! NMR data are compiled in Tables 4.1 and 4.2, respectively. For the PNi complex 8a, the 3 1P{ 1H} NMR (CDCI3) spectrum (Figure 4.12(a)) consists of an AMX pattern (cis 2 7 A X » 2 ^ A M > 2JMX) which is consistent with the formulation as the neutral cis complex. Furthermore, the methylenes of the DPPB backbone give rise to seven signals in the LH NMR spectrum because of the complex's asymmetry. In the 3 1P{1H} NMR spectrum, the low field signal (PA) of the phosphorus trans to chloride is broad at room temperature. When the sample was heated to 45 °C the signal begins to resolve into a doublet of doublets (Figure 4.12(a)). The broadness in the signals at room temperature is attributed to chloride exchange as shown in Figure 4.11. Further evidence for the chloride exchange comes from conductivity data, which shows the complex is a 1:1 conductor in nitromethane (Table 4.6). 113 references on page 143 Chapter 4 8a (b) J # 8b * [RuCl(DPPB)(PN2)]+ # (P,N,N'-coordinated PN2) (C) 8c * LRuCl(DPPB)(PN3)]+ # (P,N,N'-coordinated PN3) •A* # • ' M i • 1 I 1 I 1 1 1 I .—1 1 I • 1 : I «o so *o 90 20 :o -JO -JO -40 «« Figure 4.12 31P{ lH} NMR ( C D C I 3 , 121.4 MHz, room temperature) spectra of c/s-RuCl2(DPPB)(PNx) (x = 1 (8a), 2 (8b), 3 (8c)) 114 references on page 143 Chapter 4 For the PN2 complex 8b, the 3 1P{1H} NMR (CDCI3) spectrum (Figure 4.12(b)) shows the complex has lost chloride to form the cationic P,N,N' complex. The spectrum is identical to that of 9a (discussed above). Signals for the neutral cis species are not easily observed in the spectrum in CDCI3 (Figure 4.12(b)); however, when the solvent is changed to CD2CI2, which does not support the formation of ions as well as CDCI3, the signals are easily observed. In the spectrum in CD 2 Cl2 (Figure 4.14), the A 2 X pattern of the cationic P,N,N' complex is seen, as well as signals attributable to the neutral cis species. The two AMX patterns (cis 2 / A X . 2JAM, 2JMX) are assigned to the neutral cis complex. Two patterns appear because the complex occurs as a mixture of two diastereomeric pairs (see Figure 4.15) due to the chirality at the metal centre and the chirality arising from the P,N-coordinated PN2. One of the diastereomers exchanges on the NMR-timescale, as two of the signals appear broad (see Figure 4.14). Further evidence for the presence of the cis neutral complex is seen in the UV-visible spectrum. Comparison of the UV-visible spectrum of 8b in CHCI3 with the spectrum of the PF6" salt 9a in CHCI3 (Figure 4.13(a)) suggests 8b is not entirely ionized to the cationic P,N,N' complex. When the solvent is changed to MeOH (i.e., a solvent better able to support ion formation) the UV-visible spectra of 8b and 9a are identical (Figure 4.13(a)). Similar results are obtained with the PN3 analogue 8c (below). Thus, in MeOH 8b ionizes completely to form the cationic P,N,N' complex. For the PN3 complex 8c, the 31P{!H} NMR (CDCI3) spectrum (Figure 4.12(c)) shows both an AMX pattern (cis 2JAX, 2JAM> 2JMX) for the neutral cis complex, and an A 2 X pattern (cis 2 7 A X ) for the cationic P,N,N' complex. The A 2 X pattern is the same as that observed for the PF6- salt 9b. As well, the LR NMR (CDCI3) spectrum contains four methylene signals for the DPPB backbone, attributable to the P,N,N' cationic species (as in 9b) and six methylene signals for the neutral species 8c, similar to those seen for the PNi complex 8a. 115 references on page 143 Chapter 4 (a) PN2 complexes: 6 0 0 0 ' 5000 — 1 1000-300 350 (b) PN3 complexes: 8b CHCI3 9a CHCI3 8b MeOH 9a MeOH 400 450 500 550 Wavelength (nm) 600 1 650 700 6000 5000-V«i 4000-§ 3000-1 w 2000 1000 r 450 500 550 Wavelength (nm) 700 Figure 4.13 UV-visible spectra of complexes 8b, 8c, 9a, and 9b in MeOH and CHCI3. 116 references on page 143 Chapter 4 # Two diastereomer pairs for 8b * • [RuCl(DPPB)(PN2)]+ # (P,N,N -coordinated PN2) J\JJ -1—I—7— c J —I—I—I—I—« !—i—•—I—»—*—f~ -*0 PPM Figure 4.14 31P{*H} NMR (CD2C12, 121.4 MHz) spectrum of cw-RuCl2(DPPB)(PN2) 8b. P v ' . . Ph 'Cl Cl A-R Ph. py k N 'Cl Cl A-S P h ^ P k c r p p Cl A-S py -fix N. cr <0 Cl A-R Figure 4.15 Stereoisomers for ciVRuCl 2(DPPB)(PN 2) 8b. Phosphorus labels correspond to chemical shifts reported in Table 4.1. 117 references on page 143 Chapter 4 Comparison of the UV-visible spectrum of 8c in CHCI3 with the spectrum of 9b in C H C I 3 (Figure 4.13(b)) also shows that the neutral complex, 8c, is in equilibrium with the cationic species. When the solvent is changed to MeOH, 8c completely ionizes to the cationic species as seen by comparison of the UV-visible spectra of 8c and 9b in MeOH (Figure 4.13(b)). Furthermore, the 3 1P{ !H} NMR (CD3OD) spectrum of 8c contains only an A 2 X pattern (cis 2 / A X ) which is that of the cationic P,N,N' complex. If the complex is isolated from the C D 3 O D solution and the spectrum then measured in CDCI3, both the neutral and cationic species are again observed, showing the chloride loss is reversible. The conductivities of 8b and 8c fall within the range for 1:1 conductors (Table 4.6), but both values are lower than those found for their respective PF6~ salts (9a and 9b). The lower conductivity may be caused by the equilbria as shown in Figure 4.11, or may simply reflect different mobilities of the chloride and PF6" anions in nitromethane. To summarize, the complexes 8a, 8b, and 8c all lose chloride in polar solvents, the extent of dissociation being solvent-dependent. For 8b and 8c, loss of chloride results in the formation of P.Af.A/'-coordinated complexes similar to 6b and 6c. The equilbria described above provide some insight into the reasons why the in situ complex [RuCl(PPh3)2(PN3)]Cl 6a could not be isolated (Section 4.2). The ability of the chloride ion to dissociate/associate with the metal centre is one reason 6a could not be isolated. Addition of ether or hexanes (used in attempts to isolate 6a from CHCI3) would cause reassociation of the chloride ion. The product isolated, however, cannot be formulated as a cis neutral species analogous to 8c. The 31P{!H} NMR spectrum was inconsistent with such a formulation. The chelating DPPB ligand in 8c, compared to the two PPI13 ligands in 6a, probably limits the number of sites where the free chloride ion can reassociate. Hence, 8c is stable to chloride dissociation while 6a is unstable and several complexes are isolated. Although 6a itself was not isolated, several complexes 118 references on page 143 Chapter 4 containing P,iV,iV'-coordinated 2-pyridylphosphines have been isolated, and their reactivity with small molecules is described in the next section. 4.6 Reactivity of the P,N,iV'-Coordination Mode Many reactions catalysed by metal complexes involve the activation (i.e., coordination to promote reactivity) of small molecules. Generally, for small molecules (e.g., H 2 , O2, CO, etc.) to coordinate a metal centre, the complex should be coordinatively unsaturated or can become coordinatively unsaturated via dissociation of a ligand. The P.iV.W-coordinated 2-pyridylphosphine complexes described in this chapter have the potential to become coordinatively unsaturated, via dissociation of one of the pyridyl groups, because of the strain observed in this type of coordination (Section 4.3). It was thought these complexes may be particularly suited for the activation of H2. Incorporation of a nitrogenous base (pyridyl group) into a ruthenium bound ligand, could 11 19 promote the heterolytic cleavage of H 2 , ' with the pyridyl group 'binding' the HCI produced on formation of a hydride complex, with subsequent formation of a vacant site for substrate coordination (Figure 4.16). Joshi studied the reaction of ?ra«5-RuCl2(DPPB)(PNi) 7a, under H 2 (latm) in C 6 H 6 at 80 °C for 8 h, with the intent of producing a reaction as shown in Figure 4.16(a).2 However, the trans complex only isomerized to the cis species without formation of a hydride. The P,N,N' complexes were thus reacted with hydrogen in this thesis work to determine if a reaction of the type shown in Figure 4.16(b) could occur. This section describes the results for the reactivity of the P,Af,AT-coordinated 2-pyridylphosphine complexes toward small molecules. These reactivity studies were confined mainly to the PF6" salts to avoid possible complications which could arise from the equilibra observed with the chloride salts. 119 references on page 143 Chapter 4 (a) NH+C1-(b) NH+CT P N P H P = PPh3 or P,P = DPPB Figure 4.16 Possible mechanisms for the heterolytic cleavage of H2 by (a) the P,N-coordination mode and (b) the P,A/,iV'-coordination mode of 2-pyridylphosphines. 4.6.1 Reactivity with H 2 , O 2 , and N 2 Complexes 6b, 6c, 8a, 9b, and 9c were reacted with H2 and O2; as well, 9b was reacted with N 2 , and 8c with H2, all according to the procedure outlined in Section 2.6.6.1. The reactions were followed by 3 1P{1H} and *H NMR spectroscopy. None of the complexes showed reactivity after 24 h under the conditions tested, room temperature and one atmosphere gas pressure, the 3 1P{1H} and A H NMR spectra containing signals for the starting materials only. Thus, the P,A/,A/'-coordination mode is stable towards displacement of a pyridyl group by H2, and O2 under the conditions tested. Although no reactions were seen under these ambient conditions, complexes 6b, 6c, and 8a are capable of activating hydrogen, as judged by the fact that they catalyze the hydrogenation of imines. This is described in the next section. 120 references on page 143 Chapter 4 4.6.2 Catalytic Hydrogenation of Imines using Ruthenium 2-Pyridylphosphine Complexes The hydrogenation of imines has been of interest to our group for several years.13'14 In this respect some of the complexes described in this thesis, including some of the P^W-coordinated 2-pyridylphosphine complexes, have been tested as imine hydrogenation catalysts by Dr. C. Abu-Gnim and Mr. K. S. MacFarlane of this laboratory. The results for the hydrogenation of iV-benzylidenebenzylamine to dibenzylamine are shown in Table 4.7. Experimental details are given in Section 2.6.6.2. The substrate is not hydrogenated in the absence of a catalyst. Table 4.7 Results for the Catalytic Hydrogenation of Af-Benzylidenebenzylamine to Dibenzylamine )^ Catalyst [cat.] [sub.] H 2 time %conver. T.O. x lO"4 (b) (M) (M) (psi) (h) (h-1) 1. [RuCl(PPh3)2(PN2)]PF6 6b 7.50 0.10 500 3 53 23 2. [RuCl(PPh3)2(PN3)]PF66c 7.50 0.10 500 3 26 11 3. cw-RuCl2(DPPB)(PNi) 8a 7.90 0.15 1000 1 31 61 4. c/5-RuCl2(DPPB)(PN2) 8b 7.90 0.15 1000 1 5.4 11 5. [RuCl(PPh3)(PN3)2]Cl 2b 3.75 0.10 500 20 5.0 0.7 6. RuCl2(PPh3)(PN3) 13 3.75 0.10 500 3 5.5 4.9 7. RuCl2(PhCN)(PN3) 15c 3.75 0.10 500 20 5.0 0.7 (a) In MeOH at room temperature; substrate PhCH2NCHPh. (b) Turnover. 121 references on page 143 Chapter 4 Comparisons between all the complexes shown in Table 4.7 are not possible due to the different reaction conditions used. However, some specific comparisons can be made. All the P,A/,A/'-coordinated complexes catalyze hydrogenation of the imine to some extent. Specifically, complexes 6b and 6c, which are structurally analogous (Section 4.3), show different catalytic activity. The hydrogenation using 6b occurs at approximately twice the rate of 6c (entries 1 and 2 in Table 4.7). This difference presumably results from subtle electronic effects imparted on the metal centre by the PN 2 and PN3 ligands in 6b and 6c, respectively. Some electronic effects of these ligands are discussed in Section 4.6.3.4. Another possible comparison can be made between complexes 8a (entry 3) and 8b (entry 4). Using 8a the imine hydrogenation occurs at approximately six times the rate of that using 8b. Both complexes lose chloride in MeOH (Section 4.5); however, 8b forms an P^AT-coordinated 2-pyridylphosphine complex, while 8a presumably forms a species with an unhindered vacant site. This is most likely the reason for the higher activity (i.e., rate of hydrogenation) of 8a; however, different electronic effects between PNi and PN 2 may also be important, as seen above between PN 2 and PN3. The remaining complexes shown in Table 4.7 (entries 5 to 7) show low catalytic activity. Complex 13 (entry 6) and complex 15c (entry 7) have a similar structure with the PN3 ligand coordinated via the three pyridyl nitrogens (see Section 5.5, Figure 5.8). The activity for 13 is approximately seven times that of 15c. Complex 13 is capable of chloride dissociation in methanol (Section 5.3), providing a vacant site for catalysis. This may not be possible for 15c because of the different ancillary ligand (i.e., PhCN in 15c versus PPI13 in 13), which perhaps explains the different activities observed. Finally, one important conclusion relevant to the reactivity of the P,N,N'-coordination mode can be made. The P,A/,A/'-coordinated 2-pyridylphosphine complexes are capable of activating hydrogen (under high H 2 pressures), even though no reaction 122 references on page 143 Chapter 4 with H2 was observed under the ambient conditions descibed in the previous section. Whether this hydrogen activation proceeds via a reaction as discussed at the beginning of Section 4.6 (Figure 4.16(b)) or via another mechanism remains unknown. 4.6.3 Reactivity with CO Figure 4.17 summarizes the reactivity of complexes with CO discussed in this section. All the 3 1P{ iff} NMR and IR data are reported in Table 4.8, and the lH NMR data are reported in Table 4.9. 4.6.3.1 Reactions of [RuCl(PPh3)2(PNx)]PF6 (x = 2 , 3) with CO. Synthesis of [RuCl(CO)(PPh3)2(PNx)]PF6 (x = 2 ,3) [RuCl(PPh3)2(PNx)]PF6 (x = 2, 6b; 3, 6c) undergo rapid reactions with CO. Orange, acetone or CH2CI2 solutions of 6b or 6c turned yellow upon exposure to CO (1 atm). A gas uptake experiment with 6c in CH2CI2 (the method has been described 2 15 elsewhere ' ) under CO (1 atm) showed only one equivalent of CO was consumed in 1 h. Complex 6b was reacted with only one equivalent of CO because of the formation of, presumably, dicarbonyl complexes, which were observed in small amounts in the 31P{!H} NMR (CDCI3) spectrum of 6b under one atmosphere of CO. The substitution of the second CO is believed to displace a PPI13 ligand as the 3 1P{ 1H} NMR spectrum contained free PPh3. Experimental details for isolation of the carbonyl complexes are given in Sections 2.6.6.3 and 2.6.6.4. Elemental analyses of the products were consistent with the following formulations: [RuCl(CO)(PPh3)2(PNx)]PF6 (x = 2,10a; 3,10b). 123 references on page 143 Chapter 4 (i) [RuCl(PPh3)2(PNx)]PF6 ^ [ds-RuCl(CO)(PPh3)2(PNx)]PF6 x = 2 6 b X =HX? x = 3, 6c x = 3> 1 0 b (ii) [RuCl(DPPB)(PNx)]PF6 [RuCl(CO)(DPPB)(PNx)]PF6 x = 2, 9a (i^vC x = 2 0 % cw-lla; 80% *rans-lla x = 3 ' 9 b x = 2 ' 5 0 % c " l l b ® ; 5 0 % c i s l l h ( n ) V x = 3 c/(S~llc m-RuCl2(DPPB)(PN1) ^ Q 8a [RuCl(CO)(DPPB)(PNx)]PF6 x = 2, 50% cis lib (I) 50% cis lib (II) x = 3, ds-llc [RuCl(DPPB)(PNx)]PF6 + [RuCl(CO)(DPPB)(PNx)]PF6 x = 2, 38% 9a x = 2, 50% trans-Ub (I) 12% frans-llb (II) x = 3, 43% 9b x = 3, 57% trans-Uc [RuCl(CO)(DPPB)(PNx)]PF6 ( V ) " [RuCl(CO)(DPPB)(PNx)]PF6 x = 2, 50% cw-llb (I) x = 2, 37% trans-Ub (I) 50% cis-Ub (II) 1 3 % trans-lib (II) x = 3, cw-llc x = 3, 7% trans-Uc Figure 4.17 Summary of syntheses and reactivities of carbonyl compounds. Conditions: (i) CO (1 atm) (1 equiv. for x = 2), CH2CI2 or acetone, 1 h. (ii) CO (1 atm), CH2CI2, 1 h. (iii) N H 4 P F 6 , CO (1 atm), acetone, 21 h. (iv) A, CHCI3, Ar (1 atm), 24 h for x = 3, 16 h for x = 2. (v) CO (1 atm), CH2CI2, 6 d. Percentages reported are relative compositions of isolated products. I and II represent diastereomers. 124 references on page 143 Chapter 4 The 3 1P{1H} NMR spectra (Figure 4.18) of 10a and 10b are consistent with the structures shown (Figure 4.18). Compound 10a is isolated as a racemate, the P of the P N 2 ligand being chiral. The high field signal (Px) is assigned to the P,Af-coordinated PN 2 (Section 3.3.2) ligand and is an overlapping doublet of doublets (apparent triplet). The remainder of the spectrum consists of an AB pattern assigned to the two PPI13 ligands, which are not chemically equivalent because of the chirality of the PN2 ligand. The spectrum is consistent with the complex having trans PPh3 ligands and a mutually cis PN2 ligand. A similar, yet simpler spectrum is seen for 10b. In 10b, the two PPI13 ligands are chemically equivalent and so a simple A 2 X (cis 2 / A X ) pattern was observed. The arrangement of the chloride and CO ligands is assigned based on the observed CO stretching frequencies (IR spectra). The lower CO stretching frequencies observed (Table 4.8) in comparison to those of the complexes [cis-RuCl(CO)(DPPB)(PNx)]PF6 (x = 2, ds-llb; CM-11c), where the CO ligand is trans to phosphrous (Section 4.6.3.2), suggest that the CO ligand in 10a and 10b is trans to the N of the coordinated pyridyl groups. This leaves the chloride trans to the P of the PN X ligands (x = 2, 3) (Figure 4.18). A second species is present in the 3 1P{1H} NMR spectrum of 10a (Figure 4.21). (AMX (ppm): P A = 35.7; P M = 21.7; P x = -34.9; 2JAX = 29.1; 2 / A M = 21.3; 2 7 M X = 313 Hz). This complex is tentatively assigned a structure similar to that of the DPPB complexes described in Section 4.6.3.3, Figure 4.23, with the two PPI13 ligands replacing the DPPB ligand. To conclude this section, one of the coordinated pyridyl groups in the P,N,N'-coordination mode is rapidly displaced by CO, in contrast to the reactions with H2 and O2. It may be that polar molecules (like CO) are needed to displace a coordinated pyridyl group or, more likely, the it-acceptor ability of the CO ligand stabilizes the P,N-coordinated products. This remains to be proven. Analogous reactions with the DPPB complexes 6b and 6c were also investgated and are described in the next section. 125 references on page 143 Chapter 4 10a P A & P B 1 Px 1 <n» i>^wi|«nxmitwAi»iMi» \mv< 10b P A oc Cl different isomer (see text): * Ml 1 + P A / , OC' J Cl Px niftE» J l i U l i M Ii ilium* II iHKtomA'fc » * N * * * * * * * * i i i i i i i I 1111 | i i i i | i 1 1 i | i 1 1 1 1 1 i i i | i 11 i 11 i i i | 11 i i ) T TJ 0 PPM Figure 4.18 3 1P{!H} NMR (CDCI3, 121.4 MHz) of [RuCl(CO)(PPh3)2(PNx)]PF6 (x = 2 (10a), 3 (10b)). Phosphorus labels correspond to those reported in Table 4.8. (PF6~region not shown). 126 references on page 143 Chapter 4 Table 4.8 3 1P{!H} NMR (CDCI3) Chemical Shifts and Carbonyl Stretching Frequencies for Ruthenium PNX (x = 1, 2, 3) Carbonyl Complexes (a) Complex Spin System P A P M ( P B ) (ppm) Px 2 / A X 2JAM ( 2 ^ A B ) (Hz) 2 7 M X ( 2 J B X ) v C O ( b ) (cm-1) [ds-RuCl(CO)(PPh3)2(PNx)]PF6 x = 2, 10a ABX 36.9 33.9 -14.4 21.2 296 20.0 1953 x = 3,10b A 2 X 35.9 - -16.2 20.8 - - 1961 [cw-RuCl(CO)(DPPB)(PNx)]X x= 1;X = C1 AMX 36.9 18.6 -17.2 21.8 33.1 26.4 -x= 1;X = PF 6 AMX 36.4 18.7 -17.8 20.9 33.3 26.0 2004 cis-Ua (c) x = 2;X = PF 6 (I) AMX 39.7 18.1 -14.5 21.1 33.4 27.1 2007 cis-Ub (d) (H) AMX 33.5 23.0 -7.39 24.1 33.3 24.0 2018 x = 3; X = PF 6 AMX 32.6 21.7 -6.03 22.5 33.2 25.3 2021 cis-Uc [*rans-RuCl(CO)(DPPB)(PNx)]X x= 1;X = C1 AMX 36.4 20.3 -30.4 20.3 28.5 298 -x= 1;X = PF 6 AMX 36.4 20.1 -30.6 20.3 28.9 298 1961 trans-Ua. x = 2;X = PF 6 (I) AMX 37.7 23.9 -24.3 23.0 29.0 298 1969 trans-lib (e) (H) AMX 33.4 23.7 -28.0 21.6 28.8 291 -x = 3; X = PF 6 AMX 33.9 25.4 -22.7 22.0 28.8 288 1973 trans- 11c (a) Room temperature; C D C I 3 ; PF6": -144 ppm (septet), lJPF = 713 Hz. (b) Nujol mull / KBr plates. Where CO stretches are not reported, they were either not measured or unobserved, (c) 11a isolated as mixture of cis and trans isomers, (d) lib is a 50/50 mixture of two diastereomers, labelled I and II. (e) Produced from isomerization cis-Ub (I and II), respectively. 127 references on page 143 Table 4.9 ! H NMR Chemical Shifts for Ruthenium PNX (x = 1, 2, 3) Carbonyl Complexes (a> Complex CH2-DPPB(t>) Ph&py(c) H6-py (d> ppm (#ofH) ppm (#ofH) ppm (# of H) [m-RuCl(CO)(PPh3)2(PNx)]PF6 x = 2,10a - - - - 6.45-8.02(42) 8.05(1) x = 3,10b - - - - 6.30-8.00(40) 8.20(2) [cw-RuCl(CO)(DPPB)(PNx)]PF6 x = 1, d s - l l a ( e ) 0.90(1) 1.25-2.55(6) 2.87(1) 6.80-8.12(34) (g) 4.20(1) x = 2, cis-Ub (0 (I) 0.80(1) 1.50-2.55(5) 3.07(1) 6.70-8.10(32) 8.25(1) 4.17(1) (It) 0.95(1) 1.50-2.55(6) 4.40(1) 6.20-8.10(32) 8.75(1) x = 3,d.y-llc 1.96(1) 1.73(1) 1.37(1) 0.87(1) 6.73-7.87(30) 8.15(1) 8.73(1) 2.25(1) 2.45(1) 2.71(1) 4.25(1) Table 4.9 continued.. Complex (b)CH2-DPPB (c>Ph&py (d)H6-py ppm (# of H) ppm(#ofH) ppm (# ofH) [*rans-RuCl(CO)(DPPB)(PNx)]PF6 x = l,trans-Ua 1.40(1) 1.60(1) 2.09(1) 2.35(3) 6.80-8.15(34) (g) 3.17(1) 3.92(1) x = 2, trans-Ub (h) (I) 1.30-2.55(6) 3.47(1) 3.79(1) 6.35-8.050 8.82(1) (IT) 1.30-2.55(7) 3.47(1) 6.65-8.050 8.46(1) •x = 3, trans-Uc 1.20-2.60(6) 3.30(1) 3.70(1) 6.39-7.92(30) 8.42(1) 8.62(1) (a) Room temperature, CDCI3. (b) Broad signals, coupling not resolved, (c) Several peaks appearing as multiplets. (d) Pseudo-doublets (multiplets); see Appendix A for numbering scheme, (e) 11a isolated as mixture of cis and trans isomers, (f) l i b is a 50/50 mixture of two diastereomers, labelled I and n, corresponding to labels in Table 4.8. (g) Not observed, obscured by other resonances in phenyl region, (h) Produced from isomerization of cis- l ib (I) and (II), respectively. Chapter 4 4.6.3.2 Reactions of [RuCI(DPPB)(PNx)]PF6 (x = 2, 3) with CO. Preparation of [cw-RuCl(CO)(DPPB)(PNx)]PF6 (x = 1,2,3) The DPPB analogues of 6b and 6c, namely [RuCl(DPPB)(PNx)]PF6 (x = 2, 9a; 3, 9b), also react with CO (1 atm). The compounds isolated (Section 2.6.6.5) namely, [cis-RuCl(CO)(DPPB)(PN2)]PF60.5Et2O, cis-Ub (cis referring to the CO and Cl), and [cis-RuCl(CO)(DPPB)-(PN3)]PF6-0.25Et2O, cis-llc, were characterized by elemental analysis, IR spectroscopy, and 3 1 P { 1 H } NMR (Figure 4.19a) and lH NMR spectroscopy (Figure 4.19b). Both complexes were isolated with ether solvates, the amount being determined by integration of the *H NMR spectra. An attempt to remove the Et 2 0 solvate from cis-Ub by heating the complex under vacuum (78 °C, for 4 d) caused a 5% conversion back to the starting material, 9a. Thus, CO loss can occur in the solid state, although slowly. The reversibility of these CO reactions is discussed in the next section. The structures of cis-Ub and cis-llc are assigned based on the observed spectroscopic data. The 3 1 P { 1 H } NMR spectra are consistent with all cis phosphorus atoms, as well as a P,Af-coordinated PNX ligand (Section 3.2.2). The Px signals are assigned to the PNX (x = 2, 3) ligands, while the P A and P M signals (Table 4.8) are assigned to the DPPB ligand. The lH NMR spectra confirm the asymmetry of the complexes because of the number of signals seen for the DPPB methylenes (e.g. eight signals for the eight methylene protons in ris-11c). For both complexes, the CO and Cl are mutually cis, and the relative positions with respect to the other ligands can be assigned. Jessop et al. have determined an inverse relation between ruthenium triphenylphosphine bond lengths and phosphorus chemical shifts: as chemical shifts Q decrease (in ppm) RU-PPI13 bond lengths increase, and this correlation has been extended to DPPB by MacFarlane.16 Another factor affecting bond lengths is the trans 130 references on page 143 Chapter 4 Figure 4.19a 31p{lH} NMR (CDCI3, 121.4 MHz) spectra of [c«-RuCl(CO)(DPPB)-(PN2)]PF60.5Et20, cw-llb, and [cw-RuCl(CO)(DPPB)(PN3)]PF60.25-Et20, cis-llc. (PF6~region not shown). 131 references on page 143 Chapter 4 cw-llb(I) * Et20 solvate # # i i i i i | • i i i : i i i i | 1C 8 I I I I I I I i I i i i i | i i i i ; i i i i j i i i , | . i i : j : ! i 1 6 + 2 0 F r ' . t Figure 4.19b *H NMR ( C D C I 3 , 300 MHz) spectra of [c/s-RuCl(CO)(DPPB)-(PN2)]PF60.5Et2O, cis-Ub, and [ds-RuCl(CO)(DPPB)(PN3)]PF60.25-Et 20, as-11c. 132 references on page 143 Chapter 4 17 influence of a ligand (the ability of a ligand to weaken a bond trans to itself). Thus, by considering the trans influence of Cl and CO, and their effects on Ru-P bond lengths, as well as the differences between the phosphorus chemical shifts observed for the carbonyl complexes and the neutral chloro complexes 8a-c (Section 4.5), the relative positions of the CO and Cl can be determined. The two possible structures for the carbonyl compounds are shown in Figure 4.20 (labelled A and B), along with the structure for the analogous chloro complexes (Section 4.5). As an example, the phosphorus chemical shifts for cis-llc and 8c are given, as well as the absolute differences in the chemical shifts between the two compounds. If the CO is trans to the P of the D P P B ligand (Figure 4.20 structure A), the Ru-P bond length is expected to be longer (trans influence of Cl versus CO) in the carbonyl complex than in the neutral chloro complex. Therefore, the P A signal in the neutral, trans complex should shift upfield in the carbonyl complex, with the other signals remaining relatively unchanged (or shifting by small amounts) because they are trans to identical ligands in both complexes. This is in fact observed, the P A signal in 8c shifts upfield by 27.8 ppm in cis-llc. The other signals shift by 6.80 (PM) and 1.94 ppm (Px) . Thus, the CO is almost certainly trans to the D P P B , and the structures for the various isomers are shown in Figure 4.21, along with assignments for chemical shifts given in Table 4.8. This analysis depends on the correct assignment of the D P P B chemical shifts in cis-Uc. However, if the assignments are reversed the argument still holds, because there is a large upfield shift in both the P A and P M signals going from 8c to cis-llc. Furthermore, if the CO were trans to the P of the PN3 ligand (Figure 4.20, structure B), a larger difference in the chemical shifts of the P x signals would be expected. This example applies to the PN3 carbonyl complex cis-llc, but the same holds true for the analogous P N 2 and P N i complexes (described below). 133 references on page 143 Chapter 4 49.5 ppm -7.97 ppm / A 1.94 ppm -6.03 ppm / A 27.8 ppm — 21.7 ppm O / + N CO + 'Cl Cl A c O B 39.4 ppm A 6.8 ppm 32.6 ppm Figure 4.20 Possible structures for [ds-RuCl(CO)(DPPB)(PNx)]PF6 (x = 2, cis-Ub; 3, cis-Uc) and the structure of the cis, neutral, chloro complexes 8a-c. Chemical shifts given are for the PN3 complexes, cis-Uc and 8c. As with other P,./V-coordinated PN 2 complexes, cis-Ub is isolated as a mixture (50/50) of two diastereomers, labelled cis-Ub (I) and cis-Ub (II) in Tables 4.8 and 4.9. These labels are assigned arbitrarily in terms of the diastereomers shown in Figure 4.21. The CO stretches and lH NMR data were correlated with the 3 1P{ ^ NMR data, based on the isomerizations described below, allowing the assignment of NMR signals and CO stretches to specific diastereomers. In order to complete the 2-pyridylphosphine ligand series of cis carbonyl complexes described above, the reaction of a's-RuCr2(DPPB)(PNi) 8a with CO (1 atm) and one equivalent of NH4PF6 was undertaken (Section 2,6.6.6). The product isolated was a mixture of 20% cis and 80% trans [RuCl(CO)(DPPB)(PNi)]PF6 11a (see Section 4.6.3.3 for trans structure), confirmed by elemental analysis. Relative amounts of cis and trans isomers were assigned based on integration of the lH NMR spectrum. The 3 1P{ lH] NMR spectrum is shown in Figure 4.22(a). 134 references on page 143 Chapter 4 Cl Cl A-S A-R cis-Ub (I), cis-Ub (II) Figure 4.21 Structures of [cw-RuCl(CO)(DPPB)(PNx)]PF6 (x = 1, cis-Ua, 2, cis lib, 3, cis-Uc). Phosphorus labels correspond to the chemical shifts reported in Table 4.8 The in situ CDCI3 reaction of 8a under CO (1 atm) but without NH4PF6 was followed by ^ Pf1!!} NMR spectroscopy. Cis and trans complexes analogous to 11a were observed; however, several other reactions occurred, as evidenced by the presence of other peaks in the 3 1 P {lH} NMR spectrum, including peaks for free DPPB (-16.2 ppm) and PNi (-3.95 ppm). This reaction was not investigated further. The isolated mixture of cis/trans 11a was converted to the trans isomer by heating a CDCI3, NMR sample of the mixture in an oil-bath at 50 °C for 24 h. The spectrum, 135 references on page 143 Chapter 4 shown in Figure 4.22(b), shows some decomposition occurred as some new peaks were observed, including a peak for free DPPB (-16.2 ppm). The structure of cis-Ua is analogous to the structure of cis-llc (Figure 4.21), while trans-lla is analogous to trans-llc (Figure 4.23, C or D). The carbonyl IR stretches were assigned based on the relative intensities after correlation with the amount of cis and trans observed in the and 31P{1H} NMR spectra. The isolation of 11a as a mixture of both cis and trans prompted the investigation of whether the PN 2 and PN3 complexes cis-Ub and cis-llc, respectively, could be isomerized to trans complexes (Section 4.6.3.3). In summary, the P,N,N '-coordinated 2-pyridylphosphine complexes undergo reactions with CO, with the displacement of only one coordinated pyridyl group, to form P,/V-coordinated complexes. No evidence was found for the displacement of the second pyridyl group, suggesting that the P,iV-coordination mode is stable to displacement by CO. Thus, the P.N-coordination mode appears to be stable to displacement. The reason may be that ruthenium(II) is incapable of supporting three phosphine and two CO K-acceptor ligands; this has been noted for RuCl2(CO)2(PNi), where CO is incapable of displacing the pyridyl group of the P,iV-coordinated PNi complex.18 136 references on page 143 Chapter 4 (a) * cis-lla • trans-lla * | I ) I I I I I I I | I I I I I I I I I | I I I I I I I I I | I I I I I I I I I | I I I I I I I I I | 40 20 0 - 2 0 - 4 0 PPM Figure 4.22 31p{lH} NMR (CDC13, 121.4 MHz) spectra of (a) isolated [cis/trans-RuCl(CO)(DPPB)(PNi)]PF6 11a, and (b) after heating at 50 °C,24 h. (PF6~region not shown). 137 references on page 143 Chapter 4 4.6.3.3 Isomerization of [cw-RuCl(CO)(DPPB)(PNx)]PF6 (x = 2, 3) and Reversibility of the CO Reactions The carbonyl complexes cis-Ub and cis-llc isomerize in solution. These isomerizations were performed under two sets of conditions: first, in refluxing C H C I 3 under Ar (1 atm) (Section 2.6.6.7) arid second, at room temperature in C H 2 C I 2 under CO (1 atm) (Section 2.6.6.8). After certain times, the products were isolated by removing the solvent under vacuum, and were then analysed by 3 1P{ 1H} NMR, *H NMR, and IR spectroscopies. Relative amounts of compounds were determined by integration of the H 6 proton signals (see Appendix A) of the 2-pyridylphosphine ligands. Under the first set of conditions the complexes cis-Ub and cis-Uc undergo isomerization, but also revert back to starting materials, 9a and 9b, respectively. Hence, in the second set of experiments the isomerizations were done under an atmosphere of CO. Before the results of these experiments are considered, the structures of the isomerization products are discussed. The possible structures for the isomerization products are shown in Figure 4.23, labelled C and D. Both structures are possible based on the observed spectroscopic evidence for the experiments discussed below. The 3 lP{!H} NMR data are consistent with P,iV-coordinated 2-pyridylphosphine ligands (Px)> with cis and trans phosphorus nuclei of the DPPB ligand (PA and P M respectively). The CO stretching frequencies observed are lower than those seen for the corresponding cis complexes (Section 4.6.3.2), which is consistent with the CO being trans to either Cl or N, versus P in the cis complexes. It is not possible to differentiate between the two possible structures shown in Figure 4.23. With the cis complexes (Section 4.6.3.2), the relative positions of the DPPB and the P,A/-chelate were fixed, leaving only the assignment of the Cl and CO positions. With the isomerization products, the relative positions of the DPPB ligand and only the P of the P,A/-chelate are known, leaving three positions which need to be assigned. Thus, 138 references on page 143 Chapter 4 no definite assignment for the structures of the isomerization products are made. However, for convenience they are referred to as trans isomers, the trans referring to the trans phosphorus atoms in both structures, and to differentiate the products from the cis complexes discussed in the previous section. Figure 4.23 Possible structures for [mm?-RuCl(CO)(DPPB)(PNx)]PF6 (x = 1, trans-itu; x = 2, trans - l i b ; x = 3 trans-llc). Phosphorus labels correspond to those reported in Table 4.8. Isomerization to trans, as well as loss of CO, according to the reactions shown in Figure 4.17, occurred when cis-Ub or cis-llc were refluxed in CHCI3. The 3 1P{ lH} NMR spectra for the products isolated from these reactions are shown in Figure 4.24. These spectra contain peaks assigned to the trans complexes as well as peaks for the starting materials, 9a or 9b. Correlation of the observed intensities in the 31P{!H} NMR spectra with the intensities in the *H NMR and IR spectra, from these experiments, as well as from the room temperature experiments (described below), allowed for the assignment of the CO stretching frequencies as well as the ! H NMR data. For cis-llc, the isomerization to trans-llc also occurs at room temperature, but slowly. After 6 days at room temperature in C H 2 C I 2 and under CO (1 atm), approximately 7% of the cis complex is converted to trans, based on integration of the *H NMR spectrum of the isolated product. The NMR spectrum of this sample was measured again after 14 days (total time 20 days). At this point, the conversion to trans was only C O Cl c D 139 references on page 143 Chapter 4 (a) trans-lib (I) * trans-1 lb (II) # 9a * (b) frans-llc * 9b * V 11111111111111111111111111111111111111111111) 111111 40 20 0 - 2 0 - 4 0 PPM Figure 4.24 3lp{lH} NMR (CDCI3, 121.4 MHz) spectra after refluxing [cis-RuCl(CO)(DPPB)(PNx)]PF6 ((a) x = 2, c/s-llb; (b) x = 3, ci$-llc) in CHCI3 under Ar, (x = 2,16 h; x = 3, 24 h). (PF6~region not shown). 140 references on page 143 Chapter 4 12%. This room temprature conversion was not followed further. It should be noted that no loss of CO from the sample was detected (i.e., 31P{ lH} NMR signals for 9b were not observed). For the PN 2 complex cis-Ub, a similar isomerization occurred over 6 days. In this case, the two diastereomers of l i b (i.e., cis-Ub (I) and cis-Ub (II)) isomerized at different rates allowing for correlation of the carbonyl stretching frequencies and the 1 H NMR signals with the 3 1P{ 1H} NMR data, as well as allowing for the correlation of which cis diastereomer produced which trans diastereomer. The relative amounts of the different diastereomers are given in Figure 4.17. Again, the isomerization was slow at room temperature and was not followed further. An important question which arises from these isomerization/CO loss experiments is whether the CO loss occurs from the cis complexes, the trans complexes, or both. It is possible that the trans complexes act as 'thermodynamic sinks' from which CO cannot be lost. Thus, a competition would exist between CO loss from the cis complexes and isomerization to the trans complexes. Further experimentation is required. 4.6.3.4 7U-Acceptor Abilities of the PN X (x =1, 2, 3) Ligands Increased incorporation of the electron-withdrawing 2-pyridyl groups,19 in the PNX (x = 1, 2, 3) ligands, decreases the a-donating ability of the PNX ligands in the order: x = 1, x = 2 , x = 3. By the same token, the Tt-acceptor ability should be enhanced in the same order. This order of rc-acceptor ability is confirmed by the observed carbonyl stretches seen for the cis and trans carbonyl complexes (11a, l ib, and 11c) described in the previous two sections. The carbonyl stretches (Table 4.8) increase in energy in the following order: 11a (PNi) < l ib (PN2) < 11c (PN3). The enhanced 7t-acceptor ability as the ligand is changed from PNi to PN3 increases the competition for back donation from the metal centre, which manifests itself in the strengthening of the CO bond (i.e., less donation into the K* of the CO) and an increase in the CO stretching frequency. Thus, the 141 references on page 143 Chapter 4 observed experimental trend confirms the predicted trend for the -^acceptor ability of the PN X ligands. This order of 7t-acceptor abitity is also consistent with the order established for PPh3 and PNi (i.e., PNi is a better K acceptor than PPh3), determined from the carbonyl stretching frequencies in Ni(CO)2(PPh3)2 and Ni(CO)2(PNi)2. 4.7 Conclusions Several complexes were synthesized containing the previously uncharacterized P.A^W-coordination mode for 2-pyridylphosphine ligands. The P,N,N'-coordination mode is highly strained, based on the observed angles in the crystal structure of [RuCl(PPh3)2(PN3)]PF6, and leads to reactivity to relieve the strain. In comparison to the P.N-coordination mode the P.iV.W-coordination mode is much more reactive. The P^W-coordinated 2-pyridylphosphine complexes are capable of hydrogen activation in the hydrogenation of imines under high pressure. As well, these complexes undergo reversible reactions with Cl" and CO, which displace a coordinated pyridyl group. Finally, the carbonyl compounds characterized allow for a relative order of -^acceptor ability to be established for the 2-pyridylphosphine ligands. 142 references on page 143 Chapter 4 4.8 References (1) Boggess, R. K.; Zatko, D. A. J. Coord. Chem. 1975,4, 217. (2) Joshi, A. M. Ph. D. Thesis, The University of British Columbia, 1990. (3) Joshi, A. M.; Thorburn, I. S.; Rettig, S. J.; James, B. R. Inorg. Chim. Acta 1992, 198, 283. (4) Jung, C. W.; Garrou, P. E.; Hoffman, P. R.; Caulton, K. G. Inorg. Chem. 1984, 23, 726. (5) Stephenson, T. A.; Wilkinson, G. J. Inorg. Nucl. Chem. 1966, 28, 945. (6) Hallman, P. S.; Stephenson, T. A.; Wilkinson, G. Inorg. Synth. 1970,12, 237. (7) Hoffman, P. R.; Caulton, K. G. J. Am. Chem. Soc. 1975, 97, 4221. (8) Jessop, P. G.; Rettig, S. J.; Lee, C.-L.; James, B. R. Inorg. Chem. 1991, 30, 4617. (9) Keene, F. R.; Snow, M. R.; Tiekink, E. R. T. Acta Crystallogr., Sect. C 1988, 44, 757. (10) Geary, W. J. Coord. Chem. Rev. 1971, 7, 81. (11) James, B. R. In Comprehensive Organometallic Chemistry, ; G. Wilkinson, F. G. A. Stone and E. W. Abel, Ed.; Pergamon Press: Oxford, 1982; Vol. 8; p 285. (12) James, B. R. Homogeneous Hydrogenation; Wiley: New York, 1973. (13) Fogg, D. Ph. D. Thesis, The University of British Columbia, 1994. (14) James, B. R. Chem. Ind. 1995, 62, 167. (15) James, B. R.; Mahajan, D. Isr. J. Chem. 1977,15, 214. (16) MacFarlane, K. S. Ph.D. Thesis, University of British Columbia, 1995. (17) Huheey, J. E. Inorganic Chemistry; 3rd ed.; Harper & Row: New York, 1983, p 542. (18) Olmstead, M. M.; Maisonnat, A.; Farr, J. P.; Balch, A. L. Inorg. Chem. 1981, 20, 4060. (19) Perrin, D. D.; Dempsey, B.; Serjeant, E. P. pKaPrediction for Organic Acids and Bases; Chapman and Hall: London, 1981, p 119. 143 Chapter (20) Baird, I. R.; Smith, M. B.; James, B. R. Inorg. Chim. Acta. 1995,235, 291. 144 CHAPTER 5 A',A7',A/''-Tris(2-pyridyI)phosphine Complexes 5.1 Introduction The A^A^AT'-coordination mode of tris(2-pyridyl)phosphine (see V in Figure 1.4) has been observed with a variety of transition metals. Al l , except one, are cationic sandwich complexes containing two N,N',N"-PN2 ligands and are of the general formula [M(PN3)2]2+, (M = Mn, Co, Ni, Cu, Zn, Ru).1"3 The X-ray crystal structures of the zinc 2 and the ruthenium3 complexes have been determined and confirm the N,N',N"-coordination mode. Rarer is the half-sandwich complex containing only one N,N',N"-PN3 ligand, the only example (prior to this work) being Zn(PN3)(N03)2- In this case, the complex is neutral and contains both a monodentate and a bidentate nitrate ligand. Thus, the N,N',N"-coordination mode has generally been observed in sandwich complexes of the first-row transition metals. This chapter reports on the synthesis and reactivity of the half-sandwich complex RuCl2(PPh3)(PN3) 13. This complex was first observed in the in situ reaction of RuCl2(PPh3)3 with one equivalent of PN3 (Section 4.2). A convenient synthesis and the characterization of 13 are described (Section 5.2). One of the chlorides in 13 is labile (Section 5.3), and this led to the investigation of some chloride-substitution reactions (Section 5.4). Alternatively, the triphenylphosphine ligand in 13 can be replaced (Section 5.5). Thus a variety of A^A^Af'-halfsandwich complexes has been synthesized. Also, the reactions of 13 with O2 and H2 are discussed (Sections 5.7 and 5.8). 5.2 Synthesis and Characterization of RuCl2(PPh3)(PN3) The synthesis and reactivity, described in Sections 5.2 to 5.5, of the title compound are shown in Figure 5.1. 145 references on page 179 Chapter 5 (i) RuCl2(PPh3)3 + PN 3 ^ • RuCl2(PPh3)(PN3) 2 P P h 3 (ii) NaCl [RuCl(MeOH)(PPh3)(PN3)]BPh4 RuCl2(PPh3)(PN3) + MeOH^^T[RuCl(MeOH)(PPh3)(PN3)]+ + CF 13 (iii) RuCl2(PPh3)(PN3) + L + NH 4 PF 6 <" " [RuCl(L)(PPh3)(PN3)]PF6 1 3 j n L = C0,14a NH4C1 L = MeCN, 14b L = PhCN, 14c RuCl2(PPh3)(PN3) + x s L v / 1 V ) » RuCl2(L)(PN3) 13 1 L = CO, 15a PPh3 L = MeCN, 15b L = PhCN, 15c Figure 5.1 Synthesis of compounds described in Sections 5.2 to 5.5. Conditions: (i) A, C 6 H 6 , 7 h; (ii) NaBPh4, MeOH, 1 h; (iii) MeOH, 65 °C; L = CO, 2 h; L = MeCN, 10 min; L = PhCN, 15 min; (iv) A, C 6 H 6 ; L = CO, 42 h; L = MeCN, 17 h; L = PhCN, 4 h & 16 h at room temperature. The reaction of RuCl2(PPh3)3 with one equivalent of PN3 in CDCI3, produced [RuCl(PPh3)2(PN3)]Cl 6a (Section 4.2). When this complex was heated, 6a lost one equivalent of PPh3 to form a new complex, 13. This section describes the synthesis and characterization of this new complex. Refluxing one equivalent of RuCl2(PPh3)3 and PN3 in C6H6 for 7 h produced a red precipitate (Section 2.7.1). The product isolated was RuCl2(PPh3)(PN3), 13, and the elemental analysis was consistent with this formulation. The 3 1P{ 1H} NMR (CDCI3) spectrum of this complex was identical to the that observed by heating a solution of 6a (Section 4.2, Figure 4.3(c)). 146 references on page 179 Chapter 5 Single crystals for an X-ray structure determination of 13 were grown by Et20 diffusion into a CH2CI2 solution of the complex. The crystals contained two CH2CI2 solvates. Selected bond lengths and bond angles are given in Tables 5.1 and 5.2, respectively, while the ORTEP plot of RuCl2(PPh3)(PN3), 13, is shown in Figure 5.2. Complete crystallographic data are reported in Appendix E. Table 5.1 Selected Bond Lengths (A) for RuCl2(PPh 3)(PN 3) 13, and [Ru(PN3)2][C7H7S03]23 RuCl2(PPh3)(PN3) [Ru(PN3)2] [C7H7S03]2 Bond Bond Ru(l)-N(l) 2.075(4) Ru(l)-N(l) 2.06(1) Ru(l)-N(2) 2.090(4) Ru(l)-N(2) 2.06(1) Ru(l)-N(3) 2.117(4) Ru(l)-N(3) 2.08(1) Ru(l)-Cl(l) 2.438(1) Ru(l)-N(4) 2.08(1) Ru(l)-Cl(2) 2.438(1) Ru(l)-N(5) 2.06(1) Ru(l)-P(2) . 2.350(1) Ru(l)-N(6) 2.09(1) P(l)-C(l) 1.829(5) P(1)-C(1),P(2)-C(16) 1.81(2), 1.85(2) P(l)-C(6) 1.827(5) P(l)-C(6), P(2)-C(21) 1.84(2), 1.83(2) P(l)-C(ll) 1.829(5) P(l)-C(ll), P(2)-C(26) 1.81(2), 1.80(2) C(l)-N(l) 1.357(5) C(l)-N(l), C(16)-N(4) 1.32(2), 1.33(2) C(6)-N(2) 1.356(6) C(6)-N(2),C(21)-N(5) 1.33(2), 1.36(2) C(ll)-N(3) 1.354(6) C(ll)-N(3), C(26)-N(6) 1.37(2), 1.37(2) 147 references on page 179 Table 5.2 Selected Bond Angles (°) for RuCl2(PPh3)(PN3) 13 Chapter 5 Angle Angle Cl(l)-Ru(l)-Cl(2) 89.84(5) P(2)-Ru(l)-N(l) 92.1(1) Cl(l)-Ru(l)-P(2) 91.54(5) P(2)-Ru(l)-N(2) 92.6(1) Cl(l)-Ru(l)-N(l) 174.4(1) P(2)-Ru(l)-N(3) 178.6(1) Cl(l)-Ru(l)-N(2) 89.1(1) N(l)-Ru(l)-N(2) 94.9(1) Cl(l)-Ru(l)-N(3) 88.9(1) N(l)-Ru(l)-N(3) 87.6(1) Cl(2)-Ru(l)-P(2) 96.37(5) N(2)-Ru(l)-N(3) 86.2(2) Cl(2)-Ru(l)-N(l) 85.6(1) C(l)-P(l)-C(6) 104.2(2) Cl(2)-Ru(l)-N(2) 171.0(1) C(l)-P(l)-C(ll) 98.8(2) Cl(2)-Ru(l)-N(3) 84.9(1) C(6)-P(l)-C(ll) 98.8(2) Ru(l)-N(l)-C(l) 122.9(3) P(l)-C(l)-N(l) 120.1(3) Ru(l)-N(2)-C(6) 121.6(3) P(l)-C(6)-N(2) 121.0(4) Ru(l)-N(3)-C(ll) 121.6(3) P(l)-C(ll)-N(3) 120.7(4) In 13, the P N 3 ligand binds facially via the three nitrogens of the pyridyl rings, forming three six-membered rings. The ruthenium coordination sphere is completed by cis chlorides and a triphenylphosphine. Around ruthenium, the geometry is close to octahedral with the angles ranging from 84.9(1)° to 94.9(1)°. The Ru(l)-N(3) bond trans to the PPh3 is slightly longer than the Ru(l)-N(l&2) bonds trans to Cl, (2.117(4) A versus 2.075(4) A and 2.090(4) A , respectively). However, these values are similar to those reported for [ R u ( P N 3 ) 2 ] [C7H 7 S 0 3 ] 2 (2.06(1)-2.09(1) A , Table 5.1)3 which has two P N 3 ligands coordinated facially through the pyridyl nitrogens and is the only other ruthenium structure reported for a PN 3 ligand bound in this manner. The Ru(l)-Cl(l&2) bond lengths are identical, and the Ru(l)-P(2) bond length is typical for that of a Ru(II) phosphine complex.4 148 references on page 179 Chapter 5 C13 Figure 5.2 ORTEP plot of RuCl2(PPh3)(PN3) 13 (33% probability). 149 references on page 179 Chapter 5 Bond lengths in the PN3 ligand do not change upon coordination when compared to the free ligand,5 but bond angles do change. The C(l)-P(l)-C(6) angle (between the two py groups trans to Cl) increases slightly to 104.2(2)°, while the C(l)-P(l)-C(ll) and C(ll)-P(l)-C(6) angles decrease to 98.8(2)°, as compared to an average of 101.9° in the free ligand.5 The angles are similar to those found in [Ru(PN3)2][C7H7S03]2 (100.9(8)°, 99.6(8)°, and 99.6(7)°)/ These C-P-C angles are less distorted in comparison to [RuCl(PPh3)2(PN3)]PF6 6c (Section 4.3), where the PN3 is bound via the phosphorus and two pyridyl nitrogens forming four-membered rings. Thus, there is less strain around the phosphorus in the PN3 ligand when it binds facially via the three pyridyl nitrogens forming six-membered rings, as opposed to the four-membered rings in 6c, as would be expected. The solution structure of 13 in CDCI3 is consistent with the X-ray structure. The 3 1P{ 1H} NMR spectrum contains two singlets (Table 5.3, Figure 5.3), the result of two uncoupled phosphorus nuclei. The low field signal is assigned to the PPh3, while the high field signal is assigned to the PN3 ligand. These assignments are made based on the coordination chemical shift A (i.e., the difference between the chemical shift observed in the complex versus the free ligand, see Section 3.3.2). The A values for the PPh3 and the PN3 ligands are 47.7 and 5.56 ppm, respectively. Only a small A value would be expected for the phosphorus of the PN3 ligand because it does not coordinate the metal centre and is in an environment more like that of the free ligand. 3 1P{ 1H} NMR data for other Af',Af"-coordinated PN3 complexes (Section 5.1) have not been reported, therefore comparisons are impossible. The *H NMR ( C D C I 3 ) spectrum (Table 5.4, Figure 5.3) shows multiple peaks in the phenyl region, and is consistent with the complex containing two equivalent (trans to Cl) and one inequivalent (trans to PPh3) pyridyl rings. For example, the H6 protons (Appendix A) give rise to two signals with an integration ratio of 1:2. Thus, the solid 150 references on page 179 Chapter 5 state structure of 13 is maintained in CDCI3. However, when 13 is dissolved in MeOH the complex dissociates a chloride, as described in the next section. Table 5.3 3 1 p / l H } NMR Chemical Shifts for M#',JV"-Coordinated Tris(2-pyridyl)phosphine Complexes Complex Solvent PN3(a) PPh3(a) (ppm) PF6(h) (Hz) RuCl2(L)(PN3) L = PPh3,13 C D C 1 3 4.81 42.3 - -L = CO, 15a C D C 1 3 2.36 - - -L = MeCN, 15b C D C 1 3 7.71 - - -L = PhCN, 15c C D C 1 3 7.38 - - -[RuCl(L)(PPh3)(PN3)]X L = CO; X = Cl (c) CD 3OD 0.69 36.6 - -L = CO; X = PF6,14a C D C 1 3 -0.81 36.7 -144 713 CD 3OD 0.69 36.6 -144 708 L = MeCN; X = PF6,14b C D C 1 3 2.32 41.4 -144 713 L = PhCN; X = PF6,14c acetone-d6 3.57 42.8 -143 708 CD2CI2 2.18 41.2 -145 710 (a) Singlet, (b) Septet, (c) in situ. 151 references on page 179 Table 5.4 lU NMR Chemical Shifts for iV,iV',Ar"-Coordinated Tris(2-pyridyl)phosphine Complexes at Room Temperature Complex Solvent ppm (peakfo), # of H, assignment^ )) RuCl2(L)(PN3) L = PPh3,13 L = CO, 15a L = MeCN, 15b CDC13 CDCI3 C D C I 3 L = PhCN, 15c C D C I 3 [RuCl(L)(PPh3)(PN3)]PF6 L = CO, 14a C D C I 3 6.15(m,2H,PN3);7.17(m,9H,m-p-PPh3);7.29(m,2H,PN3);7.43(m,lH,PN3);7.59(m,6H,o-PPh3); 7.68(m,lH,PN3);7.93(m,3H,PN3);8.52(p-d,2H,H6-PN3);10.22(p-d,lH,H6-PN3) 7.30(m,2H,PN3);7.61(m,lH,PN3);7.77(m,2H,PN3);7.90(m,lH,PN3);8.14(m,3H,PN3); 9.47(p-d,2H,H6-PN3);9.98(p-d,lH,H6-PN3) 2.67(s,3H,MeCN);7.20(m,3H,PN3);7.62(m,3H,PN3);8.03(m,3H,PN3);9.69(p-d,2H,H6-PN3); 9.90(p-d,lH,H6-PN3) 7.17-7.75(m's,llH,PN3,PhCN);8.08(m,3H,PN3);9.65(p-d,2H,H6-PN3);9.96(p-d,lH,H6-PN3) 6.56(m,lH,PN3);6.74(m,lH,PN3);7.33(m,12H,o-m-PPh3);7.45(m,3H,/j-PPh3);7.54(m,lH,PN3); 7.84(m,2H,PN3);7.95(m,2H,PN3);8.26(m,lH,PN3);8.49(m,3H,PN3);9.56(p-d,lH,H6-PN3) C D 3 O D 6.66(m,lH,PN3);6.85(m,lH,PN3);7.27(m,12H,o-m-PPh3);7.42(m,3H,p-PPh3);7.58(m,lH,PN3); 7.62(m,lH,PN3);7.75(m,lH,PN3);7.92(m,lH,PN3);7.98(m,lH,PN3);8.15(p-d,lH,H6-PN3); 8.27(m,lH,PN3);8.36(m,lH,PN3);8.48(p-d,lH,H6-PN3);9.47(p-d,lH,H6-PN3) continued. Chapter 5 3 CD 6 s 00 'oo 00 EC CD & 3 CD on 3 B o u VO ""cn z PH c n . 3 PH PH u PH c n Z PH r~ c n 4 3 PH PH EC vo cn c n g EC cn o\ VO c n £ EC B cn VO z U CD EC cn oo c n 0 Q u z u c n z PH I VO EC EC •a i w © od c n Z PH I vo EC EC -a • i S 1 i—i cn od z PH EC cn o CN z PH X oo z PH EC (N O VO c n z PH I VO EC EC i—i •o i VO ON' c n z PH EC B cn r~ cn GO oo o (> r~ X o °i GO VO O cn c n z PH EC VO c n z PH EC i— i B © 00 VO VO T3 i CD a o o a z u .3 PH II PH I VO EC EC •a" i oo oo OS c n z PH VO EC EC i— i •o I © VO od X cn 6, m in od • ON cn od cn z PH EC i— i B cn T—I od § GO T3 3 on <u C u GO 3 <u a e w GO Si 3 H > B •*-» 3 O •o I o •o 3 CD GO C u -a I CL, £S Q£ \—» 3 6 <o 3 o 3 aj .3 -*-> 2H o e on s 3 , • I-H 3 B Si 3o 3 0) CD w •o 3 a op c n z PH <4-H o Z o •*—> 3 CD O •a1 EC 1, >> "a •c DH II II vo EC 00 CM 3 O oa w3 PH o EC C u II EC 3 6 n S •H-11 o ' H o II II Si 3 00 O C u a < CD -3 >< ^ 3 3 CD <D T3 C u C u s < 153 references on page 179 Chapter 5 PPh3 £ N 3 r r m - i i n 1 p i T r p i rrj rr n pi i T r r r T n T ^ r r r n m j T T T n TTTTT I I I I I I I I I I I N T T °° 6 0 4 '° , , o -io - io PPM 4o * H6, py (PN3) trans to Cl • H6, py (PN3) trans to PPh3 1 1 1 1 1 1 ' ' ' 1 | I I I I j I | | I | ] | | 1 j | | l l | | | | | j | i | | | i | | | j ) | | | | | ) | , | r mPPM Figure 5.3 31P{ 1 H } (CDC13, 121.4 MHz) and lH NMR (CDC13, 300 MHz) spectra of RuCl2(PPh3)(PN3) 13. 154 references on page 179 Chapter 5 The synthesis and structure of 13 are reminiscent of those of other ruthenium(II) complexes containing a six-electron donor ligand. Three examples are RuCl2(PPh3)([9]aneS3),6 RuCl(PPh3)2(Cp),7 and RuCl(PPh3)2(Tp) 8 (where [9]aneS3 = 1,4,7 trithiacyclononane, Cp = cyclopentadienyl, and Tp = hydrotris(pyrazol-l-yl)borate). The structures of these three compounds and 13 are shown in Figure 5.4. All of the complexes contain a facially coordinated six-electron donor ligand. The remainder of the coordination spheres is completed by triphenylphosphine and chloride ligands, relative numbers of each depending on the charge of the facial ligand. While Cp and Tp are negatively charged (-1), the thia crown ether and the tris(2-pyridyl)phosphine ligands are neutral. Finally, all of the complexes have been synthesized by PPh3 ligand displacement from RuCl 2(PPh 3) 3, although this is not the most convenient method for RuCl(PPh3)2(Cp).7 RuCl2(PPh3)([9]aneS3) RuCl(PPh3)2(Tp) Figure 5.4 Structures of some ruthenium(II) complexes containing a six-electron donor ligand. 155 references on page 179 Chapter 5 The reason for making the comparison above is that the chemistry of 13 parallels some aspects of the chemistry of RuCl(PPh3)2(Cp), which can undergo a diverse set of reactions. The remainder of this chapter describes the reactivity of RuCl2(PPh3)(PN3), and some comparisons with the chemistry of RuCl(PPh3)2(Cp) are made to demonstrate similarities between these two complexes. 5.3 Dissociation of a Chloride from RuCl2(PPh3)(PN3) in Methanol When RuCl2(PPh3)(PN3) 13 was dissolved in MeOH, the complex lost a chloride ligand and formed a cationic complex according to the equation in Figure 5.1. Evidence for this dissociation comes from conductivity and UV-visible data. No NMR data in C D 3 O D were obtained because of the low solubility of 13 in this solvent (~ < 1.5 mg/mL). The molar conductivity of RuCl 2 (PPh3)(PN3) is reported in Table 5.5. In C H 3 N O 2 , complex 13 is almost a non-conductor. In contrast, the conductivity in MeOH is much higher, however still below the range expected for 1:1 conductors. The differences in conductivity between C H 3 N O 2 and MeOH are attributed to the relative donor abilities of the two solvents. Based on the dielectric constants, C H 3 N O 2 (e = 38.6) can support the formation of ions equally as well as or better than MeOH (e = 32.6).9 However, in terms of donor ability, MeOH has a much higher donor number (DN) than C H 3 N O 2 (DN = 20.0 and 2.7 respectively).9 This suggests the formation of an ionic complex containing a coordinated MeOH according to the equilibrium shown in Figure 5.1. In order to characterize the cation formed in MeOH, it was isolated by adding NaBPh4 to a clear, orange solution of 13 (Section 2.7.2). An orange precipitate, recovered and dried under vacuum, was characterized by elemental analysis and 156 references on page 179 Chapter 5 Table 5.5 Infrared and Conductivity Data for A^A^AT'-Coordinated Tris(2-pyridyl)-phosphine Complexes Complex Infrared Stretches (a) (cm-1) A M (CH3NO2, 25 °C) 0>) ( o h m ^ m o H c m 2 ) RuCl2(L)(PN3) L = PPh3,13 L = CO, 15a L = MeCN, 15b L = PhCN, 15c (c) vco = 1942 (s) V C N = 2270 (w) V C N = 2224 (m) 9.9, 67.4 (MeOH, 25 °C)(d) [RuCl(L)(PPh3)(PN3)]PF6 L = CO, 14a vco = 1979 (s) 80.4 L = MeCN, 14b V C N = 2274 (w) 79.3 L = PhCN, 14c V C N = 2232 (m) 793 (a) Nujol Mull / KBr plates, s = strong; m = medium; w = weak, (b) Measured at ~ 10~3 M. Accepted ranges for 1:1 conductors: in C H 3 N 0 2 (75-90 ohm^moHcm 2 ); in MeOH (80-115 ohm- imol -W). 1 0 (c) See Figure 5.5. (d) Calculated using the molecular weight for RuCl2(PPh3)(PN3) (699.52 g mol"1). If calculated with the molecular weight of [RuCl(Me0H)(PPh3)(PN3)]Cl (731.56 g mol-1) the molar conductivity is 64.4 ohm-imoHcm 2 . UV-visible and IR spectroscopies. No NMR data could be recorded because of low solubility. The salt isolated is formulated as [RuCl(MeOH)(PPh3)(PN3)]BPh4, containing a coordinated MeOH. The elemental analysis obtained for this formulation was not satisfactory, but the coordinated MeOH is confirmed in the IR spectrum (see below). Table 5.6 contains the calculated carbon, hydrogen, and nitrogen percentages for several 157 references on page 179 Chapter 5 complexes, as well as those found experimentally. The found carbon percentage is low by ~ 0.76% in comparison to that calculated for the coordinated MeOH complex (entry 3). Based on the calculated percentages for the salt without coordinated MeOH (entry 2), this complex is ruled out as the impurity: contamination from this salt would raise the carbon percentage. The low carbon percentage found is possibly the result of residual NaCl or starting material, but is more likely the result of the presence of some MeOH solvate (entry 4). Table 5.6 Calculated C, H, and N Percentages for Possible Impurities in the Isolated [RuCl(MeOH)(PPh3)(PN3)]BPh4 Complex, as well as the Found Percentages Calculated for MW (g mol"1) %C %H %N 1. RuCl2(PPh3)(PN3) 699.52 56.66 3.89 6.01 2. [RuCl(PPh3)(PN3)]BPh4 983.30 69.62 4.82 4.27 3. [RuCl(MeOH)(PPh3)(PN3)]BPh4 1015.34 68.61 5.06 4.14 4. [RuCl(MeOH)(PPh3)(PN3)]BPh4-MeOH 1047.38 64.21 3.84 4.01 5. Found - 67.85 4.94 4.21 As mentioned, evidence for the coordinated MeOH in the cation comes from IR data. The IR spectra of 13, the coordinated MeOH complex, and NaBPh4 are shown in Figure 5.5. Based on comparison of these three spectra, two stretches observed in the coordinated MeOH complex spectrum can be assigned to a coordinated MeOH (starred (*) in Figure 5.5). The band at 3207 cm"1 (3342 cm"1 for neat MeOH) 1 1 is assigned to the O-H stretch and the band at 1001 cm"1 (1033 cm"1 for neat MeOH) 1 1 to the C-O stretch, the shifts to lower wavenumbers on comparison to those of neat MeOH being 158 references on page 179 Chapter 5 (a) RuCl2(PPh3)(PN3) % T r a n s m i t t a n c e 100 80 60 40 20 % T r a n s m t t a n c 4000 3600 3000 2500 2000 (b) [RuCl(MeOH)(PPh3)(PN3)]BPh4 Wavenumbers 1500 1000 500 100 80 60-40 20-VO-H 3207 cm-1 4000 3600 (c) NaBPh4 100 3000 2500 2000 Wavenumbers 1500 1000 500 T r a n s m i t t a n c 80 60-40 20-4000 3500 3000 2500 2000 Wavenumbers 1500 1000 500 Figure 5.5 IR spectra (KBr pellets) of (a) RuCl 2 (PPh 3 ) (PN 3 ) 13, (b) "[RuCl(MeOH)(PPh3)(PN3)]BPh4", and (c) NaBPh4. Starred (*) peaks are assigned to a coordinated MeOH. 159 references on page 179 Chapter 5 consistent with MeOH coordination. No bands could be assigned to a solvated MeOH, which would justify the low carbon percentage in the elemental analysis, but these could be obscured by other bands in the complex. This IR evidence supports the formulation of the cationic complex as [RuCl(MeOH)(PPh3)(PN3)]BPh4. UV-visible data are reported in Table 5.7 and shown in Figure 5.6. Based on comparison of the spectra of 13 in CH2CI2 and in the solid state, the solution structure of 13 in CH2CI2 is the same as that in the solid state (i.e., of the neutral RuCl2(PPh3)(PN3)). In contrast, when the solvent is changed to MeOH, the A^ax absorbances occur at lower wavelengths. These lower wavelengths are partially attributed to the formation of the coordinated MeOH complex. This is supported by the spectrum of [RuCl(MeOH)(PPh3)(PN3)]BPh4 in C H 2 C 1 2 , where one of the X m a x absorbances (414 nm) is essentially the same as the wavelength observed for 13 in MeOH (416 nm). It was therefore expected that the addition of LiCl to an MeOH solution of 13 would cause a shift of the 416 nm absorbance toward its position in CH2CI2 (i.e., to 434 nm). However, addition of LiCl to an MeOH sample of 13 ([LiCl]:[Ru] = 2800:1, [LiCl] = 1.33 M) resulted in a small change in the 416 nm absorbance maximum, which shifted to 422 nm. No further shift toward the position in CH2CI2 (434 nm) was observed using a saturated LiCl (-10 M) solution of 13 in MeOH. The rest of the difference giving rise to the absorbance maxima at 422 nm (saturated LiCl solution) and the 434 nm absorbance (13 in CH2CI2) is attributed to a solvation effect. Other ruthenium complexes containing coordinated methanol have been observed and characterized by different techniques. Five coordinate RuCl2(PMA)(PPh3) (PMA = o-diphenylphosphino-A^A -^dimethylaniline) undergoes a reversible reaction with MeOH in benzene, as determined by *H NMR spectroscopy,12 while Wilkinson and co-workers have isolated Ru(H)2(CO)(PPh3)2(MeOH) characterized by IR and NMR spectroscopies,13 and an X-ray structure of Ru(02CCF3)2(MeOH)(CO)(PPh3)2 by Dobson et al. clearly shows the coordinated methanol.14 160 references on page 179 Chapter 5 Table 5.7 UV-visible Data for N,N',N "-Coordinated Tris(2-pyridyl)phosphine Complexes Complex Solvent A-max ( e max)^ nm (M_ 1cm_ 1) [RuCl(MeOH)(PPh3)(PN3)]BPh4 CH 2C1 2 - 368 414 RuCl2(L)(PN3) L = PPh3,13 C H 2 C I 2 270(20500) 368(6400) 434(7600) CH 3 OH 264(20000) 350(6000) 416(7900) solid stated - 368 438 solid stated) - 368 438 L = CO, 15a CH 2C1 2 270(15600) 350(5960) 434(3050) CH 3 OH 264(8920) 338(3100) 400(1920) L = MeCN, 15b C H 2 C I 2 - 386(7920) 428(9315) 466(6540)sh CH 3 OH - 372(7670) 418(8630) 450(6630)sh L = PhCN, 15c C H 2 C I 2 268(24800) 374(12000) 434(13900) CH 3 OH 260(22200) 356(9100) 414(11300) Solid state*) - 374 434 [RuCl(L)(PPh3)(PN3)]PF6 L = CO, 15a CH 2C1 2 270(18000) 366(3070) CH 3 OH 266(19000) 352(3200) L = MeCN, 15b C H 2 C I 2 262(18900) 336(5880)sh 386(7540) 424(5570)sh L = PhCN, 15c C H 2 C I 2 260(19100) 324 (10600) 386(9610) 424(6330)sh (a) sh = shoulder. Where extinction coefficients are not given, the complex was not pure. (b) Amorphous film made from evaporation of a C H 2 C I 2 solution on a glass plate (UV cut-off 300 nm). (c) From evaporation of a MeOH solution. 161 references on page 179 Chapter 5 2 Wavelength (nm) Figure 5.6 UV-visible spectra of (a) RuCl2(PPh3)(PN3) 13 in MeOH, (b) 13 in MeOH with 1.33 M LiCl , (c) 13 in C H 2 C 1 2 , and (d) [RuCl(MeOH)(PPh3)(PN3)]BPh4 in C H 2 C 1 2 (2.05 mg dissolved in 15 mL). The left-hand scale is for (a) to (c), while the right-hand scale is for (d), where the absorbance is plotted because the BPI14 salt was not pure. More closely related, the ionic behaviour observed for RuCl2(PPh3)(PN3) parallels that of RuCl(PPh3)2(Cp), which is a non-electrolyte in acetone but dissociates appreciably in methanol.15 Haines and Du Preez isolated the coordinated MeOH complex [Ru(MeOH)(PPh3)2(Cp)]BPh4, which they identified by NMR and IR spectroscopy; however, no accompanying data were presented, and also, they were unable to obtain the product analytically pure. Nevertheless, the ability of RuCl(PPh3)2(Cp) to dissociate chloride in MeOH has led to a variety of chloride 162 references on page 179 Chapter 5 exchange reactions for the Cp complex. Similar types of reactions occur with the PN3 complex and are described in the next section. 5.4 Chloride Substitution Reactions of RuCl2(PPh3)(PN3) The ability of RuCl2(PPh3)(PN3) to lose chloride in MeOH led to the investigation of some chloride-substitution reactions, using neutral, two-electron donor ligands (Figure 5.1). These reactions are described in this section. When RuCl2(PPh3)(PN3) 13 was heated in CD3OD under one atmosphere of CO gas, the initially red suspension changed into a clear yellow solution. The 3 1P{ *H} NMR spectrum of this in situ reaction was measured, and contained two singlets (Table 5.3). The product is formulated as [RuCl(CO)(PPh3)(PN3)]Cl. The reaction was repeated on a synthetic scale in MeOH. However, attempts to isolate the chloride salt by precipitation with ether resulted in the formation of an oil. An oil was also obtained after removing the MeOH, and attempting to precipitate from an acetone solution with ether. This was most likely the result of the relative sizes of the large ruthenium cation and the small chloride anion. A similar reaction in the presence of NH4PF6 allowed for isolation of [RuCl(CO)(PPh3)(PN3)]PF6 14a as an analytically pure yellow salt (Section 2.7.3.1). The 3 1P{1H} NMR (CD3OD) spectrum of 14a (Table 5.3) matched the spectrum obtained from the in situ reaction, and consisted of two singlets for two uncoupled phosphorus nuclei. The IR spectrum contained a single CO stretch and the compound was a 1:1 conductor in nitromethane (Table 5.5). The H6 protons (Appendix A) of the PN3 ligand gave rise to three signals in the *H NMR spectrum (Table 5.4), indicating the inequivalence of the three pyridyl groups. These data are consistent with the structure shown in Figure 5.7, which shows the compound as a racemate. 163 references on page 179 Chapter 5 PPh3 PPh3 R S Figure 5.7 Structures of compounds isolated from chloride-substitution reactions, [RuCl(L)(PPh3)(PN3)]PF6, where L = CO 14a, L = MeCN 14b, or L = PhCN 14c. There is a solvent dependence for the formation of 14a. In acetone, the reaction at room temperature was slow (11 d) and a mixture of products was obtained (Section 2.7.3.2). The two products isolated were 14a (major) as well as RuCl2(CO)(PN3) 15a (minor), identified in the 3 1P{1H} NMR (CDC13) spectrum of the product. The minor product is formed via displacement of the triphenylphosphine in RuCl2(PPh3)(PN3) by CO and was synthesized independently (Section 5.5). In MeOH, the formation of the cationic MeOH complex allows for a more efficient mechanism for the formation of the salt over displacement of triphenylphosphine. Similar results were obtained for the in situ reaction of 13 with CO in CDC13. After 14 d, the 31P{!H} NMR spectrum contained mainly peaks for the starting material 13, free triphenylphosphine, as well as minor peaks for [RuCl(CO)(PPh3)(PN3)]Cl and RuCl2(CO)(PN3). Use of a similar procedure, as described above for 14a, allowed for isolation of the nitrile complexes [RuCl(L)(PPh3)(PN3)]PF6, where L = MeCN 14b, or L = PhCN 14c. The two complexes were prepared by stirring RuCl2(PPh3)(PN3) with MeCN or PhCN and N H 4 P F 6 in MeOH (Sections 2.7.3.3 and 2.7.3.5). After the solution was heated, the MeOH was removed under vacuum and the resulting residue dissolved in acetone, allowing the removal of NH4CI. The isolated complexes were characterized in 164 references on page 179 Chapter 5 the same manner as 14a, and have the structures shown in Figure 5.7. Characterization data are presented in Tables 5.3 to 5.5 and Table 5.7. Only one equivalent of MeCN was used to make 14b. When excess MeCN was added, the isolated product contained small amounts of impurities. Similarly, when the reaction to produce 14b was done by refluxing 13 and one equivalent of NH4PF6 in neat MeCN (Section 2.7.3.4), the product isolated was 14b. However, it was not analytically pure, the carbon percentage being consistently low by ~1.0%. To rule out the possibility that the impurity resulted from the formation of small amounts of a dicationic complex (i.e., [Ru(MeCN)2(PPh3)(PN3)][PF6]2), the reaction with two equivalents of NH4PF6 was undertaken. With the use of two equivalents of NH4PF6 in MeCN (using a procedure similar to that described for one equivalent), only one chloride was removed from RuCl2(PPh3)(PN3) and 14b was again isolated, suggesting that the impurity is not the dicationic complex. This suggested the most likely impurity was [RuCl(MeCN)2-(PN3)]PF6, produced by MeCN displacement of the triphenylphosphine in 13. The calculated carbon, hydrogen, and nitrogen percentages for this complex could produce the low analysis observed for 14b when it was made in neat MeCN. As well, an analogous complex, similar to that of the suggested impurity, was produced when 13 reacted with NH4PF6 in PhCN (below). Attempts were made to produce [RuCl(PhCN)(PPh3)(PN3)]PF6 14c by reaction in PhCN. When RuCl2(PPh3)(PN3) and one equivalent of NH4PF6 were refluxed in a mixture of PhCN and acetone (NH4PF6 is not soluble in PhCN), a mixture of products was obtained (Section 2.7.3.6). The mixture contained 14c and a second product which showed a singlet at 6.30 in the 31P{XH} NMR (acetone-d6) spectrum of the mixture (or 5.05 ppm in C D 2 C I 2 ) . This second product also results from refluxing RuCl2(PhCN)(PN3) (Section 5.5) in MeOH with one equivalent of NH4PF6 and excess PhCN (Section 2.7.3.7). This product is tentatively formulated as [RuCl-165 references on page 179 Chapter 5 (PhCN)2(PN3)]PF6- The complex was not further characterized because of other minor impurities (Section 2.7.3.7). Finally, when RuCl2(PPh3)(PN3) is refluxed in neat PhCN without N H 4 P F 6 (Section 2.7.4.4), the triphenylphosphine is displaced and the complex formed is RuCt2(PhCN)(PN3), the synthesis of which is described in the next section. In summary, the best route to chloride-substitution products is via reactions in methanol. It is the ability of RuCl2(PPh3)(PN3) to dissociate chloride in MeOH which allows for a mechanism for product formation, and disfavours substitution of the triphenylphosphine, which occurs in other solvents. The chloride-substitution reactions described here could be expanded to include a wider range of two-electron donors (e.g., pyridine, DMSO, PR3, etc.). As well, halogen exchange reactions to produce the bromide and iodide analogues of 13 are possibly accessible via reactions in methanol. 5.5 Triphenylphosphine Substitution Reactions of RuCl2(PPh3)(PN3) As reported in the previous section, a chloride in RuCl2(PPh3)(PN3) 13 can be replaced by neutral ligands if the reactions are done in methanol. By using a solvent which does not favour the formation of ions, it was possible to displace the triphenylphosphine in 13. This chemistry is similar to that of the cyclopentadienyl complex RuCl(PPh3)2(Cp) which undergoes a variety of phosphine substitution reactions in non-polar solvents in the presence of excess substituting ligand.7 The PPI13 in the Cp complex has been replaced by other phosphines, carbon monoxide, and isocyanides, to name a few. This section reports on triphenylphosphine displacement reactions of RuCl2(PPh3)(PN3). When a red suspension of RuCl2(PPh3)(PN3) was refluxed in C^H^ under an atmosphere of CO for 42 h, an orange-brown precipitate was isolated (Section 2.7.4.1, Figure 5.1). This precipitate consists of two products based on the 3 1P{ 1H} NMR (CDCI3) spectrum which contained two singlets at 2.36 (major) and 4.77 ppm (minor). 166 references on page 179 Chapter 5 The complex giving rise to the singlet at 2.36 ppm was separated by precipitation from CH2CI2 with Et20 as an orange solid. This product is RuCl2(CO)(PN3), and the elemental analysis obtained was consistent with this formulation. The minor product was not characterized. As mentioned, the complex gave rise to a singlet in the 3 1P{ 1H} NMR (CDCI3) spectrum (Table 5.3). The ! H NMR (CDCI3) spectrum (Table 5.4) contained two H 6 signals (Appendix A) integrating in a 2:1 ratio, indicating the presence of two equivalent pyridyl groups. A single CO stretch was observed in the IR spectrum (Table 5.5). Thus the structure of RuCi2(CO)(PN3) is analogous to that of RuCl2(PPh3)(PN3), and is shown in Figure 5.8. L Figure 5.8 Structure of compounds isolated from triphenylphosphine-substitution reactions of RuCl2(PPh3)(PN3): RuCl2(L)(PN3), where L = CO 15a, L = MeCN 15b, or L = PhCN 15c. Similar reactions (Figure 5.1) with MeCN (Section 2.7.4.2) and PhCN (Section 2.7.4.3) allowed for isolation of RuCl2(MeCN)(PN3) 15b and RuCl2(PhCN)(PN3) 15c, respectively. Characterization data for these two complexes are reported in Tables 5.3 to 5.5 and Table 5.7 and the two complexes are assigned structures similar to that of the CO complex (Figure 5.8). These two complexes were isolated in slightly different manners. The PhCN complex 15c formed as a red precipitate during the reaction in benzene, the remainder of the product being precipitated from the benzene solution by addition of hexanes. The product was then reprecipitated from CH2CI2 with Et20 to remove a C6H6 solvate which otherwise was not removed under vacuum. Finally, 15c 167 references on page 179 Chapter 5 was again dried under vacuum to remove any remaining solvates, arid an analytically pure product was produced. Complex 15b was isolated directly as a red precipitate from the C6H-6 solution without the addition of hexanes and dried under vacuum for 24 h. The analysis of this complex was calculated including 1/6 mole of C6Hg solvate. The C6H6 solvate was confirmed by integration of the *H NMR (CDCI3) spectrum (see Figure 5.9). When 15b was heated in vacuum the complex partially decomposed becoming red-brown in colour. The elemental analysis of the compound (see Section 2.7.4.2) after heating in vacuum had a much lower nitrogen percentage, suggesting MeCN was being lost. Complex 15b is also air-sensitive in the solid state (as well as in solution). Solid state samples stored in air turned brown over several months. Reactions of this compound with oxygen were not explored. • H6, py (PN3) trans to PPI13 * H6, py (PN3) trans to MeCN I l I I I [ I I I I I I I I I I I I I I 1 I I I I I I I I I 1 I I I I I I I I I I I I I I I I I II I I I M I I I I I 10 8 6 4 2 0 PPM Figure 5.9 *H NMR (CDCI3, 300 MHz) spectrum of RuCl2(MeCN)(PN3) 15b. 168 references on page 179 Chapter 5 It is suspected that the triphenylphosphine-substitution products 15a-c undergo chloride loss in MeOH similar to RuCl2(PPh3)(PN3) (Section 5.3), with formation of a cationic MeOH complex. Although conductivity measurements in MeOH were not made, at least for the MeCN and PhCN complexes (15b and 15c), a possible better binding ability of the nitrile ligands, as compared to that of the PPh3 in 13, would promote formation of a coordinated MeOH complex with dissociation of chloride. Two driving forces are in operation, allowing for substitution of the triphenylphosphine. The complex RuCl2(PPh3)(PN3) is only slightly soluble in C6H6, and this provides one driving force, because the effective concentration of the substituting ligand is high, relative to the concentration of the starting material. The longer reaction time required for the CO complex in comparison to the nitrile complexes (42 h versus 17-20 h) is probably the result of a lower concentration of CO relative to the concentrations obtained with the nitriles. Higher CO pressures would probably facilitate CO complex formation. The second driving force is the benzene itself which does not promote the formation of ions and so the competing reaction of chloride substitution does not occur. 5.6 Comparison of Substitution Products of RuCl2(PPh3)(PN3) with Those of Analogous Cp Complexes As mentioned in previous sections, RuCi2(PPh3)(PN 3), 13, shows similar reactivity to that of RuCl(PPh3)2(Cp), particularly in terms of chloride- and triphenylphosphine- substitution reactions. To further the comparison between these two complexes, Table 5.8 shows data for the N,N',N"-PN^ complexes (discussed in the previous two sections) along with those for the analogous Cp complexes, synthesized by ligand substitution of RuCl(PPh3)2(Cp) (see Table 5.8 for references). No literature could be found for Cp analogues of the PN3 complexes 15b and 15c. Although colour is a crude measure of electronic spectra, the PN3 and Cp complexes have similar electronic properties at the metal centre, based on the observed 169 references on page 179 Chapter 5 colours. A better indication of the metal centre's properties is manifested in the carbonyl and nitrile stretching frequencies of the complexes; other spectroscopic properties are not directly comparable. There is a striking similarity between the carbonyl and nitrile stretches of the iV,W,Ar'-PN 3 complexes and those of the analogous Cp complexes. For example, the cationic carbonyl complexes (entry 2, Table 5.8) produced by substitution of the chloride in 13, or in RuCl(PPh3)2(Cp), have essentially the same CO stretches, indicating that the electronic properties of the ruthenium centre, in terms of back-donation into the T I * orbital of the CO ligand, are the same. Table 5.8 Comparison of Colours and Infrared Stretching Frequencies for Analogous Cp and N,N',N"-PN'i Ruthenium Complexes Complex vco or V C N (cm-1) Colour Ref. (a) 1. RuCl(CO)(PPh3)(Cp) 1958 yellow-orange 16 RuCl2(CO)(PN3) 15a 1942 orange t.w. 2. [Ru(CO)(PPh3)2(Cp)]+ 1981 yellow 15 [RuCl(CO)(PPh3)(PN3)]+ 14a 1979 yellow t.w. 3. [Ru(MeCN)(PPh3)2(Cp)]+ 2265 yellow 17 [RuCl(MeCN)(PPh3)(PN3)]+ 14b 2274 yellow t.w. 4. [Ru(PhCN)(PPh3)2(Cp)]+ 2228 yellow 17 [RuCl(PhCN)(PPh3)(PN3)]+ 14c 2232 yellow t.w. (a) References, t.w. = this work. 170 references on page 179 Chapter 5 The implication of this trend is that the 14-electron fragments RuCl(PN3) and Ru(PPh3)(Cp) have similar electronic properties. Both fragments contain two- and six-electron donor ligands, the differences being in the charges on the donors, Cp (-1) and PPI13 (0) versus PN3 (0) and Cl(-l). Although the two fragments contain different ligands, the two ligands combined in any one fragment appear to produce similar electronic properties at the metal centre. 5.7 Reaction of RuCl2(PPh3)(PN3) with 0 2 The in situ reaction of RuCl2(PPh3)(PN3) with O2 gas (1 atm) in CDCI3 was followed by 3 1P{1H} NMR spectroscopy (Figure 5.10). After 3 d at room temperature, signals for the starting material as well as signals for a new complex were present in the spectrum (see Figure 5.10). The new signals are for the complex RuCl2(PPh3)(OPN3) 16, which was synthesized independently (described below). After 12 d, complex 16 is the only species present along with a small peak for OPPI13. Thus, the free phosphorus of the PN3 group in RuCl2(PPh3)(PN3) is oxidized to the phosphine oxide, but slowly. The presence of OPPI13 in the spectrum of the in situ reaction suggested a second ruthenium product was forming. This product is possibly a paramagnetic ruthenium-18 oxo/peroxo type species, but because of the relatively small amount of OPPI13 formed no attempts were made to try and isolate this other product. On a synthetic scale, RuCl2(PPh3)(PN3) was stirred under O2 (1 atm) for 12 d in CH2CI2 (Section 2.7.5.1). During this time an orange precipitate of RuCl2(PPh3)(OPN3) deposited and was collected by filtration, and identified by its 171 references on page 179 Chapter 5 (a) initial 13 A . (b) after 3 d 13 16 (c) after 12 d 16 A * RuCl2(PPh3)(PN3) 13 OPPh3 RuCl2(PPh3)(OPN3) 16 OPPh3 J L 13 13 16 16 1 "I I J I 1 I I | I I I I | I I 1 I | I ) I | | | | i | | i | i i | | i | | I I [ I I | I | | | I | | i i | i | i i I 50 40 30 20 10 0 PPM -10 Figure 5.10 31P{!H} NMR (CDC13, 121.4 MHz) spectra for the in situ reaction of RuCl2(PPh3)(PN3) 13 with 0 2 . 172 references on page 179 Chapter 5 3 1P{ 1H} NMR (CDCI3) spectrum. The complex also contained non-stoichiometric amounts of CH2CI2 and H2O solvates (seen in the *H NMR spectrum) which could not be entirely removed by heating the complex under vacuum at 78 °C. Another method for the synthesis of 16 was found in order to avoid these solvate problems. Reaction of R u C l 2 ( P P h 3 ) ( P N 3 ) with excess m-C1C6H4C(0)00H (m-chloroperbenzoic acid) in CHCI3 resulted in formation of RuCl2(PPh3)(OPN3) (Section 2.7.5.1). The by-product, benzoic acid, was removed by selective precipitation with hexanes. The elemental analysis of the complex isolated was consistent with the formulation, RuCl2(PPh3)(OPN3), 16, whose characterization data are given in Table 5.9 and is consistent with the structure shown in Figure 5.11. Table 5.9 Characterization Data for RuCl2(PPh3)(OPN3) 16 31p{ lH} NMR (CDCI3), ppm 40.4 (s, PPh3); 3.56 (s,PN3) lH NMR (CDCI3), ppm (a) 6.35(m,2H,PN3);7.14 - 7.33(m's,9H);7.49-7.62 (m's,9H);7.89(m,lH,PN3);8.15(m,3H); 8.45 (p-d,2H,H6-PN3);10.13(p-d,lH,H6-PN3) UV-visible, Amax (emax) C H 2 C I 2 nm, (M-lcm-1) MeOH IR (KBr pellet) 262(18500); 362(6900); 430(7350) 262(17800); 346(6590); 412(7500) vpo = 1235 cm"1 (strong) (a) m = multiplet; m's = more than one multiplet; p-d = pseudo-doublet (multiplet); H6 = pyridyl-H, adjacent to N of the PN3 ligand (See Appendix A); assignments are made where possible. 173 references on page 179 Chapter 5 Figure 5.11 Structure of RuCl2(PPh3)(OPN3) 16. Other complexes that have been synthesized containing a coordinated OPN 3 ligand have the general formula [M(OPN3)2][X]2 (M = Mn, Co, Ni, Cu, Zn, with X = CIO4; M = Ru, with X = PF6).1'19 The OPN 3 ligands coordinate the metal centres via the nitrogens of the three pyridyl groups forming octahedral complexes. Infrared data are not reported for the ruthenium complex, but the Vpo stretches for the first row transition metal complexes noted above range from 1231 cm - 1 to 1236 cm - 1. In comparison, 16 gives a similar stretch, vpo = 1235 cm'1. These stretches are at higher wavenumbers in comparison to that of the free ligand (vpo = 1212 cm - 1 for OPN 3, Section 2.3.2.5), the increase in Vpo in comparison to the free ligand possibly being attributed to an increase in pit-dTC bonding between the oxygen and phosphorus, caused by an increase in the electronegativity of the phosphorus, induced by the pyridyl groups coordinating the metal.1 This is consistent with the general trend for phosphine oxides (OPR3) which 9ft show an increase in the vpo wavenumbers as R becomes more electronegative. A comparison of the UV-visible spectra of 16 (Table 5.9) with the spectra for 13 (Table 5.7) shows that oxidation of the PN 3 ligand phosphorus has only a small influence on the electronic environment at the metal centre. In 16, the Amax absorbances are shifted to lower wavelengths by ~ 4 nm as compared to those of 13. Therefore 16, similar to 13 (Section 5.3), is expected to dissociate chloride in MeOH. Attempts were made to prepare 16 by reacting RuCl2(PPh3)3 with OPN 3 by a method similar to that used for the synthesis of 13 (Section 5.1). One equivalent of OPN 3 was refluxed with RuCl2(PPh3)3 in C6H6 for 7 h (Section 2.7.5.2). A dark red solution 174 references on page 179 Chapter 5 formed and the product was isolated by precipitation with hexanes. The red precipitate isolated contained a mixture of complexes, as determined by the presence of several signals in the 3 1P{ 1H} NMR spectrum (see Section 2.7.5.2). Some of the desired complex 16 was present. One problem may have been stoichiometric control, because of the low solubility of O P N 3 in C 6 H 6 . A similar reaction in refluxing C H 2 C I 2 , used to overcome the solubility problem encountered in C 6 H 6 , produced a similar mixture of products. The side-products possibly contain OPN3 ligands which are 0,N-, 0,N,N'- or Af.iV'-coordinated. This reaction was not investigated further. 5.8 Reactions of RuCl2(PPh3)(PN3) with H 2 This section reports on two preliminary reactions of RuCl2(PPh3)(PN3) with hydrogen. The first reaction undertaken was the reaction of R u C l 2 ( P P h 3 ) ( P N 3 ) 13 with H 2 in dimethylacetamide (DMA), which was done in hope of forming the monohydride analogue of 13, according to Figure 5.12, via heterolytic cleavage of H 2 . It was thought that such a hydride complex would be capable of dissociating chloride (as 13 does in MeOH (Section 5.3)), and provide a vacant site where a substrate could coordinate and the system effect catalytic hydrogenation. Figure 5.12 Proposed reaction between RuCl2(PPh3)(PN3) 13 and H2 in DMA. However, 13 does not react with 1 atm hydrogen in DMA according to the procedure outlined in the experimental (Section 2.7.6.1). The original starting complex, PPh3 PPh3 175 references on page 179 Chapter 5 RuCl2(PPh.3)(PN3), was recovered from the reaction solution, as determined by 31P{!H} and *H NMR spectroscopies. The catalytic hydrogenation of Af-benzylidenebenzylamine in MeOH (Section 4.6.2) indicates that 13, or derived imine complex, is capable of activating hydrogen. The inactivity in DMA is likely the result of two factors, which will become apparent after the second reaction with hydrogen is considered. In contrast to the first attempted reaction, a reaction between 13 and hydrogen does occur in MeOH. Figure 5.13 shows the UV-visible spectra for the in situ reaction of 13 in MeOH under 1 atm hydrogen (Section 2.7.6.2). The A,max of complex 13 at 418 nm shifted to 430 nm as the reaction went to completion. The final absorbance did not change with time. When the hydrogen was removed from the sample, again there was no change in the final spectrum, indicating the reaction was irreversible. The most plausible reaction with hydrogen is shown in Figure 5.14. Formation of the weakly coordinated MeOH complex allows for H 2 activation, and formation of the hydride complex. The relative concentrations of the starting complex and the hydrogen gas are probably important. The solubility of H 2 in MeOH is on the order of ~ 10~3 M atm-1 at room temperature (20 to 23 °C) , 2 1 which is approximately 100 times the ruthenium complex concentration of ~ 10-5 M. Even at this ratio, the reaction is slow, taking approximately 100 minutes to go to completion. In the case of the DMA reaction described above, although DMA might be expected to provide a driving force by trapping any HCI formed, the DMA may be coordinated to the metal centre, not allowing the H 2 access. As seen in Section 5.3 for MeOH, DMA probably coordinates to the ruthenium in 13 displacing a chloride. Dimethylacetamide (DN = 27.3) is a better donor than MeOH (DN = 20.0) and can support the formation of ions (e = 37.8 for DMA and £ = 32.6 for MeOH).9 Based on the donor numbers (DN), DMA would coordinate more strongly than MeOH, and therefore block access to the metal centre for H 2 activation. Furthermore, the relative 176 references on page 179 Chapter 5 0.5 Wavelength (nm) Figure 5.13 UV-visible spectra for the in situ reaction of RuCl2(PPh3)(PN3) 13 in MeOH with H2 (1 atm) at room temperature, (a) t = 0 min; (b) t = 52 min; and (c) t = 99 min. ([Ru] = 2.12 x 10"5 M). RuCl2(PPh3)(PN3) + MeOH [RuCl(MeOH)(PPh3)(PN3)]+ + Cl" 13 Ho RuCl(H)(PPh3)(PN3) + HCI + MeOH Figure 5.14 Proposed reaction between RuCl2(PPh3)(PN3) 13 and H2 in MeOH. 177 references on page 179 Chapter 5 concentration of H 2 (~ IO"3 M, at 1 atm)22 versus 13 (1.53 x 10"2 M) in the DMA reaction was lower than the relative concentrations in the MeOH reaction described above. Clearly, further experimentation is required to confirm the formation of any hydride complex in MeOH, and the reasons for the inactivity in DMA. An experimental limitation, however, is the solubility of RuCl2(PPh3)(PN3). Its low solubility in MeOH precluded the use of NMR experiments, which would easily confirm the formation of the hydride. Even under hydrogen, an NMR sample of 13 in C D 3 O D remained as a red suspension of the starting material. To conclude this section, the H2 reaction in MeOH described is "consistent with" the ability of 13 to hydrogenate imines at high H2 pressures in MeOH (Section 4.6.2). 5.9 Conclusions This chapter described the synthesis and reactivity of the half-sandwich N,N',N"-P N 3 complex, RuCl2(PPh3)(PN3) 13, whose structure was confirmed by X-ray crystallography. In MeOH, 13 lost chloride to form a coordinated MeOH complex which was characterized by UV-visible and IR spectroscopies. Reactions in MeOH allowed replacement of a chloride of 13 by neutral two-electron donors. In benzene, which does not promote the formation of ions, the triphenylphosphine in 13 can also be replaced with neutral two-electron donors. With other solvents, a mixture of chloride- and triphenylphosphine-substitution products was obtained. This reactivity is similar to that reported for the cyclopentadienyl complex RuCl(PPh3)2(Cp), and a comparison of the substitution products of 13 with analogous Cp complexes was made. The results indicate that a chloride and a PN3 ligand impart similar electronic properties on the ruthenium as do a triphenylphosphine and cyclopentadienyl ligand. The uncoordinated phosphorus of the PN3 ligand in 13 is slowly oxidized under O2. In addition, two reactions of 13 with H2 were investigated, and preliminary results indicate that a reaction occurs in MeOH. 178 references on page 179 Chapter 5 5.10 References (1) Boggess, R. K.; Zatko, D. A. J. Coord. Chem. 1975,4, 217. (2) Gregorzik, R.; Wirbser, J.; Vahrenkamp, H. Chem. Ber. 1992,125, 1575. (3) Keene, F. R.; Snow, M. R.; Stephenson, P. J.; Tiekink, E. R. T. Inorg. Chem. 1988, 27, 2040. (4) Jessop, P. G.; Rettig, S. J.; Lee, C ; James, B. R. Inorg. Chem. 1991, 30, 4617. (5) Keene, F. R.; Snow, M. R.; Tiekink, E. R. T. Acta Crystallogr., Sect. C 1988,44, 757. (6) Alcock, N. W.; Cannadine, J. C ; Clark, G. R.; Hill, A. F. J. Chem. Soc, Dalton Trans. 1993, 1131. (7) Davies, S. G.; McNally, J. P.; Smallridge, A. J. Adv. Organomet. Chem. 1990, 30, 1. (8) Alcock, N. W.; Burns, I. D.; Claire, K. S.; Hill, A. F. Inorg. Chem. 1992, 31, 2906. (9) Huheey, J. E. Inorganic Chemistry; 3rd ed.; Harper & Row: New York, 1983, p 340. (10) Geary, W. J. Coord. Chem. Rev. 1971, 7, 81. (11) Gordon, A. J.; Ford, R. A. The Chemist's Companion; Wiley: New York, 1972, p 191. (12) Mudalige, D. C. Ph.D. Thesis, University of British Columbia, 1994. (13) Chaudret, B. N.; Cole-Hamilton, D. J.; Nohr, R. S.; Wilkinson, G. J. Chem. Soc, Dalton. Trans. 1977, 1546. (14) Dobson, A.; Moore, D. S.; Robinson, S. D.; Hursthouse, M. B.; New, L. Polyhedron 1985, 4, 1119. (15) Haines, R. J.; Du Preez, A. L. J. Organomet. Chem. 1975, 84, 357. (16) Davies, S. G.; Simpson, S. J. J. Chem. Soc, Dalton Trans. 1984, 993. 179 Chapter 5 (17) Bruce, M. I.; Wallis, R. C ; Williams, M. L.; Skelton, B. W.; White, A. H. J. Chem. Soc., Dalton Trans. 1983, 2183. (18) James, B. R. Stud. Surf. Sci. Catal. 1991, 66, 195. (19) Keene, F. R.; Stephenson, P. J. Inorg. Chim. Acta 1991,187, 111. (20) Huheey, J. E. Inorganic Chemistry; 3rd ed.; Harper & Row: New York, 1983, p 827. (21) Fogg, P. G. T.; Gerrard, W. Solubility of Gases in Liquids; John Wiley & Sons: New York, 1991, p 307. (22) Joshi, A. M. Ph.D. Thesis, University of British Columbia, 1990. 180 CHAPTER 6 6.1 Conclusions and Recommendations for Future Work A variety of ruthenium compounds containing 2-pyridylphosphines has been described in this thesis. The initial aim of this work was to utilize the 2-pyridylphosphines to make water-soluble catalysts, but because of the variety of coordination modes exhibited by the phosphines, particularly P N 2 and PN3, the different coordination modes were investigated. The different coordination modes, shown in Chapter 1 (Section 1.3.2), have been observed in complexes, with various metal centres (see Section 1.3.2). In this work, they were observed in a series of related complexes with a single metal centre, ruthenium. Through control of stoichiometry and reaction conditions, the different modes were observed in complexes synthesized by ligand substitution of RuCl2(PPh3)3. For example, [RuCl(PNx)3]Cl (x = 2, 3) contained P- and P^-coordinated PN X ligands. The new P^AT-coordination mode was observed in [RuCl(PPh3)2(PNx)]PF6 (x = 2, 3). As well, the complex RuCl2 (PPh 3 )(PN3) was synthesized containing an A7,A7',A/"-coordinated P N 3 . These complexes were characterized by several techniques including NMR, IR, and UV-visible spectroscopies, as well as X-ray crystallography, conductivity and elemental analysis. The different coordination modes of the 2-pyridylphosphines in ruthenium complexes can now be easily established by 3 1P{ lH} and *H NMR spectroscopies. There is a correlation between the coordination mode of a 2-pyridylphosphine and its 3 1P{ 1H} NMR chemical shift. Figure 6.1 shows a plot of chemical shifts versus coordination modes for the complexes synthesized during this work. The chemical shifts for the different coordination modes fall into specific ranges. In combination with *H NMR spectroscopy, specifically the number of signals and the integration ratios of the pyridyl H6 protons (see Appendix A), the coordination mode of the 2-pyridylphosphine 181 references on page 186 Chapter 6 6b 6c P,N,N' _ a Mode P,N 1 2a-c 3 lOa-b i mini en • tion g 13 14a-b ISa-c N,N',N" _ r m n O U P 1 3 • nm i i i i 31P{1H} Chemical Shift (ppm) Figure 6.1 Illustration of the correlation between the coordination mode of a 2-pyridylphosphine and its 3 1P{ 1H} NMR chemical shift in ruthenium complexes. Labels correspond to the numbers assigned to the complexes. can be established. Thus a sufficient data base of ruthenium 2-pyridylphosphine complexes now exists, and this is useful for future investigations. Utilizing PN2 and PN3, water-soluble ruthenium complexes were synthesized (Chapter 3). The substitution of a phenyl group by a pyridyl group in going form PN2 to PN3 increased the solubility of the complexes. There was no catalysis for the hydration of maleic acid to malic acid. The propensity of the 2-pyridylphosphines to coordinate ruthenium via both the phosphorus and the nitrogen of a pyridyl group, forming coordinatively saturated complexes, was the most likely reason for the inactivity. The use of 3-pyridyl or 4-pyridylphosphines could be explored to overcome this problem. A synthesis for tris(3-pyridyl)phosphine has been described,1 although others have reported difficulties in preparing 3- and 4-pyridylphosphines. One problem which may arise, 182 references on page 186 Chapter 6 however, is the formation of polymeric products for complexes with these phosphines, with the 3- or 4-pyridyl groups bridging ruthenium centres. As an alternative, ruthenium complexes with the TPPTS ligand (the tri sodium salt of tris(m -sulfonatophenyl)phosphine) may be suitable for olefin hydration. The new P,A/,AT-coordination mode (Chapter 4) offers some interesting prospects for future work. This is a strained coordination mode, as determined from the crystal structure of [RuCl(PPti3)2(PN3)]PF6, and the reactivity of this coordination mode was explored. Although no reactions were observed with H2, O2, or N2 at room temperature and 1 atm pressure, the P,N,N'-PNX (x = 2, 3) complexes underwent rapid reactions with CO. In the case of the mixed phosphine complexes containing PN X and DPPB ligands, the reactions were reversible; however, isomerization without CO loss could be a competing reaction. This needs to be confirmed. Based on the apparently selective and reversible reactions with CO, complexes containing a P,iV,W-coordinated 2-pyridylphosphine may be suitable for separating CO from gas mixtures. Some work has been done utilizing metal complexes for the separation of gas mixtures.4 To prevent isomerization products from acting as 'CO sinks,' a tripodal ligand could be employed, as shown in Figure 6.2. L L L = a Apodal ligand Figure 6.2 A complex for the selective and reversible coordination of CO, containing a P,A/,A/'-coordinated PNX (x = 2, 3) and a tripodal ligand. 183 references on page 186 Chapter 6 One route into such a complex could be via the complex RuCl2(PPh3)(PN3) (Chapter 5). Based on the reactivity of this complex, a synthetic scheme is proposed in Figure 6.3. However, the donor properties of the pyridyl groups of the N,N',N"-coordinated PN3 ligand may change the electronic properties of the metal centre making CO binding non-reversible. Alternatively, one of the complexes shown in Figure 5.4 or a complex containing a tripodal phosphine (e.g., TRIPHOS, Ph2P(CH2)2P(Ph)-(CH2)2PPli2), could be used. The determination of the CO reaction rates would also be worthwhile. PPh, xsPN x A C 6 H 6 C U T PPh, Cl 2NH 4 C1 2 NH 4 PF 6 MeOH + 2 PFF Figure 6.3 Proposed synthesis for a complex containing a P^iV'-coordinated PN X (x = 2, 3) ligand as well as a tripodal PN3 ligand. As mentioned, the complexes [RuCl(PPh3)2(PN3)]PF6 (x = 2, 3) did not react with hydrogen at room temperature and 1 atm pressure, but these complexes (or their imine coordinated derivatives) were capable of activating hydrogen at high pressures, as illustrated by the hydrogenation of A/-benzylidenebenzylamine (Section 4.6.2). High pressure NMR spectroscopy may be useful for observing the mode of H2 activation. 184 references on page 186 Chapter 6 Furthermore, the catalysis may be improved by making the monohydride analogues of these complexes; for example, [RuH(PPh3)2(PNx)]PF6 (x = 2, 3), possibly via reaction of PNX with Ru(H)Cl(PPh3)3 5 - 7 (Figure 6.4). Figure 6.4 Proposed synthesis and structure of the hydride complexes: The hydride analogues may be well suited for hydrogenation, because displacement of a coordinated pyridyl group by substrate provides good positioning for insertion into the metal hydrogen bond. In light of the hydrogenation results and the reactions with CO, these complexes may also be suitable for hydroformylations. The synthesized complex RuCl2(PPh 3)(PN 3) also contains an N,N',N"-coordinated PN 3 , and this complex undergoes ligand substitution reactions, similar to RuCl(PPh3)2(Cp) (Chapter 5). Control of reaction conditions allowed for substitution of either a chloride or the triphenylphosphine of RuCl2(PPh3)(PN3). One direction for further work in this area is exploration of the organometallic chemistry of RuCl2(PPh3)(PN3). Based on the similarities to RuCl(PPh3)2(Cp) and the variety of organometallic complexes formed by the Cp complex,8 similar chemistry could be explored with the PN 3 complex. A second area requiring further investigation is the air-sensitivity of RuCl2(MeCN)(PN3). This complex may be suitable for catalytic oxidations, depending on its reactivity with oxygen. PPh3 + NH4C1 [RuH(PPh3)2(PNx]PF6 (x = 2, 3). 185 references on page 186 Chapter 6 6.2 References (1) Wajda-Hermanowicz, K.; Pruchnik, F. P. Transition Met. Chem. 1988,13, 101. (2) Kurtev, K.; Ribola, D.; Jones,, R. A.; Cole-Hamilton, D. J.; Wilkinson, G. / . Chem. Soc., Dalton Trans. 1980, 55. (3) Fache, E.; Santini, C ; Senocq, F.; Basset, J. M. / . Mol. Catal. 1992, 72, 331. (4) Nelson, D. A.; Hallen, R. T.; Lee, C.-L.; James, B. R. In Recent Developments in Separation Science, ; N. N. Li and J. M. Calo, Ed.; CRC Press: Boca Raton, 1986; Vol. IX; p 1. (5) Hallman, P. S.; McGarvey, B. R.; Wilkinson, G. / . Chem. Soc.(A) 1968, 3143. (6) Schunn, R. A.; Wonchoba, E. R. Inorg. Synth. 1972, XIII, 131. (7) Thorburn, I. S. M.Sc. Thesis, University of British Columbia, 1980. (8) Davies, S. G.; McNally, J. P.; Smallridge, A. J. Adv. Organomet. Chem. 1990,30, 1. 186 APPENDICES 187 APPENDIX A A.l 31P{!H} and J H NMR Data for 2-Pyridylphosphines and 2-Pyridylphosphine Oxides The 31P{!H} and lH NMR chemical shifts for PNX and OPN x (x = 1, 2, 3) are reported in Table A . l . Phosphine signals appear as singlets. Proton assignments are made based on the reported assignments for PN3 and OPN3 in CDCI3. ' The numbering scheme used for proton assignments is shown in Figure A . l . The A H NMR spectra, in CDCI3 and C6D6, of the 2-pyridylphosphines and 2-pyridylphosphine oxides are shown in Figures A.2 and A.3, respectively. Each proton in PN3 and OPN3, H3 through H6, shows a distinctive pattern (see Figures A.2 and A.3) in the X H NMR spectra. Based on these patterns in combination with the integrations, the assignments for PNi, OPNi, PN2, and OPN2 have been made. All the iff NMR signals appear as multiplets; however, H6 can be consider a pseudo-doublet. When the solvent is changed from CDCI3 to C6D6, the proton signals for the 2-pyridylphosphines and 2-pyridylphosphine oxides spread out, and the order of peaks, in terms of chemical shifts, can change. For example, for PN3 the H3 and H4 proton signals change order when the solvent is changed from CDCI3 to C6D6, see Figure A.2. Interestingly, this does not occur for OPN3. The relative changes in the shifts seen in CgDg (compared to those in CDCI3) are due to the anisotropy caused by the benzene rings and assist in making assignments.3'4 The H6 proton signals are useful for determining the number of equivalent pyridyl rings in a metal complex, and give some insight into the coordination mode of the ligand. The number of equivalent pyridyl rings, depending on the phosphine, can be determined by the number of H6 signals observed and their integration. Although the signals shift when the ligand coordinates to a metal (in comparison to the shifts of the free ligands) and some H6 signals may be obscured by other resonances, the signals generally appear 188 references on page 192 Appendix A downfield of other peaks in the phenyl region and their distinctive appearance makes them easily identifiable. Table A . l 3 1P{!H} and lH NMR Chemical Shifts of 2-Pyridylphosphines and 2-Pyridylphosphine Oxides Solvent Phosphine 31p (a) H3 0>) H4 H5 H6 H7 H8&H9 CDCI3 PNi -3.95 7.08 7.56 7.17 8.72 7.38 7.38 PN 2 -2.62 7.24 7.58 7.18 8.72 7.51 7.40 PN 3 -0.74 7.39 7.60 7.20 8.71 - -C 6 D 6 PNi -3.62 7.06 6.85 6.49 8.51 7.53 7.06 PN 2 -2.02 7.32 6.90 6.50 8.49 7.72 7.09 PN 3 -0.13 7.47 6.95 6.53 8.50 - -CDCI3 OPNi 21.32 8.30 7.88 7.40 8.78 7.88 7.46 OPN 2 17.34 8.12 7.81 7.38 8.79 8.12 7.49 OPN 3 14.56 8.20 7.80 7.38 8.78 _ -C 6 D 6 OPNi 15.53 8.48 6.97 6.46 8.32 8.19 7.02 OPN 2 14.34 8.15 6.91 6.44 8.36 8.69 7.14 OPN 3 (c) - 8.30 6.96 6.48 8.40 - -(a) Singlets, (b) All proton signals are multiplets. (c) Limited solubility. 9 Figure A . l Numbering scheme for 2-pyridylphosphines and 2-pyridylphosphine oxides. Example shown is for PN 2 . PNi and PN 3 are similarly labelled. 189 references on page 192 Appendix A Figure A.2 *H NMR (300 MHz) spectra of 2-pyridylphosphines in CDCI3 and C6D6. 190 references on page 192 Appendix A ,.niliiii|.iH|Mii|M.ili.>.|,,i>liiM|>i,i|>ii,|.iii.i,.i|iiii|iiii|.iii|ini|!iii|>iii|iiii|iiii r—i—i—i—i—i—i—i—[—1—I—n—i—i—|—i—i—i—i—I—;—i—i—i—|—i—i—i—i—i 9 0 8 9 8 6 8 * 8.2 3 0 7 .8 7 .5 7 .4 7 . 2 PCVI 9 0 8 5 8.0 7 . 5 7. C 8.5 °»U 9 0 CDCI3 C 6 D 6 Figure A.3 lH NMR (300 MHz) spectra of 2-pyridylphosphine oxides in CDCI3 and C 6 D 6 . 191' references on page 192 Appendix A A.2 References (1) Jackobsen, H. J. J. Mol. Spectrosc. 1970, 34, 245. (2) Griffin, G. E.; Thomas, W. A. J. Chem. Soc. (B) 1970, 477. (3) Keat, R. Chem. andlnd. (London) 1968, 1362. (4) Moore, D. S.; Robinson, S. D. Inorg. Chim. Acta 1981, 53, L171. 192 references on page 192 APPENDIX B Crystallographic Data for [RuCl(PPh3)(PN3)2]PF6 (2c) H23 H24 Figure B. 1 Molecular structure of cation in [RuCl(PPh3)(PN3)2]PF6 (PLUTO plot). 193 Appendix B Appendix B C3 C3 Figure B.3 Molecular structure of cation in [RuCl(PPh3)(PN3)2]PF6 (Stereoview). 195 Appendix Table B. 1 Experimental Details for [RuCl(PPh3)(PN3)2]PF6 Appendix B A. Crystal Data Empirical Formula Formula Weight Crystal Color, Habit Crystal Dimensions Crystal System Lattice Type No. of Reflections Used for Unit Cell Determination (26 range) Omega Scan Peak Width at Half-height Lattice Parameters C « H 3 9 C l F 6 N 6 P 4 R u 1074.28 yellow, prism 0.15 X 0.20 X 0.40 mm tri clinic Primitive 25 ( 20.2 - 25.4° ) 0.37° a = 12.488(1) A b= 17.869(1) A c= 10.8107(7) A a - 101.009(5)° 0= 93.344(7)° 7 = 91.416(6)° Space Group Z value Fooo ^(MoKa) V = 2362.4(3) A3 PI (#2) 2 1.510 g/cm3 1088 5.78 cm"1 B. Intensity Measurements Diffractometer Radiation Rigaku AFC6S MoKa (A = 0.71069 A) 197 Table B. 1 (cont.) Experimental Details for [RuCl(PPh3)(PN3)2]PF6 Take-off Angle Detector Aperture Crystal to Detector Distance Temperature Scan Type Scan Rate Scan Width No. of Reflections Measured Corrections graphite monochromated 6.0° 6.0 mm horizontal 6.0 mm vertical 285 mm 21'C w-20 16°/min (in u) (up to 9 scans) (1.05 -I- 0.35 tan 6)' 60° Total: 14372 Unique: 13782 (R;„, = 0.027) Lorentz-polarization Absorption (trans, factors: 0.914- 1.000) Decay (4.56% decline) C. Structure Solution and Refinement Structure Solution Refinement Function Minimized Least Squares Weights p-factor Anomalous Dispersion No. Observations (I>3<r(I)) No. Variables Reflection/Parameter Ratio Residuals: R; Rw Goodness of Fit Indicator Patterson Methods (DIRDIF92 PATTY) Full-matrix least-squares Zw(\Fo\ - |Fe|)s «5(Vo) = 0.000 All non-hydrogen atoms 6539 S95 14.35 0.038 ; 0.038 1.93 Max Shift/Error in Final Cycle Maximum peak in Final Diff. Map Minimum peak in Final Diff. Map 0.0006 0.87 e~/A3 -0.66 e " / A s 198 Appendix B Table B.2 Atomic Coordinates and Beq for [RuCl(PPh3)(PN3)2]PF6 atom * y • Ru(l) 0.2456.2(2) 0.20317(1) 0.20359(2) 2.135(5) C1<1) 0.30535(7) 0.12110(5) 0.01656(7) 3.52(2) P(l) 0.15659(7) 0.30406(5) 0.31374(8) 2.52(2) P(2) 0.20776(7) 0.10250(5) 0.30156(8) ' 2.62(2) P(3) 0.42050(6) 0.24163(5) 0.27862(7) 2.33(2) P(4) 0.88776(10) 0.33912(7) 0.8403(1) 5.54(3) F(l) 0.8454(4) 0.2716(2) 0.8986(3) 12.6(1) F(2) 0.8841(5) 0.2887(2) 0.7107(3) 15.5(2) F(3) 0.9987(3) 0.3133(3) 0.8745(6) 18.9(2) F « ) 0.9320(4) 0.4058(2) 0.7908(5) 15.6(2) F(5) 0.8874(4) 0.3892(2) 0.9774(3) 13.3(1) F(6) 0.7766(3) 0.3692(3) 0.8227(4) 14.9(2) NO) 0.2314(2) 0.2946(1) 0.1034(2) 2.57(6) N(2) •0.0215(2) 0.2444(2) 0.3827(3) 4.61(9) N(3) 0.2667(2) 0.4239(2) 0.4506(3) 4.07(7) N(4) 0.0911(2) 0.1492(1) 0.1388(2) 274(6) N(5) 0.2646(3) 0.1162(2) 0.5431(3) 4.56(6) N(6) 0.2021(3) -0.0471(2) 0.3075(3) 4.58(8) C(l) 0.1836(2) 0.3504(2) 0.1820(3) 2.74(7) C(2) 0.1676(3) 0.4211(2) 0.1532(3) J.66(8) C(3) 0.2007(3) 0.4346(2) 0.0392(4) 4.46(10) C(4) 0.2486(3) 0.3777(2) -0.0408(3) 4.33(10) C(5) 0.2634(3) 0.3082(2) -41.0060(3) 349(8) C(6) 0.0105(3) 0.2915(2) 0.3086(3) 1.09(7) *U>m X y C(31) 0.4488(3) 0.2878(2) C<32) 0.1788(3) 0.2753(2) C(33) 0.4058(4) 0.3021(2) C(34) 0.5017(4) 0.3416(2) C(35) 0.6714(4) 0.3550(2) C(36) 0.5458(3) 0-3278(2) C(37) 0.4815(2) 0.1116(2) . C(38) 0.4506(3) 0.3868(2) C(39) 0.4895(4) 0.4429(2) C(40) 0.5595(3) 0.4255(1) . C(41) . 0.5908(3) 0.3525(3) Q42) 0.5523(3) 0.2960(2) C(43) 0.5156(2) 0.1639(2) C(44) 0.5542(3) 0.1404(2) C(45) 0.6249(4) 0.0806(1) C(46) 0.6573(4) 0.0450(2) C(47) 0.6177(3) 0.0667(2) C(48) 0.5464(3) 0.1248(2) •torn X y X B., C<7) -0.0585(3) 0.3231(2) 0.2307(4) 47(1) cm -0.1673(3) 0.3043(3) 0.2295(5) 6.5<1) C(9) -0.2014(3) 0.2573(3) 0.3060(5) 6.4(1) C(10) -0.1274(4) 0.2294(3) 0.1809(5) 6.2(1) C(ll) 0.1845(3) 0.3775(2) 0.4573(3) 2.99(7) C(12) 0.1246(3) 0.1831(2) 0.5610(3) 4.42(9) C<13) 0.1527(4) 0.4408(3) 0.6649(4) 5.7(1) C(14) 0.2375(4) 0.4684(3) 0.6594(4) 5.8(1) C(15) 0.2943(4) 0.4777(2) 0.5527(4) 5.5(1) C(16) 0.0815(2) 0.0920(2) 0.2033(3) 2.78(7) C<17) -0.0064(3) 0.0419(2) 0.1658(4) 3.85(9) C(18) -0.0876(3) 0.0516(2) 0.0986(4) 4.56(10) Q19) -0.0793(3) 0.1100(2) 0.0336(4) 4.32(9) C(20) 0.0113(3) 0.1566(2) 0.0544(3) 1.55(8) C(21) 0.1760(3) 0.1106(2) 0.4665(3) 3.21(8) C(22) 0.0749(3) 0.1131(3) 0.5093(4) 5.8(1) C(23) 0.0643(4) 0.1251(3) 0.6384(5) 7-4(2) C(24) 0.1533(5) 0.1316(3) 0.7166(4) 6.4(1) C(25) 0.2510(4) 0.1271(2) 0.6681(4) 5.7(1) C(26) 0.2639(3) 0.0066(2) 0.2731(3) 1.08(7) C(27) 0.3603(3) -0.0071(2) 0.2228(4) 4.57(10) C(28) 04988(4) -0.0803(2) 0.2104(5) 5.9(1) C(29) 0.3378(4) -0.1160(2) 0.2463(4) 5.6(1) C(30) 0.2407(4) -0.1171(2) 0.2913(4) 6-6(1) t 0.4436(3) B., 2.82(7) 0.5331(3) 1.43(8) 0.6607(3) 5.1(1) 0.6983(4) 58(1) 0.6098(4) s.eo) ' 0.4830(3) 4.03(9) 0.1966(3) 2 74(7) 0.2310(3) 1.77(9) 0.1710(4) 4.9(1) 0.0784(4) 4.9(1) 0.0429(4) 48(1) 0.1020(3) 1.74(9) 0.2694(3) 2.89(7) 0.3779(4) 4.27(9) 0.1701(4) 58(1) 0-2550(5) 5-8(1) 0.1472(4) 50(1) 0.1511(1) 1.79(6) 199 Appendix B Table B.3 Bond Lengths (A) for [RuCl(PPh3)(PN3)2]PF6 Atom •torn distance atom •lom distance Ru(l) CI{1) 2.4275(6) Mi) p(i) 2.3103(6) Ru(l) P(2) 2.3077(8) M O P(3) 2.3252(6) Ml) N(l) 2.132(2) Mi) N(4) 2.153(3) P(l) C(l) 1.622(3) P(i) C(6) 1.829(3) P(i) C(ll) 1.841(3) P(2) C(16) 1.834(3) P(2) C(21) 1.829(3) P(2) Q26) 1.645(3) P(3) C(3I) 1.627(3) P(3) Q37) 1.841(3) P(3) C(<3) 1.641(3) P(4) F(l) 1.559(3) P(4) F(2) 1.512(3) P(4) F(3) 1.518(4) P(4) F(4) 1.502(3) P(4) F(5) 1.579(4) P<4) r<6) 1.516(4) N(l) Q l ) 1.355(4) N(l) C(5) 1.334(4) N(2) C(6) 1.336(4) C(10) 1.342(5) N(3) C(ll) 1.336(4) N(3) C(15) 1.334(4) N(4) Q16) 1.349(4) N(4) C(20) 1.347(4) N(5) C(21) 1.333(4) N(S) C(25) 1.349(5) N(6) C(26) 1.336(4) N(6) C(30) 1.340(5) C(l) C(2) 1.375(4) C(2) C(3) 1.364(5) C(3) Q4) 1.377(5) C<1) C(5) 1.378(5) C(6) C(7) 1.376(5) C(7) C<8) 1.390(6) C(8) C(9) 1.365(7) C<9) C(10) 1.359(7) C(ll) C(12) 1.372(4) C(12) C(13) 1.394(5) C(13) C(14) 1.352(6) C<14) C(15) 1.375(6) C(16) C(17) 1.380(4) Q17) C<16) 1.383(5) C(18) C(19) 1.368(5) •torn atom distance atom atom distance C<19) C(20) 1.391(5) C(21) C(22) 1.369(5) C(22) C(23) 1.486(6) C(23) C<24) 1.345(7) C(24) C(25) l.SS4(6) C(26) C(27) 1460(5) C(27) C<28) 1491(5) C(28) C(29) 1.365(6) C(29) C(30) 1459(6) C(31) C(32) 1486(4) C(31) C(36) 1.393(4) C(32) C(33) 1.390(5) C(33) C<34) 1.374(6) C(34) C(35) 1.380(6) C{35) C(36) 1.380(5) C(37) C(38) 1494(4) C(37) C<42) 1483(4) C(3«) C(39) 1487(5) C{39) C<40) 1.364(6) C(40) C<41) 1.360(6) C«l) C(42) 1.384(5) C(43) C(44) 1484(5) C<43) C<46) 1.397(4) C<44) C(45) 1.394(5) C<45) C(46) 1.376(6) C(46) C(47) 1467(6) a<7) a<6) 1.380(5) 200 •lom atom •torn angle atom atom atom angle Cl(l) Ru(l) P(l) 155.01(3) Cl(l) Ru(l) P(2) 93.48(3) Cl(l) Ru(l) P(3) 92.41(3) Cl( l ) Ru(l) N(l) 90.25(7) CKD Ru(l) N(4) 83 68(7) P(l) M O P(2) 104.54(3) p<0 R»(l) P(3) 98.95(3) p( l ) Ru(l) N(l) 67.92(7) P(l) Ru(l) N(4) 87.83(7) P(2) Ru(l) P(3) 103.77(3) P<2) RU(1) N(l) 163.37(7) P(J) M"> N(4) 67.98(7) P(3) Ru(l) N(l) 92.24(7) P(3) Ru(l) N(4) 170.53(7) 'N(I) Ru(l) N(4) 96.39(0) Ru(!) P(l) C( l ) 84.8(1) Ru(!) P(>) C(6) 115.6(1) R«(D P(l) C ( l l ) 136.6(1) CO) P(D C(6) 105.5(2) C( l ) P(l) C ( l l ) 105.8(1) C(6) P(D C ( l l ) 102.2(1) R„(I) P(2) C(16) B4.9(l) R»(l> P(2) C(21) 125.6(1) Ru(l) P(2) C(20) 128.1(1) C(16) P(2) C(21) 108.4(2) C(16) P(2) C(26) 104.8(1) C(2I) P(2) 0(28) 99.9(1) R»(l) P(3) C(31) 120.1(1) Ru(l) P(3) C(37) 113.75(10) Ro(l) P(3) C(43) 1148(1) C(31) P(3) CK37) 101.2(1) C(31) P(3) C(43) 99.4(1) C(37) P(3) C(43) 105.4(1) F(l) P(4) F(2) 91.0(2) F(l) P « ) F(3) 85.3(3) F( l ) P(4) F(4) 176.9(3) F(l) P(4) F(5) 86.5(2) F( l ) P(4) F(6) 93.2(3) F<3) P(4) F(3) 92.0(3) F(2) P(t) F(4) 91.6(2) F(2) P(4) F(5) 177.3(3) F(2) P(4) F(6) 94.7(3) F(3) P(4) F(4) 93.0(3) F(3) P(4) F(5) 88.9(3) F(3) P(4) F(6) 173.1(3) F(4) P(4) F(5) 90.9(2) F(4) P(4) F(6) 88.2(3) F(5) P(4) F(6) 84.3(2) •torn atom atom angle atom atom atom angle C(26) C(2?) C(28) 118.3(4) C(27) C(28) C(J») 119.2(4) C(28) C(28) C(30) 118.1(4) N(6) C(30) C(29) 124.4(4) P(3) C(31) C(32) 119.5(2) P(3) Q31) C(36) 120.8(3) C(32) C(3I) . C(38) 119.3(3) C(31) C(32) C(33) 120.1(3) C(32) C(33) C(34) 120.0(4) C(33) C(34) C(35) 120.3(4) C(3() C(35) C(36) 120.1(4) C(31) C(36) C(35) 120.2(4) atom atom »lom angle atom •torn atom angle Ru(l) N(l) C(l) 105.1(2) M O N(l) C(6) 135 3(3) C(l) N(l) C(5) 119.3(3) 0(6) N(2) qio) 110.8(4) C( l l ) N(3) C(15) 116.6(3) R»(D N(4) qio) 104.8(2) Ru(l) N(4) C(20) 136.2(2) C(16) N(4) q20) 116.9(3) C(21) N(5) C(25) 1168(4) C(26) N(6) qso) 116.4(4) P(l) C(l) N(l) 102.0(2) P(l) C(l) C(2) 135.9(3) N(l) C(l) C(2) 132.1(3) qi) C(2) qs) 118.2(3) C(2) C(3) C(4) 119.5(3) C(3) q<) C(5) 119.6(3) N(l) C(5) C(4) 121.2(3) P(D C(6) N(2) 112.7(3) P(l) C(6) C(7) 123.5(3) N(2) q») cm 123.6(3) C(6) C(7) C(8) .117.6(4) CP) qe) cm 119.5(4) C(6) C(9) C(10) 118.8(4) N(2) qio) q») 123.6(4) P(l) C ( l l ) N(3) 113.6(2) P(l) q i i ) C ( l . ) 122.8(3) N(3) C(l l) C(12) 123.6(3) C(l l) q i 2 ) qis) 118.2(4) C(12) C(13) C(») 118.8(4) C(13) qu) qis) 119.2(4) N(3) C(15) C(14) 123.5(4) P(2) qit) N(4) 102.2(2) P(2) C(16) C(17) 134»(J) 1(4) qi«) qi7) m.»(J) C(16) C(17) C(18) 117.9(3) C(17) qi«) C(19) 119.7(3) C(18) C(19) dlO) 120.0(3) K(<) qio) qi9) 130.6(3) P(2) C(21) N(5) 111.6(3) P(2> qji) qi2) 125.4(3) N(5) C(21) C(M) 113.0(3) C(21) qjj) qa) 118.4(4) C(22) Q23) C(24) 119.0(5) C(23) q»4) q » ) 119.6(4) N(5) C(25) C(24) 123.1(4) P(2) q26) N(6) 114.2(3) P(2) C(26) C(27) 122.2(3) N(6) « 2 6 ) C(27) 123.6(3) P(3) C(37) C(38) 116.5(2) P(3) q s ? ) q « ) 126.0(3) C(38) C(37) C(42) 117.6(3) C(37) qsB) C(39) 120.4(3) C(38) C(39) C(40) 120.5(4) q39) q « ) q<D 120.2(4) C(40) C(41) C(42) 1)9.8(4) C(37) C(«) q4i) 121.6(4) P(3) C(43) C(44) 120.5(3) P(3) q43) q48) 121.1(3) C(44) C(43) C(48) 1)8.4(3) C(43) q44> C(45) 120.3(4) C(44) C(45) C(46) 120.3(4) C(45) q<6) q47) 119.6(4) C(46) C(47| C(<8) 130.5(4) ^43) q48) q47) 120.7(4) H a; o 3 a. on 73 c Q APPENDIX C Crystallographic Data for [RuCl(PPh3)2(PN2)]PF6 (6b) Figure C. 1 Molecular structure of cation in [RuCl(PPh3)2(PN2)]PF6 (PLUTO plot). 202 Appendix C C15 C14 Figure C.2 Molecular structure of cation in rRuCl(PPh3)2(PN2)]PF6 (ORTEP plot). 203 Appendix C C35 C17 C35 C17 Figure C.3 Molecular structure of cation in [RuCl(PPh3)2(PN2)]PF6 (Stereoview). (Phenyl groups omitted for clarity). 204 Appendix C Figure C.4 Unit cell for [RuCl(PPh3)2(PN2)]PF6. 205 Table C. 1 Experimental Details for [RuCl(PPh3)2(PN2)]PF6 A. Crystal Data Empirical Formula Formula Weight Crystal Color, Habit Crystal Dimensions Crystal System Lattice Type No. of Reflections Used for Unit Cell Determination (20 range) Omega Scan Peak Width at Half-height Lattice Parameters C s2H<3ClF6N2P<Ru 1070.33 orange, prism 0.30 X 0.40 X 0.40 mm monodinic Primitive 25 ( 25.1 - 30.3° ) 0.34° a = 17.795(2) A b = 11.375(4) A c= 23.343(2) A 0 = 97.012(8)' Space Group Z value Fooo /i(MoKa) V = 4689(1) A 3 P2i/c (#14) 4 1.516 g/cm3 2176 5.91 cm"1 B. Intensity Measurements Diffractometer Rigaku AFC6S Radiation MoKa (A = 0.71069 X) graphite monochromated 206 Table C. 1 (cont.) Experimental Details for [RuCl(PPh3)2(PN2)]PF6 Take-off Angle Detector Aperture Crystal to Detector Distance Temperature Scan Type Scan Rate Scan Width 2#m<n No. of Reflections Measured Corrections 6.0° 6.0 mm horizontal 6.0 mm vertical 2S5 mm 21'C 32°/min (in u) (up to 9 scans) (1.15 + 0.35 tan 6)' 60° Total: 14722 Unique: 14304 (R,„, = 0.037) Lorentz-polamation Absorption (trans, factors: 0.955- 1.000) Secondary Extinction (coefficient: 7.4(4) x 10-8) C. Structui Structure Solution Refinement Function Minimized Least Squares Weights p-factor Anomalous Dispersion No. Observations (I>3c(I)) No. Variables Reflection/Parameter Ratio Residuals: R; Rw Goodness of Fit Indicator Max Shift/Error in Final Cycle Maximum peak in Final DifT. Map Minimum peak in Final Diff. Map Solution and Refinement Patterson Methods (DIRDIF92 PATTY) Full-matrix least-squares £t<,(|Fo|-|Fc|)J c'(Fo) «>(Fo') 0.000 All non-hydrogen atoms 7690 596 12.90 0.036; 0.035 1.73 0.003 0.54 t~ IXs -0.44 c-/A3 207 Table C.2 Atomic Coordinates and Beq for [RuCl(PPh3)2(PN2)]PF6 Appendix C ..on, X y I B„ •lom y t B., Ru(l) 0.25410(1) 0.16459(2) 0.05636(1) 2.141(5) COD 0.1091(2) 0.3862(3) 0.1136(1) 2.84(7) C1<1) 0.31535(5) -0.00798(7) 0.02416(4) 3.46(2) C(12) 0.1384(2) 0.4257(3) 0.1683(1) 3.60(9) P(l) 0.15152(4) 0.25754(7) 0.08641(3) 2.37(2) COD 0.1125(3) 0.5285(4) 0.1895(2) 5.0(1) P<2) 0.28773(5) 0.28867(7) -0.01672(4) 2.54(2) C(14) 0.0566(2) 0.5919(3) 0.1581(2) 5.1(1) P(3) 0.35286(5) 0.20578(8) 0.13021(4) 2.68(2) C(15) 0.0261(2) 0,5532(3) 0.1045(2) 4.6(1) P(4) -0.12506(7) 0.25121(10) 0.15880(5) 4.97(3) C(16) 0.0528(2) 0.4503(3) 0.0819(2) 3.66(9) F(D -0.1550(3) 0.3730(3) 0.1467(2) 16.2(2) C(l 7) 0.3784(2) 0.2842(3) -0.0472(1) 3.26(8) F(2) -0.0577(2) 0.2977(4) 0.2023(2) 145(2) C(18) 0.4342(2) 0.2043(3) -0.0288(2) 3.93(9) F(3) -0.0736(2) 0.2571(3) 0.1096(1) 11.3(1) C(l 9) 0.4997(2) 0.1978(4) -0.0563(2) 6.0(1) F(4) -0.0922(2) 0.1239(2) 0.1739(1) 8.80(9) C(20) 0.5073(2) 0.2665(4) -0:i029(2) 5.6(1) F(5) -0.1674(2) 0.1928(4) 0.1179(2) 12.5(1) C(21) 0.4515(2) 0.3469(4) -0.1226(2) 5.2(1) F(6) -0.1730(2) 0.2417(3) 0.2104(1) 9.9(1) C(22) 0.3863(2) 0.3552(3) -0.0948(2) 4.31(9) N(l) 0.1987(1) 0.0600(2) 0.1162(1) 2.56(6) C(23) 0.2281(2) 0.2618(3) -0.0861(1) 2.72(7) N(2) 0.1465(1) 0.1250(2) 0.0023(1) 247(5) C(24) 0.2396(2) 0.1558(3) -0.1133(1) 3.77(8) C()) 0.1443(2) 0.1312(3) 0.1333(1) 2.60(7) C(25) 0.1979(2) 0.1274(4) -0.1654(2) 4.8(1) C<2) 0.0962(2) 0.0961(3) 0.1724(1) 3.42(8) C(26) 0.1436(2) 0.2045(5) -0.1901(2) 63(1) C(3) 0.1046(2) -0.0186(4) 0.1938(2) 4.28(10) C(27) 0.1337(2) 0.5095(4) -0.1648(2) 5-0(1) C(4) 0.1583(2) -0.0905(3) 0.1749(2) 4.19(9) C<28) 0.1749(2) 0.3393(3) -0.1129(1) 3.74(8) C(5) 0.2048(2) -0.0502(3) 0.1362(1) 3.44(6) C(29) 0.2746(2) 0.4452(3) -0.0031(1) 3.04(7) C<6) 0.0957(2) 0.1945(2) 0.0230(1) 2.27(6) CX30) 0.3343(2) 0.5241(4) 0.0042(2) 4.7(1) C<7) 0.0207(2) 0.1935(3) -0.0004(1) 3.21(8) C(J1) 0.3201(3) 0.6426(4) 0.0164(2) 6.2(1) C(8) 0.0008(2) 0.1208(3) -0.0476(2) 4.04(9) C(32) 0.2486(3) 0.6802(4) 0.0211(2) 6.5(1) C(9) 0.0537(2) 0.0468(3) -0.0672(1) 3.84(9) C(33) 0.1893(3) 0.6028(3) 0.0153(2) 5.1(1) C(IO) 0.1273(2) 0.0507(3) -0.0406(1) 3.05(7) C(34) 0.2021(2) 0.4864(3) 0.0033(1) 3.58(8) } •lorn X y • B „ C(35) 0.4524(2) 0.2034(3) 0.1158(1) 3.07(7) C(36) 0.4931(2) 0.3075(3) 0.1156(2) 60(1) C(37) 0.5686(3) 04052(5) 0.1048(2) 6.6(1) C(38) 0.6039(2) 02034(5) 0.0946(2) 6.9(1) C(39) 0.5640(2) 0.1024(4) 0.0927(2) 55(1) C(40) 0.4879(2) 0.1012(3) 0.1023(2) 4.43(10) CX41) 04481(2) 0.0987(3) 0.1889(1) 3.12(8) C(42) 0.3849(2) -0.0078(4) 0.1917(2) 5.7(1) C(43) 04735(3) -0.0893(4) 0.2341(2) 74(1) C(44) 04238(3) -0.0689(5) 0.2726(2) 6.4(1) CX45) 0.2867(2) 0.0363(5) 0.2708(2) 5.6(1) C(46) 0.2989(2) 0.1205(4) 0.2298(2) 4.13(9) C(47) 04526(2) 04438(3) 0.1707(1) 3 51(8) C(48) 04153(2) 0.4427(3) 0.1479(2) 4.23(9) C(49) 04182(3) 04469(3) 0.1788(2) 5.»0) C(80) 04575(3) 0.5523(4) 04332(2) 7.0(1) C(51) 04951(3) 0.4545(5) 04561(2) 6.7(1) C(52) 04939(2) 04508(4) 04255(2) 62(1) B - = f "VM""')' + "»(" ' ) ' + fu(ee')' + Wivu'U- c a r 4 Wuac'a' c o 0 + StJaM-cc" c e o ) 208 Table C.3 Bond Lengths (A) for [RuCl(PPh3)2(PN2)]PF6 Appendix atom atom distance M i ) Cl(!) 2.4096(8) M i ) P(2) 2.3472(8) M i ) N(l) 2.161(2) P(i) C(l) 1.821(3) P(i) C(H) 1.787(3) P(2) C(23) 1.850(3) P(3) C(35) 1.843(3) P(3) C(47) 1.633(3) P(4) F(2) 1.565(4) P(4) F(4) 1.585(3) P(<) F(6) 1.562(3) N(l) C(5) 1.337(4) N(2) C(10) 1.328(4) C(2) C(3) 1.398(5) C(4) C(5) 1.375(5) C(7) C<8) 1.388(5) C(S) C(10) 1.380(4) C(ll) C(16) 1.379(4) C(13) C(14) 1.367(6) C(15) C(16) 1.391(5) C(17) C(22) 1.395(5) Q19) C(20) 1.373(6) C(21) C(22) 1.400(5) C(23) C(28) 1.385(4) atom atom dUta&ce C<25) C<26) 1.378(6) C(27) C(28) 1.380(5) C(29) C<34) 1.397(4) <3(31) C(32) 1.358(7) C(33) C(34) 1478(5) C<35) q<o) 1.378(5) C(37) C(38) 1.350(6) C(39) C(40) 1.399(5) C(41) C(46) 1.394(4) C(43) C<44) 1.356(6) 43(45) C(46) 1.389(5) C(47) C<52) 1.396(5) C(49) C(50) 1475(6) C(51) C(52) 1478(6) atom atom distance M i ) p(i) 2.2925(6) M U P(3) 2.3539(8) M U N(2) 2.180(2) P(i) C(6) 1.825(3) P(2) C(17) 1.842(3) P(2) C(29) 1.829(3) P(3) C(41) 1.844(3) P(4) F(l) 1.498(3) P(4) F(3) 1.556(3) P(4) F(5) 1.525(3) N(l) C(l) 1.359(4) N(2) C(6) 1.361(4) C(l) C(2) 1.363(4) C(3) C(4) 1.372(5) C(6) Q7) 1.379(4) C(6) C(9) 1.368(5) C(ll) C(12) 1.395(4) C(12) C(13) 1.372(5) C(14) C(15) 1-375(6) C(17) C(18) 1-375(4) C(18) C(19) 1.401(5) C(20) C(21) 1.372(6) C(23) C(24) 1.389(4) C(24) C(25) 1.385(5) atom atom distance (3(26) C(27) 1.354(6) C ( » ) 43(30) 1.384(4) C(30) C(31) 1.410(6) 43(32) C(33) 1468(6) C(S5) C(36) 1489(4) C(36) C(37) 1.401(6) C(38) C(39) 1448(6) C(41) 43(42) 1474(5) C<42) 43(43) 1489(5) 43(44) <3(45) 1.364(6) C « 7 ) C(4fi) 1480(5) C(48) C(49) 1484(5) C(50) C(51) 1474(6) 209 to I—» o •torn atom atom angle atom atom atom angle atom atom atom angle atom atom atom angle ci(i> R»0) P(I) 151.48(3) Cl(l) Ru(l) P(2) 95.63(3) R»(l) N(l) CO) 105.1(2) Ru(l) N(l) C(5) 135.8(2) C U D Ru(l) P(3) 03.72(3) CIO) R»(l) N(l) 90.71(7) CO) N(l) C(5) 119.0(3) Ru(l) N(2) C(6) 104.9(2) CIO) Ru(l) N<2) 92.40(7) PO) RuO) r(2) 103.19(3) Ru(l) N ( 2 ) C(I0) 135.5(2) C(6) N(2) C(10) 119.6(3) P<1) R»0) P(3) 103.01(3) P(l) Ru(l) N(l) 67.24(7) P( l ) C(l) N(l) 100 8(2) P0) C(l) C(3) 136.0(3) PO) RuO) N(2) 67.05(7) P(2) RU(1) P(3) 100.30(3) N(l) C(l) q 2 ) 122.9(3) C(l) 0(2) q 3 ) 117.2(3) P(2) R»(i) NO) 187.74(7) P(2) Ru(l) N(2) 88.95(7) C(2) C(3) C(4) 119.3(3) C(3) C(4) 0(5) 120.7(3) P(3) Ru(l) NO) 89.72(7) P(3) R«0) N(2) 166.35(7) N O ) C(5) C(4) 120.8(3) PO) 0(6) N(2) 100.7(2) NO) Ru(l) N(2) 80.29(9) R-0) PO) CO) 86.4(1) P O ) C(6) C(7) 136.8(2) N(2) C(6) 0(7) 122.0(3) RuO) P(D q « ) 88.86(10) R"(l) P(l) q i i ) 150.2(1) C(6) C ( 7 ) C(6) 117.5(3) 0(7) C(8) 0(9) 120.1(3) q i ) PO) q « ) 96.1(1) C(l) P(l) q i i ) 111.5(1) C(8) C(9) qio) 119.7(3) N(2) C(10) C(9) 121.0(3) q « ) PO) C ( l l ) 113.3(1) RuO) P(2) C(17) 125.2(1) P(l) C(ll) C(12) 117.3(3) PO) 0(11) C(16) 123.4(3) Ru(l) P(2) q23) 111.53(10) R«(l) P(2) C(29) 114.2(1) C(12) C(ll) C(16) 119.1(3) 0(11) C(12) C(13) 120.1(3) q " ) P(2) C(23) 95.4(1) q " ) P(2) C(29) 103.3(2) C(12) C(13) C(14) 120.7(4) 0(13) C(14) CO 5) 120.0(4) q23) P(2) C<29) 104.0(1) R»0) P(3) q35) 120.8(1) C ( H ) qi s ) C(16) 120.0(4) 0(11) C(16) 0(15) 120.1(3) Rn(l) P(3) q4i ) 108.4(1) Ru(l) P(3) q<7) 120.0(1) P(2) 0(17) CO 8) 122.0(3) P(2) 0(17) 0(22) 118.0(3) q3S) P(3) q<0 105.0(1) C(35) P(3) q47) 99.8(1) C ( I S ) C(17) C(22) 119.5(3) 0(17) C(18) qi9) 120.1(4) q « ) P(3) q « ) 100.3(2) F(l) P(4) F(2) 92.1(3) C(18) C(19) C(20) 120.0(4) qio) C(20) C(21) 120.7(4) F(l) P<4) F(3) 91.8(2) F(l) P(4) F(4) 177.9(2) C(20) C(21) C(22) 119.7(4) q i ? ) C(22) C(21) 120.0(4) P(l) P(4) F(5) 94.0(3) F(l) P(4) F(6) 69.6(2) P(2) C(23) 0(24) 116.3(2) P(2) C(23) C(28) 125.3(3) F(2) P(4) F(3) 89.6(2) F(2) P(4) F(4) 86.1(2) q24) C(23) 0(28) 1184(3) q23) C(24) q25) 120.8(3) F(2) P(4) F(5) 173.8(3) F(2) P(4) F(6) 88.3(2) q24) C(25) 0(26) 119.5(4) C(25) q26) q27) 120.1(4) F(3) P(4) F(4) 88.2(2) F(3) P(4) F(5) 90.3(2) q26) C(27) C(28) 121.1(4) q23) q28) C(27) 120.1(4) F(3) P(4) F(«) 176.8(2) F(4) P(4) F(5) 87.8(2) P(2) C(29) C(30) 122.7(3) P(2) 0(29) C(34) 119.0(2) F(4) P(4) F(«) 89.3(2) F(5) P(4) F(6) 91.6(2) C(30) q29) C(34) 118.2(3) q29) C(30) C(31) 119.5(4) P(3) C(41) C(42) 123.6(3) P(3) C(41) 0(46) 118.7(3) atom •torn atom angle atom atom a lorn angle C(42) C(41) 0(46) 117.4(3) 0(41) 0(42) 0(43) 120.8(4) qso) C(31) C(32) 120.6(4) C(31) C(32) q33) 120.6(4) q33) 121.5(4) cm C(43) 0(44) 121.4(4) 0(43) C(44) q<5) 118.8(4) C(32) qj3) qj4) 119.6(4) q 2 9 ) q34) C(44) C(45) C(46) 120.7(4) C(41) q46) C(45) 120.8(4) P(3) C(35) C(38) 120.1(3) P(3) C(35) C(40) 122.2(3) q37) 119.8(4) P(3) C(47) 0(48) 122.1(3) P(3) 0(47) 0(52) 119.2(3) qan) C(35) Q40) 117.7(3) C(35) C(36) C(39) 118.9(4) C(48) C(47) 0(52) 118.7(3) C(47) 0(48) 0(49) 120.8(4) C(36) C(37) q3B) 121.6(4) q37) C(38) 120.5(4) C(48) C(49) C(50) 120.1(4) q49) C(50) C(5I) 119.5(4) C(38) C(39) C(40) 121.3(4) C(35) q40) q39) C(50) C(51) 0(52) 121.0(4) C(47) qs2) 0(51) 119.9(4) a; n C O o s a . 0£, o Q cr v ' a APPENDIX D Crystallographic Data for [RuCl(PPh3)2(PN3)]PF6 (6c) Figure D. 1 Molecular structure of [RuCl(PPh3)2(PN3)]PF6 (PLUTO plot). 211 Appendix D Figure D.2 Molecular structure of cation in [RuCl(PPh3)2(PN3)]PF6 (Stereoview). 212 Appendix D Table D. 1 Experimental Details for [RuCl(PPh3)2(PN3)]PF6 A . Crystal Data Empirical Formula Formula Weight Crystal Color, Habit Crystal Dimensions Crystal System Lattice Type No. of Reflections Used for Unit Cell Determination (20 range) Omega Scan Peak Width at Half-height Lattice Parameters C 5 i H 4 2 C I F 6 N 3 P 4 R u 1071.32 orange, prism 0.15 X 0.20 X 0.25 mm monoclinic Primitive 25 ( 25.0 - 33.6° ) 0.38° a = 17.812(1) A b = 11.353(2) A c = 23.391(1) A 0 = 97.738(5)° Space Group Z value Dco/c Fooo /i(MoKa) V = 4686(1) A 3 P2,/c(#14) 4 1.518 g/cm 3 2176 5.92 cm-1 B. Intensity Measurements DifTractometer Rigaku AFC6S Radiation MoKa (A = 0.71069 A) graphite monochromated 214 Table D. 1 (cont.) Experimental Details for [RuCl(PPh3)2(PN3)]PF6 Take-off Angle Detector Aperture Crystal to Detector Distance Temperature Scan Type Scan Rate Scan Width No. of Reflections Measured Corrections 6.0° 6.0 mm horizontal 6.0 mm vertical 285 mm 21.0°C u-20 16.0°/min (in u) (up to 9 scans) (1.10 + 0.35 tan 0)° 60.0° Total: 14834 Unique: 14294 (R, n, = 0.039) Lorentz-polarization Absorption (trans, factors: 0.937 - 1.000) Decay (5.65% decline) C. Stru< Structure Solution Refinement Function Minimized Least Squares Weights p-factor Anomalous Dispersion No. Observations (I>3.00<r(I)) No. Variables Reflection/Parameter Ratio Residuals: R; Rw Goodness of Fit Indicator Max Shift/Error in Final Cycle Maximum peak in Final Diff. Map Minimum peak in Final Diff. Map Solution and Refinement Patterson Methods (DIRDIF92 PATTY) Full-matrix least-squares 1 _ 4f o' «»(F«) — e>3(/V) 0.000 All non-hydrogen atoms 8121 595 13.65 0.033 ; 0.031 1.76 0.01 0.38 e~/\3 -0 .36 e"/A3 215 Appendix D Table D.2 Atomic Coordinates and Beq for [RuCl(PPh3)2(PN3)]PF6 atom •'• H., H.<!) 0.24432(1) 0.10103(2} 0.445449(9) 2.239(4) Cl(l) 0.18300(4) -0.01229(G) 0.47615(3) 3.54(2) 0.341)53(4) 0.25475(G) 0.41681(3) 2.46(1) pm 0.14603(4) 0.20535(7) 0.37125(3) 2.60(1) l>(3) 0 21240(4) 0.26495(6) 0.51869(3) 2.02(1) P(4I 0.6176G(G) 0.25006(9) 0.33405(5) 5.21(3) r ( i ) 0.5655(2) 0.2683(3) 0.3821(1) 11.6(1) F(2) 0.56G3( ]) 0.1208(2) 0.3205(1) 7.99(7) F(3) 0.5317(2) 0.2940(3) 0.2661(1) 13.6(1) F(4) 0.G691(2) 0.2309(3) 0.2849(1) 10.20(9) F(5) 0 G1GS( >) 0.3759(2) 0.3443(2) 14.0(1) F(C) O.G$ll(2) 0 1967(3) 0.3775(1) 11.5(1) Ml) 0.3504(1) 0.1194(2) 0-49955(8) 2.56(5) N(2) 0.2902(1) 0.0575(2) 0.38527(9) 2.73(5) K(3) 0 4451(1) 0.4331(2) 0.4311(1) 3.89(6) C(l) 0.4025(1} 0 1910(2) 0.4800(1) 2.47(5) C(2) 0.4774(1) 0.1931(3) 0.5039(1) 3.35(6) C(3) 0.4991(2) 0.1179(3) 0.5502(1) 4.26(7) C(4) 0.4473(2) 0.0432(3) 0.5687(1) 4.06(7) C(5) 0.3729(2) 0.0437(2) 0.5421(1) 3.16(6) C(6) 0.3532(1) 0.1295(2) 0.3688(1) 2.65(5) C(7) 0.4006(2) 0.0960(3) 0.3296(1) 3.46(7) C(8) 0.3924(2) -0.0177(3) 0.3076(1) 4.37(8) C(9) 0.3396(2) •0.0915(3) 0.3261(1) 4.36(6) C(34) 0.2269(2) 0.4418(2) C(35) 0.2999(2) 0.4619(2) C(36) 0.3141(2) 0.5987(3) C(37) 0.2557(3) 0.6777(3) C(38) 0.1631(2) 0.6404(3) Q39) 0.1679(2) 0.5221(3) C(40) 0.2723(1) 0.2556(2) C(41) 0.3249(2) 0.3331(3) C(42) 0.3660(2) 0.3014(4) Q43) 0.3561(2) 0.1943(4) C(44) 0.3013(2) 0.1184(3) C(45) 0.2599(2) 0.1487(3) C(46) 0.1219(2) 0.2818(3) C(47) 0.0656(2) 0.2028(3) C(48) -0.0002(2) 0.1974(3) C(49) -0.0080(2) 0.2688(4) C(50) 0.0480(2) 0.3462(3) « 5 1 ) 0.1129(2) 0.1633(3) • ton, -'• « II., C(10) 0.2932(2) -0.0626(2) 0.3652(1) 3.43(7) C(ll) 0.3926(2) 0.3643(2) 0.3923(1) 2.97(G) C(12) 0.3700(2) 0.4293(3) 0.3376(1) 4.23(B) C(13) 0.4033(2) 0.5329(3) 0.3229(2) 5.6(1) C(14) 0.4571(2) 0.5846(3) 0.3622(2) 6.0(1) C(I5) 0.4769(2) 0.5327(3) 0.4147(2) 5.16(9) C(16) 0.1476(2) 0.3450(3) 0.3315(1) 3.79(7) C(17) 0.1686(2) 0.4413(3) 0.3546(1) 4.46(8) COS) 0.1676(2) 0.5461(3) 0.3235(2) 6.4(1) C(19) 0.1407(3) 0.5536(4) 0.2690(2) 7.6(1) C(20) 0.1055(3) 0.4585(4) 0.2464(2) 7.3(1) C(21) 0.1050(2) 0.3545(3) 0.2770(2) 5.60(10) C(22) 0.1501(2) 0.0997(3) 0.3119(1) 3.43(7) C(23) 0.1969(2) 0.1236(3) 0.2711(1) 4.60(8) C(24) 0.2114(2) 0.0396(5) 0.2305(1) 6.3(1) C(25) 0.1751(2) -0.0656(5) 0.2278(2) 7.5(1) C(26) 0.1262(2) -0.0882(4) 0.2659(2) 8.0(1) C(27) 0.1141(2) -0.0072(4) 0.3081(2) 6.2(1) C(28) 0.0466(1) 0.2046(3) 0.3844(1) 3.13(6) C(29) 0.0098(2) 0.1021(3) 0.3961(1) 4.49(8) C(30) -0.0658(2) 0.1029(4) 0.4050(2) 6.7(1) Q31) -0.1045(2) 0.2052(4) 0.4044(2) . 6.0(1) C(32) -0.0688(2) 0.3084(4) 0.3963(2) 6.8(1) C(33) 0.0067(2) 0.3095(3) 0.3855(2) 5.32(9) • U„ 0.5057(1) 3.09(6) 0.5009(1) 3.50(7) 0.4899(2) 4.99(9) 0.4833(2) 6.3(1) 0.4855(2) 5.8(1) 0.4971(1) 4.50(8) 0.5883(1) 2.91(6) 0.6164(1) 4.12(7) 0.6687(1) 5.75(10) 0.6928(1) 6.9(1) 0.6670(1) 5.22(9) 0.6146(1) 4.03(7) 0.5480(1) 3.31(6) 0.5287(1) 1.95(7) 04552(2) 4.96(9) 0.6015(2) 8.7(1) 0.6216(1) 544(9) 0.5950(1) 4.48(8) i " W a » 7 + 2Viaaa' ec* a»0+ 2t/jsM*ce" eoaa) 216 Table D.3 Bond Lengths (A) for [RuCl(PPh3)2(PN3)]PF6 .• Hull) 2.4066(7) K . i(l) l'(2) 2.3478(7) l(,.(l) N(l) 2.180(2) l'( 1) C( l ) 1.818(3) I 'd) ('(II) 1.811(3) 1 •(•-') C('.'.•) 1.844(3) i'(:i) C(3I) 1.830(3) l'(.l) Q I C ) 1.836(3) l '(i) 1(2) 1.589(2) I'd) I'd) 1.569(2) P(i) F(6) 1.536(3) M l ) c<5) 1.331(3) N(2) C(I0) 1.330(3) N(3) C(I5) 1.344(4) C(V) C(3) 1.392(4) C(J) C(5) 1.386(4) C(7) C(8) 1.390(4) C(9) C(10) 1.385(4) C<12) C(13) 1.383(4) C(14) C(15) 1.365(5) C(16) C(21) 1.397(4) C(18) C(19) 1.373(5) C(20) C(2I) 1.3S2(5) C(22) C(27) 1.370(4) atom atom distance C(24) C(25) 1.355(C) C(2C) C(27) 1.380(5) C(28) C(33) 1.387(4) C(30) C(31) 1.349(5) C(32) C(33) 1.400(5) C(34) C(39) 1.366(4) C(36) C(37) 1.366(5) C(38) C(39) 1.403(5) C(40) Q45) 1.394(4) C(42) Q43) 1.301(5) C(44) C(45) 1.385(4) C(46) C(51) 1.393(4) C(46) C(49) 1.375(5) C(50) C(51) 1.387(4) atom Ku(l) I 'd) 2.2854(7) Ru(l) l'(3) 2 3152(7) llu(l) N(2) 2.160(2) P(l) C(6) 1.825(3) l'(2) C(16) 1.64(1(3) P(2) C(28) I.M'.iCI) P(3) C(40) 1.652(3) P(4) F(l) 1.55601) P(4) 1(3) 1.565(3) P(4) F<5) 1.527(3) N(l) C( l ) i.:ir.;i(:t) N(2) C(G) 1.357(3) N(3) C ( l l ) 1.333(3) C( l ) C(2) 1.375(3) C(3) C(4) 1.366(4) C(6) C(7) 1.377(4) C(8) C(9) 1.370(4) C ( l l ) C(12) 1.3S7(4) C(13) C(14) 1.369(5) C(16) C(17) 1.3S2(4) C(17) C(16) 1.393(4) C(19) C(20) 1.376(6) C(22) C(23) 1.401(4) C(23) C(24) 1.385(5) atom alom distan (v C(25) C(26) 1.351(6) C(28) C(29) 1.382(4) C(29) C(30) 1.391(4) Q31) C<32) 1.359(5) C(34) C(35) 1.396(4) C(35) C(36) 1.381(4) Q37) C(38) 1.366(5) Q40) C(41) 1.383(4) C(41) C(42) 1.367(4) C(43) C(44) 1.380(5) C(46) C(47) 1.375(4) C(47) C(48) 1.399(4) C(49) C(50) 1.364(5) 217 00 alo . i . """" . aiiKl.- .10.11 Sllfcl.- ».„,„ . t o n . ..,„„ «•.«!.• atom . t o . . . t\ l a m .. .git-Cl( l ) Hul l ) I'(D 151.59(3) CIO) Ru(l) l'(2) 94.16(3) llu(l) NO) C( l ) 104.6(2) Hul l ) N(l) C(5) 136.2(2) Cl( l ) Ru(l) PCD 96.20(3) C l ( l ) Hul l ) N ( l ) 92.43(6) C( l ) N ( l ) C(.'.| 119.1(2) l t „ ( l l N(2) C(6) 104.9(2) C1(l) II..1I) H(2| 90 7.1(6) I'd) I M D P(2| 10.1.16(3) Hi.(l) N(2) C(10) 136.7(2) C(6) N(2) C(10) 119.4(2) I ' l l ) RnO) P(3) 102.47(2) P O ) R » ( l ) N O ) 66.95(6) C(I1) N(3) C(15) 116.0(3) P(l) C ( l ) N ( l ) 100.8(2) P(I) l l u ( l ) N(2) 67.33(6) P(2) Ru(l) P(3) 100.46(3) I'd) C( l ) C(2) 130.0(2) N(l) C ( l ) C(2) 122.8(2) P(2) Hu(l) N O ) 107 81(6) I'(2) R o d ) Km 69.59(6) C O ) C(2) C(3) 117.2(3) C(2) C(3) C(4) 119.9(3) P(3) Ru(l) N(D 89.00(0) P(3) Ru(l) N(2) 167.30(6) C(3) 0(4) C(5) 120.0(3) N(l) C(5) C(4) 120.7(3) N(l> II "(I) N(2) 80.07(7) H u d ) I'd) C ( l | 87.02(8) P(l) C(0) N(2) 100.8(2) PO) C(6) C(7) 136.0(2) Ru ( l ) I'd) 0(6) 66.45(9) llu(l) l'(l) C ( l l ) 151.87(9) K(2) C(6) C(7) 122.8(2) C(6) C(7] C(8) 117.3(3) C ( l ) I'd) 0(6) 96.6(1) C O ) I ' l l ) C ( l l ) 110.9(1) 0(7) C(8) C(9) 119.6(3) C(8) C(9) C(10) 120.5(3) C(G| I'd) C ( l l l 111.6(1) R « ( l ) P(2) C.(I6) 119.76(10) N(2) C(10) C(9) 120.3(3) P(D C ( l l ) N(3) 115.3(2) Ru(l) P(2) C(22) 108.45(9) R u ( l | P(2) C(28) 120.99(9) P ( l ) C ( l l ) C 0 2 ) 120.2(2) N(3) C ( U ) C(12) 124.4(3) C O 6) P(2) C(22) 100.1(1) C(I6) P(2) C(28) 99.8(1) C ( l l ) C(I2 | C(13) 117.5(3) C(12) C(13) C(14) 119.0(3) C(22) P(2) C(2S) 105.1(1) R „ ( l ) P(3) C(34) 114.14(9) C O 3) C(14) C(I5) 119.4(3) N(3) C O 5) C(14) 123 7(3) Ri.(l) P(3) C(40) 111.57(8) llu(l) P(3) C(46) 124.90(10) P(2) C(16) C(17) 121.6(2) P(2) C(16) C(2I) 118.9(2) C(34) P(3) C(40) 104.0(1) C(34) P(3) C(46) 103.4(1) C(17) C(16) C(21) 119.3(3) C(16) C(17) C(18) 120.2(3) C(40) P(3) C(46) 95.6(1) F ( D P(4) F(2) 88.2(1) C(17) C(18) C O 9) 120.1(4) C(18) C(19) C(20) 120.1(4) F<1) P(<) F(3) 90.4(2) F( l ) P(4) F(4) 177.7(2) C(19) C(20) C(21) 120.5(4) q i 6 ) C(21) C(20) 119.8(4) F( l ) P ( D F(5) 93.0(2) F( l ) P(4) F(6) 90.2(2) P(2) C(22) C(23) 118.5(2) P(2) C(22) C(27) 124.1(2) F(2) P(4) F(3) 86.8(2) F(2) P(4) F(4) 89.5(1) C(23) C(22) C(27) 117.0(3) C(22) C(23) C(24) 120.4(4) F(2) PCO F(5) 177.5(2) F(2) P(4) F(6) 88.6(2) C(23) C(24) C(25) 121.2(4) C(24) C(25) C(26) 118.9(4) F(3) PH) F H ) 89.2(2) F(3) P(4) F(5) 91.0(2) C(25) C(26) C(27) 121.3(4) C(22) C(27) C(26) 121.2(4) F(3) P H ) F(6) 175.3(2) F(4) P(4) F(5) 89.2(2) P(2) C(28) C(29) 121.9(2) P(2) C(28) C(33) 120.5(2) F(4) P(4) F(6) • 90.0(2) F(5) P(4) F(6) 93.6(2) C(29) I ' l l ) C(28) C(40) C(33) C(4I) 117.5(3) 125.2(2) C(28) P(3) C(29) C(40) C(30) C(45) 121.2(3) 115.9(2) """" n l i . n i ul nm ni """" M o m . . . » l r C(41) C(40) CI45) 118.8(3) C(40) C(41) C(42) 119.6(3) C(21l) C(3II) C(3I) 120.5(4) C(3I1) C(3I) C(32) 119.7(3) 0(41) C(42) C(43) 121.0(3) C(42) C(43) C(44) 120.0(3) C(31) C(32) C(33) 120.7(3) C(2S) C(33) C(32) 120.2(3) C(43) 0(41) C(45) 119.6(3) C(40) C(45) C(44) 120.7(3) I'M) C ( . ' l l ) 0(35) 119 0(2) P(3) C(34) C(39) 122.9(2) P(3) C(4G) C(47) 121.8(2) P(3) C(46) C(51) 118.9(2) C(35) C(34> 0(39) 118.0(3) 0(31) C(35) C(36) 121.7(3) C(47) C(4C) C(5I) 118.9(3) C(46) C(47) C(48) 120.0(3) C(35) f:(3C) C ( : i : i 119.7(3) 0 » 6 | C(37) C(36) 120.1(3) C(47) C(46| C(49) 120.2(3) C(48) C(49) C(50) 120.3(3) C(37) C ( 3 f | C(39) 120.6(3) 0(31) C(39) 0(38) 119.7(3) C(49) C(50) C(S1) 119.8(3) C(46) C(5I) C(50) 120.8(3) H P a; a o 3 CL •S4 Q ro' APPENDIX E Crystallographic Data for RuCl2(PPh3)(PN3)-2CH2Cl2 (13) Figure E. 1 Molecular structure of RuCl2(PPh3)(PN3>2CH2Cl2 (PLUTO plot). 219 Appendix E Figure E.2 Molecular structure of RuCl2(PPh.3)(PN3) (Stereoview). 220 Table E.l Experimental Details for RuCl2(PPh3)(PN3) A . Crystal Data Empirical Formula Formula Weight Crystal Color, Habit Crystal Dimensions Crystal System Lattice Type No. of Reflections Used for Unit Cell Determination (28 range) Omega Scan Peak Width at Half-height Lattice Parameters C 3 5 H 3 i C l 6 N 3 P 2 R u 869.39 red, prism 0.15 X 0.18 X 0.25 monoclinic P 25 ( 20.1 - 29.4° ) 0.36° a = 17.269(2) A b = 10.797(1) A c = 20.604(1) A P = 107.461(6)° Space Group Z value D c a ( e Fooo /i(MoKa) V = 3664.6(6) A 3 P2i/c (#14) 4 1.576 g/cm3 1752 9.83 c m - 1 B. Intensity Measurements Diffractometer Radiation Rigaku AFC6S MoKcr (A = 0.71069 A) graphite monochromated 221 Table E. 1 (cont.) Experimental Details for RuCl2(PPh3)(PN3) Take-off Angle Detector Aperture Crystal to Detector Distance Temperature Scan Type Scan Rate Scan Width 2#moi No. of Reflections Measured Corrections 6.0° 6.0 mm horizontal 6.0 mm vertical 28.5 cm 21.0°C u-20 16.0°/min (in omega) (8 rescans) (1.00 + 0.35 tan 6)' 55.0" Total: 9154 Unique: 8870 (R,„, = 0.049) Lorentz-polarization Absorption (trans, factors: 0.96 - 1.00) Decay (19.0% decline) C. Structure Solution and Refinement Structure Solution Refinement Function Minimized Least Squares Weights p-factor Anomalous Dispersion No. Observations (I>3cr(I)) No. Variables Reflection/Parameter Ratio Residuals: R; Rw Goodness of Fit Indicator Max Shift/Error in Final Cycle Patterson Methods Full-matrix least-squares 1 _ 4 F V _ 0.00 All non-hydrogen atoms 4184 424 9.87 0.039 ; 0.035 1.78 0.0003 Maximum peak in Final Diff. Map Minimum peak in Final Diff. Map 0.72 c-/A3 -0.64 e~/A3 222 Table E.2 Atomic Coordinates and Beq for RuCl2(PPh3)(PN3) Appendix E Appendix Table E.3 Bond Lengths (A) for RuCl2(PPh3)(PN3) atom acorn distance atom atom distance M i ) Cl(l) 2.438(1) M i ) Cl(2) 2.438(1) M i ) P(2) 2.350(1) M O N(l) 2.075(4) M i ) N(2) 2.090(4) M O N(3) 2.117(4) Cl(3) C(34) 1.739(7) Cl(4) C(34) 1.701(7) Cl(5) C(35) 1.717(9) Cl(6) C(35) 1.758(8) P(l) C(l) 1.829(5) P(i) C(6) 1.827(5) P(l) C(U) 1.829(5) P(2) C(16) 1.845(5) P(2) C(22) 1.848(5) P(2) C(28) 1.854(5) N(l) C(l) 1.357(5) N(l) C(5) 1.341(6) N(2) C(6) 1.356(6) N(2) C(I0) 1.352(6) N(3) C(ll) 1.354(6) N(3) C(15) 1.346(6) C(l) C(2) 1.375(6) Q2) C(3) 1.380(8) C(3) C(4) 1.372(8) C<4) C(5) 1.379(6) C(6) C(7) 1.383(7) C(7) C(8) 1.379(7) C(8) C(9) 1.376(7) C(9) C(10) 1.386(7) C(ll) C(12) ' 1.389(7) C(12) C(13) 1.369(8) C(13) C(14) 1.360(8) C(14) C(15) 1.382(7) C(16) C(17) 1.389(6) C(16) C(21) 1.386(7) C(17) C(18) 1.385(7) C(18) C(19) 1.380(8) C(19) C(20) 1.361(9) C(20) C(21) 1.385(7) C(22) C(23) 1.384(7) C(22) C(27) 1.383(6) C(23) C(24) 1.372(7) C(24) C(25) 1.367(7) C(25) C(26) 1.363(8) C(26) C(27) 1.395(7) C(2S) C(29) i:371(7) C(28) C(33) 1.396(7) •lorn atom distance atom atom distance Q29) C(30) 1.397(7) C(30) C(31) 1.372(8) C(31) C(32) 1J74(8) C(32) C(33) 1.382(7) 224 Table E.4 Bond Angles (°) for RuCl2(PPh3)(PN3) Appendix E •torn •torn atom angle Cl(l) Rn(l) Cl(2) 89.84(5) CHI) R"(D N ( » 174.4(1) Cl(l) Ro(l) N(3) 88.9(1) Cl(2) Ru(l) N(l) 85.6(1) Cl(2) R"(i) N(3) 84.9(1) P(2) M D N(2) 92.6(1) N(l) M l ) N(2) 94.9(1) N(2) Ru(l) N(3) 86.2(2) C(l) P(l) C(ll) 98.8(2) Ru(l) P(2) C(16) 112.6(2) R u(l) P(2) C(28) 122.4(2) C(16) P(2) C(28) 103.6(2) M D N(l) C(l) 122.9(3) C<1) N(I) C(5) 116.7(4) Ru(l) N(2) C(10) 121.6(3) RU(1) N(3) C(ll) 121.6(3) C(ll) N(3) C(15) 117.6(4) P(l) C(l) C(2) 117.3(4) C(l) C(2) C(3) 120.0(5) C(3) C(4) C(5) 119.3(5) P(l) C(6) N(2) 121.0(4) N(2) C(6) C(7) 122.2(5) C(7) C(8) C(9) 117.6(5) N(2) C{10) C(8) 123.2(5) atom atom atom angle p(D C(ll) C(12) 118.4(4) C(U) C(12) q u ) 120.4(5) C(13) C(H) C(15) 119.0(5) P(2) C(16) C(17) 118.0(4) C<17) q i6) C(21) 116.1(5) C(17) C(18) C(19) 119.9(6) C(19) C(20) C(21) 120.4(6) P(2) C(22) C(23) 124.4(4) C(23) C(22) C(27) 118.5(5) C(23) C(24) Q25) 120.7(5) C(25) C(26) C(27) 119.6(5) P(2) C(28) C(29) 121.4(4) C(29) C(28) C(33) 118.6(5) C(29) C(30) C(31) 119.9(6) C(31) C(32) C(33) 118.1(6) Cl(3) C(34) Cl<4) 112.2(4) atom atom atom angle Cl(l) M l ) P(2) 91.54(5) Cl(l) M D N(2) 89.1(1) Cl(2) M D P(2) 96.37(5) Cl(2) Rn(l) N(2) 171.0(1) P(2j Ru(l) Ml) 92.1(1) P(2j M D N(3) 178.6(1) Ml) M l ) N(3) 87.6(1) CO) P(i) C(6) 104.2(2) cm P(i) C(ll) 98.8(2) Ru(l) P(2) Q22) 117.9(2) Q16) P(2) q22) 101.1(2) C(22) P(2) q28) 96.0(2) M D N(l) C(5) 120.3(3) R«(l) N(2) C<6) 121.6(3) C(6) N(2) C(10) 116.7(4) Ru(l) N(3) qis ) 120.7(4) P(l) C(l) NO) 120.1(3) N(l) QI) C(2) 122.4(5) C(2) « 3 ) q4) 118.1(5) NO) qs) q4) 123.5(5) PO) qo) 0(7) 116.4(4) Q6) q?) C(8) 120.6(5) 0(8) q » ) qio) 119.6(5) P(l) q i i ) N(3) 120.7(4) atom atom atom angle N(3) q i i ) 0(12) 120.9(5) C02) qi3) qi4) 118.9(5) N(3) qi5) q " ) 123.1(5) P(2) qie) q2i) 123.8(4) Q16) q i7) q i s ) 120.8(5) C(18) qio) C(20) 120.0(6) Q16) q2i) C(20) 120.7(5) P(2) q22) q27) 117.1(4) Q22) q23) q24) 120.4(5) C(24) q25) q26) 120.2(5) Q22) q27) q26) 120.6(5) P(2) C(28) q33) 119.8(4) C(28) q29) qsoj 120.0(5) Q30) qs i ) q32) 121.3(6) C<26) qss) q32) 121.9(5) 0(5) q j s ) Cl(6) 112.7(4) 225 

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