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Binding and activation of small molecules by ruthenium complexes containing a chelated aminophosphine… Mudalige, Dona Chandrika 1994

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BINDING AND ACTIVATION OF SMALL MOLECULES BYRUTHENIUM COMPLEXES CONTAINING A CHELATEDAMINOPHOSPHINE LIGANDByDONA CHANDRIKA MUDALIGEB.Sc. (Hons.), The University of Colombo, 1986A THESIS SUBMITTED iN PARTIAL FULFILLMENT OFTHE REQUIREMENTS FOR THE DEGREE OFDOCTOR OF PHILOSOPHYinTHE FACULTY OF GRADUATE STUDIES(Department of Chemistry)We accept this thesis as conformingto the required standardTHE UNIVERSITY OF BRITISH COLUMBIAMarch 1994© Dona Chandrika Mudalige, 1994In presenting this thesis in partial fulfilment of the requirements for an advanceddegree at the University of British Columbia, I agree that the Library shall make itfreely available for reference and study. I further agree that permission for extensivecopying of this thesis for scholarly purposes may be granted by the head of mydepartment or by his or her representatives. It is understood that copying orpublication of this thesis for financial gain shall not be allowed without my writtenpermission.(Signature)Department of________________The University of British ColumbiaVancouver, CanadaDate 20DE-6 (2/88)ABSTRACTRuthenium(II) and Ru(III) complexes of the type RuC1(P-N)(PR3) havebeen prepared, generally by reaction of the appropriate aminophosphine P-N withRuC12(PR3)and RuC13(PR)2DMA), respectively [n 2 or 3; P-N = PMA (odiphenylphosphino-N,N-dimethylaniline), PAN (1 -(dimethylanuno)-8-(diphenyl-phosphino)naphthalene), or (R)-AMPHOS ((R)-(+)-N,N-dimethyl- 1 -[o-(diphenylphosphino)phenyljethylamine); R = Ph or p-tolyl; DMA N,N-dimethylacetamide].HPh2 N(CH3)2 CH3 N(CH3)2PPh2PMA PAN (R)-AMPHOSThe X-ray crystal structure of RuC1(PMA)(P(p-tolyl)3) reveals a squarepyramidal geometry, with trans-chlorides, the N-arm of the PMA chelate and theP(p-tolyl)3 in the basal plane. These structural features are presumed to be sharedalso by the Ru(II)-(AMPHOS) and Ru(II)-(PAN) complexes. As evidenced by31P{1H} and ‘H NMR spectroscopic studies, the Ru(II)-(P-N)complexes retaintheir solid state structure in solution. The crystallographically characterizedRuCI3(PMA)(PPh)and RuCI3(AMPHOS)(PPh)complexes show a meridionalarrangement of chloride ligands in an octahedral structure, with the N-arm of theIIP-N chelate trans to the monodentate phosphine. The X-ray structure of (R)AMPHOS was also determined.Chloroform or CH21 solutions of RuC12(PMA)(PR3)react rapidly andreversibly with 1 atm of H2 in the absence of an added base to give in situformation (85% conversion) of the dihydrogen complex(i2-H)RuClPMA)-(PR3). The2-H moiety is characterized by means of ‘H NMR spectroscopy; forthe R p-tolyl complex, the short T1 value (Ti() = 13.4 ± 0.2 ms at 232 K and300 MHz), and the relatively large H-D coupling for the q2-HD isotopomer (JHD= 30 Hz), support the formulation. The H-H distance for the dihydrogen moiety in(2-)RuClPMA)(P(p-tolyl) is estimated to be 0.87 ± 0.03 A by variabletemperature T1 measurements. Solution reactions of the Ru(II) and Ru(III)complexes of PMA and AMPHOS with 1 atm of H2 in the presence of 1,8-bis(di-methylaniino)naphthalene [Proton Sponge (PS)] result in the formation of thecorresponding Ru(II)-chloro(hydrido) complexes Ru(H)Cl(P-N)(PR3).Evidencefor formation of the monohydride complexes by an overall heterolytic cleavage ofH2 va a molecular hydrogen complex is also presented. Based on kinetic studiesof the reaction of RuC13(AMPHOS)(PR)(R = p-tolyl) with H2 in DMA, amechanism involving a “Ru(H)C12” intermediate en route to the RuC12-(AMPHOS)(PR3)species is proposed within an overall process for the formationof the Ru(H)Cl(AMPHOS)(PR complex.Studies on the catalytic hydrogenation of styrene (1 atm of H2 at 30 °C inDMA) using the RuC13(P-N)(PR)complexes, where P-N = PMA or AMPHOSand R = Ph or p-tolyl, in the presence of PS reveal that the correspondingmonohydride complexes Ru(H)Cl(P-N)(PR3are probably the catalytically activespecies. The catalytic asymmetric hydrogenation of (z)-a-acetamidocinnamic and111tiglic acids, carried out in benzene/methanol under 17-68 atm H2, using RuC13(R-AMPHOS)(PPh3)as catalyst precursor result in complete hydrogenation of theolefmic bond, but with only 6 and 0% e.e., respectively.Reaction of the five-coordinate RuC12(PMA)(PR3)complex in solutionwith a variety of small molecules results in a range of adducts of the formRuCl2(PMA)(PR3)(L)where the chlorides are either cis [L = H2 (see above), N2,SO2, and H2S] or trans (L = H20, MeOH, and CO). With L = EtSH, a mixture ofcis- and trans-dichloro adducts was obtained. These adducts were either isolatedor studied in situ, and characterized mainly by NMR and IR spectroscopies.Characterization of the RuC12(PMA)(P(p-tolyl)3)(L)complexes, where L = H20or H2S, includes single-crystal X-ray structure determinations, which reveal atrans- and cis-dichloro arrangement respectively in the octahedral complexes; theP(p-tolyl)3 group is trans to the N-arm of the aminophosphine in both complexes.The molecular structure of the H2S adduct provides the second example of astructurally characterized transition metal-H2S complex. Of note, the RuCl2-(PMA)(P(p-tolyl)3)(SH2complex could also be obtained by the solid statereaction of the precursor five-coordinate complex with 1 atm H2S at roomtemperature. The solution reaction of RuC12(PMA)(PR3)with 02 results information of a species which is tentatively proposed to be the peroxo-bridgedcomplex [RuCl2(PMA)(PR3)]p-O.The reaction of RuC12(PMA)(PR3)withCO at -20 °C in solution, or in the solid state at room temperature, results information of the mono-CO adduct with trans-chlorides, while the solution reactioncarried out at room temperature results in a mixture of cis-trans and cis-cisisomers of the dicarbonyl Ru(CO)2C1(PMA); the carbonyl-containing specieswere characterized mainly by NMR and IR spectroscopies. The five-coordinateRuC12(PAN)(P(p-tolyl)3)complex shows no reactivity toward the small moleculesivinvestigated, presumably because of steric effects. Preliminary studies on thereaction ofRuC12(AMPHOS)(P(p-tolyl)3) with SO2 reveal formation of the SO2adduct.VTABLE OF CONTENTSPageABSTRACT.iiTABLE OF CONTENTS viLIST OF TABLES xiiiLIST OF FIGURES xviLIST OF SYMBOLS AND ABBREVIATIONS xxNUMERICAL KEY TO RUTHENIUM COMPLEXES xxivACKNOWLEDGMENTS xxvCHAPTER 1 Introduction1.1 General Introduction; Chelating P-N Ligands 21.2 Homogeneous Catalysis 61.2.1 Homogeneous Catalytic Hydrogenation 101.2.2 Asymmetric Homogeneous Hydrogenation 111.3 Scope of the Thesis 151.4 References - Chapter 1 17CHAPTER 2 General Experimental Procedures2.1 Materials 282.1.1 Solvents 282.1.2 Gases 292.1.3 Phosphines 292.1.3.1 (R)-(+)-N,N-dirnethyl-1-[o-(diphenyl-phosphino)phenyl]ethylamine, [(R)-AMPHOS] .... 292.1.3.2 o-Diphenylphosphino-N,N-dimethylarnline,(PMA) 30vi2.1.3.3 1 -(Dimethylamino)-8-(diphenylphosphino)-naphthalene, (PAN) 312.1.4 Phosphine Oxides 322.1.4.1 Triphenyiphosphine Oxide 322.1.4.2 Tri(p-tolylphosphine) Oxide 322.1.4.3 o-(Diphenylphosphine oxide)-N,N-diinethylaniline 322.1.5 Olefmic Substrates Used for Hydrogenation Studies 332.1.6 OtherMaterials 332.2 Ruthenium Complexes 332.2.1 Ruthenium Precursors 332.2.1.1 Dichlorotris(triphenylphosphine)ruthenium(II),RuCI2(PPh3) 332.2.1.2 Dichlorotris(tn-p-tolylphosphine)ruthemum(II),RuCl(P(p-tolyl)3)3 342.2.1.3 Trichlorobis(triphenylphosphine)(dimethylacetamide)ruthenium(III). DMA solvate,RuCI(PPhDMA).(DMA) 342.2.1.4 Trichlorobis(tri-p-tolylphosphine)(dimethylacetamide)ruthemum(JII). DMA solvate,RuC13(P(p-tolyl)DMA).(DMA) 352.2.1.5 Cis-Dichlorotetrakis(dimethylsulfoxide)ruthenium(II), cis-RuC12(DMSO)4 352.2.1.6 Dichloro(ri-i ,5-cyclooctadiene)ruthenium(II)dimer, [RuCI(ri-COD)(j.t—Cl)] 352.2.1.7 Dichloro(ri6-benzene)ruthemum(II) dimer,[RuC1(6-benzene)(t-Cl)J 362.2.1.8 Hydridochlorotris(triphenylphosphine)ruthenium(II).DMA solvate,Ru(H)Cl(PPh3).(DMA) 362.2.2 Aminophosphine Complexes of Ruthenium(II) 372.2.2.1 Dichloro(o-diphenylphosphino-N,N-dimethylaniline)(triphenylphosphine)ruthenium(II),RuC12(PMA)(PPh3),la 37VI’2.2.2.2 Dichloro(o-diphenylphosphino-N,N-dimethylaniline)(tri-p-tolylphosphine)ruthenium(II),RuC1(PMA)(P(p-tolyl)3),lb 372.2.2.3 Dichloro[( 1 -(dimethylamino)-8-(diphenylphos-phino)naphthalene)](tri-p-tolylphosphine)ruthemum(II), RuC12(PAN)(P(p-tolyl)3,2 382.2.2.4 Dichloro { (R)-N,N-dimethyl- 1 -[o-(diphenylphosphino)phenyl]ethylamine } (triaiylphosphine)ruthemum(II), RuC12(AMPHOS)(PR3,(R = Ph, 3a; R =p-tolyl, 3b) 382.2.2.5 Dicfflorobis(o-diphenylphosphino-AçNdimethylaniline)ruthenium(II), RuC12(PMA) 392.2.2.6 Chlorohydrido(o-diphenylphosphino-N,Ndimethylaniline)(triarylphosphine)ruthenimn(II), Ru(H)Cl(PMA)(PR3,(R = Ph, 4a; R = p-tolyl, 4b) 402.2.2.7 Chlorohydrido { (R)-N,N-dimethyl- 1 -[o-(diphenylphosphino)phenyl]ethylamine } (triarylphosphine)ruthenium(II), Ru(H)Cl(AMPHOS)(PR3,(R = Ph, 5a; R =p-tolyl, 5b) 402.2.3 Aminophosphine Complexes of Ruthemum(III) 412.2.3.1 Tnchloro(o-diphenylphosphino-AçN-dimethylaniline)(triphenylphosphine)ruthenium(III),RuC1(PMA)(PPh),6a 412.2.3.2 Trichloro(o-diphenylphosphino-N,N-dimethylaniline)(tri-p-tolylphosphine)ruthenium(III),RuC1(PMA)(P(p-tolyl)),6b 422.2.3.3 TricMoro[(R)-,N-dimethyl- 1 -(o-(diphenylphosphino)phenyl)ethylamine](triphenylphosphine)ruthenium(III),RuC13(AMPHOS)(PPh),7a 422.2.3.4 Tñchloro[(R)-JV,N-dimethy1- 1 -(o-(diphenylphosphino)phenyl)ethylaminej(tri-p-tolylphosphine)ruthenium(III),RuC1(AMPHOS)(P(p-tolyl)),7b 43viii2.2.4 Dichloro(o-diphenylphosphino-N,N-dimethylaniline)(triaaylphosphine)(ligand)ruthenium(II),RuC1(PMA)(PR3)(L),R Ph, p-tolyl 432.2.4.1 L = H2:(rj-H)RuCIPMA)(PR3(R Ph, 8a; R p-tolyl, 8b) 432.2.4.2 L = H20:RuC1(PMA)(PR)(0H(R Ph, 9a; R p-tolyl, 9b) 442.2.4.3 L = H2S:RuC1(PMA)(PR3)(SH(R = Ph, lOa; R =p-tolyl, lOb) 452.2.4.4 L = CH3O :RuC1(PMA)(PR)(CHOH),(R = Ph, ha; R =p-tolyl, lib) 462.2.4.5 L = Ethanethiol: RuC12(PMA)(PPh3)(EtSH), 12 462.2.4.6 L = SO2:RuC1(PMA)(PR)(S0,(R = Ph, 13a; R =p-tolyl, 13b) 472.2.4.7 L N2:(a-N)RuC1PMA)(PR(R Ph, 14a; R =p-tolyl, 14b) 472.2.4.8 L = 02: [RuC1(PMA)(PR3)]J.t-02),(R = Ph, 15a; R =p-tolyl, 15b) 472.2.4.9 L = CO : 482.2.4.9.1 Ru(CO)2C1(PMA), 16 482.2.4.9.2 RuC1(PMA)(PR3)(CO),(R = Ph, 17a; R =p-tolyl, 17b) 482.3 Instrumentation 492.4 Hydrogenation Experiments 502.4.1 Gas Uptake Experiments 502.4.2 Work-up of Hydrogenation Products 512.4.3 Analysis of Hydrogenation Products 522.4.3.1 Optical rotation measurements 532.5 References - Chapter 2 54ChAPTER 3 Ruthenium Complexes Containing ChelatingAminophosphine Ligands3.1 Introduction 57ix3.2 Synthesis of Ruthenium(ll)-(P-N) Complexes.593.2.1 Reaction of P-N Ligands with Non-Phosphine Precursors.. 593.2.2 Reaction of P-N Ligands with RuCI2(PR3) 613.2.3 Alternate Method for the Synthesis ofRuCl(AMPHOS)(PR),(R = Ph, 3a; R = p-tolyl, 3b) 633.3 Characterization ofRuCl2(P-N)(PR3)Complexes 653.3.1 X-ray Structure Determination ofRuC12(PMA)(P(p-tolyl)3), lb 653.3.2 NMR Studies on RuCI2(P-N)(PR3)Complexes 683.3.2.1 31P{1H} Solution NMR studies 683.3.2.2 1H NMR studies 723.4 Synthesis and Characterization of Ru(III)-(P-N) Complexes 763.4.1 Magenetic Susceptibility Measurements 793.4.2 X-ray Structure Determination ofRuCl3(PMA)(PPh),6a, andRuCl3(AMPHOS)(PPh),7a 793.5 Summary of Results 863.6 References - Chapter 3 88CHAPTER 4 Ruthenium Complexes Containing AminophosphineLigands in Dihydrogen Activation and CatalyticHydrogenation4.1 Introduction 944.2 Molecular Hydrogen Complexes 994.3 Interaction ofRuCl2(PMA)(PR3)Complexes (R = Ph, la;R p-to1yl, ib) with H2 in the Absence of an Added Base:Formation of a Molecular Hydrogen Complex 1074.4 Interaction ofRuC12(P-N)(PR3)Complexes with H2 in thePresence of Proton Sponge: Synthesis of Ru(H)C1(P-N)(PR3Complexes 114x4.4.1 Interaction ofRuC12(PMA)(PR3)Complexes (R = Ph,la; R =p-tolyl, Ib) with H2 1144.4.2 Interaction ofRuCl(PAN)(P(p-tolyl),2, andRuC1(AMPHOS)(PR3)Complexes (R = Ph, 3a;R =p-tolyl, 3b) with H2 1164.5 Interaction of Ru(III)-(P-N) Complexes with Dihydrogen 1174.5.1 Interaction ofRuC13(PMA)(PR Complexes (R = Ph,6a; R=p-tolyl, 6b) with H2 1174.5.2 Interaction ofRuCl(AMPHOS)(PR Complexes (R =Ph, 7a;R=p-tolyl, 7b) with H2 1184.6 Kinetics of The Reaction ofRuC13(AMPHOS)(P(p-tolyl),7b,with Dihydrogen 1264.7 Catalytic Hydrogenation Studies 1354.7.1 Hydrogenation of Styrene Catalyzed by RuC13(PMA)(PR3)(6a and 6b), andRuCI3(AMPHOS)(PR (7aand 7b) Complexes 1354.7.2 Catalytic Hydrogenation of Prochiral Substrates 1384.8 Summary of Results 1404.9 References - Chapter 4 142CHAPTER 5 Reactions of Dichloro(aminophosphine)(tris-alkyiphosphine) Complexes of Ruthenium(II)with Small Molecules5.1 Introduction 1505.2 Reactions ofRuCl2(PMA)(PR3),la and Ib, with Small Molecules 1535.2.1 ReactionsoflaandlbwithHO 1535.2.2 Reactions of la and lb with H2S 1605.2.2.1 A brief summary ofH2S complexes 1735.2.3 Reactions of la and lb with Methanol 1765.2.4 Reaction of la with Ethanethiol 1805.2.5 Correlation Between the Molecular Structure, and theN-CH3 1H NMR Resonances of Complexes 1, 9, and 10... 184x5.2.6 Reactions of la and lb with SO2 .1865.2.7 ReactionsoflaandlbwithN2 1895.2.8 Reactions of la and lb with 02 1935.2.9 Reactions of la and lb with CO 2015.2.9.1 Formation of the bis-CO adductRu(CO)2C1(PMA), 16 2015.2.9.2 Formation of mono-CO adductRuC1(PMA)(PR3)(CO), 17 2085.2.9.3 Proposed mechanism for the solution reactionofRuC12(PMA)(PR)with CO 2115.3 Reaction ofRuC1(PAN)(P(p-tolyl)),2, and RuC12(AMPHOS)-(P(p-tolyl)3) with Small Molecules 2115.4 Summary of Results and Conclusions 2135.5 References- Chapter 5 219CHAPTER 6 General Conclusions and Suggestions for FutureWork 226APPENDIX 231A-i X-ray Crystallographic Analysis of RuCl(PMA)(P(p-tolyl)3),lb 231A-2 X-ray Crystallographic Analysis ofmer-RuC1(PMA)(PPh),6a 237A-3 X-ray Crystallographic Analysis ofmer-RuC13(AMPHOS)-(PPh3), 7a 243A-4 X-ray Crystallographic Analysis of RuCl(PMA)(P(p-tolyl))-(OH2), 9b 249A-5 X-ray Crystallographic Analysis ofRuC12(PMA)(P(p-tolyl)3)(SH2), lOb 255A-6 X-ray Crystallographic Analysis of (R)-AMPHOS 261xliLIST OF TABLESTable Page3.1 Selected bond lengths (A) forRuC12(PMA)(P(p-tolyl)3), ib,with estimated standard deviations in parentheses 653.2 Selected bond angles (deg) forRuC1(PMA)(P(p-tolyl)3), Ib,with estimated standard deviations in parentheses 673•3 3lp {1H} NMR data (121.4 MHz, 20 °C)forRuCl(P-N)(PR3complexes 693.4 31P{1H} NMR data (121.4 MHz, C6D 20°C) for [RuC1(P-P)(L-Cl)]2 complexes 713.5 1H NMR data (300 MHz, CDC13 20 °C) for RuC12(P-N)(PR3complexes 733.6 Selected bond lengths (A) forRuC1(PMA)(PPh),6a, withestimated standard deviations in parentheses 823.7 Selected bond lengths (A) forRuC13(AMPHOS)(PPh),7a, withestimated standard deviations in parentheses 823.8 Selected bond angles (deg) for RuC1(PMA)(PPh),6a, withestimated standard deviations in parentheses 833.9 Selected bond angles (deg) forRuCl3(AMPHOS)(PPh),7a, withestimated standard deviations in parentheses 843.10 Selected bond lengths (A) forRuCl(PMA)(PPh),6a, andRuC13(AMPHOS)(PPh),7a, with estimated standard deviationsin parentheses 854.1 31P{lH} NMR data (121.4 MHz, CDCI3)for the complexesRuCl2(PMA)(PR)(R = Ph, la; R =p-tolyl, Ib) andRuC1(PMA)(PR3)(L) 1094.2 Variable temperature T1 and T2* data (300 MHz, CD21)forthe q2-H resonance of 8b at -11.02 ppm 1124.3 31P{1H} NMR data (121.4 MHz, CD21 20 °C)forRu(H)Cl(PMA)(PR complexes 1144.4 31P{1H} NMR data ( C6D,20 °C) for “Ru(H)Cl(AMPHOS)(PR3)” complexes 122xlii4.5 Kinetic data at 30 °C for the reaction ofRuC13(AMPHOS)(P(p-tolyl)3), 7b, with H2 in DMA, using 3 mM [Ru]T in the presenceof9mMPS 1344.6 Hydrogenation of styrene with RuC13(P-N)(PR)complexes ascatalyst precursors 1374.7 Asymmetric hydrogenation of prochiral alkenes withRuC13(AMPHOS)(PPh),7a 1395.1 31P{1H} NMR data (121.4 MHz,d8-toluene, 20 °C)forthecomplexesRuC12(PMA)(PR3)(0H,9. The values in bracketsare for the corresponding precursor complex, 1 1545.2 Selected bond lengths (A) forRuC1(PMA)(P(p-tolyl)3)(0H,9b, with estimated standard deviations in parentheses 1585.3 Selected bond angles (deg) forRuC12(PMA)(P(p-tolyl)3)(0H,9b, with estimated standard deviations in parentheses 1595.4 Selected bond lengths (A) forRuC1(PMA)(P(p-tolyl)),ib,andRuCl2(PMA)(P(p-tolyl)3)(0H,9b, with estimatedstandard deviations in parentheses 1605.5 Selected bond lengths (A) forRuC12(PMA)(P(p-tolyl)3)(SH,lOb, with estimated standard deviations in parentheses 1635.6 Selected bond angles (deg) forRuC1(PMA)(P(p-tolyl))(SH,lOb, with estimated standard deviations in parentheses 1655.7 31P{1H} NMR data (121.4 MHz, CDC13 20°C for thecomplexesRuCl2(PMA)(PR3)(SH,10. The values in bracketsare for the corresponding precursor complex, 1 1665.8 Ru-P bond distances, and 31P{1H} NMR data (121.4 MHz,CDC13,20 °C) forRuCI2(PMA)(P(p-tolyl) ib, RuC1(PMA)(P(p-to1yl)3(OH) 9b, andRuCl(PMA)(P(p-tolyl))(SHlOb 1685.9 31P{1H) NMR data (121.4 MHz, 20 °C) for the complexesRuCl2(PMA)(PR)(CHOH),11, prepared in situ in CD21;the values in brackets are for the corresponding precursorcomplex, 1 1775.10 31P{1H} NMR data (121.4 MHz, CDC13 20 °C) for thecomplexesRuCl2(PMA)(PR3)(S0,13; the values in bracketsare for the corresponding precursor complex, 1 188xiv5.11 3lP{lH} NMR data (121.4 MHz, CDCI3 20°C) for thecomplexesRuC12(PMA)(PR3)(a-N,14; the values in bracketsare for the corresponding precursor complexes 1925.12 31P{ ‘H) NMR data (121.4 MHz, CDC1320°C) for thecomplexes “[RuCl(PMA)(PR3)](p.-O)”, 15; the values inbrackets are for the corresponding precusor complex 1 1965.13 31P{1H} NMR data (121.4 MHz, CDC13 -50 °C, 1 atm CO)for the complexesRuCI(PMA)(PR3)CO, 17; the values inbrackets are for the corresponding precursor complex 1 2095.14 31P{1H} (121.4 MHz, CDC13 20 °C) and ‘H NMR (300 MHz,CDC13,20 °C) data for irans-RuC1(PMA)(PR)(L)complexes 2155.15 31P{1H} (121.4 MHz, CDC13 20 °C)and1HNMR(300 MHz,CDC13,20 °C) data for cis-RuCl(PMA)(PPh)(L)complexes 216xvLIST OF FIGURESFigure Page1.1 Some bidentate aminophosphine ligands used in homogeneouscatalysis 41.2 The aminophosphines used in the present work 51.3 Types of chiral diphosphine ligands used in asymmetrichydrogenation 131.4 Chelation of the catalyst by acylaminoacrylic acid 143.1 31P{1H} NMR spectrum (121.4 MHz, 20°C) ofRuC12(AMPHOS)(PPh),3a, in C6D 643.2 An ORTEP diagram ofRuCl(PMA)(P(p-tolyl)),lb 663.3 Proposed structures for lb in solution 693.4 Suggested geometries for [RuC12(P-P)j complexes 703.5 Ditertiary phosphines listed in Table 3.4 713.6 1H NMR spectrum (300 MHz, 20 °C) ofRuCl2(PMA)-(P(p-tolyl)3), ib, in CDC13 743.7 1H NMR spectrum (300 MHz, 20 °C) ofRuCl2(PAN)-(P(p-tolyl)3), 2, in CD2I 743.8 ‘H NMR spectrum (300 MHz, 20 °C) of in situ formedRuCI2(AMPHOS)(PPh3),3a, via reaction of“Ru(H)C1(AMPHOS)(PPh”with CDC13 753.9 An ORTEP diagram ofRuCl(PMA)(PPh,6a 803.10 An ORTEP diagram ofRuC13(AMPHOS)(PPh) 7a 814.1 Some early examples of molecular hydrogen complexes 1004.2 1H NMR spectrum (300 MHz, 20 °C) of the reaction mixtureobtained after the reaction ofRuC1(PMA)(P(p-tolyl)3),lb,with 1 atm of H2 in CDC13 solution 1084.3 Temperature dependence of T1 for the molecular hydrogenmoiety in(r-)RuClPMA)(P(p-tolyl),8b 1114.4 High field ‘H NMR spectrum (300 MHz, CD21 20 °C) of(r2-HD)RuClPMA)(P(p-to1yl) complex 111xvi4.5 31P{1H} NMR spectrum (121.4 MHz, 20 °C) of themixture obtained after the reaction of 6b with 1 atm H2 inDMA solution 1194.6 31P{ ill) NMR spectrum (202.5 MHz, 20 °C) of“Ru(H)Cl(AMPHOS)(PPh)”,5a, in C6D solution, with anexpansion of the downfield 31P resonance in the inset 1214.7 Possible structures for the “dimeric” Ru-hydrides formed fromRuC13(AMPHOS)(PR) 1224.8 1H NMR spectrum (500 MHz, 20 °C) of“Ru(H)C1(AMPHOS)(PPh)”,5a, in C6D solution with anexpansion of the hydride region in the inset 1244.9 1H NMR spectrum (500 MHz, 20 °C) of“Ru(H)C1(AMPHOS)(PPh3)”,5a, in C6D solution(0-3 ppm region expanded) 1254.10 Uptake plot for the reaction of 7b with H2 in DMA (5 mL) at30 °C. [RU]T = 3.0 x i- M, P(H2)= 380 torr ([H2]= 0.88 xio-3 M), [PS] = 9.0 x io3 M 1274.11 Uptake plots for the H2-reduction of 7b in DMA (5 mL) at 30 °C,at different P(H2). [Ru]T = 3.0 x io M, [PS] = 9.0 x103 M 1274.12 Uptake plots after solubility correction for the H2-reduction of 7bin DMA (5 mL) at 30 °C at different P(H2). [Ru]T = 3.0 x i03 M,[PS] = 9.0 x io3 M 1294.13 Uptake plots after solubility correction for the H2-reduction of 7bin DMA (5 mL) at 30 °C at different [Ru]T. [H2] = 1.04 x i0 M(450 torr), with 3 equivalents of PS 1294.14 Dependence of the maximum rate on [H2] at 30 °C, [RuJT = 3.0 xi- M, [PS]=9 x i0 M inDMA(5 mL) 1314.15 Dependence of the maximum rate on [Ru]T at 30 °C, [H2] = 1.04 xM, with 3 equivalents of PS in DMA(5 mL) 1314.16 Plots of log [Ru]t against time for the H2-reduction of 7b inDMA (5 mL) at 30 °C, at different H2 pressures. [Ru]T = 3.0 xi0 M, [PS] = 9.0 x l0 M 1334.17 The initial portion of the plots of log [Ru]t against time for the H2-reduction of 7b in DMA (5 mL) at 30 °C, at different H2 pressures.[Ru}T = 3.0 x M, [PS] 9.0 x i0 M 133xvii4.18 Uptake plots for styrene hydrogenation catalyzed by differentRu(III)-(P-N) complexes in DMA (5 ruL) at 30 °C and P(H2)= 760torr ([H2]= 1.76 x i- M). [Ru] = 1.50 x io3 M, [PS] = 9.0 xio3 M, [styrene] = 0.15 M 1364.19 Prochiral alkenes used in hydrogenation studies and theirreduction products 1395.1 31P{1H} NMR spectrum (121.4 M}lz, 20 °C) of in situgeneratedRuCl2(PMA)(PPh3)(0H,9a, in d8-toluene 1555.2 ‘H NMR spectrum (300 MHz, 20 °C) of in situ generatedRuC12(PMA)(PPh3)(0H,9a, in d8-toluene 1555.3 An ORTEP diagram ofRuC1(PMA)(P(p-tolyl))(0H,9b 1575.4 An ORTEP diagram ofRuCI(PMA)(P(p-tolyl))(S lOb 1625.5 Top: an ORTEP diagram of [Ru(PPh3)(’S4’)(SH2].THF (THFand H atoms are omitted except of H(5A) and H(5b). Bottom:association of enantiomers via S-H S bridges 1645.6 31P{1H} NMR spectrum (121.4 MHz, 20°C) of in situ generatedRuC12(PMA)(P(p-tolyl))(SH,lOb, in CDC13 1675.7 ‘H NMR spectrum (200 MHz, 20 °C) of in situ generatedRuC1(PMA)(P(p-tolyl))(SH,lOb, in CDC13 1695.8 ‘H NMR spectrum (500 MHz, 20 °C) of in situ generatedRuCl2(PMA)(P(p-to1yl)3)(SH), lOb, in C6D 1695.9 31P{1H} NMR spectrum (121.4 MHz, 20°C) of isolatedRuC1(PMA)(P(p-tolyl))(SH,lOb, dissolved in C6Dunder argon 1725.10 1H NMR spectrum (300 MHz, 20 °C) of isolated RuCl2(PMA)-(P(p-tolyl)3)(SH), lOb, dissolved in C6D under argon 1725.11 31P{1H} NMR spectrum (121.4 MHz, 20°C) of in situgeneratedRuC12(PMA)(PPh)(CHOH),11 a, in CD21 1785.12 1H NMR spectrum (300 MHz, 20 °C) of in situ generatedRuCl(PMA)(PPh3)(CHOH),ha, in CD21 1785.13 31P{1H} NMR spectrum (121.4 MHz, 20 °C) of in situ generatedRuCl2(PMA)(PPh)(EtSH), 12, in C6D 1815.14 ‘H NMR spectrum (300 MHz, 20 °C) of in situ generatedRuCl(PMA)(PPh3)(EtSH), 12, in C6D 1825.15 Structure of trans-RuC12(PMA)(PR)(L)complexes 1855.16 Possible structures for cis-RuCl(PMA)(PR3)(L)complexes 185xviii5.17 31P{1H} NMR spectrum (121.4 MHz, 20°C) ofRuC12(PMA)-(P(p-tolyl)3)(SO), 13b, in CDC13 1875.18 1H NMR spectrum (300 MHz, 20 °C) ofRuC12(PMA)-(P(p-to1y1)3)(SO), 13b, in CDCI3 1875.19 Common coordination modes of terminal SO2 complexes 1895.20 31P{1H} NMR spectrum (121.4 MHz, 20°C) of la, under 3 atmnitrogen in C6D 1905.21 1H NMR spectrum (300 MHz, 20 °C) of la, under 3atm nitrogenin C6D 1905.22 31P{1H} NMR spectrum (121.4 MHz, 20 °C) of lb under 1 atm02 in CDC13;the INSET shows resonances of 15b expanded 1945.23 1H NMR spectrum (200 MHz, 20 °C) of la under 1 atm 02in C6D;the INSET shows the N-methyl region expanded 1955.24 JR spectra (in CHC13 solution, 0.1 mm KBr cell) of Ia, la under 1atm 02, OPPh3 and PMA oxide 1985.25 Proposed structure for the dioxgen adduct,[RuCl(PMA)(PR)].t-0,15, with P indicating the mono-dentate phosphine PPh3, 15a, or P(p-tolyl)3, 15b 1995.26 Variable temperature 31P{1H} NMR spectra (121.4 MHz, CDC13)of la under 1 atm CO 2025.27 Cis, trans and cis, cis isomers ofRu(C0)2C1(PMA), 16 2035.28 Variable temperature 1H NMR spectra (300 MHz, CDCI3)of Iaunder 1 atm CO 2045.29 31P{1H} NMR spectrum (202.5 MHz, 20 °C) of la under 2 atm13CO in CDC13 2055.30 1.C{H} NMR spectrum (125.8 MHz) of launder 2 atm 13C0in CDC13 2055.31 JR spectra (in CHC13,0.1 mm KBr cell) of la, and la under 1 atmCO. at different temperatures 207xixLIST OF SYMBOLS AND ABBREVIATIONS[ ] molar concentration[ ]o initial concentration[ IT total concentration[ it concentration at time t* chiral centre[cL]specific rotation at 25 °C at 589 rim (the sodium Dline)A angstrom, 10-8 centimeterAnal, analysisBINAP (R)- or (S)-2,2’-bis(diphenylphosphino)-l, 1’-binapthylBPPFA 1,1 ‘-bis(diphenylphosphino)-2’-( 1 -N,N-a-dimethylaminoethyl)ferrocenehr broadBut tertiary butylCalcd calculatedCHIRAPHOS 2,3 -bis(diphenylphosphino)butaneCOD 1,5-cyclooctadieneCp cyclopentadienylCp* pentamethylcyclopentadienylCy cyclohexyl6 chemical shiftd doubletxxDIOP O-isopropylidene-2,3-dihydroxy- 1 ,4-bis(diphenyl-phosphino)butaneDIPAMP 1 ,2-bis(ortho-anisylphenylphosphino)ethaneDIPPE 1 ,2-bis(diisopropylphosphino)ethaneDMA N,N-dimethylacetarnideDMSO dimethylsulfoxide1 ,2-DPNEA 2-(diphenylphosphino)- 1 -(1 -dimethylaminoethyl)naphthalene1, 8-DPNEA 8-(diphenylphosphino)- 1 -(1 -diniethylaminoethyl)naphthaleneDPPB 1 ,4-bis(diphenylphosphino)butaneDPPE 1 ,2-bis(diphenylphosphino)ethaneDPPM 1,1 -bis(diphenylphosphino)methaneDPPP 1,3 -bis(diphenylphosphino)propanee.e. enantiomeric excessEt ethylFc ferrocenylhapticity of degree n{ 1H} broadband proton decoupledisoPFA 1 -[x-N,N-dimethylaminoethyl]-2-(diphenylphos-phino)ferroceneisoPOF 1 -[a-methoxyethyl]-2-(diisopropylphosphino)-ferroceneJ coupling constant, in Hzk rate constantkobs observed rate constantdescriptor for bridging,cdp. descriptor for bridgingL ligandlitreLEUPHOS [f3-(N,N-dimethylantino)tertiaiybutylj-diphenyiphosphineM central metal atom in a complexmolarity, mole L4m multiplet (NMR)medium intensity (IR)Me methylP-N chelating tertiary phosphine-amineP-P chelating ditertiary phosphinePCN o-diphenylphosphino-N,N-dimethylbenzylaminePEN (2-diphenylphosphinoethyl)N,N-dimethylaminePh phenylPHEPHOS [-(N,N-dñnethylamino)benzyl]diphenylphosphinePNH2 (o-aminophenyl)diphenylphosphinePPFA 1 -[cc-N,N-dimethylaminoethyl]-2-(diisopropyl-phosphino)-ferrocenePR3 tertiary alkyl or aryl phosphinePr’ isopropylPS Proton Sponge® [1, 8-bis(dimethylamino)naphthalenejp-tol para-tolylq quartet(R)- absolute configuration(latin: rectus; right)RT room temperatureS solvent or substratexdi(5)- absolute configuration (latin: sinister; left)s singlet (NMR), strong (IR)second(s)T1 spin-lattice (or longitudinal) relaxation time (NMR)T2 transverse relaxation timet triplettert tertiaryTHF tetrahydrofuranTiglic acid trans-2, 3 -dimethylacrylic acidTMS tetramethylsilanev/v volume-to-volume ratioVALPHOS [f3-(NN-dimethylamino)isopropyl]diphenylphosphinew weakW1/2 linewidth at half heightxxiiiNUMERICAL KEY TO RUTHENIUM COMPLEXESThe complexes listed below are further identified, where necessary, by thelabels: a (for R = Ph) and b (for R p-tolyl).RuC12(PMA)(PR3),IRuCl(PAN)(P(p-tolyl),2RuC12(AMPHOS)(PR3),3Ru(H)Cl(PMA)(PR),4“Ru(H)C1(AMPHOS)(PR)”,5RuC13(PMA)(PR),6RuCI3(AMPHOS)(PR3),7(2-)RuC1(PIvA)PR 8RuCl(PMA)(PR3)(0H,9RuC12(PMA)(PR)(S1,10RuC1(PMA)(PR)(CHOH),11RuC12(PMA)(PPh3)(EtSH), 12RuCI(PMA)(PR)(S0,13(a-N2)RuC1PMA)(PR3,14[RuCl(PMA)(PR)](j.t-0”,15Ru(CO)2C1(PMA), 16RuCl(PMA)(PR3)(CO), 17xxivACKNOWLEDGMENTSI wish to express my sincerest appreciation and thanks to Professors B. R.James and W. R. Cullen, my research supervisors, for their expert guidance andassistance during the course of my studies and the preparation of this thesis. Iwould also like to thank the members of both research groups for providingassistance in many practical matters. Many thanks must also go to the members ofProfessor M. Fryzuk’s research group. Special thanks are due to Professor A. Storrfor allowing the use of his gas uptake apparatus.I wish to thank Dr. S. J. Rettig for crystal structure determinations. I alsowish to express my gratitude to members of the support services includinganalytical, electronic, glass blowing, mechanical, and NMR divisions of thechemistry department. Financial support of this research from the Natural Sciencesand Engineering Research Council of Canada and the University of BritishColumbia is gratefully acknowledged.I would also like to thank my parents for their love and support throughoutmy studies and for always believing in my success. Finally, I owe everything toyou Lal, my beloved husband, for your unfailing love, support, companionship,constant encouragement, and for always being there.xxvChapter 11Introduction1.1 General Introduction; Chelating P-N LigandsSince the early 1960s there has been a considerable interest in low valentruthenium complexes containing tertiary phosphine ligands due to their well-documented use in homogeneous catalysis.14 Although ruthenium systemsgenerally have been less studied than their rhodium counterparts, the recentspectacular success achieved by ruthenium complexes as homogeneous catalysts5-8for asymmetric hydrogenation of some prochiral alkene and ketomc substrates hasbegun to attract increasing attention to ruthenium chemistry.Studies on ruthemum(II) diphosphine (P-P) complexes were initiated byChart and Hayter9 in the early 1960s with the synthesis of a series ofcoordinatively saturated complexes of general formula RuX2(P-P) and RuXY(PP)2. where X and Y are anionic ligands such as halides, hydrides or a-bondedalkyl or aryl groups. Since then an extensive array of diphosphines has beenincluded in the series.10 The catalytic activity of the five-coordinated Ru(II)complexes RuCl2(PPh3)and Ru(H)Cl(PPh3),first synthesized by Stephensonand Wilkinson,11 in a variety of reactions12 and specially in homogeneoushydrogenation of alk-l-enes (one of the most efficient yet discovered)’3 drewattention to this class of compounds containing phosphine ligands, and gave rise toa burst of such complexes containing a wide array of monodentate and chelatingphosphines.’°J4”5However, a problem associated with these complexes can bedegradation of the phosphine ligands under hydrogenation conditions by oxidative2addition of a phosphorus-carbon bonded moiety, leading to ligand loss and catalystdeactivation.16 Thus, increasing attention is being focussed on development ofnon-phosphine ligands and their complexes for use in homogeneous catalysis.In recent years, a major thrust in research on homogeneous catalysis hasbeen directed towards designing low-valent transition-metal complexes containingtertiary phosphine ligands with additional donor functions such as oxygen’7-20 and nitrogen.21-3 These are commonly referred to as ‘hybrid’ ligands, aterm first used by Sacconi’s group;24 because of the ability of such ligands tosometimes dissociate at the 0- or N-site they are also known as ‘hemilabile’ligands.25 The features that are generally desirable for an active homogeneouscatalyst are a low oxidation state, a high basicity or nucleophilicity, and an abilityto undergo facile ligand dissociation to generate coordinatively unsaturated intermediates.26-8 The use of these hybrid ligands lies in a combination of desirablefeatures for catalytic activity that they may confer to metal complexes. Theseinclude:28’9 the high electron density of the central metal atom due to thepresence of an ether or amine a-donor, the stability of the low valent metalcomplex brought about by the metal to ligand dit-dit backbonding of the aryl phosphine arm of the chelate, and the susceptibility of the weaker donor to displacement by a substrate molecule during the catalytic cycle; further, the chelateeffect3°confers additional stability on the catalyst precursor in the absence of thesubstrate. The use of a P-N ligand at UBC was initiated29dwith the anticipationthat incorporation of a N-base could assist in heterolytic activation of H2, e.g.:C1R “ + H2 H—Ru NH2 Cl2(1.1)3N(CH3)2PPh2i’N(CHRPPh2PPh20NH2PEN3’ R = i-Pr: VALPHOS32= PhCH2 : PHEPHOS3233= (-Bu : LEUPHOS32PNH234-6PCN3738‘PPh2CH2N(CH3)1,8-DPNEA391 ,2-DPNEA39R = Ph : PPFA32b,4042R = i-Pr: isoPFA41’2Figure 1.1: Some bidentate aminophosphine ligands used in homogeneouscatalysis.Ph21 CH31 N(CH3)2HCH31 .N(CH3)24The presence of nitrogen as a donor atom in a P-N phosphine (e.g. Figure1.1) gives such ligands a greater chelating ability than a correponding P-0phosphine because of the better donating ability of the N-donors compared to the0-donors,43 and studies have been concentrated more on P-N ligands and theircomplexes.Some common bidentate aminophosphine ligands that have been studied areshown in Figure 1.1, along with the corresponding references. The ligandsemployed in the present work (PMA,44 PAN,25 and the chiral ligand (R)AMPHOS45)have been reported in the past; they are listed separately in Figure1.2 and the previous work done on them is described in Chapter 3 (Section 3.1).Ph2 I(CH3)2PAN (R)-AMPHOSFigure 1.2: The aminophosphines used in the present thesis work.As evident from a review of the literature, the use of the platinum groupmetal complexes of P-N ligands is promising in terms of their use as homogeneouscatalysts in hydrogenation,4042 hydroformylation,45’6and asymmetric Gngnardcross-coupling32’3reactions. Of special note is the highly efficient chemoselectivereduction catalytic activity shown by the Ir-PNH2 system in dihydrogen andPMA.PP’25hydrogen transfer reductions of cçf3-unsaturated ketones to unsaturated alcohols,which surpasses the selectivity obtained with analogous diphosphine ligands.43’7The isolation and characterization of the novel dihydrogen complex (q2-H)-(isoPFA)Ru(j.i-C1)2t-H)RuH(PPh3(A) from the reaction of dihydrogen withRuC1(PPh)(iso FA)42add further interest to studies on complexes containingP-N ligands.H! —ci -p Ru —.H----Ru -PPh3CN Cl H(A)1.2 Homogeneous CatalysisHomogeneous catalysis has gained an ever increasing interest over the pastyears due to its wide application in effecting various organic transformations. Themany books available on the subject reflect the current interest.43’8-5Althoughcommercial use of homogeneous catalysts dates back as early as 1910, a broaderuse began only in the 1940s.48 Since this time, homogeneous catalysis has receivedenormous interest, and now constitutes a field of extensive research anddevelopment. Transition metal complexes, particularly of the platinum metals,catalyze a wide range of chemical reactions such as hydrogenation, hydrosilylation, oxidation and hydrocyanation of unsaturated organic substrates,isomerization and polymerization of olefms, and epoxidation reactions. Rapidgrowth has continued in the use of homogeneous catalysts for large scaleproduction of chemical intermediates and polymers. Of the many industrial6processes which currently use homogeneous catalysis, the hydroformylation ofolefms (Oxo process), the oxidation of ethylene (Wacker process), thecarbonylation of methanol (Monsanto process), oligomerization of dienes, ZieglerNatta systems, and hydrocyanation of butadiene to adiponitrile, are the mostsignificant.48’52The advantages and disadvantages of the use of homogeneous catalysts,especially in industrial applications, have been widely discussed.48’53 Although amuch greater volume of industrial production is done employing heterogeneouscatalysts, the use of homogeneous catalysts is of great interest due to their higherselectivity, specificity, and reproducibility, which in turn result in pure products athigher yields. In addition, the higher activity (per metal atom) of homogeneouscatalysts allows for the use of relatively mild reaction conditions. Because of theiramenability to study by spectroscopic and other kinetic techniques, thehomogeneously catalyzed reactions are better understood mechanistically thantheir heterogeneous counterparts. These mechanistic studies lead to systematicways of modifying the properties of the catalyst and reaction conditions to obtainoptimum results:In spite of these advantageous features, the difficulty in separating thesoluble catalyst from the reaction products, the moisture- and oxygen-sensitivity,and low thermal stability of the catalyst remain as principal drawbacks for awidespread use of homogeneous catalytic systems in industrial applications. Toovercome the catalyst separation problem, much effort has been directed toward:(i) the so called “third generation” catalysts (the 15t and 2nd generation of catalystsbeing heterogeneous and homogeneous, respectively), where the soluble catalyst isbonded to an insoluble polymer support,5457 and (ii) the design of water-soluble7catalysts where the use of aqueous and non-aqueous phases allows for simpleseparation of product and catalyst.58The major thrust in homogeneous catalysts lies in their use in asymmetricsynthesis. By incorporation of a chiral ligand into the catalyst, synthesis ofoptically active compounds has been made possible.592 Isolation of a singleoptical isomer is classically brought about by the use of biochemical processes63’4or by the costly process of resolution of a racemic mixture. A measure of theefficiency of such a process is given by the enantiomeric excess which is defmedas:IR-SI% enantiomenc excess (/o e.e.) = x 100R+SSpectacular success in the use of homogeneous catalysts in asymmetric synthesisis evident from the essentially 100% enantiomeric excess obtained in manyreactions.7’656The importance of optically pure compounds can be readily recognized bythe chiral specificity required for bioactive products. The desired biologicalactivity is usually associated with only one of the two or more stereoisomers of achiral compound. In an extreme case, exemplified by thalidomide, one opticalisomer is therapeutic while the other has serious undesired biologicalconsequences (tetragemcity in the case of the thalidomide example). The tragedyof the thalidomide babies emphasized the importance of achieving the synthesis ofoptically pure drugs.67 Accordingly, both pharmaceutical and agrochemicalindustries have paid an increasing attention to the use of homogeneous asymmetric8catalysis for production of drugs, food additives, flavouring agents, andagrochemicals.68The production of the amino acid drug (5)-Dopa, which is usedto treat Parkinson’s disease, and the production of the constituents of the sugarsubstitute aspartame (NutrasweetTM), are the most significant of suchdevelopments, both based on Rh catalysts containing chiral phosphine ligands.48In addition, the production of (5)-Naproxen, a commonly used antiinflammatorydrug whose (R)-isomer is a liver toxin, is on the verge of industrial production byenantioselective hydrogenation;48currently it is produced by an optical resolutionmethod.cOOHH2N.-CHCH3 ICH2MeOCOOH[1OH(AS)-NaproxenOH(S)-DopaCO2MeI CH2OHj.._CH2_C NH—C— CNHAspartan91.2.1 Homogeneous Catalytic HydrogenationHomogeneous catalytic hydrogenation of unsaturated organic substrates isone of the most extensively studied reactions involving homogeneouscatalysis.2”3’69-72 Olefms have been the most thoroughly examined substrates.However, hydrogenation studies on many other functional groups, such as carbon-carbon triple bonds (acetylenes),73’4 carbon-nitrogen double and triple bonds(imines and nitriles),’5’7577 and carbon-oxygen double bonds (aldehydes andketones),7’89have gained momentum in recent years.Historically the first example of a catalytic homogeneous hydrogenation ofan organic substrate was reported in 1938, and involved the H2-reduction ofbenzoquinone catalyzed by cupric acetate solution.80 Activation of dihydrogen bya ruthenium complex was initially reported in 196 1,81 and this was one of the firstreports of a homogeneous reaction catalyzed by a ruthenium species. Halpern’sgroup showed that ruthenium(III) chloride in aqueous HC1 catalyzed the hydrogenreduction of Fe(III) and Ru(IV) substrates at 80 °C and 1 atm pressure.81 In thesame year, the same group reported that aqueous HC1 solutions containingchlororuthenate(II) complexes were active for the hydrogenation of several olefmiccompounds including maleic, fumaric, and acrylic acids.82 Significant advances inhomogeneous catalytic hydrogenation were made by Wilkinson’s group with theisolation and study of the extremely active (at room temperature and 1 atmhydrogen) hydrogenation catalysts RhCI(PPh3)83 and Ru(H)Cl(PPh3).84 Theactivity of the rhodium complex was also discovered independently by Coffey.85Since the early and mid-1960s, interest in homogeneous catalytic hydrogenationreally began to grow, and innumerable systems have been studied and somemechanisms deduced. Although the mechanisms of homogeneous hydrogenation10differ from system to system, some common, fundamental processes are present inall hydrogenation cycles. 13,69 These include:(1) activation of molecular hydrogen.(2) activation of substrate.(3) hydrogen transfer to the substrate.(4) release of the product and regeneration of the catalyst.The initially reported hydrogenation catalysts were generally of the Group8-10 metals in low oxidation states, typically involvingd6-d8 species, but there arenow many catalysts based on the earlier Group 3-5 metals. 13,71,86 The catalysts orprecursors are frequently coordinatively unsaturated, thereby allowing sites foractivation of substrates andlor molecular hydrogen during the catalytic cycle.1.2.2 Asymmetric Homogeneous HydrogenationAsymmetric homogeneous catalysis that can lead to the formation of asingle enantiomer of a targeted chiral compound has become a theme offundamental importance. Asymmetric hydrogenation is one of the most powerfultools for the synthesis of chiral compounds, and has had the broadest generalimpact on asymmetric catalysis.87 The most widely studied of such processes isthe hydrogenation of prochiral olefms, for example, Equation 1.2.H2 H H- ,CH3HO NHAcHO2C NHAc + HO2C NHAc(S)-isonr (R)-isonr (1.2)11Use of chiral metal complexes in catalyzed transformations of the typeshown in Equation 1.2, leading preferentially to either (R)- or (5)-isomer, has beenstudied extensively with excellent results. Many reviews on the subject have beenpublished, 14,88 but a brief overview will be presented here.Soon after the discovery of the efficient olefin hydrogenation catalystRhCl(PPh3),8385 the search for a chiral analogue began. The basic strategy wasto replace the triphenylphosphine ligands with chiral phosphines. The earliestattempts were reported in 1968 by Homer and coworkers, and by Knowles andSabacky:89 RhCl(PPh3) was modified with chiral, monodentate phosphineligands of the type P*PhR1R2and used to hydrogenate substituted styrenes andother substrates, but the optical yields were generally low (less than 8%), except inthe hydrogenation of a-acetamidoacrylic acids where e.e. values of upto 15% wereobtained.89 After experiments using chiral monodentate phosphines, it wasrealized that the incorporation of chiral bidentate phosphines gave the best results.The use of the chiral diphosphine DIOP (Figure 1.3) was first reported by Kagan’sgroup,9° and virtually all more recent work on asymmetric hydrogenation hasemployed catalysts containing chiral diphosphines; this has given much of theimpetus for the synthesis of new ligands. Hundreds of different chiral diphosphines have been reported,9’ and the most effective of such ligands can becategorized into four basic groups, as shown in Figure 1.3.62bAlthough there are still many unanswered questions regarding asymmetrichydrogenation and associated ligand/substrate effects, several trends have emergedfrom the numerous reactions carried out over the years using different ligand12q pOMePPOMeDIPAMP - Phosphorus chiralityPPh2PPh2DIOP - Backbone carbon chiralityCH3 ..-N(CH3)2PPh1—PPh2BPPFA- Planar chiralitycoizai‘- PPhBINAP - Axial chiraiityFigure 1.3: Types of chiral diphosphine ligands used in asymmetrichydrogenation.metal-substrate combinations. Chelating phosphines seem to be more effectivethan the monodentate ones.59C,91 The diphosphines that form a more rigid chelate(e.g. a five-membered ring) seem to have generally a higher enantioselection overones which form more flexible chelates (six- and seven-membered chelates).59More precisely it is formulated that a chiral array of phenyl groups, induced by thechelate ring conformation adopted by the diphosphine, can be the origin ofasymmetric bias, which discriminates the enantiotopic faces of the prochiralsubstrate in the substrate binding step.59C Most of the diphosphines that have13shown successful results contain aryl substituents at the phosphorus atom, butrecently good results have also been obtained with phosphines substituted withchiral aliphatic groups.92Varying results have been obtained with different types of substrates, buthighest optical yields (>90% e.e.) have been achieved more consistently with (Z)(x-acylarnno-cinnamic or -acrylic acids or their esters (Equation l.3).43H%%c_c_CO2R2H2R3CH2CO2R—M4COR1 catalyst NHCOR1 (1.3)The acyl group can play a crucial role in determining the e.e. values withinolefmic substrates. Structural data indicate that the acyl ketomc oxygen binds tothe metal forming a chelate, at least in rhodium systems (Figure 1.4).93 Thisprovides a rigid system with a special phosphine/substrate arrangement, whichsubsequently leads to high optical yields.sssPMFigure 1.4: Chelation of the catalyst by acylaminoacrylic acid.14Until about 1980 the success of asymmetric hydrogenation was associatedwith rhodium-diphosphine catalysts in the hydrogenation of substrates related toamino acid precursors. However, with the advent of the B1NAP ligand94 (Figure1.3), the most striking set of results in asymmetric hydrogenation has beenobtained with ruthenium chemistiy in the last five years.7”4Both rhodium- andruthenium-BINAP catalysts have been studied, but the rhodium system has morelimited utility. In contrast, some Ru(BTNAP) catalysts, associated most closelywith Noyori and Takaya, have been spectacularly successful for H2-reduction of awide range of functionalized olefms7’1495 and ketones5’796 with uniformly highenantioselectivity. There have also been major advances in design of systems forasymmetric hydrogenation of imines, using mainly Rh, Jr and Ru catalysts75’697and a Ti system.98 Thus, the scope of asymmetric hydrogenation has widened, butthe quest for better catalysts continues in order to accommodate a broaderspectrum of substrates, and to improve the selectivity and efficiency of the existingcatalytic systems.1.3 Scope of the ThesisMuch of the impetus for the present thesis work originated from theisolation and characterization of the dihydrogen complex (A) (see page 6), formedby the reaction between dihydrogen and the RuC12(PPh3)(iso FA) complex,where it was concluded that the P-N ligand promoted formation and stabilizationof the ri2-H complex.42 Transition-metal dihydrogen complexes constitute animportant class of compounds that has opened up a new era in metal-catalyzedhydrogenation reactions. Ever since the first report of a dihydrogen complex in1984 by Kubas and coworkers,99 an enormous number of such complexes hasbeen reported’°° (a brief review is presented in Chapter 4). However, the structure15of (A) is one of the few reported to reveal anr12-H ligand by ciystallography, andit is the first crystal structure of a bimetallic dthydrogen complex.42Thus, it was ofinterest to study dihydrogen activation by other Ru(P-N) systems, and to evaluatetheir potential as hydrogenation catalysts. Activation of small molecules other thandihydrogen also constitutes complementary aspects in coordination chemistry andhomogeneous catalysis. Although five-coordinate, 16-electron ruthenium(II)complexes are good candidates for study of such reactions, not much attention hasbeen paid in the past to this possibility, except for RuC12(PPh3)system.12’0Due to their coordinative unsaturation and high basicity/nucleophilicity, the five-coordinate Ru(P-N) complexes are especially suitable for such studies.With the above goal, the chemistry of ruthenium complexes containingaminophosphine ligands PMA, PAN, and (R)-AMPHOS was explored. Thesynthesis of the ligands and the general experimental procedures are outlined inChapter 2, and Chapter 3 is devoted to the synthesis and characterization of someRu(P-N) complexes. Activation of dihydrogen by, and the catalytic hydrogenationactivity of the Ru(P-N) systems are presented in Chapter 4, including somepreliminary results on the kinetics of hydrogen activation by Ru(III)-AMPHOScomplexes. The chirality of AMPHOS allowed for the use of Ru-AMPHOScomplexes in some catalytic asymmetric hydrogenation studies (Chapter 4).The potential of some RuC12(P-N)(PR3)complexes for binding a variety ofsmall molecules is studied, and the results are of considerable interest and promise(Chapter 5). Finally, a summary of results is presented in Chapter 6, together withsuggestions for future work.161.4 References- Chapter 11 James, B. R. Inorg. Chim. Acta Rev. 1970, 4, 73.2 James, B. R. Homogeneous Hydrogenation; Wiley: New York, 1973.3 Masters, C. Homogeneous Transition-Metal Catalysis- A Gentle Art; Chapman andHall: New York, 1981; pp 51- 60.4 Pignolet, L. H. Homogeneous Catalysis with Metal Phosphine Complexes; Plenum:New York, 1983.5 Noyori, R. Chem. Soc. Rev. 1989, 18, 187.6 Mashima, K.; Kusano, K.; Ohta, T.; Noyori, R.; Takaya, H. J Chem. Soc., Chem.Commun. 1989, 1208;PureAppl. Chem. 1990, 62, 1135.7 Noyori, R; Takaya, H. Acc. Chem. 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Rev. 1992, 121, 155, and referencestherein.101 Cenini, S.; Fusi, A.; Capparella, G. I Inorg. Nuci. Chem. 1971, 33, 3576.26Chapter 227General Experimental ProceduresAll reactions were carried out in deoxygenated solvents, in an atmosphereof argon or nitrogen, by using a double-manifold vacuum system and Schlenktechniques. Elemental analyses were performed by Mr. P. Borda of thisdepartment. Additional characterization data are given in the designated sectionsof the thesis.21 Materials2.1.1 SolventsSolvents of spectral or reagent grade were obtained from MCB, BDH,Mallinckrodt, Fisher, Eastman, or Aldrich Chemical Co. Benzene, toluene,hexanes, ether, and tetrahydrofuran (THF) were distilled from sodiumlbenzophenone under a nitrogen atmosphere. Dichioromethane, methanol, and ethanolwere distilled from calcium hydride and Mg/I respectively. !VN-dimethylacetaniide (DMA) was stirred over CaH2 for a minimum of 24 h, and vacuumdistilled at 3 0-40 °C, and stored under argon in the dark. DMA used in gas uptakestudies was further purified by distilling from Ru(H)Cl(PPh3)(ca. 500 mgfL).’All solvents were deoxygenated by freeze-pump-thaw cycles prior to use. Thedeuterated solvents used (C6D,C7D8,CD3O , CD21 and CDC13) wereobtained from Merck Frosst Canada Ltd., and were dried over activated molecularsieves (Fisher: Type 4A), and stored under argon.282.1.2 GasesPurified (C.P. grade) argon, nitrogen, hydrogen, hydrogen sulfide, carbonmonoxide, carbon dioxide, oxygen, and sulfur dioxide were purchased from UnionCarbide Ltd. or Matheson Gas Co. All gases except hydrogen were used assupplied. Hydrogen was purified by passing through an Engeihard Deoxo catalyticpurifier to remove traces of oxygen. Deuterium and 13C-labelled carbon monoxidewere obtained from Merck Frost Canada Ltd., and were used without furtherpurification.2.1.3 PhosphinesTriphenyiphosphine, and tri(p-tolyl)phosphine were used as supplied fromStrem Chemicals, Inc.2.1.3.1 (R)-(+)-N,N-dimethyl-1- jo-(diphenylphosphino)phenyi]ethylamine, [(R)-AMPHOSJ(R)-AMPHOS was prepared by the method described by Payne andStephan2 with minor modifications. (R)-N,N-dimethyl-1-phenylethylamine wasprepared from (R)- 1-phenylethylamine by reaction with formaldehyde and formicacid.3 (R)-N,N-dimethyl-1-phenylethylamine (1.20 g, 0.01 mol) was dissolved indry, freshly distilled diethyl ether (15 mL), and 8.6 mL (0.01 mol) of 1.6 Mbutyllithium in hexanes was added. The solution was stirred for 24 h undernitrogen, cooled in an ice-bath, and P(C6H5)2C1 (2.96 g, 0.01 mol) was addedslowly. The mixture was allowed to warm to room temperature, and then stirredfor 2 h, when the resultant orange-yellow solution was cooled and water (10 mL)29was added; the organic layer was separated and the aqueous phase was extractedwith ether (3x15 mL). The combined ether extracts were dried over anhydrousMgSO4.After filtration, the solvent was removed under reduced pressure, and theresulting oil was recrystallized from hot methanol, to yield a white crystallinematerial. Yield: 1.43 g (32%). Anal. Calcd forC22H4NP: C, 79.25; H, 7.26; N,4.20. Found: C, 79.21; H, 7.25; N, 4.10. [ct] = +53.7°(CHCI,c = 0.25), [lit.[cL] +54.4°(CH2C1,c = 8)].23lP{1H} NMR (C6D, 121.4 MHz, 20 °C) ö:-11.30 (s). 1H NMR (C6D,300 MHz, 20 °C) ö: 1.21 (d, 3H, 3HH = 6 Hz; CHCl-I3), 2.04 (s, 6H, N(CH3)2,4.35 (dq, lH, 3HH = 6 Hz, 4J1-p = 6 Hz; CH3-CR), 6.80-7.70 (m, 14H, Ph). Crystals of X-ray quality were obtained from abenzene solution of AMPHOS. A single crystal X-ray structure determinationrevealed the absolute configuration of the aminophosphine, which is shown inAppendix (A-6).2.1.3.2 o-Diphenylphosphino-N,N-dimethylaniJine, (PMA)The ligand PMA was prepared by the method described by Fritz et al.4 withminor modifications. o-Bromo-N,N-dimethylaniline was prepared from o-bromoaniline, by methylation with alkaline dimethyl sulfate according to the procedureof Gilman and Banner.5 The product was vacuum distilled to obtain a colorlessliquid (bp 100-101 °C, - 15 mm Hg). To a cooled solution (-20 °C) of nbutyllithium in hexane (9.4 mL, 0.015 mol, 1.6 M), 2-bromo-N,N-dimethylaniline(2.95 g, 0.015 mol) in ether (6 mL) was added slowly, with stirring. The mixturewas allowed to warm to room temperature, left for 1 h, and cooled again to -40 °C.Chlorodiphenylphosphine (2.7 mL, 0.0 15 mol) in ether (3 mL) was addeddropwise with stirring, and the mixture was allowed to warm to room temperature,30and then left for 1 h. Water (20 mL) was added to the resultant pale-yellow turbidsolution with stirring. The organic layer was separated, the aqueous layer wasextracted with ether (3x15 mL), and the combined ether extracts were dried overanhydrous MgSO4.Filtration, and removal of solvent under vacuum, resulted in awhite solid, which was recrystallized from hot ethanol to yield an analytically pureproduct. Yield: 2.66 g (58%). Anal. Calcd forC20HNP: C, 78.67; H, 6.60; N,4.59. Found: C, 78.86; H, 6.56; N, 4.57. 31P{1H} NMR (C6D, 121.4 MHz, 20°C) 6: -7.13 (s). ‘H NMR (C6D, 300 MHz, 20 °C) 6: 2.50 (s, 6H, N(CH3)2,6.80-7.50 (m, 14H, Ph).2.1.3.3 1 -(Dimethylamino)-8-(diphenylphosphino)naphthalene, (PAN)The synthesis of this aminophosphine was carried out according to themethod described by Dekker et al.,6 with minor modifications. 1-(Dimethyl-amino)-8-lithionaphthalene was prepared by treating a ether solution of 1-(dimethylamino)naphthalene with BuLi.7 To a cooled solution (-30 °C) of 1-(dimethylamino)-8-lithionaphthalene (2.79 g, 15.8 mmol) in THF (60 mL), 1equiv. of P(C6H5)2C1 (2.9 mL, 15.8 mmol) was added, and the solution wasslowly warmed to room temperature. After being stirred for two days, the yellow-orange solution was evaporated to dryness, and the residue was taken up inbenzene (- 10 mL), which caused separation of a pale yellow solid and a yellowfiltrate. The solid was isolated by filtration, and washed with benzene to yield thepure product, a pale yellow powder, 1.41 g (25% yield). Anal. Calcd forC24H2NP: C, 81.10; H, 6.24; N, 3.94. Found: C, 80.70; H, 6.34; N, 3.78.3lP{1H} NMR (CDC13, 121.4 MHz 20 °C) 6: 5.60 (s). ‘H NMR (CDC13, 300MHz, 20 °C) 6: 2.22 (s, 6H, N(CH3)2;6.70-7.80 (m, 16H, Ph).312.1.4 Phosphine OxidesThe phosphine oxides listed below were synthesized solely to allow fortheir identification (by NMR spectroscopy) in reaction mixtures, to be described inthe later chapters.The method described by Mercer el al.8 was used as follows: hydrogenperoxide (10 mL of a 3% aq. solution) was added to a mixture of the phosphine(0.9 mmol) in ethanol (25 mL) at 50 °C. The resultant solution was heated atreflux for 15 mm and cooled to room temperature. The solvent was removed undervacuum and the residue was recrystallized from ethanol and water to yield a pale.-yellow/white crystalline material.2.1.4.1 Triphenylphosphine Oxide31P{1H} NMR (121.4 MHz), & 34.96 (CDC13);31.35 (C6D).2.1.4.2 Tri(p-tolylphosphine) Oxide31P{1H} NMR (121.4 MHz), 6: 35.14 (CDC13); 31.82 (C6D). 1H NMR(300 MHz): 2.40 (CDC13), 1.97 (C6D)(-CH3).2.1.4.3 o-(Diphenylphosphine oxide)-N,N-dimethylaniline31P{lH} NMR(121.4 MHz), 6: 32.92 (CDC13); 30.37 (C6D). 1H NMR(300 MHz): 2.39 (CDC13 orC6D)(-N(CH3)2.322.1.5 Olefinic Substrates Used for Hydrogenation StudiesStyrene was obtained from Aldrich, and was passed through a column ofneutral alumina (Fisher, chromatographic grade) prior to use. (Z)-a-Acetamidocinnamic acid was recrystallized from hot ethanol, and tiglic acid (trans-2,3-dimethylacrylic acid) was sublimed under reduced pressure at room temperature (-20 °C), to yield colorless crystals.2.1.6 Other MaterialsProton sponge (1, 8-bis(dimethylamino)naphthalene), obtained fromAldrich, was purified by passing an n-pentane solution of the amine through acolumn of alumina, and evaporating the eluate to yield a white solid.Polyvinylpyridine (PVP) was used as supplied from Aldrich.2.2 Ruthenium ComplexesThe primary ruthenium source, RuCI3. 3H20, was supplied on loan fromJohnson Matthey Ltd. (- 40% Ru).2.2.1 Ruthenium Precursors2.2.1.1 Dichlorotris(triphenylphosphine)ruthenium(II), RuCl2(PPh39RuC13.3H20 (1.0 g, 3.83 mmol) was refluxed in methanol (200 mL) for 5miii under nitrogen. After the mixture was cooled, PPh3 (6.6 g, 25.2 mmol) wasadded, and the solution was refluxed for 3 h. The resultant dark brown product33was filtered, washed with methanol and ether, and dried under vacuum. Yield:3.53 g (97%). Anal. Calcd forC54H4512P3Ru: C, 67.64; H, 4.73; Cl, 7.39.Found: C, 67.48; H, 4.67; Cl, 7.28.2.2.1.2 Dichlorotris(tri-p-tolylphosphine)ruthenium(II),RuCI(P(p-toIyI)3)9’10The title compound was synthesized in the same manner as described forthe triphenyiphosphine derivative, but using P(p-tolyl)3 (6.9 g, 22.8 nimol). Yieldof the purple product: 3.30 g (80%). Anal. Calcd forC63H12PRu: C, 69.74;H, 5.85; Cl, 6.53. Found: C, 69.68; H, 5.77; Cl, 6.40.2.2.1.3 Trichlorobis(triphenylphosphine)(dimethylacetamide)ruthenium(III). DMA solvate,RuCI3(PPh2DMA).(DMA)”RuC13.3H20(1.0 g, 3.8 mmol) and two equivalents of PPh3 (2.0 g, 7.6mmol) were stirred in DMA (30 mL) for 24 h at room temperature. The greenproduct was filtered, washed with a limited amount of DMA (as it is soluble inDMA) and hexanes, and vacuum dried. Yield: 2.29 g (66%). Anal. Calcd forC44H8N2O13PRu:C, 58.31; H, 5.30; N, 3.09; Cl, 11.76. Found: C, 58.29;H, 5.37; N, 3.17; Cl, 11.90. JR (Nujol, cm-i): VCO at 1633 (uncoordinated DMA),VCO at 1597 (coordinated DMA), in agreement with the reported data.11342.2.1.4 Trichlorobis(tri-p-tolylphosphine)(dimethylacetamide)ruthenium(IH). DMA solvate,RuCI3(P(p-toIy ))(DMA).(DMA)’The title compound was synthesized in the same way as for thetriphenyiphosphine analogue, but using P(p-tolyl)3 (2.3 g, 7.6 mmol). Yield of thegreen product: 2.10 g (55%). Anal. Calcd forC50H6NO1Ru:C, 60.64; H,6.06; N, 2.83. Found: C, 60.57; H, 5.95; N, 2.64. JR (Nujol, cml): 1646(uncoordinated DMA), 1599 (coordinated DMA), in agreement with thereported data.”2.2.1.5 Cis-Dichlorotetrakis(dimethylsulfoxide)ruthenium(II),cis-RuC2(DMSO)412A DMSO solution (10 mL) ofRuC13.3H20(1 g, 3.8 mmol) was refluxed inair for 5 mm; the volume was then reduced, and the bright yellow product wasprecipitated by the addition of acetone. The product was filtered, washed withacetone and ether, and vacuum dried. Yield: 0.83 g (45%). Anal. Calcd forC8H24O4S1Ru: C, 19.88; H, 4.97. Found: C, 19.75; H, 5.07. JR (Nujol,cm-i): v at 1107, 1078 (S-bonded DMSO), at 925 (0-bonded DMSO), inagreement with the literature data.122.2.1.6 Dichloro(q4-i,5-cyclooctadiene)ruthenium(II) dimer,[RuC1(q-COD)(i-CI)I2’RuC13.3H20(1.0 g, 3.8 mmol) and 1,5-cyclooctadiene (5 mL, 37 mmol)were stirred together in ethanol (40 mL) at room temperature. After 4-5 days, a35light brown solid was deposited, which was filtered, washed with ethanol andvacuum dried. Yield: 0.75 g (70%). Anal. Calcd forC8H1212Ru: C, 34.30; H,4.32; Cl, 25.31. Found: C, 34.69; H, 4.50; Cl, 25.15.2.2.1.7 Dichloro(i6-benzene)ruthenium U) dimer,[RuC1(r)6-benzene)(j-CI)12’4RuC13.3H20(0.50 g, 1.9 mmol) and 1,3-cyclohexadiene (3 mL, 31 mmol)in ethanol (30 ml) were refluxed for 4 h under a nitrogen atmosphere. The brownproduct was isolated by filtration, washed with ethanol, and dried under vacuum.Yield: 0.76 g (80%). Anal. Calcd forC12H14Ru2:C, 28.81; H, 2.42. Found:C, 28.53; H, 2.38.2.2.1.8 Hydridochlorotris(triphenylphosphine)ruthenium(II).DMAsoivate, Ru(H)C(PPh3).(DMA)’la, 15RuC12(PPh3)(0.5 g, 1.9 mmol) was stirred in DMA (10 mL) for 48 h,under hydrogen. The purple product was isolated by filtration, washed with DMAunder argon, and dried under vacuum. Yield: 0.96 g (50%). Anal. Calcd forC59H4NOC1P3Ru: C, 68.87; 5.48; N, 1.38. Found: C, 68.74; H, 5.41; N, 1.37.IR (Nujol, cm): V(Ru4-{) at 2035 (w). 1H NMR (CDC13,20 °C): 8, -17.4 ppm(q, 2pH = 26 Hz, Ru-H), in agreement with the literature data. fla,iS362.2.2 Aminophosphine Complexes of RutheniumQl)The complexes of the type RuC12(P-N)(PR3) were synthesized employingthe method described by Jung and coworkers. 16 The properties and characterization of these complexes are presented in Section 3.3.2.2.2.1 Dichtoro(o-diphenylphosphino-N,N-dimethylaniline)(triphenylphosphine)ruthenium(H), RuC12(PMA)(PPh3,1 aRuC12(PPh3)(1.92 g, 2.0 mmol) and PMA (0.61 g, 2.0 mmol) were stirredin dichloromethane (50 mL) for 16 h under argon, at room temperature. Theresultant green solution was concentrated (— 5 mL), and hexanes were added (30mL) to precipitate the green product. The product was isolated by filtration andwashed with hexanes. Repeated washing with hexanes (—j 6 times), and a furtherre-precipitation step using CH21 and hexanes was required to remove the excesstriphenyiphosphine. Drying under vacuum resulted in 1.20 g (82%) of the product.Anal. Calcd forC38H5NC12PRu: C, 61.71; H, 4.77; N, 1.89; Cl, 9.59. Found:C, 61.49; H, 4.81; N, 1.86; Cl, 9.70.2.2.2.2 Dichloro(o-diphenylphosphino-N,N-dimethylanhline)(tri-ptolylphosphine)ruthenium(II),RuC12(PMA)(P(p-tolyl)3,lbThe synthesis was the same as described for the PPh3 analogue, but usingRuCl2(P(p-toly )3)(2.17 g, 2 mmol). Yield of the green product: 1.25 g (80%).Anal. Calcd for41HNC1PRu: C, 63.00; H, 5.29; N, 1.79. Found: C, 62.72;H, 5.38; N, 1.84. Crystals of X-ray quality were obtained by layering hexanes ontoa dichloromethanefbenzene (5:1) solution of the compound. The molecular37structure is described in Section 3.3.1, and the complete structural parameters arelisted in Appendix (A-i).2.2.2.3 Dichloro(1 -(dimethylamino)-8-(diphenylphosphino)naphthalene)(tri-p-tolylphosphine)ruthenium(II),RuC12(PAN)(P(p-tolyl)3), 2A solution (CH2C1,20 mL) of RuC12(P(p-tolyl)3)3 (0.61 g, 0.56 nunol)and PAN (0.22 g, 0.62 mmol) was stirred at room temperature, under anatmosphere of argon for 16 h. The resultant bright green solution wasconcentrated, and hexanes were added to obtain a green product. As for theanalogous PMA complex described above, washing with hexanes several times,and re-precipitation from CH21 and hexanes was required to obtain ananalytically pure compound. Drying under vacuum resulted in 0.40 g (85%) of thegreen product. Anal. Calcd forC45H3NC12PRu:C, 64.98; H, 5.21; N, 1.68; Cl,8.52. Found: C, 64.82; H, 5.40; N, 1.55; Cl, 8.44.2.2.2.4 Dichloro {(R)-N,N-dimethyl-1- Lo-(diphenylphosphino)phenyll ethyiamine}(triarylphosphine)ruthenium(II),RuCl2(AMPHOS)(PR3),(R = Ph, 3a; R =p-tolyi, 3b)Synthesis of the title compound by using the method described above forthe PMA and PAN aminophosphine complexes (Sections 2.2.2.1 and 2.2.2.3) wasnot successful (see Section 3.2.2). However, an indirect method, employing acorresponding hydridochloro complex and CHC13 gave the required product (seeSection 3.2.3 for the NMR characterization), but with poor yields (25-30%). Inthis method, the complex Ru(H)C1(AMPHOS)(PR3(see Section 2.2.2.7.) (-.‘ 0. lg,380.1 mmol) was stirred in CHC13 (5 mL) for 5-6 h, and after the resultant greensolution was concentrated to 1 mL, hexanes were added to precipitate the greenproduct. The product obtained was not analytically pure as evidenced by its NMRspectrum (see Section 3.2.3), and the elemental analysis results.For 3a, Anal. Calcd forC40H39NC12PRu: C, 62.58; H, 5.12; N, 1.82.Found: C, 63.63; H, 5.77; N, 2.01.For 3b, Anal. Calcd forC43H5NC1PRu : C, 63.78; H, 5.60; N, 1.73.Found: C, 64.63; H, 6.15; N, 1.90.2.2.2.5 Dichlorobis(o-diphenylphosphino-N,N-dimethylaniline)ruthenium(II), RuC12(PMA)The title complex was prepared by stirring a suspension of [Ru(COD)C12](0.08 g, 0.14 mmol) and PMA (0.16 g, 0.54 mmol) in dichloromethane (3 mL),under argon. After 3 days the original brown turbid solution had turned to a clear,brown-red solution, while a small amount of dark brown solid had collected at thebottom of the Schienk tube. Hexanes were added to the filtrate to obtain a rosy-redprecipitate. The product was filtered, washed with hexanes and vacuum dried.Yield of the rosy-red product: 0.11 g (5 0%). Anal. Calcd forC40HN21PRu:C, 61.36; H, 5.15; N, 3.58. Found: C, 61.02; H, 5.30; N, 3.30.392.2.2.6 Chlorohydrido(o-diphenylphosphino-N,N-dimethylanhline)(triarylphosphine)ruthenium(II),Ru(H)Cl(PMA)(PR3),(R Ph, 4a; R =p-tolyl, 4b)A benzene solution (2 mL) ofRuC12(PMA)(PR3(0.05 mmol) and protonsponge (PS) (0.04 g, 0.20 mmol) was stirred under hydrogen for 16 h. The originalclear green solution, which turned red within 2-3 miii of exposure to hydrogen,turned turbid overnight. The turbidity was due to precipitation of the protonsponge-HC1 salt (PSHClj, which was identified by its 1H NMR spectrum17(CD2I,400 MHz, 20 °C) ö: 2.02 (s, -N(CH3)2,3.32 (s, -N(CH3)2, 18.79 (s,acidic proton). Filtration of this mixture through a layer of Celite removed the salt,resulting in a red-clear filtrate, to which hexanes were added to precipitate anorange-yellow product. After the mixture was stirred for about 15 miii, the productwas isolated by filtration, washed with hexanes (3x15 mL), and vacuum dried.Yield: - 0.03 g (78%). The hydridochloro complexes were found to be air-sensitive and thus handling of the solids was done under an argon atmosphere in aglove-bag. Elemental analysis results within acceptable error limits could only beobtained for 4b. Anal. Calcd forC41H2NC1P2Ru: C, 65.90; H, 5.66; N, 1.87; Cl,4.74. Found: C, 65.88; H, 5.91; N, 1.86; Cl, 4.98. IR (Nujol, cm-i) of 4a and 4b:V(Ru..H) at 2079 (w).2.2.2.7 Chlorohydrido{(R)-N,N-dimethyl-1-Io-(diphenylphosphino)phenyll ethylamine) (triarylphosphine)ruthenium(II),Ru(H)Cl(AMPHOS)(PR3),(R = Ph, 5a; R :=ptoIyI, 5b)These hydride complexes were prepared by using exactly the sameprocedure as described above in 2.2.2.6., but using precursor RuCl3(AMPHOS)-40(PR3) species (Sections 2.2.3.3 and 2.2.3.4) ( 0.62 mmol) and PS (0.40 g, 1.87mmol), in 10 mL of benzene. The yields of the orange-yellow products formedwere estimated to be about 40%. The products were much more air-sensitive thanthe hydrido(PMA) complexes (2.2.2.6.), and decomposed to green-black solidsafter a few seconds of exposure to air. Anal. Calcd for 5a, R Ph,C80HN21P4Ru:C, 65.52; H, 5.50; N, 1.91. Found: C, 64.18; H, 5.65; N,2.00. The extreme air-sensitivity of the compounds, and the practical limitationsassociated with elemental analysis, made it impossible to obtain a carbonelemental analysis result within an acceptable range; much worse results wereobtained for 5b. However, the compounds are well characterized by using othertechniques (see Section 4.5.2). JR (Nujol, cml) of 5a and 5b: v(RuH) at 208 1(w)and 2064 (br, w) (see Section 4.5.2).2.2.3 Aminophosphine Complexes of Ruthenium(lll)Properties and characterization of these complexes are presented in Section3.4.2.2.3.1 Trichloro(o-diphenylphosphino-N,N-dimethylaniline)(triphenylphosphine)ruthenium(III), RuC13(PMA)(PPh,6aThe title complex was prepared by refluxing a suspension of RuC13-(PPh3)2DMA).(DMA) (1.0 g, 1.10 mmol) and PMA (0.34 g, 1.10 mmol) in 100mL of hexanes for 24 h. After the reaction mixture was cooled, the red-coloredproduct was isolated by filtration, and washed with hexanes (4x15 mL).Recrystallization from CH2I and hexanes afforded an analytically pure41compound. Yield: 0.77 g (90%). Anal. Calcd forC38H5NC1P2Ru: C, 58.89; H,4.55; N, 1.81. Found: C, 58.71; H, 4.74; N, 1.78. Crystals of X-ray quality wereobtained by layering hexanes onto a dichloromethane solution of the compound.The molecular structure is described in Section 3.4.2 along with some selectedstructural parameters; complete X-ray details are listed in Appendix (A-2).2.2.3.2 Trichloro(o-diphenylphosphino-N,N-dimethylaniline)(tri-ptolyiphosphine)ruthenium(III), RuC13(PMA)(P(p-tolyl)),6bThis was prepared in exactly the same way as described above for the PPh3complex, but usingRuCI3(P(p-tolyl)2DMA).(DMA) as precursor (1.0 g, 1.01mmol). Yield: 0.73 g (88%). Anal. Calcd forC41HNC13P2Ru: C, 60.26; H,5.06; N, 1.71; Cl, 13.02. Found: C, 60.38; H, 5.24; N, 1.55; Cl, 13.25. Themolecular weight of 6b determined by Signer method (884 g mo11) agrees withthat calculated using the above formulation (817 g moll).2.2.3.3 Trichloro[(R)-N,N-dimethyl-1-(o-(diphenylphosphino)-phenyl)ethylaminej (triphenylphosphine)ruthenium(III),RuC13(AMPHOS)(PPh),7aThe same procedure described above in 2.2.3.1 was followed, but usingRuCI3(PPh)2DMA).(DMA) (1.0 g, 1.10 mmol) and AMPHOS (0.37 g, 1.10mmol); the procedure resulted in 0.71 g (80%) of a bright-red product. Anal. CalcdforC40H39NC1P2Ru: C, 59.82; H, 4.89; N, 1.74. Found: C, 59.67; H, 5.02; N,1.69. The molecular weight of 7a determined by Signer method (876 g mol1)agrees with that calculated using the above formulation (803 g mo[l). Crystals ofX-ray quality were obtained by layering hexanes onto a dichloromethane solution42of the compound. The molecular structure is presented in Section 3.4.2 along withsome selected structural parameters; complete X-ray details are listed in Appendix(A-3).2.2.3.4 Trichloro[(R)-N,N-dimethyl- 1-(o-(diphenylphosphino)-phenyl)ethylamine](tri-p-totyiphosphine)ruthenium(III),RuC1(AMPHOS)(P(,p-tolyl)) 7bThe same procedure as described for 2.2.3.2 was again followed.RuC13(P(p-tolyl))2DMA). (DMA) (1.0 g, 1.01 mmol) and AMPHOS (0.34 g,1.01 mmol) yielded 0.66 g (77%) of a bright-red product. Anal. Calcd forC43H5NC13P2Ru: C, 61.11; H, 5.37; N, 1.66; Cl, 12.58. Found: C, 61.38; H,5.60; N, 1.75; Cl, 12.36.2.2.4 Dichloro(o-diphenylphosphino-N,N-dimethylanhline)(triaryphosphine)(Iigand) rutheniumQl)RuCI2(PMA)(PR3)(L), R = Ph, p-tolylThe properties and characterization of these complexes (except for thecomplex where, L = H2) are further presented in Chapter 5; and those of thecomplexes with L = H2 are presented in Chapter 4.2.2.4.1 L = H2:(1-H)RuC1PMA)(PR3,(R = Ph, 8a; R =p-tolyl, 8b)A solution ofRuC12(PMA)(PR3)(0.03 mmol) in either CDCI3 or CD21(0.8 mL) was stirred under hydrogen (1 atm) for 2 h. The original dark greensolution turned to a lighter olive-green color within a few minutes. Character-43ization of the species in solution by means of NMR spectroscopy indicated theproduct to be the dihydrogen complex [(q2-H)RuC1(PMA)(PR3](85%)(Section 4.3). When the reaction was carried out in toluene, a yellow productprecipitated at the bottom of the Schienk tube, and this material was filtered offunder hydrogen. The product is thought to be the dihydrogen complex, butcharacterization of the complex in the solid state was not possible (see Section4.3). The IR spectrum did not show any bands attributable to vH..H. Theformulation of the product in solution under H2 as the dihydrogen complex wasconfirmed by means of T1 measurement studies, and the formation of the r12-HDisotopomer in solution (see Section 4.3). The isotopomer was prepared by treatinga CD21 solution of[(q2-H)RuC1(PMA)(P(p-tolyl)3],8b (olive-green color),with 1 atm of D2 gas for 1 mm. The resultant orange-red solution species wascharacterized by means of NMR spectroscopy. ‘H NMR (300 MHz, CD2I 20°C, upfield region): -10.96 [1:1:1 triplet(1JHD 30Hz) of 1:2:1 triplets (cis-2JHp8.5 Hz).2.2.4.2 L = H20:RuC1(PMA)(PR3)(0H,(R = Ph, 9a; R =p-tolyi, 9b)The title complexes were prepared in situ in a NMR tube, by adding anequimolar amount of H20 (0.70 iL, 0.04 mmol) to a CDC13 solution (0.8 mL)containing RuC12(PMA)(PR3)(0.04 nimol), under an argon atmosphere. Theresultant green-red solution showed quantitative formation of the H20 adduct, asevidenced by NMR spectroscopy (see Section 5.2.1). After few days some redcolored crystals of 9b were deposited at the bottom of the NMR tube; these wereisolated, and the material was characterized by X-ray diffraction analysis. Thecrystallographic data are presented in Chapter 5 (Section 5.2.1), and in Appendix44(A-4). JR of 9a and 9b (CHC13 solution, in a 0.1 mm KBr cell, cm-i): VOH 3470(br), OH 1739 (s).2.2.4.3 L = H2S:RuC1(PMA)(PR3)(SH,(R = Ph, lOa; R p-tolyl, lOb)Hydrogen sulfide gas (2 mL) was injected into a solution of RuCI2(PMA)-(PR3) (0.06 mmol) in benzene (1 mL). Hexanes were added to the resultant redsolution under an argon atmosphere, and the mixture stirred for 15 miii. Theyellow product was filtered, and dried under vacuum overnight. Yield: - 95%.Alternatively, the complex lOb could also be prepared by reacting a solid powderof RuCl(PMA)(P(p-tolyl)3)with H2S (1 atm) at room temperature; H2S gas at 1atm was introduced to a Schienk tube containing RuCl(PMA)(P(p-tolyl)3(0.03mmol) for 1 miii, during which time the color of the green solid turned yellow.The solid was ‘stirred’ for a further 2 h, and was then analyzed by means of NMRand JR spectroscopies (see Section 5.2.2 for NMR characterization). Yield: 100%.Complex la did not react with H2S under similar conditions. The H2S adductslOa and lOb are air-sensitive and thus handling of the solids was done under anargon atmosphere. Acceptable elemental analysis results could only be obtainedfor complex lOb: Anal. Calcd forC41H3NSC12PRu:C, 60.37; H, 5.31; N, 1.72;S, 3.93. Found: C, 60.62; H, 5.33; N, 1.67; S, 4.25. JR of lOa and lOb (Nujol,cm l): vsH at 2506 (s) and 2466 (s). Red-brown crystals of the p-tolyl analoguewere obtained by layering hexanes onto a THF solution of lOb. The X-raycrystallographic results are presented in Section 5.2.2, and in Appendix (A-5).452.2.4.4 L = CH3O :RuC12(PMA)(PR3)(CHOH),(R = Ph, 1 la;R =p-tolyl, lib)Methanol (0.5 mL) was added to a suspension ofRuC12(PMA)(PR3)(0.04mmol) in toluene or benzene (1 mL). The green suspension, which turned to aclear, red solution immediately upon adding methanol, was stirred under argon for5 h. Hexanes were added to the resultant red-brown turbid solution to precipitatea rosy-red product, which was filtered, washed with hexanes and dried undervacuum. Yield: 83%. For ha, Anal. Calcd. forC39HNOC12PRu:C, 60.70; H,5.09; N, 1.82. Found: C, 62.99; H, 5.44; N, 1.65. The results agree better for acomposition of the form lla.1/2(CH)with C, 62.22; H, 5.22; N, 1.73. For lib,Anal. Calcd for,C425NOC12PRu: C, 61.99; H, 5.57; N, 1.72. Found: C,60.83; H, 5.94; N, 1.67. The elemental analysis results agree well with acompound of the form [RuC1(PMA)(P(p-tolyl)3)(CH3OH)].(CHOH),with achemical composition of C, 61.06; 5.84; N, 1.66 (see Section 5.2.3).2.2.4.5 L= Ethanethiol: RuC12(PMA)(PPh3)(EtSH), 12The title complex was prepared in situ by adding approximately equimolaramounts of ethanethiol to a C6D solution containing RuCI2(PMA)(PPh3)in anNMR tube. On addition of the thiol, the green color of the solution changedimmediately to red, and the product formed was characterized by means of NMRspectroscopy (see Section 5.2.4).462.2.4.6 L = SO2:RuC1(PMA)(PR3)(S0,(R = Ph, 13a; R =p-tolyl, 13b)The title complexes were prepared in the same way as described for theH2S adducts (Section 2.2.4.3, solution reaction), but using SO2 gas. The yields ofthe orange-yellow products were 95%. Satisfactory elemental analysis resultscould only be obtained for 13b. Anal. Caled for 13b,C41HNO2SC1PRu:C,58.23; H, 4.89; N, 1.66; S, 3.79. Found: C, 58.80; H, 5.17; N, 1.58; S, 3.59. JR of13a and 13b (CHC13 solution in 0.1 mm KBr cell, cm-i): at 1287 and 1122.2.2.4.7 L = N2:(a-N)RuC1PMA)(PR3,(R = Ph, 14a; R =p-tolyl, 14b)These complexes were prepared by stirring a CDC13 solution (0.8 mL) ofRuCl2(PMA)(PR3)(0.02 mmol) under N2 overnight at a total pressure of 1 atm.The NMR spectrum of the resulting lighter green solution (the initial color, beforereacting with N2, is dark bright green) showed 25% equilibrium conversion tothe dinitrogen adduct. The conversion was increased to 65% when 3 atm of N2was used in a sealed NMR tube experiment. JR of 14a and 14b (CHC13 solution ina 0.1 mm KBr cell, cm-i):“NN at 2161.2.2.4.8 L = 02: [RuCl(PMA)(PR3)]p-O,(R = Ph, 15a;R =p-tolyl, 15b)The title complexes were prepared in situ by injecting 1 mL of 02 gas intoa solution (CDC13 or C6D, 0.8 mL) of RuCl2(PMA)(PR3(0.03 mmol) in anNMR tube. The resultant dark blue-green solution species were characterized byNMR and JR spectroscopies. JR (CHC13 solution in 0.1 mm KBr cell, cm-i): v02at 904 (R = p-tolyl, 15b) and 908 (R = Ph, 15a). NMR data are given in Section5.2.8. Attempts to isolate the products were unsuccessful (Section 5.2.8).472.2.4.9 L = CO:2.2.4.9.1 Ru(CO)2C1(PMA), 16The title complex was prepared by injecting 1 mL of CO gas into a solutionof RuC12(PMA)(PR3)(0.03 mmol in 0.8 mL CDC13) in an NMR tube. Uponreaction with CO, the color of the dark green solution changed immediately toolive-green, and then turned yellow over a period of 15-20 miii. The resultingyellow solution species was characterized by NMR and JR spectroscopies, and theproduct was formulated as the bis-CO adduct, 16, which was confirmed by NMRstudies on a 13C0 reaction product (see Section 5.2.9.1).2.2.4.9.2 RuC1(PMA)(PR3)(CO), (R = Ph, 17a; R p-tolyl, 17b)The title complexes were obtained by the solid state reaction ofRuCl2(PMA)(PR3)with CO (1 atm, room temperature). RuC12(PMA)(PR3(0.02mmol) was stirred under CO for 6 h. The dark green solids, which turned brown-grey within a few minutes of exposure to CO, are formulated as the mono-COadducts. Anal. Calcd for 17a,C39H5NOC12PRu: C, 61.02; H, 4.60; N, 1.83.Found: C, 60.44; H, 4.80; N, 1.71. Anal. Calcd for 17b421NOC1PRu: C,62.30; H, 5.10; N, 1.73; Cl, 8.76. Found: C, 62.15; H, 5.18; N, 1.71; Cl, 8.97. JRof 17a and 17b (Nujol, cm-i): at 1962. Alternatively, formation of the mono-CO adduct in solution could only be achieved at temperatures below 0 °C (e.g.under conditions identical to those given in 2.2.4.9.1, but at -50 °C, when an olivegreen solution resulted, see Section 5.2.9.2).482.3 InstrumentationThe solution nuclear magnetic resonance (NMR) spectra were recordedusing Bruker AC 200 (200 MHz for 1H, 50.3 MHz for 13C, 81.0 MHz for 31P),Varian XL 300 (300 MHz for 1H, 75.0 MHz for 13C, 121.4 MHz for 31P),Bnicker WH 400 (400.0 MHz for 1H), or Brucker AMX 500 spectrometers (500MHz for 1H, 125.8 MHz for 13C, 202.5 MHz for 31P). The chemical shifts weremeasured and are reported as (ppm), relative to (CH3)4Si [‘H] and PPh3 [3 1P]as external standards, where positive shifts are to lower fields. The chemical shiftof PPh3 with respect to 85% H3P04 appears at ö (ppm): -5.59 (CDC13),-5.63 (CD2C1), -5.32 (C6D), -5.10 (d8-toluene).Variable temperature NMR studies, and ‘H NMR longitudinal relaxationtime (T1) measurements, were performed using the Varian XL 300 spectrometer.The T1 measurements were carried out by using a standard (180°-t-90°) pulsesequence.Infrared spectra were recorded by using a Bomem MB-102 FT IR spectrometer. Solid state spectra were obtained from Nujol mulls between KBr plates, andsolution spectra were recorded using KBr cells of 0.1 mm path length.Optical rotation values were measured by using a Jasco J-7 10 spectropolarimeter at room temperature at the sodium-D line (589 nm). A thermostated glassoptical cell of 1 cm path length and -1 mL capacity was used to hold the testsolutions (see Section 2.4.3.1).49Single crystal X-ray difraction studies were carried out by Dr Steven Rettigof the UBC Chemistry Departmental Crystallographic Service.2.4 Hydrogenation ExperimentsCatalytic hydrogenation of alkenes employing H2 gas at 1 atm H2pressure was monitored using a gas uptake apparatus.18 Experiments performed athigher hydrogen pressures (up to 80 atm) were conducted in glass lined, highpressure steel vessels.2.4.1 Gas Uptake ExperimentsGas uptakes studies for stoichiometric, kinetic, or catalytic hydrogenationpurposes were measured by means of a constant pressure gas uptake apparatusdescribed in detail elsewhere in the literature.’8In a typical gas uptake experiment,5-10 mL of solvent (DMA or toluene) were placed in a 25 mL reaction flask underargon. Base (proton sponge), and substrate (for catalytic hydrogenationexperiments) were directly added to the flask; 1-5 mmol of catalyst precursor wereaccurately weighed into a small glass bucket, which was suspended in the flask viaa glass hook. After the contents of the flask were degassed by freeze-pump-thawcycles, H2 was introduced to a pressure about 10 torr lower than the requiredpressure, and the contents were allowed to equilibrate at the desired temperature(10-15 miii) in the oil bath. After thermal equilibrium was attained, the shaker wasstopped, and the pressure was adjusted to the required value. Then the uptakeexperiment was started by dropping the bucket and contents into the solution byturning the glass hook, and starting the shaker and the timer simultaneously; the50H2 absorbed was determined by measuring with a gas-burette the amount added tothe system required to maintain the constant (initially chosen) pressure.2.4.2 Work-up of Hydrogenation ProductsAfter the hydrogenation of styrene, the product and any unreacted substratewere separated from the solution mixture by using vacuum distillation in aKugefrohr apparatus. 12cAfter catalytic hydrogenation experiments employing tiglic acid, the solventwas removed with the aid of a rotary evaporator, and the resulting residue wastaken up in a minimum amount of CDC13 (0.6 mL) and analyzed by 1H and 13CNMR spectroscopy (see Section 2.4.3).After the hydrogenation of ct-acetamidociimamic acid, the fmal reactionmixture was evaporated to give a viscous oil, which was dissolved in 10-20 mLof CH21.After the solution was stirred for 15-30 miii, an off-white compoundseparated out; this was filtered, and washed well with CH21 to give a pure whiteproduct. Since both the substrate (a-acetamidocinnamic acid) and product (Nacetylphenylalanune) have negligible solubility in CH21,this procedure enabledisolation of the product and any unreacted substrate. 19 The mixture was analyzedby optical rotation measurements (see Section 2.4.3.1).512.4.3 Analysis of Hydrogenation ProductsThe isolated product mixture from the catalytic hydrogenation experimentswas analyzed by ‘H NMR spectroscopy to determine the % conversion of thesubstrate to product(s).The optical purity of a chiral product, the enantiomeric excess (% e.e.), wasdetermined either by optical rotation measurements (2.4.3.1), or by 13C NMRspectroscopy with the aid of chiral solvating agents. The latter method was used inthe measurement of the e.e. of 2-methylbutyric acid, the hydrogenation product oftiglic acid. The chiral solvating agent (CSA), (R)-(+)-c-methylbenzylamine (-. 0.1mL) was added to the product mixture in CDC13 (Section 2.4.2), and the 13C{1H}NMR spectrum was recorded.2°Addition of CSA caused the resonance of the 2-methyl carbon of the product (16.8 ppm) to split into a pair of signals (17.19 and17.13 ppm), where the one at lower field (17.19 ppm) was assigned to the (R)-(-)2-methylbutyric acid-CSA adduct, and the one at 17.13 ppm was assigned to the(5-(+)-2-methy1butyric acid-CSA adduct.2°These two peaks were integrated, andthe optical yield was calculated using Equation 2.1.% e.e.=xi00 (2.1)(R+S)Optical rotation measurements were used in determining the % e.e. in thehydrogenation of c-acetamidocinnamic acid, the value of the specific rotation forpure N-acetyl-L-phenylalanine being taken as + 47.8 ° (c = 1.01, C2H5OH) (seeSection 4.6.2).522.4.3.1 Opticai rotation measurementsThe optical rotation for the a-acetamidocinnamic acid hydrogenationproduct was measured at the sodium D-line (589 nm), and the specific rotation ofthe sample was calculated using Equation 2.2.(2.2)lxCwhere,[cLJ specific rotation at temperature T, measured at the sodium-Dlinecx = observed rotation1 = pathlength of the cell in decimetersC = concentration of solution in g/mLThe optical purity of a reaction product in tenns of the % e.e. wasdetermined by comparing its specific rotation with that of the pure enantiomer(Equation 2.3)Enantiomeric excess (e.e.) = x 100 (2.3)[cx]D purewherereaction = specific rotation of the reaction product[a] = specific rotation of the pure enantiomer532.5 References - Chapter 21 Dekleva, T. W., Ph.D. Dissertation, The University ofBritish Columbia, Vancouver,Canada, 1983.2 Payne, N. C.; Stephan, D. W. Jnorg. Chem. 1982, 21, 182.3 Pine, S. H.; Sanchez, B. L. .1. Org. Chem. 1971, 36, 829.4 Fritz, H. P.; Gordan, I. R.; Schwarzhans, K. E.; Venanzi, L. M. I Chem. Soc. 1965,5210.5 Gilman, H.; Banner, I. J. Am. Chem. Soc. 1940, 62, 344.6 Dekker, G. P. C. M.; Buijs, A.; Elsevier, C. 3.; Vrieze, K.; Leeuwen, P. W. N. M.V.; Smeets, W. 3. J.; Spek, A. L.; Wang, Y. F.; Stam, C. H. Organomelallics 1992,11, 1937.7 Jastrzebski, J. T. B. H.; Koten, G. V.; Goubitz, K.; Arlen, C.; Pfeffer, M.I Organomet. Chem. 1983, 246, C75.8 Mercer, G. D.; Beaulieu, W. B.; Roundhill, D. M. I Am. Chem. Soc. 1977, 99,6551.9 a) Hallman, P. S.; Stephenson, T. A.; Wilkinson, G. Inorg. Synth. 1970, 12, 237.b) Stephenson, T. A.; Wilkinson, G. I Inorg. Nuci. Chem. 1966, 28, 945.c) Hoffman, P. R.; Caulton, K. G. I Am. Chem. Soc. 1975, 97, 4221.10 Armit, P. W.; Sime, W. 3.; Stephenson, T. A.; Scott, L. .1 Organomet. Chem.1978, 161, 391.11 a) Wang, D. K. W. Ph.D. Dissertation, The University of British Columbia,Vancouver, Canada, 1978.b) Thorburn, I. S. M.Sc. Dissertation, The University of British Columbia,Vancouver, Canada, 1980.c) Dekieva, T. W.; Thorburn, I. S.; James, B. R. Jnorg. Chim. Ada 1985, 100, 49.5412 a) Evans, I. P.; Spencer, A.; Wilkinson, G. I Chem. Soc., Dalton Trans. 1973, 204.b) Mercer, A.; Trotter, 3. .1 Chem. Soc., Dalton Trans. 1975, 2480.c) Joshi, A. M., Ph.D. Dissertation, The University of British Columbia, Vancouver,Canada, 1990.13 Bennett, M. A.; Willcinson, G. Chem. JncL (London) 1959, 1516.14 a) Zelonka, R. A.; Baird, M. C. Can. J. Chem. 1972, 50, 3063.b) Bennett, M. A.; Smith, A. K. I Chem. Soc., Dalton Trans. 1974, 233.15 a) Markham, L. D., Ph.D. Dissertation, The University of British Columbia,Vancouver, Canada; 1973.b) James, B. R.; Markham, L. D. I Catal. 1972, 27, 442.16 Jung, C. W.; Garrou, P. E.; Hoffhian, P. R.; Caulton, K. G. Inorg. Chem.1984, 23, 726.17 Staab, H. A.; Saupe, T. Angew. Chem. liii. Ed Eng!. 1988, 27, 865.18 a) James, B. R.; Mahajan, D. Isr. I Chem. 1977, 15, 214.b) Joshi, A. M., M.Sc. Dissertation, The University of British Columbia, Vancouver,Canada, 1986.19 a) Kim, T. J., Ph.D. Dissertation, The University of British Columbia, Vancouver,Canada, 1984.b) Thorburn, I. S., Ph.D. Dissertation, The University of British Columbia,Vancouver, Canada, 1985.20 Ashby, M. T.; Halpem, J. I Am. Chem. Soc. 1991, 113, 589.55Chapter 356Ruthenium Complexes Containing Chelating AminophosphineLigands3.1 IntroductionThe recent interest in platinum group metal complexes containing P-Nligands is evident from a survey of recent literature (Section 1.1). The past workwas mostly involved with complexes of Rh, fr, Pd, and Pt, and little attention hasbeen paid to the analogous ruthenium systems. Previous work in our laboratory onthe ferrocene based, P-N ligands PPFA and isoPFA (Figure 1.1) led to thesynthesis and characterization of the five-coordinate ruthenium-(P-N) complexesRuCl2(PPFA)(PPh3)and RuC12(isoPFA)(PPh3).1,2 Isolation and characterizationof the novel dihydrogen complex[L(ii-H)Ru(,.t-Cl)(t-H)RuH(PPh]whereLisoPFA, formed from a 1 atm H2 reaction with RuC12(isoPFA)(PPh3,togetherwith some catalytic activity of such species for hydrogenation of 1-hexene, provedthe potential of Ru-(P-N) complexes for catalytic activity,2’3and thus gave theimpetus for continuation of the studies. Convenient preparation in good tomoderate yields of the aminophosphine ligands PMA, PAN, and AMPHOS madethem specially desirable for the present work (Figure 1.2). As these ligands havebeen used by other groups, a brief look at the earlier work seems in order.Since the first report by Payne and Stephan in l982 of a ‘Rh-AMPHOS’catalyzed asymmetric hydrosilylation of acetophenone, studies on AMPHOS aredominated by the use of its complexes in such asymmetric hydrosilylationreactions. AMPHOS complexes of Rh(I), Ir(I), Pd(II), and Pt(II) have been synthesized and their potential as hydrosilylation catalysts has been studied.57 In57contrast, the use of such complexes in asymmetric hydrogenation is littlestudied;8’9 optical yields in the range 10-18% have been reported for thehydrogenation of prochiral, substituted acrylic acid substrates by an in-situ formedRh(I) species containing AMPHOS.89 Some coordination cheniisiry of a Pd(0)-AMPHOS complex has been reported.’° Complexes of PAN have been studied byVrieze’s group; a recent report describes carbonylation studies on Pd(II)- andPt(II)-PAN complexes.” The PMA ligand has been used in number of metalcomplexes. For example, complexes of the form MX2(PMA) (X = halide) havebeen isolated with Ni(II),’2 Co(II),’2 Pd(II),’3 and Pt(II),’3”4and several Rh(I)complexes of the type [Rh(P-N)2]X (X = BPh4, dO4, PF6, or SbF6) are alsoreported.’5 These studies on the PMA complexes are mainly concerned withcoordination chemistry, while Jr-PMA complexes have been used in catalytichomogeneous hydrogenation:’6-2’IrCl(CO)(PMA) has shown higher catalyticactivity than IrCl(CO)(PPh3)2 for 1-hexene hydrogenation,’6”7 and[(H)2fr(PhP6H4)N(Me)CH(P A Jhas proved to be a selective catalyst (upto 95% selectivity) for transfer hydrogenation of cL,f3-unsaturated ketones to allylicalcohols using 2-propanol as hydrogen donor.18-20 Mixed ligand complexescontaining chiral P-P ligands of the type lr(H)(P-P)(PMA), where P-P = B1NAP,have also been reported with promising results in asymmetric hydrogenation of prochiral c3-unsaturated ketones to chiral allylic alcohols with achemoselectivity and enantioselectivity of 95% and 67%, respectively.2’Apolymer bound Rh-PMA complex has been employed in catalytic hydrosilylationof 1-hexene.22 The Ru-PMA chemistry is essentially unexplored, except for thebrief report on a RuCI2(PMA) complex characterized by a single v(RuCl) at 319cm1 as the trans-dichloro isomer.1458Thus, considering the literature onPMA-, PAN-, and AMPHOS-containingcomplexes, it is evident that their use in homogeneous hydrogenation (includingchiral systems) is relatively undeveloped. Of particular note is the scarcity ofruthenium complexes with these ligands. Thus, synthetic pathways to give readyaccess to such complexes is needed. In addition, it is of interest to compare thereactivity of anunophosphines to that of chelating P-P ligands with the rutheniumprecursors generally employed to access ‘Ru-(P-P)’ complexes.23 Of furtherinterest is the more hemilabile nature of the aininophosphine ligands; complexeswith fluxional arm-on-off behaviour,15a,2426 and complexes with only the P-annof the P-N chelate coordinated, are reported.27-9Thus, in the characterization ofthese complexes it is crucial to pay special attention to possibility of non-chelationof the P-N ligand.This Chapter describes the synthesis and characterization of Ru(P-N)complexes where P-N represent PMA, PAN, and the chiral (R)-AMPHOS ligands.In Chapter 4, the role of these complexes in dihydrogen activation and catalytichydrogenation is presented.3.2 Synthesis of Ruthenium(II)-(P-N) Complexes3.2.1 Reaction of P-N Ligands with Non-Phosphine PrecursorsIn an attempt to obtain a ruthenium(II) complex containing a P-N ligand(where P-N=PMA, PAN, or AMPHOS), the synthetic routes reported by otherworkers into the analogous Ru(P-P) complexes via Ru’I(arene) precursors,3032Rull(diene) precursors,3335 and Ru”(DMSO)4precursors23’367were employed;the reactions outlined in Equations 3.1-3.3 show the expected products.59RuC12(DMSO)4 + P-N RuC12(DMSO)P-N)(3.1)1/2 [RuC1(benzene)] + P-N [RuC1(benzene)(PN)]C1 (3.2)1/n [RuC12(COD)J + P-N RuC12(COD)(PN)(3.3)Reactions 3.1 and 3.2 were carried out with AMPHOS ligand;RuC12(DMSO)4and 1 equivalent of AMPHOS in CH21 solution at roomtemperature over 16 h resulted in a brownish-green solution which contained manyproducts as evidenced by its 3lP NMR spectrum (121.4 MHz). The brown solidisolated by the addition of hexanes to the reaction mixture also contained amixture of species none of which could be characterized. Reaction of [RuCl2-(benzene)]2with 1 equivalent of AMPHOS per ruthenium in toluene, both at roomtemperature (overnight) and under reflux (6 h) also led to formation of a mixtureof products.The reaction of [RuCl2(COD)]fl with 1 equivalent of AMPHOS or PAN perruthenium at room temperature (overnight) in CH21 also produced a mixture ofspecies as evidenced by NMR spectra. However, reaction of the COD precursorwith either 1 or 2 equivalents of PMA per ruthenium led to formation of a singleproduct, which was isolated and characterized as RuCl2(PMA).The elementalanalysis results agreed well with the formulation (Section 2.2.2.5). The 31P{ ‘H)NMR spectrum (121.4 MHz, CDC13) consisted of a single resonance at 64.45ppm, and the ‘H NMR spectrum (300 MHz, CDC13)showed a single peak at 3.24ppm for the N-methyl resonance of the aminophosphine ligand. The downfield60shift of this signal compared to that of the uncoordinated ligand (2.33 ppm inCDC13) indicates coordination of the N-arm of the P-N chelate. Although it wasnot possible to obtain any distinctive far IR bands in the region of v(RUC1) (300-400 cm’) in order to differentiate between a cis- or trans-dichloro isomer, thesimilarity of the ‘H NMR chemical shift of the N-methyls to that reportedpreviously for trans-RuC12(PMA) (6 = 3.25 in CDCI3)’4indicates the product tobe the trans-isomer. Corresponding to the trans arrangement of the PR3 and N-arm of the P-N chelate in structurally characterized P-N complexes RuCln(PN)(PR3(n = 2 or 3) within the present thesis work (Sections 3.3.1 and 3.4.2), thebis-PMA complex is proposed to have a similar phosphorus/nitrogen arrangementwith cis-phosphines. The presence of a single peak for the N-methyls suggests thetrans-dichloro arrangement, because related cis[Rh(PMA)2(Y)Z]+ complexeswhere (Y)Z = (Me)I, (Cl)2 (CN)2, or 02 ligands have been shown to give eithertwo or four signals for the N-methyl resonances. 15b3.2.2 Reaction of P-N Ligands with RuCJ2(PR3)Complexes of the type RuC12(P-N)(PR3)where P-N = PMA or PAN weresuccessfully synthesized by the phosphine exchange reaction (Equation 3.4)pioneered by Stephenson and coworkers.38 The phosphine exchange wasconfirmed by the presence of 1P resonance of the free PR3 ligand in the NMRspectrum of the reaction mixture.61RuC12(PR3) + P-N CH21 RuC12(PN)(PR3)+ 2 PR3(3.4)la, P-N=PMA,R=Phib, P-N = PMA, R=p-tolyl2, P-N=PAN,Rp-tolylThe green product was precipitated by adding hexanes. After the productwas filtered off repeated washing with hexanes (6 x 20 mL), and reprecipitation ofthe product from CH21 using hexanes, were required to remove PR3 formed inthe reaction. This is specially important with PPh3 which has a much lowersolubility than P(p-tolyl)3. Analytically pure RuC12(PMA)(PR)la and ib, andRuC12(PAN)(P(p-tolyl)3)2 complexes, were obtained by this procedure. Thecomplexes are air-sensitive in solution, but are stable in the solid state, and arecharacterized by X-ray analysis (for ib), and by NMR spectroscopic methods(Section 3.3).The analogous phosphine exchange reaction with AMPHOS ligand resultedin unreacted RuC12(PR3)complex in the reaction mixture, as indicated by the31P{1H} NMR spectrum. As both RuC12(PR3)and RuCl2(P-N)(PR3)hadsimilar solubilities it was not possible to precipitate the product preferentially.Several attempts were made to overcome this problem, including the use of excessligand (up to 2 equivalents), use of longer reaction times, and use of elevatedreaction temperatures. However, none of these methods gave an analytically pureRuC12(AMPHOS)(PR3)complex. The product obtained was always a mixture ofthe mixed phosphine complex (— 70-80%) and RuC12(PR3) (30-20%) asindicated by the 31P{1H} NMR spectrum. Further examples of such incomplete62reaction with some P-P ligands (DPPM, DPPE, DPPP, and CHIRAPHOS) havealso been reported.233.2.3 Alternate Method for the Synthesis ofRuCI2(AMPHOS)(PR3),(R = Ph, 3a; R =p-tolyl, 3b).The title complexes were prepared using chloride abstraction (from CHC13solvent) by the corresponding hydrido(chloro) complex Ru(H)Cl(AMPHOS)(PR3) (Equation 3.5), the hydrides being made by H2-reduction of RuC13-(AMPHOS)(PR (Section 4.5.2).Ru(H)C1(AMPHOS)(PR3+ CHCI3 RuC12(AMPHOS)(PR3)+ CH2I3a, R = Ph3b, R PtOIYI (35)In this method, the yellow-brown hydride complex was dissolved in CHCI3 toyield a green solution, from which RuC12(AMPHOS)(PR3)was precipitated byaddition of hexanes. The product obtained analyzed for higher C, H, and Ncontents than calculated (Section 2.2.2.4), and this is attributed to the presence ofoxides and unidentified products seen in the 31P{ ‘H) NMR spectrum (Figure3.1). These impurities could not be removed by further dissolution arid reprecipitation steps. The formation of the CH21 by-product in the reaction wasconfirmed by carrying out the reaction in CDC13. The ‘H NMR spectnim of thereaction mixture showed a 1:1:1 triplet at 5.19 ppm with a HD value of 1.20 Hz,which is assigned to the proton resonance of the CHDC12species (see Figure 3.8).630’-J L-oxide-—wi-.1—-—IIIIIIIIIIIIIIIIIIIIIIIIIIIIIII1IIIIIIIIII(IIIIIIIIIIIIIIIIII‘IIIIIIIIIIj908070605040302010PPMFigure3.1:31P{1H}NMRspectrum(121.4MHz,20°C)ofRuCI2(AMPHOS)(PPh3),3a,inC6D;*unidentifiedimpurities.3.3 Characterization of RuCI2(P-N)(PR3)Complexes3.3.1 X-ray Structure Determination ofRuCI2(PMA)(P(p-tolyl)3),lbCrystals of lb suitable for a single crystal X-ray diffraction study weregrown by a layering technique, and the structure, analyzed by Dr. S. J. Rettig ofthis department, revealed an approximately square-pyramidal geometly, withtrans-chlorides, the monodentate phosphine and the NMe2 in the equatorialpositions, and the P-arm of the P-N chelate in the apical position (Figure 3.2). TheRu atom is about 0.42 A above the mean plane of the equatorial atoms towards theapical phosphorus, with the P-N ligand subtending an angle of 81.81(8)° at theruthenium. The structural parameters are listed in the Appendix (A-i), while someselected bond distances and angles are given in Tables 3.1 and 3.2, respectively.Table 3.1: Selected bond lengths (A) forRuCl2(PMA)(P(,p-tolyl)3) ib,with estimated standard deviations in parentheses.Bond Length (A) Bond Length (A)Ru(l)-Cl(1) 2.387(1) P(1)-C(13) 1.840(3)Ru(1)-Cl(2) 2.379(1) P(2)-C(21) 1.831(4)Ru(i)-P(1) 2.170(1) P(2)-C(28) 1.823(3)Ru( 1)-P(2) 2.290(1) P(2)-C(35) 1.832(4)Ru(i)-N(1) 2.238(3) N(1)-C(2) 1.464(4)P(i)-C(i) 1.836(3) N(l)-C(l9) 1.483(4)P( i)-C(7) 1.828(3) N( l)-C(20) 1.500(4)65C5 C4Figure 3.2: An ORTEP diagram of RuC1(PMA)(P(p-to1y1)3), lb.C6c9C8Cl 0CliC3C19Cz0C41ciaC39 C4oC3C’C23C33£34£25£32£2766The structure of lb is similar to those of the structurally characterized, precursorcomplex RuC12(PPh3)9 and the analogous P-N complex RuC12(isoPFA)-(PPh3).2b The mixed phosphine complexes containing chelating ditertiaryphosphines of the type Ph2(CH)PPh (n = 3 or 4),23,40 and chiral analogare also reported to have a similar structure in the solid state; insolution, the species undergo phosphine dissociation and dimerization (see below).In the two structurally characterized complexes, the sixth coordination site appearsto be occupied by an ortho-phenyl hydrogen of the monodentate phosphine.21”39However, this feature is not observed in the structure of lb.Table 3.2: Selected bond angles (deg) for RuCl(PMA)(P(p-tolyl)3), ib, withestimated standard deviations in parentheses.Bonds Angle (deg) Bonds Angle (deg)Cl( 1)-Ru( 1)-Cl(2) 156.58(3) C( 1)-P( 1)-C( 13) 104.8(2)Cl(l)-Ru(1)-P(1) 92.59(4) C(7)-P(l)-C(13) 101.1(1)Cl( 1 )-Ru( 1 )-P(2) 92.99(4) Ru( 1 )-P(2)-C(2 1) 104.6(1)Cl(1)-Ru(1)-N(1) 86.71(8) Ru(1)-P(2)-C(28) 115.6(1)Cl(2)-Ru( I )-P( 1) 109.75(4) Ru( 1)-P(2)-C(35) 126.2(1)Cl(2)-Ru( 1 )-P(2) 88.16(4) C(2 1 )-P(2)-C(28) 104.9(2)C1(2)-Ru( 1)-N( 1) 89.53(8) C(2 1)-P(2)-C(35) 102.7(2)P( 1)-Ru( 1 )-P(2) 104.74(4) C(28)-P(2)-C(3 5) 100.5(2)P(1)-Ru(1)—N(1) 81.81(8) Ru(1)—N(1)—C(2) 109.2(2)P(2)-Ru(1)-N(1) 173.45(8) Ru(1)-N(1)-C(19) 105.0(2)Ru(1)-P(1)—C(1) 101.1(1) Ru(1)—N(1)—C(20) 115.4(2)Ru(1)—P(1)—C(7) 121.2(1) C(2)-N(1)—C(19) 113.6(3)Ru( 1)-P( l)-C( 13) 121.9(1) C(2)-N( 1)-C(20) 106.9(3)C( 1 )-P( 1)-C(7) 104.5(2) C( 19)-N( 1)-C(20) 106.9(3)673.3.2 NMR Studies on RuCI2(P-N)(PR3)Complexes3.3.2.1 31P{IH} Solution NMR studiesAmbient temperature 31P{1H} NMR spectra (in C6D,CDC13 or CD21)of the complexes RuC12(P-N)(PR3)(where P-N = PMA, PAN, or AMPHOS andR=Ph or p-tolyl) consist of a simple AX spin pattern. The data are summarized inTable 3.3. The 2Jpp values are consistent with cis-phosphines42and, by comparison with the reported data for other square-pyramidal ruthenium complexescontaining apicallbasal pairs of phosphines,2b343 the downfield resonance at 85-101 ppm is assigned to the aminophosphine (PA), and that at 43-54 ppm isassigned to the monodentate phosphine in the basal plane (Figure 3.3). As these31P NMR data would equally fit a structure with trans-chloride ligands asobserved for lb in the solid state (Figure 3.3, (i)), or a one containing cis-chlorideligands (Figure 3.3 (ii)), it is difficult to ascertain which isomer exists in solution.However, combined ‘H NMR and structural data pennit a tentative preference forthe trans-isomer (Section 3.3.2.2).The 31P{1H} NMR spectral data clearly demonstrate the marked differencein solution behaviour of these aminophosphine complexes, which retain amonomeric structure, compared to the corresponding all-phosphine complexesRuC12(PR3)3(R = Ph or p-tolyl),44’5 and RuC12(P-P)(PR3),3’4648which undergo dimerization with dissociation of PR3 ligand in solution (Equations 3.6 and3.7).2 RuCI(PR3) - [RuC1(PR3)2(ji- 1)] + 2 PR36682 RuC1(P-PXPR3)- [RuC1(P-PXp.-C1)]2 + 2PR3Table 3.3: 31P{1H} NMR data (121.4 MHz, 20 °C) for RuC12(P-N)(PR3complexes.Chemical shifts, ö(ppm)87.49; 54.0785.17; 52.5588.13; 52.6687.22; 50.51101.76; 43.2989.07; 45.4687.35; 43.6689.80; 43.8287.37; 43.302Jpp (Hz)36.7836.6736.7036.7232.8037.1536.6637.8037.30(3.7)NR3P Cl R3cr cr N(i) (ii)Figure 3.3: Proposed structures for lb in solution.SolventComplex,PN; R=la, PMA; Ph1 b, PMA; p-tolyl2, PAN; p-tolyl3a, AMPHOS; Ph3b, AMPHOS;p-tolylC6DCDC13C6DCDC13CD21C6DCDC13C6DCDC1369The chelating ditertiary phosphine complexes in solution have been shown to havea dimeric structure with bridging chlorides and two square pyramids sharing abasal edge (Figure 3.4).23,40C1i1 CI 11111,C1ii,R’ orBBP-P = DPPP, DPPB, DIOP, CHIRAPHOS, BINAPFigure 3.4: Suggested geometries for [RuCl2(P-P)] complexes.The AB spin patterns observed for the solution 31P{1H} NMR spectra of thenonchiral DPPP and DPPB derivatives (Table 3.4, Figure 3.5) provide evidencefor the proposed structure,2340 and differ considerably from the AX patternobserved for the aminophosphine complexes. With chiral phosphines(CHIRAPHOS and BINAP) two AB quartets of equal intensity were seen due tothe inequivalency of the A atoms and the B atoms within the dimeric structure;however, with the chiral ligand DIOP a single AB pattern was observed, and thiswas attributed to coincidental degeneracy of the resonances (Table 3.4) within asystem with a more flexible phosphorus backbone.23’407031P{1H} NMR data (121.4 MHz, C6D 20 °C) for [RuC1-Table 3.4:(P-P)(p.-C1)]2complexes.a[RuC1(P-P)(ji-Cl)]2Complex Chemical shifts 2Jpp, (Hz)P-P = (ppm)DPPP = 59.0, öB 51.0 57.0DPPB = 64.0, öB = 54.9 47.3DIOP = 50.7, B = 47.5 46.1CHIRAPHOS = 88.0, 8B = 78.3 38.2öc = 87.0, D = 75.7 39.2BJNAP öÃ= 75.8, öB=5.8 40.6öc = 58.6, 6D = 58.2 43.2a Data taken from Ref. 23; the P-P ligands used are shown in Figure 3.5.Figure 3.5: Ditertiary phosphines listed in Table 3.4.Ph2(CH)PPhn=3, DPPP=4, DPPBPPh2PPh2CHIRAPHO SHHDIOP B1NAP713.3.2.2 1H NMR studiesThe 1H NMR spectrum of lb (300 M}{z, CDC13 Figure 3.6) shows asingle resonance for the N-methyls (3.25 ppm, 6H), which is at lower field thanthat of the free ligand, indicating coordination of the amine group.l5bl7Thedownfield shift of the N-methyl resonances of the complex is common to otheraminophosphine complexes 2, 3a, and 3b (Table 3.5).In contrast to the single peak observed in lb (and also for la), complexes 2,3a, and 3b show two peaks for each of the N-methyl groups (Table 3.5, seebelow). The single N-methyl resonance seen for lb is explained if lb retains itssolid state structure in solution with trans-chlorides (Figure 3.3 (i)). From thestereoview of the structure (Appendix A-i) it is clear that the five-memberedchelate ring adopts an envelope conformation; a fast ring flip in solution, togetherwith the trans-chloro arrangement, would render the N-methyls equivalent in lb(and Ia). This suggestion is also supported by the presence of two signals for theN-methyl resonances for the corresponding chloro(hydrido) complex Ru(H)Cl(PMA)(P(p-tolyl)3),which is assumed to have the same structure but with onechloride replaced by hydride (Section 4.4). Further evidence to support suchconclusions is also obtained from an NMR and structural data correlation for thesix-coordinate ligand adducts formed by la and lb with small molecules (Section5.2.5). Such stereochemical effects on the nonequivalency of methyl substituentson the PMA ligand have been shown previously for cis- and trans-[Rh(PMA)2(Y)Z] complexes where (Y)Z = (Me)I, (Cl)2 (CN)2,or 02 ligands. 15b72Table 3.5: 1H NMR data (300 MHz, CDC13 20 °C) forRuCI2(P-N)(PR3complexes.Complex, Solvent Chemical shiftsP-N; R=la, PMA; Ph C6D 3.09 (s, NMe2); 6.7-7.8 (in, Ph)CDC13 3.22 (s, NMe2); 7.0-7.7 (m, Ph)ib, PMA;p-tolyl C6D 2.00 (s, Me); 3.13 (s, NMe2); 6.8-7.8 (m, Ph)CDCI3 2.30 (s, Me); 3.25 (s, NMe2); 6.8-7.6 (m, Ph)2, PAN; p-tolyl CD21 2.33 (s, Me); 2.95 (s, NMe); 3.65(s, NMe);6.7-7.9 (m, Ph)3a, AMPHOS; Ph C6D 1.05 (d, Me); 2.31 (s, NMe); 2.87 (s, NMe),6.18 (dq, CH); 6.7-7.9 (m, Ph)CDCI3 1.50 (d, Me); 2.28 (s, NMe); 2.85 (s, NMe); 5.8(dq, CH); 6.6-7.6 (m, Ph)3b, AMPHOS; p-tolyl C6D 1.05 (d, Me); 2.00 (s, Me ofp-tolyl); 2.35(s, NMe); 2.95 (s, NMe); 6.11 (dq, CH);6.8-7.8 (m, Ph)The corresponding ‘H NMR spectra (Table 3.5) of RuCI2(PAN)(P(p-tolyl)3) 2 (Figure 3.7) andRuC12(AMPHOS)(PPh33a (Figure 3.8) consist of twoN-methyl resonances (at 3.65 and 2.95 ppm for 2, and 2.85 and 2.28 for 3a)compared to the single resonance observed for the corresponding free ligands (at73Figure 3.6: ‘H NMR spectrum (300 MHz, 20 °C) ofRUCI2(PMA)(P(p-tolyl)3),lb. in CDC13.I PPMFigure 3.7: ‘H NMR spectrum (300 MHz, 20 °C) of RuC1(PAN)(P(p-to1y1)3,2, in CD21.Ii I II I I 1 ii iij I I iii £IjI I lIIIj liii III 111111 lij Ill IIIIIi iiB 7 6 5 4 3 2 iPPM 07 g 4 3 274N-CH3pi‘IIIrlyrTTT-[-rrTrrnIrrrrprnYrrTTTrTTTTrTTIIirTTTTThIII8765‘132IPPMFigure3.8:111NMRspectrum(300MHz.20°C)ofinsituformedRuCI2(AMPHOS)(PPh3),3a,viareactionof“Ru(H)C1(AMPHOS)(PPh3)”withCDCI3;,S=CHDC12generatedinthereaction.N-CH3-CH3-CIIS2.20 and 2.00 ppm for PAN and AMPHOS, respectively). The nature and therigidity of the PAN ligand, and the diastereotopic N-methyls in AMPHOS accountfor these observations, even within the assumed trans-chloride structure (Figure3.3 (i)). The downfield shift of the N-methyls indicate coordination of the N-armof the chelate, and thus the N-methyl resonance proved to be a valuable NMRhandle in determining the possible hemilabile nature of these ligands. In addition,coordination of the AMPHOS ligand in 3a is also exhibited by the downfield shiftof the methyne proton (5.8 ppm, dq,3JHH=6.8 Hz,4Jp=6.8 Hz) compared tothat of the free ligand (4.15 ppm, dq,3JHH=6 Hz,4JPH6 Hz).3.4 Synthesis and Characterization of Ru(lll)-(P-N) ComplexesRuthemum(III) complexes of the form RuC13(PMA)(PR)[RPh, 6a; Rp-tolyl, 6bJ and RuC13(AMPHOS)(PR [R=Ph, 7a; R=p-tolyl, 7b] were synthesized in good yields, employing the phosphine exchange reaction fromRuC13(PR)2DMA) precursors (Equation 3.8).RuC13(PR)2DMA) + P-N hexanes RuC13(P-N)(PR) + PR3 + DMAre (3.8)Refluxing a suspension of RuC13(PR)2DMA) (R=Ph or p-tolyl) and anequimolar amount of the appropriate aminophosphine in hexane for 24 h resultedin formation of the corresponding Ru(III)-(P-N) complexes as air-stable, red-brown powders.76RuC13.3H20 + 2 PR3 DMA RuC13(PR)2DMA).(DMA)24 h, 25 °CP-Nhexanes, reflux24 hRuC13(P-N)(PR)Scheme 3.1: Synthetic route to Ru(ffl)-(P-N) complexes.The synthetic procedure starting from RuC13.3H20is summarized inScheme 3.1. This basic method was developed previously by Thorburn in ourlaboratory to obtain complexes with one chelating ditertiary phosphine (P-P) perruthenium. Reaction of the DMA complex with P-P ligands under similarconditions resulted in dimeric mixed-valence compounds of the type [RuC1(P-P)]2Qi-Cl)323,4749 A range of such complexes containing different P-P ligandshas been synthesized and characterized by various spectroscopic and analyticaltechniques.23’4°Trace water in the presence of phosphine is considered to beresponsible for the redox process (Equation 3.9),48,49 and Scheme 3.2 summarizesthe possible pathways.48H204 RuC13(PR)2DMA) + 4 P-P 2RuC15P-P) + OPR3 + 7 PR3+ 2HC1 + 4DMA (3.9)The difference in reactivity of P-N ligands compared to the corresponding P-Pligands is presumably attributable to the a-donor ability of the amine function77which must stabilize the Ru(III) oxidation state leading to the monomeric RuCl3-(P-N)(PR3)complexes. A complex with P-P ligands such as RuC13(P-P)(PR)might be unstable due to the it-acceptor ability of the phosphine donors, and thiswould lead to dissociation of a phosphine ligand resulting in a ‘RuCl3(P-P)’intermediate, which would then lead to the mixed-valence dimer (Scheme 3.2).RuC13P2(DMA)- I P = monodentate phospbine- DMAI + PP-P = bidentate phosphineClP I cici’Reduction Cl’,CI-,.[i.uci2(p-P)] Ru2CI6(PP)RuC13(PP) ReductionRu2C15PP)Scheme 3.2: Possible pathways for formation ofRu11u”-dimers fromRuCl(PR)DMA) complexes; [ ] implies an undetected species.The solid state structure of the complexes 6a and 7b, determined by X-raystructural studies (Section 3.4.2), confirmed the RuC13(P-N)(PR)formulations,Dimerization78and the existence of a monomeric structure in solution was determined bymolecular weight measurements (Signer method).5°3.4.1 Magenetic Susceptibility MeasurementsThe magnetic susceptibilities of the Ru(III)-(P-N) complexes weredetermined at 20 °C by the Evans’ method51 using CDC13 solutions containing—2% (v/v) t-butanol and the Ru(III)-(P-N) complex. The solution magneticmoments neff values for 6b and 7b (1.79 and 1.87, respectively) are consistentwith the presence of one unpaired electron per molecule (.pin only = 1.73B.M.).52 The limited solubility of the corresponding triphenylphosphinederivatives 6a and 7a prevented reliable solution magnetic susceptibilitymeasurements.3.4.2 X-ray Structure Determination ofRuCI3(PMA)(PPh)6a, andRuCI3(AMPHOS)(PPh)7aDark-red crystals of 6a and 7a suitable for X-ray crystallography wereobtained by a solvent layering technique. Single crystal, X-ray diffraction studiescarried out by Dr. S. J. Rettig of this department reveal a distorted octahedralgeometry with meridionally arranged chloride ligands for each complex, with theN-donor tran.c to the monodentate phosphine (Figures 3.9 and 3.10). Someselected bond distances of 6a and 7a are given in Tables 3.6 and 3.7, respectively.Some selected bond angles of 6a are listed in Table 3.8, and those of 7a aresummarized in Table 3.9. The complete structural parameters for both complexesare listed in the Appendix (A-2, 6a; and A-3, 7a).79C9C28Figure 3.9: An ORTEP diagram ofRuC13(PMA)(PPh),6a.C4C5 C8C38C37docliC13C14C15C30C29 C32C33 C34C20C21C27C2280C32Figure 3.10: An ORTEP diagram ofRuC13(AMPHOS)(PPh),7a.C33C34C25C38 C37C31C14 P2C12CL’cLZCSc21doC5C4C88lTable 3.6: Selected bond lengths (A) forRuC13(PMA)(PPh),6a, withestimated standard deviations in parentheses.Bond Length (A) Bond Length (A)Ru(1)-Cl(1) 2.3338(9) P(1)-C(13) 1.841(4)Ru( 1 )-Cl(2) 2. 3 264(9) N( 1 )-C(2) 1.470(5)Ru( 1)-C1(3) 2.4005(9) N( 1)-C(3 7) 1.508(5)Ru( 1)-P( 1) 2.3 606(9) N( 1)-C(3 8) 1.482(6)Ru( 1)-P(2) 2.3565(9) P(2)-C( 19) 1.837(4)Ru(1)-N(1) 2.338(3) P(2)-C(25) 1.832(4)P(1)-C(1) 1.808(4) P(2)-C(3 1) 1.826(4)P( 1 )-C(7) 1.826(4)Table 3.7: Selected bond lengths (A) forRuC13(AMPHOS)(PPh),7a, withestimated standard deviations in parentheses.Bond Length (A) Bond Length (A)Ru( 1)-Cl( 1) 2.3 98(2) P( 1)-C(1 7) 1.827(7)Ru(1)-Cl(2) 2.319(2) P(2)-C(23) 1.831(7)Ru( 1)-Cl(3) 2.356(2) P(2)-C(29) 1.849(7)Ru( 1)-P( 1) 2.401(2) P(2)-C(35) 1.846(7)Ru(1)-P(2) 2.374(2) N( 1)-C(7) 1.52(1)Ru(1)-N(1) 2.355(6) N(1)-C(9) 1.484(9)P(1)-C(1) 1.835(7) N(1)-C(10) 1.48(1)P(1)-C(11) 1.834(7)82Table 3.8: Selected bond angles (deg) forRuC13(PMA)(PPh),6a,withestimated standard deviations in parentheses.Bonds Angle (deg) Bonds Angle (deg)Cl(1)-Ru(1)-P(2) 88.35(3) C(3 1)-P(2)-Ru(1) 114.5(1)Cl( 1 )-Ru( 1 )-Cl(3) 92.12(3) C( 1 9)-P(2)-C(25) 100.9(2)C1(1)-Ru(1)-Cl(2) 175.25(4) C(19)-P(2)-Ru(1) 113.5(1)Cl(1)-Ru(1)-N(1) 93.54(9) C(25)-P(2)-Ru(1) 117.3(1)C1( 1 )-Ru( 1 )-P( 1) 90.06(3) C( 1 3)-P( 1 )-C(7) 104.4(2)P(2)-Ru( 1 )-Cl(3) 84.04(3) C( 1 3)-P( 1 )-C( 1) 103.2(2)P(2)-Ru(1)-Cl(2) 94.76(3) C(13)-P(1)-Ru(1) 125.3(1)P(2)-Ru( 1 )-N( 1) 175.40(8) C(7)-P( 1 )-C( 1) 104.1(2)P(2)-Ru(1)-P(1) 104.96(3) C(7)-P(1)-Ru(1) 115.6(1)Cl(3)-Ru(1)-Cl(2) 91.77(3) C(1)-P(1)-Ru(1) 101.4(1)Cl(3)-Ru( 1)-N( 1) 91.70(8) C(3 7)-N( 1)-C(3 8) 106.6(3)C1(3)-Ru( 1)-P( 1) 170.81(3) C(37)-N( 1)-C(2) 109.7(3)C1(2)-Ru( 1 )-N( 1) 83.63(9) C(3 7)-N( 1 )-Ru( 1) 109.2(2)Cl(2)-Ru( 1)-P( 1) 85.68(3) C(3 8)-N( 1)-C(2) 108.2(3)N(1)-Ru(1)-P(1) 79.25(8) C(38)-N(1)-Ru(1) 110.8(3)C(3 1)-P(2)-C(19) 106.9(2) C(2)-N(1)-Ru(1) 112.1(2)C(3 1)-P(2)-C(25) 102.2(2)83Table 3.9: Selected bond angles (deg) forRuC13(AMPHOS)(PPh),7a, withestimated standard deviations in parentheses.Bonds Angle (deg) Bonds Angle (deg)C1(1)—Ru(1)—Cl(2) 99.15(7) Ru(1)-P(1)-C(17) 118.9(2)Cl(1)-Ru(1)-C1(3) 88.53(7) C(1)-P(1)-C(1 1) 104.1(3)C1(1)-Ru( 1)-P( 1) 170.08(7) C( 1)-P( 1)-C( 17) 103.0(3)C1(1)-Ru(1)-P(2) 85.73(7) C(1 1)-P(1)-C(17) 103.1(4)C1( 1)-Ru( 1)-N( 1) 86.5(2) Ru( 1 )-P(2)-C(23) 117.3(2)C1(2)-Ru( 1)—C1(3) 171.61(8) Ru( 1)-P(2)—C(29) 115.1(2)C1(2)-Ru( 1)-P( 1) 89.87(7) Ru( 1)-P(2)-C(35) 115.1(2)C1(2)-Ru( 1 )-P(2) 86.00(7) C(23 )-P(2)-C(29) 100.3(3)C1(2)-Ru( 1)-N( 1) 87.2(1) C(23)-P(2)-C(35) 107.3(3)Cl(3 )-Ru( 1 )-P( 1) 82.24(7) C(29)-P(2)-C(3 5) 99.4(3)Cl(3)-Ru(1)-P(2) 98.01(7) Ru(1)-N(1)-C(7) 111.4(4)Cl(3)-Ru( 1)-N( 1) 90.0(1) Ru( 1)-N( 1)-C(9) 107.3(4)P(1)-Ru(1)-P(2) 99.09(7) Ru(1)-N(1)-C(10) 111.1(5)P( 1)-Ru( 1)-N( 1) 89.9(2) C(7)-N( 1)-C(9) 108.1(6)P(2)-Ru( 1)-N( 1) 168.7(2) C(7)-N( 1)-C( 10) 111.2(6)Ru( 1)-P( 1 )-C( 1) 107.4(2) C(9)-N( 1)-C( 10) 107.5(6)Ru(1)-P(l)-C(11) 118.4(3)84Table 3.10: Selected bond lengths (A) forRuC13(PMA)(PPh),6a, andRuC1(AMPHOS)(PPh),7a, with estimated standarddeviations in parentheses.Cl’Ph3ç C13RuC1 NBond Length (A)6a 7aRu(1)-C1(1) 2.4005(9) 2.398(2)Ru(1)-C1(2) 2.3338(9) 2.3 19(2)Ru(1)-Cl(3) 2.3264(9) 2.356(2)Ru(1)-P(1) 2.3606(9) 2.401(2)Ru(1)-P(2) 2.3565(9) 2.374(2)Ru(1)-N(1) 2.338(3) 2.355(6)The aminophosphine ligand in these complexes subtends an angle of78.9(7)° or 89.9(2)° at the ruthenium center in 6a or 7a, respectively. Presumably,the steric effects exerted by the six-membered chelate is responsible for themarginally longer Ru(1)-Cl(3), Ru(l)-P(l), and Ru(1)-P(2) bonds in 7a comparedto those of 6a (Table 3.10). The Ru(1)-Cl(2) and Ru(1)-Cl(3) bond lengths of 6a(Table 3.10, average 2.330 A) and 7a (average 2.33 8 A) are within the range foundfor the trans-Ru(III)-Cl bond distances in the low spin mer-RuC13(PPh3)-85(DMA)2, (average 2.347 A);4° mer-RuCI3(DMSO),(average 2.346 A);53 merR’uCl3{PhPCHC(Ô)OEt}L (L =Ph2CHC(O)OEt, coordinated at the phosphorus atom), (average 2.342 A);54 and mer-RuCI3(DMS) (DMS = dimethylsulfide), (average 2.344 A)55 complexes. However, the Ru(l)-Cl(l) bonds trans tothe P-arm of the aminophosphine show significant lengthening (2.4005(9) A in 6a,and 2.398(2) A in 7a), which results from the stronger trans influence ofphosphines compared to that of the chloride ligand.56 The average values of thetrans Ru-Cl bond lengths in 6a and 7a are significantly shorter than thecorresponding value of 2.383 A found for RuCI2(PMA)(P(p-tolyl)3),lb (Table3.1), which seems reasonable in tenns of the difference in oxidation states.3.5 Summary of ResultsPhosphine exchange reactions for Ru(II) and Ru(III) precursors with thechelating aminophosphine ligands PMA, PAN, and AMPHOS led to the synthesisof novel Ru(II)-(P-N) (Ia, ib, 2, 3a, and 3b) and Ru(III)-(P-N) (6a, 6b, 7, and 7b)complexes. Except for 3a and 3b, the complexes were isolated in good yields, andthe molecular structures of ib, 6a, and 7a were detennined by X-ray crystallographic studies. The solid state structures of the RuC12(P-N)(PR3)complexeswere found to be the same as that assumed for analogous RuC12(P-P)(PR3complexes. However, unlike these all-phosphine complexes, which undergo dissociation of PR3 ligand in solution with generation of Ru11’ dimers [RuC1(P-P)]2j.t-Cl), the axninophosphine complexes retain their monomeric five-coordinate structure, and as a result give rise to solution 31P{ lH} NMR spectraconsisting of a simple AX spin pattern. The 31P resonances provide an excellentNMR spectroscopic probe for these Ru-(P-N) and Ru-(P-P) complexes.86A different reactivity of the P-N ligands compared to the P-P analogues isdemonstrated by the formation of monomeric Ru(III)-(P-N) complexes byphosphine exchange reaction at Ru(I11) precursors; similar reactions with P-Pligands result in dinuclear mixed-valence complexes.873.6 References - Chapter 31 Hampton, C. R. S. M., Ph.D. Dissertation, The University of British Columbia,Vancouver, Canada, 1989.2 a) Hampton, C. R. S. M.; Cullen, W. R.; James, B. R.; Charland, J.-P. I Am. Chem.Soc. 1988, 110, 6918.b) Hampton, C. R. S. M.; Butler, I. R.; Cullen, W. R.; James, B. R.; Charland,3.-P.; Simpson, 3. Inorg. Chem. 1992, 31, 5509.3 Rodgers, G. E.; Cullen, W. R.; James, B. R. Can. I Chem. 1983, 61, 1314.4 Payne, N. C.; Stephan, D. W. Inorg. Chem. 1982, 21, 182.5 Kreuzfeld, H.-J.; Dobler, C.; Abicht, H.-P. I Organomer. Chem. 1987, 336, 287.6 Kinting, A.; Kreuzfeld, H.-J.; Abicht, H-P. 1 Organomet. Chem. 1989, 370, 343.7 Dobler, C.; Kinting, A. I Organomer. Chem. 1991, 401, C23.8 Yamamoto, K.; Tomita, A.; Tsuji, 3. Chem. Leti. 1978, 3.9 Homer, L.; Simons, G. Z Naturforch., B. Anorg. Chem., Org. Chem. 1984, 39B(4),512.10 De Graaf, W.; Harder, S.; Boersma, 3.; Van Koten, G. I Organomer. Chem.1988, 358, 545.11 Dekker, 0. P. C. M.; Buijs, A.; Elsevier, C. J.; Vrieze, K.; Leeuwen, P. W. N. M.V.; Smeets, W. 3. 3.; Spek, A. C.; Wang, Y. F.; Stam, C. H. Organomerallics 1992,11, 1937.12 Christopher, R. E.; Gordon, I. R.; Venanzi, L.M. I Chem. Soc., (A) 1968, 205.8813 Fritz, H. P.; Gordon, I. R.; Schwarzhans, K. E.; Venanzi, L. M. J. Chem. Soc. 1965,5210.14 Rauchfuss, T. B.; Patino, F. T.; Roundhill, D. M. Inorg. Chem. 1975, 14, 652.15 a) Rauchfuss, T. B.; Roundhill, D. M. I Organomet. Chem. 1973, 59, C30.b) Rauchfuss, T. B.; Roundhill, D. M. I Am. Chem. Soc. 1974, 96, 3098.16 Rauchfuss, T. B.; Clements, J. L.; Agnew, S. F.; Roundbill, D. M. Jnorg. Chem.1977, 16, 775.17 Roundhill, D. M,; Bechtold, R. A.; Roundhill, S. G. N. Inorg. Chem. 1980, 19, 284.18 Farnetti, E.; Nardin, G.; Graziani, M. I Chem. Soc., Chem. Commun. 1988, 1264.19 Farnetti, E.; Kaspar, J.; Graziani, M, I Mo!. Catal. 1990, 63, 5.20 Farnetti, E.; Nardin, G.; Graziani, M. I Organomet. Chem, 1991, 417, 163.21 Mashima, K.; Akutagawa, T.; Zhang, X.; Takaya, H.; Taketomi, T.; Kumobayashi,H.; Akutagawa, S. I Organomet. Chem. 1992, 428, 213.22 Michaiska, Z. M. I Mo!. CataL 1983, 19, 345.23 Joshi, A. M.; Thorburn, I. S.; Rettig, S. J.; James, B. R. Inorg. Chim. Acta 1992,198-200, 283.24 Hayashi, T.; Fukushima, M.; Konishi, M.; Kumada, M. Tetrahedron Lett.1980, 21, 79.25 Cullen, W. R.; Woollins, 3. D. Can. I Chem. 1982, 60, 1793.26 Hayasbi, T.; Konishi, M.; Fukushima, M.; Kanehira, K.; Hioki, T.; Kumada, M.I Org. Chem. 1983, 48, 2195.8927 Dobson, G. R.; Taylor, R. C.; Walsh, T. D. Inorg. Chem. 1967, 6, 1929.28 Knèbel, W. 3.; Angelici, R. 3. Inorg. Chem. 1974, 13, 627.29 Hedden, D.; Roundhill, D. M.; Fultz, W. C.; Rheingold, A. L. I Am. Chem. Soc.1984, 106, 5014.30 Mashima, K.; Kusano, K.; Ohta, T.; Noyori, R.; Takaya, H. .1 Chem. Soc., Chem.Commun. 1989, 1208.31 Bennett, M. A.; Ennett, 3. P. Inorg. Chim. Ada 1992, 198-200, 583.32 Fogg, D. E.; James, B. R. I Organomet. Chem. 1993, 462, C21.33 Kawano, H.; Ikariya, T.; Ishii, Y.; Saburi, M.; Yoshikawa, S.; Uchida, Y.;Kumobayashi, H. I Chem. Soc., Perkin Trans. 1 1989, 1571.34 Bennett, M. A.; Wilkinson, G. Chem. mci (London) 1959, 1516.35 Ohta, T.; Noyori, R.; Takaya, H. Inorg. Chem. 1988, 27, 566.36 Evans, I. P.; Spencer, A.; Wilkinson, G. .1. Chem. Soc., Dalton Trans. 1973, 204.37 Carmichael, D.; Floch, P. L.; Ricard, L.; Mathey, F. Inorg. Chim. Ada1992, 198-200, 437.38 Annit, P. W.; Boyd, A. S. F.; Stephenson, T. A. I Chem. Soc., Dalton Trans.1975, 1663.39 LaPlaca, S. J.; Ibers, 3. A. Jnorg. Chem. 1965, 4, 778.40 Joshi, A. M., Ph.D. Dissertation, The University of British Columbia, Vancouver,Canada, 1990.9041 Mezzetti, A.; Consiglio, G. I Chem. Soc., Chem. Commun. 1991, 1675.42 a) Verkade, J. G. Coorci Chem. Rev. 1972/73, 9, 1.b) Pregosin, P. S.; Kunz, R. W. N?kfR. Basic Princ. Frog. 1979, 16, 28.c) Krassowski, D. W.; Nelson, 3. H.; Brower, K. R.; Hauenstein, D.;Jacobson, R. A.Inorg. Chem. 1988, 27, 4294.43 a) Hoffman, P. R.; Caulton, K. G. I Am. Chem. Soc. 1975, 97, 4221.44 James, B. R.; Thompson, L. K.; Wang, D. K. W. Inorg. Chim. Ada1978, 29, L237.45 a) Jardine, F. H. Prog. Jnorg. Chem. 1984, 31, 265.b) Dekieva, T. W.; Thorburn, I. S.; James, B. R. Jnorg. Chim. Ada 1985, 100, 49.46 a) James, B. R.; Wang, D. K. W. Inorg. Chim. Ada 1976, 19, L17.b) Wang, D. K. W., Ph.D. Dissertation, The University of British Columbia,Vancouver, Canada, 1978.47 James, B. R.; Pacheco, A.; Rettig, S. I.; Thorburn, I. S.; Ball, R. G.; Ibers, 3. A.I Mo!. Catal. 1987, 41, 147.48 Thorburn, I. S., Ph.D. Dissertation, The University of British Columbia, Vancouver,Canada, 1985.49 Thorburn, I. S.; Rettig, S. J.; James, B. R. Inorg. Chem. 1986, 25, 234.50 a) Clark, E. P. Indust. Eng. Chem. Anal. Ed. 1941, 13, 820.b) Zoeliner, R. W. I Chem. Ed 1990, 67, 714.51 a) Evans, D. F. J. Chem. Soc. 1959, 2003.b) Lie, D. H.; Chan, S. I. Anal. Chem. 1970, 42, 791.c) Lagodzinskaya, G. V.; Klimenko, I. Yu. I Magn. Reson., 1982, 49, 1.52 Figgis, B. N. Introduction to Ligand Fields; Wiley: New york, 1966; Chapter 10.9153 Alessio, E.; Balducci, G.; Calligaris, M.; Costa, G.; Attia, W. M.; Mestroni, G.Inorg. Chem. 1991, 30, 609.54 Braunstein, P.; Matt, D.; Nobel, D; Bouaoud, S.-E.; Carluer, B.; Grandjean, D.;Lemoine, P.1 Chem. Soc., Dalton Trans. 1986, 415.55 Jaswal, 3. S.; Rettig, S. 3.; James, B. R. Can. I Chem. 1990, 68, 1808.56 Appleton, T. 0.; Clark, H. C.; Marizer, L. E. Coord Chem. Rev. 1973, 10, 335.92Chapter 493Ruthenium Complexes Containing Aminophosphine Ligands inDihydrogen Activation and Catalytic Hydrogenation4.1 IntroductionThe un-catalyzed usually assumed suprafacial addition of hydrogen toalkenes or other unsaturated substrates, whilst being thennodynamicallyfavourable in the ground state, is a symmetry forbidden process.1 A transitionmetal complex can catalyze hydrogenation reactions by overcoming the netsymmetry restrictions through a series of symmetry allowed reaction stepsinvolving metal-hydride intermediate(s). Thus, the basic steps in catalytichydrogenation of unsaturated substrates usually involve activation of bothdihydrogen and substrate at a metal center (which can occur in either order),transfer of hydrogen, and release of the product.2’3The formation of intermediatemetal hydrides in the catalytic cycle has been recognized as occurring primarily intwo ways.3’45Oxidative addition (homolytic cleavage) is the most common modeof dihydrogen activation. However, the preferred pathway adopted by a givencomplex is largely dependent on the type and oxidation state of the metal, whichwill be evident from a closer examination of each of the two basic processes.A Oxidative addition (homolytic cleavage of hydrogen)5Three different patterns can be recognized in this mode of dihydrogenactivation:94(i) monometallic H2 oxidative addition to coordinatively unsaturatedcomplexes of oxidation state n, with an overall two-electron change(Equation 4.1).M + H2 - ([j)jfl+2 (4.1)(ii) monometallic H2 oxidative addition to coordinatively saturatedcomplexes, accompanied by the loss of a neutral ligand with a two-electron change (Equation 4.2).M(CO) + H2 - (H)M’2 +42(iii) bimetallic (mononuclear or dmuclear) H2 oxidative addition inwhich the metal undergoes a one-electron change (Equation 4.3).2 Mn (or Mn - Mn) + H2 - 2 ()f4l (4.3)The addition of hydrogen as shown above under categoiy (i) is particularlycommon in square-planar d8 complexes (especially in Rh(I) and lr(I))6’7 as thisresults in the favored octahedral d6 configuration (Equation 4.4).IrCl(CO)(PPh3)2 + H2 - (H)2IrCl(CO)(PPh3) (4.4)Oxidative addition of dihydrogen is often reversible and the forward reaction isusually considered to be favored for complexes with a low oxidation state, highmetal basicity, and unsaturation in the coordination sphere.8 The hydrogenaddition usually affords a cis.adduct,3b,9although a reaction yielding a trans95adduct has been reported; however, the possibility of isomerization of an initiallyformed cis complex to give the trans-product is not excluded. 10Several coordinatively saturated complexes add dihydrogen with loss of aneutral ligand (category (ii), for example Equations 4.2 and 4.5”), and in thesesystems prior loss of the ligand is thought to occur in order to avoid the formationof a higher energy, 20-electron intermediate.1rH(CO)3(PPr) + H2 - Ir(H)3(CO2PPr’) + CO(4.5)Dinuclear complexes can react with H2 with a net hydrogen addition to twometal centeres, where the formal oxidation state and the coordination number ofeach metal are increased by one (Equations 4.3 and 4.612).2 Co(CN)53 or Co2(CN)106 + H2 - 2 HC0(CN)53(4.6)B Heterolytic cleavage of dihydrogen’3This mode of dihydrogen activation involves a net substitution of a hydridefor another ligand (for example, X = halide), with no change in the formaloxidation state of the metal (Equations 4.7 and 4.8).MX+H2—. H)Mfl+ W+xRuC12(PPh3) + H2 - - Ru(H)Cl(PPh3)+ W + C1(4.8)96The net heterolytic cleavage of dihydrogen can be explained by invokingtwo possible mechanisms.3b,4,14The first involves oxidative addition of H2 toform a dihydride or formation of a molecular dihydrogen species (see below),which subsequently breaks down via reductive elimination of HX into the metalhydride (Equation 4.9)./XM—X+H2 M—H M—H+HX(4.9)The second mechanism involves a polarized H2-metal intermediate, which canlose the positively polarized end of the H2 molecule to an external (path (i)) orinternal base (path (ii), Equation 4.10). 15M base M—H + baseH + X+In both of the mechanisms of overall heterolytic cleavage of dihydrogen theoxidation state of the metal remains unchanged, and therefore the process isgoverned by a) the substitution lability of the complex, b) the stability of theM—X + H2M—H +HX(4.10)97hydride complex, and c) the availability of a suitable base which may be thesolvent, an added base, or the displaced ligand itself. It is not possible todistinguish between the net heterolytic cleavage via addition-elimination and the“genuine” heterolytic cleavage involving a polarized intermediate. Arguments foreither are usually made on the basis of the metal oxidation state in the precursorcomplex. Metals in lower oxidation states are thought to undergo heterolyticcleavage via the addition-elimination process, whereas metals in higher oxidationstates are thought to follow the mechanism involving the polarized M-H2intermediate.3b,14Ruthemum(II) systems appear to lie close to a balance of thismechanistic variation, thus making the mode of reactivity more ambiguous than forother systems.3bl6It is certainly possible that Ru(II) systems give a monohydrideby an initial formation of a Ru(IV) dihydride intermediate.3bHowever, thediscovery of molecular hydrogen complexes and the related M-(H2)/M- )equilibria’7 (see below) has modified this viewpoint somewhat because theruthenium complexes that were thought to be Ru(IV)-dihydrides have beenreformulated as r12-H2 complexes (see below).As outlined above, a basic requirement for catalytic activity is the formationof a hydrido complex of sufficient stability that it is readily formed, and at thesame time it must be labile enough so that subsequent transfer of the hydride tosubstrate can occur. Many hydrido complexes which are catalytically active arestable enough to be isolated and characterized. 18984.2 Molecular Hydrogen ComplexesThe interaction of H2 with a metal center to give a species containing acoordinated dthydrogen molecule has long been considered, but the species wasregarded as a transient to hydride formation.19 Indirect evidence for possibledihydrogen binding was cited by Ashworth and Singleton in 1976 based on theirstudies with RuH4(PPh3) and [RuH3(DPPE)2] complexes, which wereformulated as Ru(IV)-polyhydride complexes;2°however, the observation thatthese species undergo reaction with an initial loss of H2, and the analogy with thesimilar behaviour found in complexes with the reversibly bonded dioxygen ligand,led to the alternate, speculative formulations20 Ru(H2)(H)(PPh3 and[Ru(H2)H(DPPE)],that is, Ru(II)-dihydrogen complexes. It was not until 1983that such possible dihydrogen coordination at a metal was demonstrateddirectly.21,22Further indirect evidence for an unusual, novel binding of dthydrogen wasreported by Kubas from an JR spectroscopic study on, and the observed lability ofH2 in MH2(CO)3PR)(M = Mo, W; R = Pr’, Cy) complexes23 (Figure 4.1).Subsequently the Kubas group reported direct evidence for the first molecularhydrogen complex W(H2)(CO)3(PPr’,which was shown to contain a side-onbonded dihydrogen ligand (r12-H)by X-ray (H-H = 0.75 (16) A) and neutrondiffraction (H-H = 0.84 A) analysis.21’2 The 1H NMR spectrum of the H-Disotopomer showed a 1:1:1 triplet with a 14{f) value of 33.5 Hz, reasonably closeto that of HD gas (43.2 Hz).24 Because the HJJ value for hydride-deuteridecomplexes is typically <2 Hz,19 such a large HD value indicated the presence ofan H-D bond of somewhat reduced order, and thus provided further evidence forthe presence of a ‘nonclassical’ ri2-H ligand. The next stable dihydrogen complex99[IrH(r12-)(PPh3bq)] (bq = 7,8-benzoquinolmate) (Figure 4.1) was reported byCrabtree’s group,25 using a new criterion of T1 measurements for characterizingmolecular hydrogen complexes26 (see below). Following this, Moms et al.reported that the complexes [MH(H2)(DPPE)](M = Fe, Ru) (Figure 4.1),formed by protonating M(H)2(DPPE) species contained fl2-H2 as evidenced byX-ray and NMR data,27 thus confirming the original speculation of Ashworth andSingleton.2°OC PPh3 (PIP roc_%IPh3PI>HPR3 I-I’ HM=Mo,W M=Fe,RiiR = Pr’, Cy N—C = 7,8-benzoquinolinate P_P DPPEFigure 4.1: Some early examples of molecular hydrogen complexes.Since their original discovety, dthydrogen complexes have continued toattract increasing attention, which is apparent from the many recentpapers28’930 and review articles. 19,32,3 3 The detection of this new form ofdihydrogen binding led to reformulation of several complexes as dihydrogencomplexes, which for many years were thought to be polyhydrides in metals ofunusually high oxidation states. For example, the complexes Ru(H)4(PR3)(R =Ph or Cy) have been reformulated as Ru(H2)(H)(PR34and the dinuclearcomplexes [Ru(H)2Cl(PR3](R = Ph or p-tolyl) were found to containr12-Hligands and were in fact [(ri2-H)(PR3Ru(t-H)(p.-Cl)u PR)2] 35,36100Some common features are evident from the many dihydrogen complexesreported to date. 19,3 3 The metals are usually of d2-d8 formal electronconfigurations and span a range of coordination numbers (4-9) and formaloxidation states (0-VT), with a majority of the complexes being of octahedralgeometry. All are neutral or catiomc and are 18-electron species (counting i12-Has a two-electron donor), containing at least one it-acceptor ligand, except for thematrix isolated, “ligand free” pdH237 and the cluster complexes Cu2H2(H )x andCu3(H2).38Of the over 100 dihydrogen complexes reported to date, only a few arestable with respect to dihydrogen elimination in the absence of H2,33b,39 ordihydride formation33b,40,l(Equation 4.11).+ H2HH(4.11)The factors governing such equilibria, and thus the stability of some dihydrogencomplexes, can be understood in terms of the bonding scheme put forward fordihydrogen binding to metal centers.3233 The metals involved have both empty orpartly filled da and filled or partly filled d orbitals, and the principal componentof the M-(’q2-H)bonding is comprised of electron donation from the occupied a(H2) orbital to a da(M) orbital. Back donation from a metal d orbital to theempty o*(H2) orbital occurs to a lesser extent, and is responsible for both101stabilizing the M-(H2) bond and promoting H-H dissociation to givedihydrides.32’3 A certain amount of back-bonding is considered necessary for astable M-(ri2-H)species, but too much back-bonding will result in the homolyticcleavage of the H-H bond to give a dihydride. Thus, among other factors, weaklyit-basic metals, higher oxidation states (e.g. +2 vs. 0), and the presence of it-acidicligands, are expected to stabilize the dihydrogen form.32’3 According to Morris cial. the critical amount of back bonding necessary to stabilize a dihydrogencomplex is reflected in the v(N2)value of the corresponding dinitrogen complex,which is proposed to be in the 2060-2150 cm-1 range.42 More recently, Lever etal. showed how the electrochemical potential E 1/2 for a d5/d6 system of thedimtrogen complex can be used for predicting the stability of the correspondingdihydrogen complex.43Obtaining proof for molecular hydrogen coordination has paralleled theincreasing interest in such complexes. Historically, in the discovery of thedthydrogen complexes, infrared spectroscopy provided the first hint for thepresence of an92-H ligand.23 However, only a few complexes have exhibited theVHH mode in the suggested range 2400-3100 cml.32,33 Thus, infrared and Ramanspectroscopy have been of limited use in characterization of dihydrogencomplexes. The most direct proof was obtained by X-ray crystallography andespecially neutron diffraction methods.33bHowever, the difficulty in obtainingcrystals suitable for such studies and the problems of chemical instability and/orphysical disorder remain as principal drawbacks of this method.So far, 1H NMR spectroscopy has been the most widely used andconvenient diagnostic tool for identifying the presence of an ri2-H ligand. Asmentioned above, in the HD isotopomer, observation of a 1:1:1 triplet with a HD102value in the range 25-3 5 Hz,33b close to that of the free HD gas (43.2 Hz),24 hasbeen useful in identifying a non fluxional H-D ligand, the 3HD value for hydridedeuteride complexes being <2 Hz.33bHowever, due to fluxionality in polyhydridecomplexes this coupling could be unresolved or severely underestimated.33b,44Thus, the 1H NMR short Ti-relaxation time criterion introduced by Crabtree andHamilton26’45 has been the most widely used in characterizing the r12-H2ligand.46’7 The theory is based on the proxiniity of the hydrogen atoms, for in thecase of ther2.H2 ligand, where such protons are less than 2 A apart, the dipole-dipole (DD) mechanism is assumed to be the principal mode of NMR relaxation insolution. For such a mechanism, the rate of relaxation R(DD) is related to theinternuclear distance HH by Equation 4.12, and as a result short T1 values (< 100ms) are typically found for ii2-H ligands.45R(DD)= {(DD)} =O.3Y)(ri6{2+ 4t22} (4.12)2t 1+o t 1+4o ;where,rotational correlation time (s radl)y gyromagnetic ratioLarmor frequency (rad s)h Planck’s constant (6.626 x iO34 3 s)r H-H internuclear distance (cm).As predicted by theory (Equation 4.12), a minimum value for T1 should beobtained when the Brownian motion is best matched with the Larmor frequency co,at which ‘ta, a measure of the Brownian motion, is related to co by Equation 4.13.103;=063 (4.13)Thus, obtaining the T1(wn) by a series of T1 measurements at differenttemperatures allows the Equation 4.12 to be solved for the rj-j value. Therefore,the measurement ofT1 is not only diagnostic, but it also measures the internucleardistance in an 92-H ligand. However, the rj-j- values so obtained were shown tobe considerably longer than the values obtained by the crystallographic methods,which are in the range 0.8-1.0 A33b (the value is 0.74 A in free dihydrogen gas’9).Morris’s group attributed this discrepancy to the neglecting of H2 rotation aroundthe M-H2 axis, and put forward a correction factor of 0.794 for the situation wherethere is rapid dihydrogen rotation (Equation 4. 14).48 The ‘corrected’ values socalculated for most mononuclear complexes have been found to be in reasonableagreement with those obtained from structural methods.rreal = 0.794 (rcalcd) (4.14)The primary goal of the present study was to evaluate hydrogen activationby Ru-(P-N) complexes, with respect to that by the well known RuCl2(PPh3)complex which undergoes reaction according to Equation 4.RuC12(PPh3) + H2 base Ru(H)C1(PPh3)+ base H + C115104In reaction 4.15 use of either triethylamine49or dimethylacetamide (DMA)3’5°asbase has resulted in successful hydride fonnation. However, in similar reactionsinvolving ruthenium-(P-N) complexes, careful choice of a base has to be made inorder to prevent the possible involvement of the basic amine functionality of the(P-N)-chelate (see below), and to obtain the analogous Ru(H)Cl(P-N)(PR3)complex. Proton Sponge (PS) as added base is favored because of its strongbasicity (pK = 12.1)51 and the bulkiness which prevents the complications thatcan arise through its coordination. Rare examples of PS coordination52 andreaction with the metal center (dehydrogenation of the PS with concominantreduction of the metal),53 have been reported, although such reactions are morecommon with less sterically demanding bases such as NEt3 (pK = 10.6).5254.55Another aspect of P-N chemistry is the possibility of involvement of theamine functionality of the P-N chelate in dihydrogen activation at Ru(II) centersvia a four-centered transition state (Equation 4.10). In fact, this possibility was aprimary objective of the original P-N work,56 and direct evidence for heterolyticcleavage of H2 promoted by the amine functionality of a coordinated PPFA ligandhas been obtained (Equation 4. l6).57 Thus it was of further interest to pursue theseideas with other Ru(II)-(P-N) complexes. In the same report by Hampton et a!. useof isoPFA in place of the PPFA ligand resulted in the formation of the noveldinuclear-dihydrogen complex (Equation 4.17), adding further dimensions to Ru-(P-N) chemistry.Described in this chapter are the reactions of Ru(III)- and Ru(II)-(P-N)complexes with dihydrogen in the presence of an added base (Proton Sponge),105H+BuOH Ph3 -P ,NRuCI2(PPFAXPPh3) + H2 - RuCH2I or toluene Ci- o’_...Buc1.-.1i’(4.16)C6HIMeOH H- .-Cl -.RuC12(isoPFA)(PPh3)+ H2 -. - c------ RuHRU.çPPh3(4.17)the reactions resulting in formation of Ru(II)-monohydride complexes. With thePMA ligand, a monomeric complex of the form Ru(H)Cl(PMA)(PR3is obtained.With AMPHOS, the available evidence could not distinguish between themonomeric or the dimeric formulations [Ru(H)Cl(AMPHOS)(PR)]2,for which amechanism of formation is proposed based on kinetic studies involving constantpressure gas-uptake experiments. The reaction of RuCI2(PMA)(PR3)withhydrogen in the absence of an added base results in the formation of thedihydrogen complex (q2-H)RuCIPMA)(PR3.Also presented are somepreliminary results showing the potential of Ru(II)- and Ru(III)-PMA complexes(la, ib, 6a, and 6b) and Ru(III)-AMPHOS complexes (7a and 7b) for catalytichydrogenation of simple olefms; styrene is used as the substrate to avoidcomplications due to double bond isomerization reactions. The chirality of theAMPHOS ligand allows for Ru(III)-AMPHOS complexes to be used asasymmetric hydrogenation catalysts; some results in this area are presented usingsimple, prochiral alkenes as substrates.1064.3 Interaction of RuCI2(PMA)(PR3)Complexes (R = Ph, Ia; R = p-tolyl, Ib)with H2 in the Absence of an Added Base: Formation of a MolecularHydrogen ComplexSolutions of la or lb (CH2C1 or CHC13)react rapidly and reversibly with1 atm H2 to give in situ formation (85% conversion, Equation 4.18) of themolecular hydrogen complexRuC1(r-H)(PMA)(PR3(R = Ph, 8a; R =p-tolyl,8b), as evidenced by 1H and 3lP NMR spectroscopy.58 The reaction isaccompanied with a color change from dark-green to lighter olive-green withinfew seconds of exposure to H2 atmosphere.RuC12(PMA)(PR3) + H2 - (r12-H)RuC1PMA)(PR3la R=Ph 8a R=Phlb R =p-tolyl Sb R pt()1yl (4.18)The 1H NMR spectrum of 8b (300 MHz, CDC13 20 °C, Figure 4.2)consists of a broad resonance at -11.02 ppm (2H) which is assigned to the r12-H2resonance. The N-methyl resonances appear as two singlets at 3.56 and 3.07 ppm,in addition to the methyl resonance from the p-tolyl phosphine at 2.13 ppm. Thespectrum of 8a (300 MHz, CDC13 20 °C) consists of signals at 8: -11.02 (br s,ri2-H2), 3.08 (s, NMe), 3.56 (s, NMe), 6.6-7.7 (m, Ph protons). The 31P{1H}NMR spectrum of lb under 1 atm of dihydrogen (121.4 MHz, CDC13)consists ofa new AX spin pattern (data summarized in Table 4.1) which is assigned to ther12-H complex. The coupling constants and the chemical shift values of the H2107.1-0 00Figure4.2:‘HNMRspectrum(300MHz,20°C)ofthereactionmixtureobtainedafterthereactionofRuC12(PMA)(P(p-to1yI)3),1 b,with1atmofH2inCDC13solution.*andL-:N-methylsandCH3ofp-tolylphosphinein(r2-H)RuC1(PMA)(P(p-toly1)3,8b;•andIi:N-methylsandCH3ofp-tolylphosphineoflb.•*‘‘‘ririrriII111-2-4-jiiiIIIII-iDPP4—12Table 4.1: 3lP{1H} NMR data (121.4 MHz, CDC13)for the complexesRuC12(PMA)(PR)(R = Pb, la; R =p-tolyl, ib) andRuC1(PMA)(PR3)(L).Complex, L 6A ppm 6x ppm 2j Hzla,none 85.17 52.55 36.67lb,none 87.22 50.51 36.728a, q2-H 53.24 49.44 26.878b, r2-H 53.51 47.60 27.0014a, a-N2 53.06 43.25 27.3214b, a-N2 53.30 41.80 27.30adduct are related to those observed for similar ligand adducts formed by la or lbwith ligands such as H2S, EtSH, SO2 and N2 (Table 5.15); the data for the rispecies (Section 5.2.7) are given in Table 4.1 for purposes of comparison.The presence of an ii2-H ligand in 8b is established by the T1 criterionproposed by Hamilton and Crabtree.45 The short T1 value of 22 ms (300 MHz, 20°C, W1/2 = 17 Hz) of the broad resonance at -11.02 ppm (Figure 4.2) is typical ofr12-H resonances.3345 When the H2 atmosphere is removed by vacuum orreplaced by argon, the signal at -11.02 ppm disappears, and only lb is seen in thereaction mixture as evidenced by 31P and 111 NMR spectroscopy. Thus, 8b (andsimilarly 8a) fall into the class of labilei2-H complexes. The broadness of the109resonance is attributed to the rapid rotation of the dihydrogen ligandalongthe M-H2 axis.33 On lowering the temperature of the sample, a further broadeningof the 92-H resonance is observed (Table 4.2), indicating a slowing of theinternal motion, such behaviour being characteristic of many dthydrogencomplexes.33’45The temperature dependence of T1 for 8b over the range 202-293 K (Table4.2) gives a sharp V-shaped plot (Figure 4.3) as predicted by Equation 4.12, fromwhich the minimum T1 value of 13.4 ± 0.2 ms (at 232 K) is obtained. Using thisT1 mm value, an internuclear distance of 0.87 ± 0.03 A is calculated for ther)2-H ligand according to Equations 4.12-4.14; the data show a significantlengthening of the H-H bond distance upon coordination with respect to that offree H2 gas (0.74 A’9).The presence of the 1i2-H ligand in 8b is further confirmed by preparingthe correspondingr12-HD isotopomer, which is obtained by reaction of 8b (inCD21)with 1 atm of D2 gas. The 1H NMR spectrum (in CD21,300 MHz,20 °C, Figure 4.4) of the HD complex consists of a 1:1:1 triplet(1HD 30 Hz) of1:2:1 triplets (cis 2HP = 8.5 Hz) centered at -10.96 ppm, which is assigned to the12FjJ ligand. HD for HD gas is 43.2 Hz24 and for hydride-deuteride complexesis <2 Hz.19 Thus, the relatively large HD value of 30 Hz is indicative of a H-Dligand of reduced bond order, and the value of HD is within the range (18-34 Hz)reported for other r)2-HD complexes.’9’59Of particular note is the relatively large2Hp value of 8.5 Hz obtained for the H-D complex. Resolution ofcoupling of theH-D ligand to phosphines or metal is unusual,19’60and only in few cases has such110-3.73.2 3.7 4.2 4.7 5.21/9 x io, K1Figure 4.3: Temperature dependence of T1 for the molecular hydrogen moiety in(2..H)RUC1(PMA)(P(p..tolyl)3), 8b.Figure 4.4: High field 1H NMR spectrum (300 MHz, CD2I 20 °C) of the(i2..HD)RuC1(PM)(P(p-to1yI)3complex.I.4.3 Ii-4.5II1jprj=3OHz23= 8.5 HzI I I I I I I I I I I I I I I I I I J I I I I I I I I I I I I I I I I I I—io.B—iO.S—ii.O—il.2 PPM —fl..4yW111Table 4.2: Variable temperature T1 and T2* data (300 MHz, CD21)for theresonance of 8b at -11.02 ppm.Temperature, 0, K T1, msa Lmewidth, w1/2, Hz T2*, msb293 22±1 17 18.7271 18±2 21 15.2252 15±2 23 13.8242 14±1 24 13.3232 15±2 26 12.2222 17±2 27 11.8212 19±2 29 11.0202 22±2 43 7.4a T1 data were obtained by the inversion-recovery method using the conventional 1 80°-t-90°pulse sequence.b T2* values were calculated from the observed linewidths according to the relation:linewidth = 1/nT2*resolved coupling being reported in the literature; for example 2.0-3.6 Hz forCpRu(R2PCH4)(HD) (R Ph, Me)6’ and 7.5 Hz for [(HD)(DPPB)Ru(pCl)3RuC1(DPPB)J 62Attempts to isolate the dihydrogen complexes 8a or 8b were unsuccessfuldue to the incomplete reaction of la and lb with H2 in CH21 or CHC13 (only85% conversion to the r)2-H complex at 1 atm H2), and many attempts atcrystallization were fruitless. However, when the reaction of la (or ib) with 1 atmof H2 was carried out in toluene, a yellow product precipitated, and this is thought112to be the corresponding dihydrogen complex. Although the product could befiltered out under H2 as a yellow solid, the instability of the complex prevented itscharacterization. Inspection of the JR spectrum of a Nujol mull of the productreveals no absorbance ascribable to vHH. This is not unusual, however, as suchabsorptions are known to be very weak and have been located only in fewinstances as a broad band in the range 2400-3 100 cm1 (4300 cm1 for freeH2).32b33 In the absence of a H2 atmosphere (under vacuum) the yellow solidsturn to off-white, and dissolution of this off-white solid in CDCI3 or CD21under an argon atmosphere results in a green solution containing the precursorcomplex 1, as characterized by NMR spectroscopy.In addition to reaction with dihydrogen, la (as well as ib) reacts with arange of other small molecules (N2, SO2, CO. H20, H2S, MeOH, and EtSH)resulting in a series of six-coordinate ligand adducts of the form RuCI2(PMA)-(PR3)(L) (see Chapter 5 for details). The dinitrogen complexes RuCl(PMA)-(PR3)(a-N2(R = Ph, 14a; p-tolyl, 14b) both exhibit the JR stretch at 2161cm (s, CHCI3 solution, in 0.1 mm KBr cell under nitrogen). According toMonis’s group, for stable dihydrogen binding, the vr...j value of the correspondinga-N2 complex should fall within the range 2060-2150 cm, and if the value isgreater than 2150 cm4 the dihydrogen complex should be unstable with respect toH2 elimination.33bThus, the observed instabilty of the dihydrogen complexes 8aand 8b with respect to hydrogen loss (in solution under an argon atmosphere), andthe v value of 2161 cm’ of the a-N2 complexes 14a and 14b, are consistentwith the suggestion for the stability ofri2-H complexes.1134.4 Interaction of RuCI2(P-N)(PR3) Complexes with H2 in the Presence ofProton Sponge: Synthesis of Ru(H)Cl(P-N)(PR Complexes4.4.1 Interaction ofRuCI2(PMA)(PR3) Complexes (R = Ph, la;R =p-tolyl, ib) with 112Reaction of benzene (or CH21) solutions of la or lb with 1 atm ofdihydrogen in the presence of Proton Sponge (4 equivalents) results in theformation of Ru(H)Cl(PMA)(PR3complexes (R = Ph, 4a; R = p-tolyl, 4b), whichare characterized by elemental analysis and spectroscopic (NMR and IR) methods.The reaction proceeds rapidly with a color change from green to dark red within afew minutes of exposure to a hydrogen atmosphere with concominant precipitationof PSHC1. The orange solid 4b is isolated analytically pure in 80% yieldfollowing addition of hexanes to the filtrate obtained after removal of PSH+Clusing Celite (Section 2.2.2.6). The product was found to be extremely air-sensitive, and thus handling of the solid was done under an argon atmosphere in aglove-bag. The 31P{1H} NMR spectra of 4a and 4b consist of an AX pattern with2Jpp values (Table 4.3) characteristic of cis-phosphines.63Table 4.3: 1P{1H}NMRdata(121.4MHz, CD21 20 °C)forRu(H)Cl(PMA)(PR complexes.Complex, R= 6A. ppm ox, ppm 2Jpp, Hz4a,Ph 89.50 72.91 334b,p-tolyl 88.93 70.04 34114The 11-i NMR spectrum (300 MHz, CD21 20 °C) of 4b consists of sharpsmglets at 3.50 (N-Me), 2.90 (N-Me), and 2.25 (Me of p-tolyl) ppm, along with abroad peak at -27.6 ppm. When the temperature was lowered, this broad signalsharpened and resolved into a pseudo-triplet (at -80 °C) with a 2HP value of 28Hz indicating cis-phosphine hydride coupling.64 The 1H NMR spectrum of 4a isidentical, except for the absence of the p-tolyl peak at 2.25 ppm. Comparison ofthe NMR spectroscopic data of 4a and 4b with those of the Ru(II)-dichlorocomplexes (la and ib, Table 3.3) suggests a square pyramidal structure for thehydridochloro complex similar to that of lb (Figure 3.2) but with a chloridereplaced by a hydride ligand. The presence of the hydride is also seen by IRspectroscopy; the v(RUH) value of 2079 cm4 for 4a and 4b (w, Nujol mull) fallswithin the range found for other Ru(II)-hydride phosphine complexes.35’57In the reaction of lb with dthydrogen, use of 1 or 2 equivalents of PS ratherthan 4 equivalents led to formation of a mixture of Ru(II)-(-H)8b andmonohydride 4b complexes.. Similar results were obtained with la as well. Thus,it seems almost certain that the formation of the ruthenium hydride follows thesequence shown in Equation 4.19, via the intermediate dihydrogen complex.H2 PS_________“Ru(H)CI” + PSHC1la or lb Saor8b 4aor4b (4.19)Such an overall net heterolytic cleavage of H2 via a molecular hydrogen specieshas been discussed in some detail.33b,65 The H2 reaction with the closely relatedRuCl2(PPh3)3 species in the presence of a base does yield Ru(H)Cl(PPh3),the115well known hydrogenation catalyst, but the system is more complex because of aninitial phosphine dissociation and formation of a dimeric species.3657 6 Asequence similar to lb —* 4b starting from five-coordinate, catiomc, monochlororuthemwn(II) phosphine-containing species has been reported.67On the whole the H2 reactivitiy of the RuCl2(PMA)(PR3)complexes hassome resemblance to that observed by Hampton et al. of this department forRuC12(P-N)(PR3)complexes, where P-N is the ferrocene based PPFA and isoPFAligands35’5766(Figure 1.1, page 4). The Ru(II) complex containing isoPFA ligandreacted with 112 in DMA, a base, giving a mixture of[(q2-H)(isoPFA)Ru(.t-Cl)-(p.-H)RuH(PPh3)2Jand Ru(H)Cl(PPh3)(isoPFA) complexes, whereas the samereaction in the presence of PS, a stronger base than DMA, produced just theRu(H)Cl(PPh3)(isoPFA) complex.35’57 This, like the reactivity of RuCl2(PMA)-(PR3) complexes with H2 (Equation 4.19), is readily explained by the deprotonation of the (r12-H2) complexes by an external base, a reaction of molecularhydrogen complexes that is being studied in greater detail by several groups.334.4.2 Interaction ofRuC12(PAN)(Pp-tolyl)3),2, and RuCI2-(AMPHOS)(PR3)Complexes (R = Ph, 3a; R = p-tolyl, 3b) withH2Benzene (or CH21)solutions of 3a or 3b undergo reaction with 1 atm ofH2 in the presence of 3 equivalents of PS to give quantitative formation of aspecies of a composition Ru(H)Cl(AMPHOS)(PR).The same product is obtainedin the reaction ofRuCl3(AMPHOS)(PR with 1 atm H2 under similar conditionsand the characterization of the species is presented in Section 4.5.2.116Reaction of CH21 solutions of 2 with 1 atm of H2 in the presence of 3equivalents of PS results in formation of a hydride species in Ca. 60% yield, asevidenced by the NMR spectrum of the in situ reaction mixture. The NMR data forthe product are: 31P{ ‘H) (CD2C1,121.4 MHz), 6: 111.59 (d), 63.00 (d), 2Jpp34.1 Hz; 1H (CD2I,300 MHz), 6: -20.2 (br m, hydride), 2.37 (s, p-tolyl), 2.90(s, -NMe), 3.41 (s, -NMe), 6.9-8.0 (m, Ph). By comparing the NMR data withthose of the AMPHOS and PMA systems, the product is formulated asRu(H)C1(PAN)(P(p-tolyl)3).Resonances of the unreacted precursor complex 2 arealso seen in the NMR spectrum(31P{1H} (CD2I, 121.4 MHz), 6: 101.83 (d),43.04 (d), 2Jpp = 32.5 Hz; ‘H (CD2C1,300 MHz), 6: 2.45 (s, p-tolyl), 3.01 (s,-NMe), 3.70 (s, -NMe), 6.9-8.0 (m, Ph)), and the yield of the product was noteffected by a prolonged 4 d reaction. This incomplete reaction of the Ru(ll)-PANcomplex with 1 atm of H2 contrasts to the quantitative reactions observed in 16-18h under similar conditions with the Ru(II)-AMPHOS and Ru(ll)-PMA systems.This behavior also parallels the non-reactivity of 2 with other small moleculesinvestigated (Section 5.3).4.5 Interaction of Ru(III)-(P-N) Complexes with Dihydrogen4.5.1 Interaction ofRuC13(PMA)(PR)Complexes (R = Ph, 6a; R ptolyl, 6b) with 2When a DMA solution of 6b (or 6a) is reacted with 1 atm of H2 (withoutany added base), a rapid reaction occurs with a color change from dark red toorange-red. Examination of the reaction mixture by 31P NMR spectroscopyclearly shows the presence of two species (Figure 4.5); the resonances are assignedto the dihydrogen complex[(r2-H)RuCl PMA)(P(p-toly1)3],8b, (-. 33%) and117the DMA adduct [RuC12(PMA)(P(p-tolyl)3)(DMA)] (— 67%). The same productmixture is obtained when the Ru(II) complex lb is reacted with H2 in DMA, theidentity of the DMA adduct being obtained by running the 31P NMR spectrum(12 1.4 MHz) of lb in DMA under an argon atmosphere (52.80 (d) and 69.63 (d)2Jpp = 39.9 Hz; cf Section 5.4). However, when DMA solutions of 6b (or 6a) arereacted with 1 atm H2 in the presence of 6 equivalents of PS, Ru(H)Cl(PMA)(P(ptolyl)3) 4b is obtained as the only product, while use of 4 equivalents of PSresulted in a 1:8 mixture of the dihydrogen complex 8b and the hydridochiorocomplex 4b.Thus, from these results it is clear that the Ru(III)-PMA complexes 6a and6b react with dihydrogen with the mitial formation of the “Ru(II)-(PMA)C12”complexes la or lb. The presence of a base such as DMA or PS is thought to berequired for this initial reduction from Ru(III) to Ru(II). The Ru(II) species canthen react with 1-12 to give the(92-H)complex, which undergoes further reactionin the presence of PS, a stronger base than DMA, to give the hydridochlorospecies.4.5.2 Interaction ofRuCI3(AMPHOS)(PR)Complexes (R = Ph, 7a;R = p-tolyl 7b) with H2DMA or toluene solutions of 7a (or 7b) react with 1 atm H2 in the presenceof 3 equivalents of PS to give a hydride species. The amount of PS used for thereaction does not seem to have an effect on the type of products formed (efSection 4.5.1). The reaction proceeds with a color change from brown-red to red,and when the reaction is carried out in toluene the solution becomes turbid due to118**4.iiIIIijrlr1rIr1Tr11T1rrriiiiiillilliilliiTi1111111iiiiIIIIIJIlllJIiill8070605040302010PPMFigure4.5:31P{1H}NMRspectrum(121.4MHz,20°C)ofthemixtureobtainedafter thereactionof6bwith1atmH2inDMAsolution.*RuCI2(PMA)(P(p-tolyl)3)(DMA);4.(r2-H)RuC1(PMA)(P(p-to1y1)3.precipitation of PSH+C1. The presence of a strong base such as PS is necessaiyfor the reaction, in either solvent in the absence of PS, a complex reaction with H2proceeds with some dissociation of the AMPHOS ligand, and a mixture ofproducts is formed, as evidenced by3 ‘P NMR spectroscopy.The yellow product 5a, isolated from the reaction mixture of 7a, followingaddition of hexanes to the toluene filtrate obtained after removal of PSH+C1 usingCelite, did not analyze well for the expected formulation Ru(H)Cl(AMPHOS)(PPh3) (Section 2.2.2.7). The extreme air-sensitivity of this hydride complex isconsidered to be the reason for not obtaining acceptable chemical analysis results,because the product is reasonably well characterized by NMR and IR spectroscopic methods.The 31P{ lH} NMR spectrum (202.5 MHz, C6D 20 °C, Figure 4.6) of theyellow product (yields deep red solutions upon dissolution) consists of two closelyspaced AX patterns. When expanded, it is clear that the apparent “doublet”centered at 81.8 ppm is actually two closely spaced doublets (Figure 4.6 inset).The 2Jpp values of about 32 and 34, and about 33 and 36 Hz (Table 4.4) found for5a and 5b, respectively, are indicative of cis-2Jpp coupling63 as within theRu(H)Cl(PMA)(PR3complexes (Section 4.4.1). Such closely spaced chemicalshifts are generally considered to be associated with isomers of a single cornpound.57’68 Thus, together with the 1H NMR data which show two hydrides cis totwo phosphine ligands (see below), one possibility is the presence of cis and transisomers (Figure 4.7, considering the chirality of AMPHOS and the symmetry ofthe proposed structures, (iii) and (iv) each with a C2 axis agree with the NMRdata). NMR evidence for the presence of similar geometrical isomers has been120ppm-.iij.•Figure4.6:31P{‘H) NMRspectrum(202.5MHz,20°C)of“Ru(H)C1(AMPHOS)(PPh3Y’,5a,inC6Dsolution,withanexpansionofthedownfield31Presonanceintheinset.r70i..6560CI’t,. ‘1pA R till Cl,,1 •,111i PR3HI H RV Cl )JA(i) (ii)Hx x:R3P,,Cli,,,,• ,Il’13A’ IClyA(iv)Figure 4.7: Possible structures for the “dimeric” Ru-hydrides fonned fromRuC13(AMPHOS)(PR3).Table 4.4: 31P{1H} NMR data (C6D,20 °C) for “Ru(H)Cl(AMPHOS)(PR3)” complexes.Complex, R = Chemical Shifts 2Jpp, Hz5a,Pha öA81.90 öx=61.69 32.40öÃ’= 81.86 3x’=62•5 34.425b, pto1ylb = 89.09 oX = 65.66 33.21= 88.33 0X’ = 66.17 36.97a The values are measured at 202.5 MHz.b The values measured at 121.4 M1-{z.reported by Osborn’s group for [Ir(H)I(DIOP)]2(p.-I,and the structure of thetransoid isomer has been confirmed by an X-ray structure determination.68The hydride region of the ‘H NMR spectrum (500 MHz, C6D 20 °C,Figure 4.8) of 5a consists of two doublets of doublets centered at -25.35 and(iii)122-25.55 ppm, respectively. Such close hydride resonances are again consistent withthe presence of isomers in solution.68 The 2PH values of 43.95 and 32.35, and42.73 and 30.52 Hz, indicate that the hydride ligand is cis to the two phosphineligands in each of the two isomers.64 Broadband and selective phosphorusdecoupling experiments revealed that the two hydrides are coupled only tophosphorus nuclei and not to each other. The alkyl region of the ‘H NMRspectrum (Figure 4.9) consists of two sets of resonances for each of the N-methyl(s, 3H each) and methyl (ci, 6 Hz, 3H) groups of the coordinated AMPHOS ligand,and adds further evidence for the presence of two isomers. The methyne signals ofthe two isomers are not resolved and appear together as a multiplet at 4.6 ppm.As evident from the ‘H NMR spectrum, the two isomers are present inunequal proportions (major/minor - 1.5). Osborn’s group have also observedsimilar results for their iridium complex, and they have tentatively assigned themajor isomer to be transoid.68 Such an assignment cannot be readily made in thepresent work. Variable temperature NMR spectroscopy over the temperature range0-80 °C (300 MHz, d8-toluene) revealed essentially no change in the isomer ratiofrom that observed at room temperature (20 °C). The JR spectrum of 5a (Nujolmull) revealed a weak signal consisting of a poorly resolved relatively sharpersignal and a broader one at 2081 and 2064 cm1, respectively; these signals are inthe range for a VRuH vibration and the presence of two such signals may alsoindicate the presence of two isomers.Another equally plausible explanation for the observed spectroscopicbehaviour is the presence of diastereomers of a monomeric formulation of the fonriRu(H)Cl(AMPHOS)(PR3).The chirality of the ligand (the present work used (R)123Figure4.8:1HNMRspectrum(500MHz,20°C)of “Ru(H)Cl(AMPHOS)(PPh3)”,5a,inC6Dsolutionwithanexpansionofthehydrideregionintheinset.2pH=42.73HzI23pH13052Hz2JPH=43.9?Hz‘1=32.35Hzppm5o--1•0-i5-O-I--25xx.II IIILLippm282.6W2:22.01.81.61.41.20.8Figure4.9:1HNMRspectrum(500MHz,20°C)of“Ru(H)CI(AMPHOS)(PPh3)”,5a,inC6D(0-3ppmregionexpanded).•: N-methyl (s)andmethyl resonances(d)of AMPHOSligandinoneisomerof5a.xN-methyl(s)andmethylresonances(d)of AIVIPHOSligandintheotherisomerof 5a.AMPHOS) would give rise to diastereomers if the chirality of the complex at themetal is preserved in solution. Although a molecular weight determination wouldprovide direct evidence for a dimeric or monomeric formulation, such studies werethwarted by the extreme air-sensitivity of the hydridochioro species. Attempts inobtaining a mass spectrum were also fruitless because of the air-sensitivity of thecomplex.4.6 Kinetics of The Reaction of RuCI3(AMPHOS)(P(p-tolyl)),7b, withDihydrogenThe 112 uptake by DMA solutions (5 mL) of 7b in the presence of 3equivalents of PS per Ru was measured as a function of time using the constantpressure gas uptake apparatus (Section 2.4.1). A typical uptake plot is shown inFigure 4.10. Due to slow dissolution of the complex in DMA at 30 °C, thecomplex was first dissolved in DMA under vacuum and the solution was shaken inthe oil bath (30 °C) for 10 minutes for equilibration of the temperature. The shakerwas then stopped and 112 was introduced to the required pressure, and the uptakemeasurements were started by turning on the shaker and the timer. Thus, theuptakes shown in Figures 4.10 and 4.11 are a composite of the H2 uptake by thecomplex and the solubility of H2 in DMA solution.A typical gas uptake plot (Figure 4.10) for reaction of 7b with H2 consistsof an initial relatively rapid uptake, equivalent to 1 mole of H2 per mole of Ru(III)(plus the amount required for solubility), followed by a region of much sloweradditional uptake amounting to 0.5 mole of H2. Thus, the total uptake of 1.5 moles1266..5..4•.1o 3•.0— 02,10• I I I0 2.5 5 7.5 10Time x sFigure 4.10: Uptake plot for the reaction of 7b with H2 in DMA (5 mL) at30 °C. [RuJT = 3.0 x i03 M, P(H2)= 380 torr ([H2] 0.88x l0 M), [PS] = 9.Ox i0 M.6-5.X K KKXXKKD4.. KK D 0K D.0 3..0 P(H2),torr.00—2- K 7600 0K0•0 620K0• .3801- K0 0Xa00- I I I0 0.2 0.4 0.6 0.8Time x iO, $Figure 4.11: Uptake plots for the H2-reduction of 7b in DMA (5 mL) at 30 °C, atdifferent P(H2). [RuJT = 3.0 x M, [PS] = 9.0 x103 M.127of H2 per Ru corresponds to a net reaction with an overall stoichiometry shown byEquation 4.20. This agrees with the spectroscopic studies of the reaction (Section4.4.2) in which the final product is proposed to be of composition Ru(H)C1-(AMPHOS)(PR3), a species which may be either dimeric or monomeric insolution (Section 4.5.2).RuC13(AMPHOS)(P(p-tolyl))+ 2 PS 1.5 H2 Ru(H)Cl(AMPHOS)(P(p-tolyl)3+ 2PSW+ 2CF (4.20)The kinetics of the initial 1:1 portion of the H2 uptake were studied at30 °C by measuring the gas uptake at different H2 pressures (380-760 torr), anddifferent total ruthenium concentrations, by varying one parameter at a time. Threeequivalents of Proton Sponge were used for all the experiments. As the uptakeplots shown in Figure 4.11 include uptake corresponding to the solubility of H2,they were re-plotted after substracting the solubility of H2 (Figure 4.12, thesolubility of H2 in DMA at 30 °C being calculated from the Henry’s law constantKH = 2.32 x 10-6 M torr1 at 30 °C69). The maximum rates at different [H2] werethen obtained from the maximum slopes of the plots. A similar procedure wascarried out for different [Ru]T at 450 torr H2 ([H2] = 1.04 x i03 M), and theuptake plots after the solubility correction are shown in Figure 4.13. The ratedependences on [H2] and on fRuIT were determined by plotting the maximum ratevs. [H2] and [Ru]T, respectively (Figures 4.14 and 4.15). These resulted inreasonable linear rate plots, except for the [Ru]T dependence which deviates froma simple first-order dependence at higher [Ru]T (see below).1283 00—ICTime x SFigure 4.13: Uptake plots after solubility correction for the H2-reduction of7b in DMA (5 mL) at 30 °C at different [Ru]T. [H2] = 1.04 x i03M (450 torr), with 3 equivalents of PS.129000 0to20000e0 C00IC000CP(H2), torr0000 7600 6200C 3800.1 0.2 0.3Time x s0.4 0.5 0.6Figure 4.12: Uptake plots after solubility correction for theH2-reduction of7b in DMA (5 mL) at 30 °C at different P(H2). [Ru]T = 3.0 x i03M, [PS] 9.0 x103 M.4-3-1—CC0CC[Ru]T, x i03 MCD 4.00 00 o 2.0D00 00 1.5000000 81.0000-y0 0.25 0.5 0.75Based on the observed kinetics and the overall stoichiometry, the followingmechanism is proposed for the reaction of 7b with H2:k1‘RuC13” + H2 + PS - ‘Ru(H)C1” + PSW + Clk1 (4.21)‘Cl2M+ +k2 ‘RuC1” + PSW + CF(4.22)‘RuC121’ + H2 + ps k3 + PSW + Cl(4.23)The k1, k2, and k3 values are considered to be rate constants for the individualforward steps, with the k1 step approximately corresponding to the initial 1:1 H2uptake. The k1 and k2 steps (in conjunction with a Li step that has been shown toexist7O) account for a stoichiometry of 0.5 mol of H2 per Ru; these together withthe k3 step account for the total uptake of 1.5 mol H2 per Ru. The overall H2-uptake profile for the net reaction (Equation 4.20) depends on the relative valuesof k1, Li, k2, and k3. The observed kinetic data are considered to correspond tothe rate law which is of the form:rate-d[Ru(Ill)]= k1 [Ru(ffl)J [H2](4.24)1300 0.5 1 1.5 2FH2Ix1O3MFigure 4.14: Dependence of the maximum rate on [H2] at 30 °C, [Ru]T = 3.0x i03 M, [PS] = 9 x i03 M in DMA (5 mL).2-—I’,1.5-1—0.5-Oii.T0T___________________0 1.5T y = 0.006x +0.000 /0IT0IU I I0 0.5 1 1.5 2 2.51 I0 1 2 3 4[RU)TI1O3M5Figure 4.15: Dependence of the maximum rate on [Ru]T at 30 °C, [H2] = 1.04x 1o3 M, with 3 equivalents of PS in DMA (5 mL). The INSETshows the initial portion of the rate plot expanded.131The pseudo first-order rate constants kobs = 1.5 x 10-2 S_i (= kl[Ru]T) andk’obs = 6.0 x iO-3 s1 (=k1[H2])were obtained from the slopes of the plots shownin Figures 4.14 and 4.15 respectively, from which k1 values of 5.0 and 5.8M1i were calculated.As the rate dependence on [RU]T becomes less than first-order at higherconcentrations (Figure 4.15), the individual uptake plots shown in Figure 4.12were analyzed by plotting log [Ru(III)]t vs. time, with the assumption that anuptake of 1 mol of H2 corresponds to 1 mol of “RuCl3”in the k1 step (Equation4.21). The complete semi-log plots are shown in Figure 4.16, and it is evident thatreasonably linear pseudo first-order plots can only be drawn for the initialportions. The complications may be attributed to contributions from the k2 and k3steps in the 1:1 portion of the uptake, thus leading to a complex dependence of rateon the ruthenium concentration. From the slopes of these initial portions of thesemi-log plots (Figure 4.17), the pseudo first-order rate constants k’obs and thebimolecular rate constants k1 were obtained (Table 4.5). A plot of k’0bs vs. H2yielded a k1 value of about 6.8 M1 s1. Given the complexity of the system, andthe different approximate approaches followed for analysis of the kinetic data, thevariation in the k1 values 5.0, 5.8, and 6.8 M1sis not too unreasonable.The intermediate “Ru(H)Cl21’and “RuCl2”species of the proposed mechanism were not detected by 31P NMR spectroscopy at a [Ru]T 1.8 x 10-2 M.The absence of any 3lP resonances in the NMR spectrum of the reaction mixtureafter 1 mole of H2 uptake provides indirect but strong evidence for formation of aparamagnetic Ru(llI) species. The deviation from the first-order behaviour athigher [Ru] (Figure 4.15) suggests that the k2 and k3 steps may also be occurring132Figure 4.16:Figure 4.17:Plots of log [Ru]t against time for theH2-reduction of 7bin DMA (5 mL) at 30 °C, at different H2 pressures. [Ru]T = 3.0 xi0 M, [PS] = 9.0 x M.0.25The initial portion of the piots of log [Ru]t against time for theH2-reduction of 7b in DMA (5 mL) at 30 °C, at different H2pressures. [Ru]T = 3.0 x i0 M, [PS] = 9.0 x 10 M.3.35.4.-4.5.5.P(H2), torr90 0 0 76000 0 0 62000000D 3800 0000000I I--—0 0.1 0.2. 0.3 0.4 0.5Timex 103s0.05 0.1 0.15 0.2‘nmexlo-3,s133Table 4.5: Kinetic data at 30 °C for the reaction ofRuCI3(AMPHOS)(P(p-tolyl)3), 7b, with H2 in DMA, using 3 mM [RuJT in the presenceof9mMPS.P(H2), tOIT [H2] X 103, M k’obs X 102, s_i k1,M1 S1760 1.76 1.3 7.2620 1.44 0.9 6.0380 0.88 0.6 6.6to some extent concomitantly with the k1 step, especially at higher [RuIT, and thusthe absence of any signal in the 31P NMR spectrum is surprising. The JR spectrumof the reaction mixture after 1 equivalent of H2 uptake contained many strongbands in the 1900-2500 cm’ region, which are present in the JR spectrum of theDMA solvent. These strong bands would mask any presumably weaker vRuHband which would appear in the same region. Interestingly, when the H2 uptakewas camed out in toluene at 30 °C with 3 equivalents of PS, a total uptake of only1.0 ± 0.2 mols of H2 per mol of Ru(III) was obtained. This observation adds to thecomplexity of the system and tends to suggest that some or all of the reactions(Equations 4.21-4.23) are in equilibrium, the direction of which could bedependent on the solvent.A similar mechanism like that proposed for reaction 4.20, involvingheterolytic dihydrogen cleavage at a Ru(III) center with the fonnation of aintermediate Ru(III)-hydride species, has been documented in the literature for H2134activation by clilororuthenate(III) complexes in both aqueous HC1 and DMAsolutions,7’as well as for H2 activation by RuX3(PPh)2and RuX3(AsPh3)2species (X = Cl or Br).7° For the RuBr3(PPh)2system, where all k1, k2, and k3steps operate, a k1 value of about 7.5 M1 s1 (at 15 °C) is reported.7°4.7 Catalytic Hydrogenation StudiesThe ruthenium complexes of PMA and AMPHOS react with 1 atm of H2 inthe presence of PS to generate monohyciride complexes Ru(H)Cl(PMA)(PR3(4aand 4b) and “Ru(H)C1(AMPHOS)(PR3)”(5a and 5b). As described in Section 4.1,such hydride complexes are frequently important in catalytic hydrogenationreactions, and thus it was of interest to evaluate the catalytic actvity of 4a, 4b, 5a,and 5b complexes.4.7.1 Hydrogenation of Styrene Catalyzed by RuCI3(PMA)(PR)(6aand 6b), andRuC13(AMPHOS)(PR (7a and 7b) Complexes.In order to determine the catalytic activity of “Ru-PMA” and “RuAMPHOS” complexes, a brief study of alkene hydrogenation using the titlecomplexes was undertaken. Styrene was used as the substrate allowing for easyidentification by 1H NMR spectroscopy of any unreacted substrate (styrene: 6, 5.1and 5.6, m, -CH=CH2;6.6, dd, -CHCH2)and product (ethylbenzene: 6, 1.03, t,-CH2C3;2.04, q, -CH2C3)after the hydrogenation experiment; also, possiblecomplications due to double bond isomerization reactions, typically associated135N4?CTimex 103,sSx10Figure 4.18: Uptake plots for styrene hydrogenation catalyzed by differentRu(I1l)-(P-N) complexes in DMA (5 mL) at 30 °C and P(H2) 760torr ([H2] = 1.76 x M); [Ru] = 1.50 x i- M, [PS] = 9.0 xio M, [styrene] = 0.15 M.with other simple alkenes such as 1-hexene72, are avoided. The hydrogenationreactions were carried out in DMA (5 mL) in the presence of excess PS (6equivalents) to ensure complete and exclusive formation of inonohydride species(4a, 4b, 5a, or 5b) under the hydrogenation conditions (cf Section 4.5.1). All thereactions were monitored using a constant presssure gas-uptake apparatus, and theuptake plots and the results obtained are shown in Figure 4.18 and Table 4.6,respectively. The results show complexes 6a, 6b, 7a, and 7b to be active ascatalyst precursors in hydrogenation of styrene under mild conditions.DDD• a8xxAxAIA0 7b6b7a6aA0 2.5 5 7.5136Table 4.6: Hydrogenation of styrene with RuCI3(P-N)(PR)complexes ascatalyst precursors. aCatalyst Max. Rate Conversion, % T.O.F.b(x i05, M s-i) (1 h) (h-i)RuC13(PMA)(PPh),6a 1.1 15 26RuCI(PMA)(P(p-tolyl)),6b 1.9 22 46RuC13(AMPHOS)(PPh),7a 10 15 24RuCl(AMPHOS)(P(p-to1yl)3), 7b 1.6 27 38a Conditions: DMA (5 ml), [Ru] = 1.5 mM, [PS] = 9mM, [styrene] = 150 mM,I atmH2,30°C.b Turn-over frequency.The corresponding hydridochioro species 4a, 4b, 5a, or 5b are the onlyphosphorus-containing species seen at the end of the catalytic runs (a 31P NMRspectrum of the resultant solution in DMA was obtained). Thus, it seems that“Ru(H)Cl” is the catalytic species which is obtained unaltered after thehydrogenation reaction. As evident from these preliminary data, the PMA andAMPHOS complexes of Ru(III) show comparable initial rates which fall offgradually as the reaction proceeds. Within the catalytic systems, the p-tolylanalogues showed about twice the activity of the corresponding PPh3 complexes.This is presumably related to the higher electron density at the metal of the p-tolylcontaining complexes,73 which must promote a rate of a slow step in the overallcatalysis, possibly reaction of a Ru(ll)-aIlcyl with H2.3 The overall catalyticactivity of the Ru(H)Cl(P-N)(PR3species is much lower than that of the well137known Ru(H)C1(PPh3)system, where turn-overs as high as 2000 h1 have beenobtained in hydrogenation of terminal olefins under similar conditions.’744.7.2 Catalytic Hydrogenation of Prochiral SubstratesA study of the hydrogenation of two prochiral olefinic carboxylic acidsusing the complex RuC13(AMPHOS)(PPh),7a, was undertaken to determine itspotential as an asymmetric hydrogenation catalyst precursor. All the trials werecarried out in a C6H / MeOH (9:1) solvent mixture (10 mL) in the presence of 3equivalents of PS at room temperature (—‘ 20 °C). Use of methanol was essential asthe alkene substrates used are insoluble in benzene. The experiments above 1 atmH2 (14.7 psi) were carried out in a 30-50 mL steel bomb, and the work-up andanalysis of the hydrogenation products were carried out according to proceduresdescribed under the Experimental Sections 2.4.2 and 2.4.3. The studies wereconducted on (Z)-a-acetamidocinnaniic acid and tiglic acid substrates whichundergo reduction as shown in Figure 4.19, and the results obtained aresummarized in Table 4.7.Interaction of 7a with H2 (3-5 atm) in theC6H/MeOH medium in thepresence of PS in the absence of substrate resulted in formation of thehydridochloro complex 5a, which is thought to be the catalytic species formedunder the hydrogenation conditions. The prochiral substrates were nothydrogenated at 1 atm of H2, whereas styrene was reduced under similarconditions in DMA. This is consistent with results seen with many other catalyticsystems, where substituted olefms are reduced less efficiently than the terminal138NHCOCH3_______POOHHCOOH + H2 O—cH2H-co3N-acetyl-[R(-) or S(+)]-phenylalanine[cx] = ±47.8°(c=1.O1,C2H5OHH -COOH_____+ H2 ‘ CH32H-COOHH3C CH3 *R(-) or S(+)-2-methylbutyric acid[cx] = t 19 ° (neat)bFigure 4.19: Prochiral alkenes used in hydrogenation studies and their reductionproducts. The specific rotations given are those for the pure enantiomers; a measured in the present work on a sample obtained fromAldrich (reported value in Aldrich = ± 40.00, c = 1, CH3O )b Aldrich hand-book of fme chemicals (1993).Table 4.7: Asymmetric hydrogenation of prochiral alkenes withRuC13(AMPHOS)(PPh),7a.a,bSubstrate H2 pressure % Conversion % e.e.psi (atm)(Z)-ct-acetamidocinnaniic acid 1000 (68) 100 6250 (17) 100 4125 (8.5) 83 014.7(1) 0 —tiglic acid 250 (17) 100 0125(8.5) 38 014.7(1) 0 —a All the results are reported for a 24 h reaction time period.b Conditions: [Ru] = 1.5 mM, [alkene] = 7.5 x 10-i M, [PS] = 4.50 mM,in6HIMeOH (9:1) solvent mixture (10 mL) at room temperature (— 20 °C).139ones.75 Use of higher H2 pressures (250-1000 psi) resulted in quantitativeconversion to the corresponding hydrogenation product for each of the twosubstrates investigated. However, the minimal or zero optical yields obtainedclearly show that 7a is a poor chiral catalyst precursor. Although the reason forthis is not readily apparent, it could be due to a non-rigidity of the P-N chelate inthe catalytic species, as formation of a rigid chelate by the chiral ligand isimportant in effective chiral induction.76 The absence of any chiral induction inthe tiglic acid system perhaps implies that, for the acetamidocinnamic acidsubstrate, chelation through the olefmic double bond and the carbonyl of the amidegroup is important in obtaining the small optical yield (Section 1.2.2). Althoughthe results obtained from the present study are not encouraging for the use ofRu(AMPHOS) systems in asymmetric hydrogenation, more work on relatedsubstrates, including prochiral ketones and ketimines, and use of different reactionconditions, will help in drawing more defmite conclusions regarding the efficiencyof Ru(AMPHOS) complexes as chiral catalyst precursors.4.8 Summary of ResultsThe Ru(II) (la and ib) and Ru(III) (6a and 6b) complexes of PMA werefound to react with 1 atm of H2 at ambient temperature to form “(ri2-H)RuC1”(8a and 8b) or “Ru(H)Cl” (4a and 4b) complexes, depending on whether thereaction is carried out in the absence or presence of an added base (PS),respectively. Evidence for formation of a monohydride complex by an overallheterolytic cleavage of dthydrogen via a molecular hydrogen complex is alsopresented. The presence of an added strong base such as PS was essential in orderto observe a reaction of Ru(III)-AMPHOS complexes 7a and 7b with H2 (1 atm,140room temperature), under which conditions “Ru(H)Cl” species (5a and 5b) areformed without dissociation of the AMPHOS ligand. Based on kinetic studies ofthe reaction of 7b with H2, a mechanism, involving “Ru(H)C12”and “RuC12”intermediates, is proposed for the fonnation of the Ru(ll)-monohydride species,5b. Studies on catalytic hydrogenation of styrene using 6a, 6b, 7a, and 7bcomplexes in the presence of PS revealed that the corresponding monohydridecomplexes are probably the catalytically active species, but these are much lesseffective than the well known Ru(H)Cl(PPh3)system. The prochiral olefms (Z)a-acetamidocinnamic and tiglic acids were not reduced under 1 atm H2 with 7a ascatalyst precursor; use of higher H2 pressures (17-68 atm) gave quantitativereduction of these substrates, but with minimal chiral induction.1414.9 References - Chapter 41 Pearson, R. G. Acc. Chem. Res. 1971, 4, 152.2 James, B. R. Homogeneous Hydrogenation; Wiley: New York, 1973.3 a) James, B. R. Adv. Organomel. Chem. 1979, 17, 319.b) James, B. R. in Comprehensive Organometallic Chemistry; Wilkinson, G., Stone,F. G. A., Abel, E. W., Eds.; Pergamon Press: Oxford, 1982; Vol. 8, Chapter 51.4 Dolcetti, G.; Hoffman, N. W. Inorg. ChEm. Acta 1974, 9, 269.5 a) Collman, 3. P.; Hegedus, L. S.; Norton, J. R.; Finke, R. G. Principles ofOrganotransition Metal Chemistry; University Science Books: Mill Valley, CA,1987; p. 279.b) Crabtree, R. H. The Organometaiic Chemistry of the Transition Metals; Wiley:NewYork, 1988; p. 121.6 Burk, M.; McGrath, M. P.; Wheeler, R.; Crabtree, R. H. I Am. Chem. 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Chem. 1989, 28, 4437.b) Mezzetti, A.; Del Zotto, A.; Rigo, P.; Farnetti, E. I Chem. Soc., Dalton Trans.1991, 1525.68 Chan, Y. Ng C.; Osborn, 3. A. .1 Am. Chem. Soc. 1990, 112, 9400.69 Thorburn, I. S., M.Sc. Dissertation, The University ofBritish Columbia, Vancouver,Canada, 1980.70 a) Wang, D. K. W., Ph.D. Dissertation, The University of British Columbia,Vancouver, Canada, 1978.b) James, B. R.; Rattray, A. D.; Wang, D. K. W. J. Chem. Soc., Chem. Commun.1976, 792.71 a) Harrod, 3. F.; Ciccone, S.; Halpern, J. Can. I Chem. 1961, 39, 1372.b) Hui, B. C.; James, B. R. Can. I Chem. 1974, 52, 348.72 Bennett, M. A.; Ennett, J. P. Inorg. Chim. Acta 1992, 198-200, 583, and referencestherein.73 Barnett, K. W.; Pollmann, T. G. I Organomet. Chem. 1974, 69, 413.74 Markham, L. D., Ph.D. Dissertation, The University of British Columbia,Vancouver, Canada, 1973.75 Reference 5a, Chapter 10.76 a) Kagan, H. B. in Comprehensive Organometallic Chemistry; Wilkinson, G., Ed.;Pergamon Press: Oxford, 1982; Vol. 8, Chapter 53.b) Morrison, 3. D., Ed.; Asymmetric Synthesis; Academic Press: New York, 1985;Vol. 5.c) Bosnich, B. Ed., Asymmetric Catalysis; Martinus Nijhoff Publishers: Dordrecht,1986.148Chapter 5149Reactions of Dichloro(aminophosphine)(trisalkyiphosphine) Complexes of Ruthenium(lI) with SmallMolecules5.1 IntroductionOne of the important aspects of coordination chemistry is the binding andactivation of small, naturally occurring molecules (“activation” is of general useand implies coordination of the small molecule in attempts to promote itsreactivity). Provided a proper choice of electronic and steric factors is made inselecting the transition metal complexes for such reactions, subsequentcoordination of small molecules can lead to their activation. The primerequirement of a transition metal complex to be used in such reactions iscoordinative unsaturation, which may occur in the precursor complex itself or in aspecies generated in solution from the precursor complex via a ligand dissociationreaction. Hence, coordinatively unsaturated, 1 6-electron, five-coordinate Ru(II)complexes would be good candidates for the study of such reactions. Althoughcomplexes of this form [RuCI2(PR3),1RuCI2(P-P)(PR3),1RuC12(P-N)(PR3)(PN = PPFA, iso-PFA)2]have been well studied in terms of the activation ofdihydrogen (both stoichiometnc and catalytic), little attention has been paid totheir coordinative unsaturation and coordinative reactivity. Hence, the primarygoal of the work described in this Chapter is to study the coordinative reactivity ofthe analogous ruthemum(II) complexes generated in the present work,[RuC12(PMA)(PR3),(R = Ph, la; p-tolyl, ib), and RuCl(PAN)(P(p-toly1)3),2,]toward a series of small molecules. The inability to obtain a pure complex of theform RuC12(AMPHOS)(PR3)(see Section 2.2.2.4) thwarted such studies withRu(II)-AMPHOS complexes.150The small molecules employed in the present study include N2, 02, CO,C02, HS, SO2,H20, alcohols (CH3OH) and thiols (CH3C2SH), all of whichcan donate an electron pair and form a bond with the central metal, thus attainingan 1 8-electron coordinatively saturated complex. Although the type of such smallmolecules with similar donor reactivity is numerous, the choice of the moleculeslisted above, specially H2S, SO2,C02,N2, and 02 was based on current interestin their activation, and the complexity of the coordination chemistry exhibited bythem.For example, in recent years there has been a growing interest in thereaction ofH2S with transition metal complexes, which stems from the importanceof metal sulfur complexes in industrial and biological systems. The interaction ofH2S, HS, RS-, and S2 with transition metals is commonly found in nature, in theformation of ores, in the biological sulfur cycles, as well as in [MxS3] clustersfound in active centers of redox enzymes like ferredoxins or mtrogenases.3Hence,studies on transition metal complexes with such sulfur ligands may serve as thebasis for better understanding of these metalloenzymes.4Also, the interaction oftransition metal complexes with H2S is important in hydrodesulfurizationcatalysis,5 and in potential routes to the recovery of H2 from H2S.6 Despite theindustrial7 and biological3’8importance of H2S gas, research into its interactionwith transition metal complexes is not well developed. This situation is in markedcontrast to the vast amount of work devoted to the coordination chemistry of theaquo complexes.9 Although H2S reacts with many transition metal complexes,isolation of metal complexes containing H2S ligands is especially challenging, andin fact only very recently was the first H2S complex characterizedcrystallographically.’° Metal complexes of H2S and SH ligands easily undergodeprotonation reactions, and are therefore less stable (see Section 5.2.2.1).151Consequently there are many examples of complexes with SR and SR2 as ligandsand fewer examples of complexes with H2S and SH- as ligands. Hence, it was ofinterest to study the reactivity of the Ru(II)-PN complexes, la, ib, and 2, withH2S, and compare the results with those obtained for reactions with H20, thiols,and alcohols.Interest in the coordination chemistry of SO2 has been increasing, particularly in view of associated environmental hazards of the gas. Large quantities ofthis pollutant are currently released into the atmosphere from industrial sources,including the smelting of ores, and the combustion of coal, and this spurs studiesinto potential “SO-fixing” reactions.11 Thus transition metal complexescontaining SO2 ligands are of great interest as possible intennediates in theremoval of SO2 from industrial and automobile effluents, and from organicsulfonyl compounds (desulfonation reactions).’2Research on transition metal dinitrogen complexes has been enormouslystimulated13 since the initial report of the first dinitrogen complex [(H3N)5Ru-N2]+.14 The discovery was greeted with considerable acclaim, due to thepostulated initial metal-dinitrogen binding process in nitrogenases;’5nitrogenasescatalyze the reduction of N2 to NH3, and produce the major source of fixednitrogen in nature. Thus, research on transition metal dinitrogen complexes isdirected towards a better understanding of these enzymes, and attaining catalyticnitrogen fixation. One key step in such reactions is obtaining a metal-N2 complex,with an appropriately activated dinitrogen; the initial bonding can be achieved byfine tuning of the steric and electronic factors within the metal complex.’31525.2 Reactions of RuCI2(PMA)(PR3),Ia and Ib, with small molecules5.2.1 Reactions of la and lb with 1120The H20 adducts of the title complexes were prepared En stu in an NMRscale experiment by adding approximately an equivalent amount of H20 toCDCI3 solutions containing the precursor ruthemum(ll) complexes. The greencolor of the solution changed immediately to olive-green and quantitativeconversion to the H20 adduct, 9, (Equation 5.1) was evident from the 31P{1H}NMR spectrum of the resulting solution, the spectrum at ambient temperatureconsisting of an AX spin pattern. NMR data for (9a) and (9b) are shown in Table5.1, and the corresponding spectrum of (9a) in d8-toluene is shown in Figure 5.1.RuC12(PMA)PR3)+ H20 CDC1 PaiCl(PMA)(PRXOH)(1) (9)laRPh 9aR=Phlb R =p-tolyl 9b R =p-to)yI (51)Compared to the precursor five-coordinate ruthenium complexes, the sixcoordinate H20 adducts show considerable change in the chemical shift of A,which is assigned to the aminophosphine (see Section 5.2.2). The change in thechemical shift of B is not significant. These data indicate that the H20 ligand iscoordinated trans to the phosphorus arm of the aminophosphine ligand. The 2Jppvalues show a marginal increase from those of five-coordinate precursorcomplexes, and are still in the range for cis-phosphines.’6153Table 5.1: 3lP{1H} NMR data (121.4 MHz, d8-toluene, 20 °C) for thecomplexesRuC12(PMA)(PR3)(0H,9. The valuesin brackets are for the corresponding precursor complex, 1.Complex, R= 6A ppm ppm 2J&j, Hz9a, Ph 69.92 (89.36) 53.88 (54.02) 38.85 (36.78)9b,p-tolyl 71.47 (89.84) 53.27 (52.63) 38.73 (36.97)The 1H NMR spectrum of the complex 9a (Figure 5.2) is consistent withthe proposed structure. The resonance due to coordinated water is seen as a broadsignal at 2.52 ppm (2H), and is absent in the corresponding D20 adduct. The peakat 2.99 ppm (6H) consists of the N-CH3 resonance of the aininophosphine, andshows little variation in the chemical shift compared to that of the precursor five-coordinate complex (3.03 ppm, 6H). The spectrum of 9b (300 MHz, in d8-toluene)consists of peaks at & 1.90 (2H, coordinated H20), 2.04 (911, CH3 of p-tolyl),3.03 (6H, N(CH3)2 and 6.70-7.80 (Ph protons). These values differ onlymarginally from the chemical shifts of the precursor complex lb (300 MHz, in dtoluene) which are at 2.00 (9H, CH3 ofp-tolyl), 3.07 (6H, N(CH3)2and 6.7- 7.7(Ph protons).The IR spectrum of 9a (CHC13 solution, in 0.1 mm KBr cell) consists of amedium intensity broad peak at 3470 cm1 and a medium intensity relatively15431P{1H} NMR spectrum (121.4 MHz, 20°C) of in situ generatedRuC12(PMA)(PPh)(0H,9a, in d8-toluene.Figure 5.2: 1H NMR spectrum (300 MHz, 20 °C) of in situ generatedRuCI(PMA)(PPh3)(0H,9a, in d8-toluene.goFigure 5.1:-N(Me)2greasecoordinated H20solvent111 I hlhhuhlhl If ‘‘11111111111111 11111IllIlIf 111171 (‘‘fIll 171 I h1f 11111111flI IB 7 6 5 4 3 2 IPPM 0155sharper peak at 1739 cm assignable to the stretching v(OH), and bending ö(OH)vibrations of coordinated water, respectively; the corresponding frequencies ofunbound water appear at 3603 and 1604 cm, respectively.The solid state structure of the water adduct (9b) (Figure 5.3), determinedby an X-ray diffraction study, revealed a distorted octahedral geometly, withtrans-chlorides, and aquo Iigand coordinated to the Ru center trans toanilnophosphine. The structural data confirmed the structure proposed by solutionNMR studies. The structural parameters are listed in the Appendix (A-4), andsome selected bond distances and angles are given in Tables 5.2. and 5.3,respectively. Corresponding bond distances of the structurally characterized five-coordinate ruthenium(II) complex lb are also listed separately in Table 5.4 forcomparison.The Ru(1)-P(1, 2) bond lengths of 2.220 and 2.284 A (average 2.252 A) arewithin the normal range found for Ru(JI) tertiary phosphine complexes.5bl7lSThesignificant increase in the Ru(1)-P(1) bond length in forming the water adduct 9b(Table 5.4) clearly demonstrates the trans influence of the H20 ligand. The Ru(1)-0(1) distance of 2.252(4) A is significantly longer than those in some aquo-Ru(ll)complexes (e.g.: [RuH(HO)(CO)(PPh3J,2.15 A;’ [Cp*Ru(CO)2(0H)]+,2.171 A;20 [Ru(HO)6J,2.12221 implying a relatively weaker interactionprobably due to the trans effect of the phosphine ligand. The aquo ligand is seen tobe hydrogen-bonded intramolecularly to the two chloride ligands as depicted bythe nonbonded distances of 2.84(6) and 2.79(7) A for H(1)...Cl(l) andH(2). . . Cl(2), respectively, which are less than the van der Waal contact for the twoatoms (3.00 A).22 The presence of H-bonding is also revealed by the markedly156C4C5HiC29Figure 5.3: An ORTEP diagram ofRuC12(PMA)(P(p-tolyl)3)(0H,9b.C6 CISC14Ci6C3cigcliC30CiTC18HZC40C39C38C33 C38C3ZC37C31C41C34157Table 5.2: Selected bond lengths (A) for RuCl(PMA)(P(p-toly1)3)(OH),9b, with estimated standard deviations in parentheses.Bond Length (A) Bond Length (A)Ru(1)-Cl(1) 2.418(1) P(2)-C(28) 1.861(4)Ru(1)-Cl(2) 2.3 85(1) P(2)-C(35) 1.831(4)Ru(1)-P(1) 2.220(1) N(1)-C(2) 1.474(5)Ru(1)-P(2) 2.284(1) N(1)-C(19) 1.477(5)Ru( 1)-N( 1) 2.326(4) N( 1)-C(20) 1.475(5)Ru(1)-O(1) 2.252(4) O(i)-H(1) 0.96(6)P( 1)-C( 1) 1.830(4) O( 1)-H(2) 0.69(6)P(1)-C(7) 1.822(4) H(1)...Cl(1) 2.84(6)P(1)-C(13) 1.859(4) H(2)...Cl(2) 2.79(7)P(2)-C(21) 1.835(4)non-linear Cl(1)-Ru(1)-Cl(2) angle 162.91(4) of the chlorides which are benttowards the aquo ligand. Such hydrogen-bonding, together with crystal packingeffects, could be contributing factors to the observed difference in the 0-H bonddistances of the aquo ligand (O(1)-H(1) vs. 0(2)-H(2)), and the Ru-Cl bonds(Ru(1)-Cl(1) vs. Ru(1)-C1(2)).158Table 5.3: Selected bond angles (deg) forRuC12(PMA)(P(p-tolyl)3)(0H,9b,with estimated standard deviations in parentheses.Bonds Angle (deg) Bonds Angle (deg)Cl( 1)-Ru( 1 )-Cl(2) 162.91(4) P( 1 )-Ru( 1 )-P(2) 98.04(5)Cl(l)-Ru(l)-P(1) 90.73(4) P(1)-Ru(1)-O(1) 168.8(1)Cl( 1 )-Ru( 1 )-P(2) 96.26(5) P( 1 )-Ru( 1)-N( 1) 80.20(9)Cl(1)-Ru(1)-O(1) 82.2(1) P(2)-Ru(1)-O(1) 91.4(1)Cl(1)-Ru(1)-N(1) 83.7(1) P(2)-Ru(1)-N(1) 178.24(9)C1(2)-Ru(1)-(P1) 104.30(5) O(l)-Ru(1)-N(l) 90.3(1)C1(2)-Ru(l)-P(2) 89.74(5) O(1)..H(1)..Cl(1) 95(4)Cl(2)-Ru(1)-O(1) 81.6(1) O(1)..H(2)..Cl(2) 104(6)C1(2)-Ru( 1)-N( 1) 90.8(1)159(1)Cl Ru C1(2)PR3(2)Bond Length (A)9b lbRu(1)-Cl(1) 2.418(1) 2.387(1)Ru(1)-C1(2) 2.385(1) 2.379(1)Ru(1)-P(1) 2.220(1) 2.170(1)Ru(1)-P(2) 2.284(1) 2.290(1)Ru(1)-N(1) 2.326(4) 2.238(3)5.2.2 Reactions of la and lb with H2SWhen H2S was bubbled into a benzene (or CHC13 or CH21)solution of1, the green color of the solution changed instantaneously to red brown. The31P{1H} NMR spectrum of this solution (see below) is consistent with thepresence of a single product which is formulated as RuC12(PMA)(PR3)(SH,10(Equation 5.2). The product was isolated as a yellow powder, and the identity ofTable 5.4: Selected bond lengths (A) forRuC12(PMA)(P(p-tolyl)3,ib, andRuC12(PMA)(P(p-tolyl)3)(0H,9b, with estimated standarddeviations in parentheses.CI.— NMe2(9b) (lb)16010 was established by elemental analysis (see Section 2.2.4.3) and spectroscopicmethods (see below).RuC12(PMA)(PR3) + H2S - RuC(PMA)(PR3)(SH2(1) (10)la R=Ph lOa R=Phlb R =p-tolyl lOb R =p-tolyl (5.2)Dark red brown crystals of the H2S adduct were obtained from a THFsolution of RuCl2(PMA)(P(p-tolyl)3)(SH), lOb, by layering with an equalvolume of hexanes at room temperature. A single crystal X-ray diffraction study oflOb revealed a distorted octahedral geometry around the Ru center as shown inFigure 5.4; the chlorides are cis, and the H2S is trans to a chloride. The structuralparameters are listed in the Appendix (A-5), and some selected bond distances andbond angles are given in Tables 5.5 and 5.6, respectively. The trans bond anglesare in the range 170.00 to 174.6 0 and the cis angles range from 8 1.3° to 94.3°. Thechelate bite angle, P(1)-Ru(1)-N(1) of 81.3(3)°, shows little deviation from that ofthe five-coordinate complex, RuCl2(PMA)(P(,p-tolyl)3Ib, (81.81(8)°), and isalso in the range found for the H20 adduct, 9b (80.20(9)°).As shown in Figure 5.4, only one H atom of the coordinated H2S ligandwas located, which tends to suggest the alternate formulation of a Ru(III)-mercaptocomplex. However, the structural parameters (Ru-Cl and Ru-S distances in Ru(II)vs. Ru(IIl) complexes), spectroscopic evidence (NMR), and reversible solutionbehavior (see below) unambigously show the complex to be the Ru(II)-H2Sadduct. The Ru-Cl bond distances (average value of 2.449 A) are comparable to161C4C5C40cliC21jgi4C3C41clidoC9C17C14C15C16C27C33C38C37C20 C34C35C24C22C36C23C39C25An ORTEP diagram of RUCI2(PMA)( t01y1)3XSM2) lOb.162those of the analogous Ru(II)-H20complex, 9b (average 2.402 A). However, theyare distinctly longer than the Ru-Cl bond distances in RuCI3(PMA)(PPh),6a,(average 2.354 A) (Section 3.4.2). The Ru-S bond length of 2.330(4) A iscomparable to that of Sellmann’s complex, Ru(SH2)(PPh3’4’), (2.399(5) A)(Figure 5.5), which is the only other structurally characterized H2S complexreported prior to this thesis work.1° Also, the Ru-S bond length in lOb issignificantly shorter than that of the terminal mercapto complexes reported in theliterature23’4(average Ru-SH bond length 2.46 A), again supporting the ‘Ru(II)SH2’ formulation. In lOb, the length of the single S-H bond located (1.25 A) isshorter than that found in gaseous H2S (1.33 A),25 and is comparable to that ofTable 5.5: Selected bond lengths (A) forRuCl2(PMA)(P(p-toly1)3)(SH),lOb, with estimated standard deviations in parentheses.Bond Length (A) Bond Length (A)Ru(1)-Cl(1) 2.469(4) P(1)-C(13) 1.85(1)Ru(1)-C1(2) 2.429(3) P(2)-C( 19) 1.85(1)Ru( 1 )-P( 1) 2.256(4) P(2)-C(26) 1.84(1)Ru( 1)-P(2) 2.304(3) P(2)-C(33) 1.85(1)Ru(1)-N(1) 2.37(10) N(1)-C(2) 1.45(1)Ru(1)-S(1) 2.330(4) N(l)-C(40) 1.48(2)P(1)—C(1) 1.84(1) N(1)—C(41) 1.5 1(2)P(1)-C(7) 1.81(1) S(1)-H(l) 1.25163C13C12C14C 16C23Figure 5.5: Top: an ORTEP diagram of [Ru(PPh3X’S4tXSH2)].THF (THF and Hatoms are omitted except of H(5A) and H(5b). Bottom: associationof enantiomers via S-H S bridges.’0C24164Table 5.6: Selected bond angles (deg) for RuCl(PMA)(P(p-tolyl)3)(SH2,lOb, with estimated standard deviations in parentheses.Bonds Angle (deg) Bonds Angle (deg)Cl( 1 )-Ru( 1 )-Cl(2) 94.3(1) N( 1 )-Ru( 1)-P(2) 175.9(3)Cl(1)-Ru(1)-N(1) 89.1(3) S(1)-Ru(1)-P(1) 93.8(1)C1(1)-Ru(1)-S(1) 83.1(1) S(1)-Ru(1)-P(2) 92.7(1)C1(1)-Ru(1)-P(2) 88.0(1) S(1)-Ru(1)-C1(2) 174.6(1)Cl(1)—Ru(1)-P(1) 170.0(1) P(1)-Ru(1)-P(2) 101.7(1)N(1)-Ru(1)-S(1) 89.8(2) P(1)-Ru(1)-Cl(2) 88.0(1)N( 1)-Ru(1)-P( 1) 81.3(3) P(2)-Ru( 1)-C1(2) 91.9(1)N( 1)-Ru( 1 )-C1(2) 85.4(2) Ru( 1)-S( 1)-H( 1) 124.2Sellmann’s H2S complex, where both H atoms of the H25 ligand were located withan average bond length of 1.20 A. The Ru(1)-S(1)-H(1) angle 124.2° in lOb islarger than the values found for the Ru-S-H angles in Sellmann’s complex (Figure5.5, Ru(1)-S(5)-H(5a) = 102° and Ru(l)-S(5)-H(5b) = 1210), where H-bondingeffects are evident.165Table 5.7: 31P{1H} NMR data (121.4 MHz, CDC13 20 °C for thecomplexesRuC12(PMA)(PR3)(SH10. The values in bracketsare for the corresponding precursor complex, 1.Complex, R= 0A ppm 3x ppm 2Jp, }{zlOa, Ph 54.50 (85.17) 48.41 (52.55) 30.11 (36.67)lOb, p-tolyl 55.90 (87.22) 46.50 (50.51) 30.30 (36.72)The NMR spectra of lOa and lOb provide added proof for the Ru(II)-SH2formulation; a Ru(III)-SH complex would be paramagnetic and thus not givewell resolved spectra as obtained for lOa and lOb. The ambient temperature31P{1H} NMR spectra of lOa, and lOb, consist of an AX spin pattern, and the2Jpp values for each are within the range found for cis-phosphines.16 Thespectrum of lOb in CDCI3 is shown in Figure 5.6; the data are shown in Table 5.7and show little variation between the phenyl and the p-tolyl analogue. However,the chemical shifts of lOa and lOb show significant change compared to those ofthe starting five-coordinate la and lb complexes . Based on the NMR data alone itis difficult to assign the 0A and ö to the particular aniinophosphine andmonodentate phosphine. However, a combined structural and solution 31P{1H}NMR shift correlation, with an inverse relation between the chemical shift and RuP bond length, may permit such an assigmnent.5b26Based on such a correlation,the 31P signal at 55.90 ppm could be assigned to the aminophosphine (Ru-P bondlength 2.256 (4) A), and that at 46.50 ppm to the P(p-tolyl)3 group (Ru-P bondlength 2.304(3) A).166-d 0’ —aFigure5.6:31P{1i-i}NMRspectrum(121.4MHz,20°C)of insitugeneratedRuCI2(PMA)(P(p-toIyI)3)(SH),1Ob,inCDCI3.In keeping with the earlier reports by Dekleva26aand Jessop et a!. 5b,26b aclear inverse relation between the 31P chemical shift and the Ru-P bond length isobserved among the structurally characterized complexes RuC12(PMA)(P(p-tolyl)3) ib, RuC12(PMA)(P(p-tolyl)0H 9b, and RuC1(PMA)(P(p-tolyl)3)(SH2) lOb (Table 5.8): the Ru-P(p-tolyl)3 bond lengths decrease in the order lOb> lb > 9b, while the 31P chemical shift show an increase in the same order. Theaminophosphine ligands also show a similar relation, where the Ru-(P-N) bondlengths vary in the order lOb > 9b> lb and the 31P chemical shifts vary in thereverse order.Table 5.8: Ru-P bond distances, and 31P{’H} NMR data (121.4 MHz,CDC13,20 °C) for RuCl(PMA)(P(p-tolyl) lb, RuCI(PMA)-(P(p-tolyl)3(OH2)9b, andRuC12(PMA)(P(p-tolyl))(SHlOb.Complex Bond Length A ö ppmRu-P(p-tolyl)39b 2.284(1) 52.10lb 2.290(1) 50.51lOb 2.304(3) 46.50Ru-(P-N)lb 2.170(1) 87.229b 2.220(1) 69.33lOb 2.256(4) 55.90168free H2Sppm 8ppmFigure 5.7: ‘H NMR spectrum (200 MHz, 20 °C)RuC1(PMA)(P(p-to1y1)3)(SH2,1 Ob,4 3of in situ generatedin CDCI3.Figure5.8: ‘H NMR spectrum (500 MHz, 20 °C) of in situ generatedRuC12(PMA)(P(p-tolyl)3)(SH,lOb, in C6D.p-tolyl CH3-N(Me)-N(Me)7 6 5 4 3 ifree H2Sp-tolyl CH3•N(Me) -N(Me)bound H2S8 7 6 5 2 1 0169The 1H NMR spectrum of lOb (200 MHz, CDC13 20 °C, Figure 5.7), isconsistent with the fonnulationRuC1(PMA)(P(p-tolyl)3)(SH.The broad signallocated at 0.95 ppm, which integrates to 2H, is assigned to the coordinated H2S;the signal is close to the sharp peak at 0.75 ppm from free H2S. However, in C6Dthe resonance of uncoordinated H2S appears at 0.25 ppm, and that of coordinatedH2S is shifted downfield to 1.2 ppm, allowing for much better resolution (Figure5.8). These observations are similar to those reported by Sellmann et a!. where abroad signal at 1.96 ppm and a sharp one at 1.00 ppm (CD2C1ITHF-d81:2) wereassigned to coordinated and free H2S, respectively.’0The resonances of the twoN-CH3 groups of the aminophosphine ligand are observed as two singlets of 3Heach at 3.41, and 3.05 ppm (CDC13,Figure 5.7). This contrasts to the single peakobtained for the N-CH3 groups of the H20 and the CH3O adducts (Figsures 5.2and 5.12, see Section 5.2.5). The resonances of the CH3 groups of the p-tolylphosphine are observed as a singlet (9H) at 2.15 ppm and those of the aromaticprotons of the aminophosphine and p-tolyl phosphine are seen as multiplets spreadover the 6.35-8.10 ppm region. The 1H NMR spectrum of lOa (300 MHz, inC6D) consists of peaks at ö: 1.05 (br, 2H, coordinated H2S), 2.97 (s, 3H,N-CH3), 3.66 (s, 3H, N-CH3), 6.50-8.40 (Ph protons).The presence of the H2S ligand in lOa and lOb is also shown by theJR stretches at 2595 and 2490 cm1 (CHC13 solution, in 0.1 mm KBr cell)assigned to v(SH), which are at considerably lower frequencies than those for H2Sgas (2615 and 2628 cml),27 probably indicating some lengthening of the S-Hbonds upon coordination to ruthenium. in Seilmann’s H2S complex, much lowerV(SH) values of 2410 and 2290 cm1(KBr) were attributed to the presence ofS-H.... S and S-H...0 hydrogen bridges, as revealed from the molecular structure170(Figure 5.5).’° In H2S complexes that are not H-bridged, V(SH) stretches appear inthe range 2590 to 2510 cml.28,36,37,38The reaction of la, and of ib, with H2S was also examined in the solidstate. At ambient temperature, lb reacts with H2S in a rapid reaction, with anaccompanying color change from green to yellow in few seconds. Microanalyticaldata of the yellow product lOb agreed well with the formulaC41H43NSC12PRu(Section 2.2.4.3), and the IR spectrum (Nujol mull) showed V(SH) stretches at2506 and 2466 cm1. Surprisingly, complex la did not react with H2S gas undersimilar conditions. A solid state reaction for the complex [Ir(H)(MeCO-(PPh3)2]BF4with H2S was briefly reported by Crabtree et a!. in 1983,29 wherethe resulting product was formulated as the bis(H2S) adduct [Ir(H)2(HS)-(PPh3)2]BF4,solely based on the chemical shift difference of the hydride ligandin the precursor and the fmal product! The H2S resonances were not observed inthe NMR spectrum (in CD21)and the complex could not be characterized byany other method due its instability in the absence of an H2S atmosphere. TheH2S adducts lOa and lOb obtained in the present study were fairly stable as solidsunder argon and did not lose H2S under vacuum over a period of 24 h at ambienttemperature. They are air-sensitive and turned green and then black when exposedto air.When the H25 adduct lOb was dissolved in C6D under argon, theexistence of both the five-coordinate complex, ib, and the H2S adduct was evidentfrom the 31P{1H} and ‘H NMR spectra (Figures 5.9 and 5.10). The value of theequilibrium constant K = 3.6 x 102 M for the reaction lOb lb + H25 iscalculated from the NMR integrations. Further, a spectrum similar to that shown in171lObr—11 I I I I I I I IF I I I 1 I Iab 70 60 50 40 30 20 PPMFigure 5.9: 31P{1H} NMR spectrum (121.4 MHz, 20°C) of isolatedRuC12(PMA)(P(p-toly1))(SH), lOb, dissolved in C6D underargon.•N(Me)2 (Ib)p-tolyl CH3 (lOb)Figure 5.10: 1H NMR spectrum (300 MHz, 20 °C) of isolatedRuCl(PMA)(P(p-to1yl)3) SH2,lOb, dissolved in C6D underargon.lblbI ObI 111 :gop-tolyl CH3 (Ib)9 8 7 6172Figure 5.9, consisting of both lb and lOb was obtained, when the in-situ generatedH2S adduct in solution (under H2S atmosphere) was subjected briefly to vacuumand the solution examined by NMR spectroscopy. When this mixture was resubjected to an H2S atmosphere, lOb was the only species seen in solution. Theseobservations clearly demonstrate that the reaction 5.2 is a reversible equilibriumwhich favors full formation of the H2S adduct under an H2S atmosphere. Thesefindings provide added evidence for the Ru(II)-H2Sformulation.5.2.2.1 A brief summary of H2S complexesAs mentioned briefly in the Introduction (Section 5.1), the most demandingtask in studies involving H2S coordination chemistry is the isolation of metal-H2Scomplexes; this difficulty stems from the subsequent S-H bond cleavage reactionsof the H2S ligand upon coordination. The instability of the H2S complexes, interms of S-H bond cleavage, is exemplified by the numerous examples reported inthe literature. The reactions with H2S can be categorized into two fundamentalclasses based on the type of product formed.(A) Reactions of H2S with metal complexes, leading to the formation ofterminal (M-SH) or M(H)(SH), or bridging mercapto (M-SH-M)complexes.24’301,32(B) Reactions ofH2S with metal complexes, leading to the formation ofterminal (M=S) or bridging sulphide (M-S-M) comp1exes.32b334173Thus, hydridomercapto complexes M(H)(SH), mercapto complexes (M-SH), bismercapto complexes M(SH)2, and sulfides M-S, are the products commonlyobtained from transition metaIJH2S reactions.For a long time, ‘thiohydrates’ were regarded as the only ‘H2S complexes’which could be isolated,35 and these were formed by addition of H2S to Lewisacids in liquid hydrogen sulfide: (e.g. AIC13.H2Sand TiC14.nH2S,n = 1, 2). Suchspecies decompose below room temperature. Although Morelli et a!. providedsome evidence in 1967 for the H2S intermediate Pt(PPh3)2(HS), en route to theformation ofPt(PPh3)2(H)(SH),0athe first isolable H2S complexes were reportedin 1976. The two Ru(II) complexes [Ru(NH35(H2S)]and [Ru(NH3)4(isomco-tinamide)(H2S)],reported by Kuehn and Taube,9 were obtained as BF4 saltsby direct displacement of H20 by H2S in aqueous solution, but the complexesdecomposed in the solid state in the absence of an H2S atmosphere and there wasno direct evidence for the presence of coordinated H2S.9 The W(CO)5(H2S)complex reported by Herberhold and Suss28 was obtained by bubbling H2Sthrough a solution of W(CO)6 in pentane, while photolyzing the reaction mixture.The tungsten complex showed greater stability, and decomposed at 90 °C undernitrogen in the solid state, but in solution (benzene, ether, or acetone) the complexdecomposed at room temperature;28 the characterization of the complex waslimited to JR data.Continuing research in the H2S area led to the suggested formulation ofseveral other H2S complexes, as shown in the following examples:174H2S[Mn(CO)4(0H2)(PPh3]BF [Mn(CO)4(PPh3)(SH2]BF + H20CH21 (5.3)(ref 36)H2S[Ir(H)2(MeCOPPh3)]BF4 [Ir(H)2HS)(PPh3)]BF4+ 2 MeCO(5.4)(ref. 29)H2SCpM(CO)3X - [CpM(CO)3(SH2)]XX BF4,AsF6M = Mo W (5.5)(ref 37)H2SRe(CO)5BF4 [Re(CO)5(SH2)]BF4 (5.6)(ref 38)H2SCpRu(PPh3)2(OTf) [CpRu(PPh3)2(SH]OTfOTf= OSO2CF3 (57)(ref 39)In reactions (5.3) to (5.7), the formulations of the M-SH2 complexes were basedon spectroscopic evidence, and none was structurally characterized. Moreover,they were unstable, and none were chemically analyzed within an acceptable errorlimit, leaving in all cases the formulation in doubt.175The first structurally characterized H2S complex was reported only recentlyby Sellmann et a!. in 1991 (Equation 5.8);1° the product was characterized by Xray analysis and spectroscopy (NMR, IR and mass spectroscopy), and in fact priorto this thesis work was the only well characterized H2S complex isolated.Although the THF-free H2S adduct was highly labile (regarding loss ofH2S), theTHF solvate was stable at 25 °C, losing H2S only slowly in vacuum. However,1) HS(p, -70 °Ci/x [Ru(PPh3)(’S41J Ru(PPh3)(’S4’)(SH2.THF2)THF -S42 1,2-bis[(2-nrcaptopheny1)thioJethane(2-) 4—. s s—(5.8)when the reaction with [Ru(PPh3)’S4’]and gaseous hydrogen sulfide was carriedout at room temperature in THF, a bridging sulfido complex of the form[Ru(PPh3)’S4’]2(p-S was formed, depicting a more common reactivity of H2Sgas with transition metal complexes. In contrast, in the present thesis work, thereaction of H2S gas at room temperature with the five-coordinate complexRuC12(PMA)(P(p-tolyl)3),in the solid state or solution, led to the formation of astable H2S complex, which was fully characterized by chemical, spectroscopic,and structural methods.5.2.3 Reactions of la and lb with MethanolA rapid reaction, complete within seconds, was observed when 2-3equivalents ofCH3O were added to solutions of la or lb in benzene or CH21,176with an accompanying color change from green to red. The 31P{1H} NMRspectrum of the in situ reaction mixture of la (or lb) in CD21 (Figure 5.11)consists of a AX spin pattern, with chemical shifts and 3AX values different tothose of la (lb), indicating fonnation of a single product, which is formulated asthe CH3O adductRuC12(PMA)(PR3)(CHOH)11 (Equation 5.9). The 31P{1H}NMR data of ha and llb are listed in Table 5.9, the 2Jpp values indicating cisphosphine ligands.’6The corresponding values of la and lb are listed in brackets.Table 5.9: 31P{1H} NMR data (121.4 MHz, 20 °C) for the complexesRuC12(PMA)(PR)(CHOH),hi, prepared in situ in CD2I;athe values in brackets are for the corresponding precursorcomplex, 1.Complex, R=ppm oX, ppm 2AX, Hzha, Ph 69.97 (86.68) 51.17 (52.56) 39.06 (36.18)ilb,p-tolyl 66.57 (88.19) 52.22 (50.54) 38.88 (36.73)a Based on the discussion in Section 5.2.2, A and X are assigned as thephosphorus atoms of the PMA and PR3 ligands, respectively.The 1 NMR spectrum of the in situ reaction mixture of 11 a (Figure 5.12)consists of a broad peak at 1.38 ppm assignable to the CH3 resonance of177I hull 1111111 I hlIllIllhlIllIlil 1111160 60 40 2OPPM 0Figure 5.11: 31P{1H} NMR spectrum (121.4 MHz, 20°C) of in situ generatedRuC12(PMA)(PPh)(CHOH),I la, in CD2I.free MeOHFigure 5.12: ‘H NMR spectrum (300 MHz, 20 °C) of in situ generatedRuC12(PMA)(PPh3)(CHOH ,ha, in CD21.I I iI I’11-N(CH3)2bound MeOHgreaseI l I I I I I I I I 141 I I I I I I I I I I I I I I I I l 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 liii I I I I I178C6H or CH21RuCI2(PMA)(PR3) + CH3O RuC(PMAXPR3)(CHOH)(1) (11)la R=Ph ha R=Phlb R = p-tolyl 11 b R = p-tolyl (59)coordinated methanol. The absence of such a signal in the NMR spectrum of theCD3O analogue further confirmed the formulation. The resonance due touncoordinated CH3O is seen as a singlet at 3.32 ppm and that due to the N-CH3of the anunophosphine is located at 3.10 ppm (6H) (Figure 5.12). As observed forthe H20 adduct (Section 5.2.1), the resonance of the -N(C1-13)2moiety of 1 laappears as a single peak (3.10 ppm, see Section 5.2.5 for explanation). The NMRspectrum of the in situ formed 11 b (in CDC13)consists of resonances at & 1.63 (s,coordinated CH3OH), 2.22 (s, 9H, CH3 ofp-tolyl), 2.96 (s, 6H, -N(CH3)2,3.38(uncoordinated CH3O ) and 6.9-7.7 (Ph protons).The colors of the solutions of the in-situ generated methanol adducts are redto red-brown, but dissolution of the isolated orange-red solids of ha and libresulted in green solutions. The NMR spectrum of the resulting solution from I haconsists of peaks at a position intermediate between that of the precursor five-coordinate complex and that of the in situ formed methanol adduct. Thus, the 31PNMR spectrum (121.4 MHz, ha dissolved in CDC13)consists of resonances at79.30 (d) and 52.98 (d) ppm with a 2Jpp value of 37. 2 Hz. When compared withthe data in Table 5.9, even after allowing ± 2 ppm for a solvent effect on thechemical shift, the peak at 79.30 ppm is distinctly different from that of la andthat of in situ formed ha; the shift at 52.98. ppm shows little deviation. Theobserved variation in shift could be due to exchange of methanol between the179coordinated and free states. As methanol is believed to be coordinated trans to theP-arm of the anilnophosphine chelate (see Section 5.2.5 and Figure 5.15), such anexchange would significantly effect the chemical shift of the aminophosphine (öpJ(see the footnote in Table 5.9).The 1H NMR spectrum of 1 la (dissolved in CDC13)consists of resonancesat & 2.28 (coordinated CH3OH), 3.17 (-N(CH3)2,3.30 (free CH3OH), and 6.9-7.8 (Ph protons). Again, it is clear that the chemical shifts for coordinated and freeMeOH are different, and appear closer together = 1.02 ppm) than in theMeOH adduct formed in situ (zS. = 1.71 ppm) with an excess of MeOH in CDC136: 1.65 (coordinated MeOH), 2.95(-N(CH3,3.36 (free MeOH)]. The N-methylresonance of the MeOH adduct (dissolved in CDC13) at 3.17 ppm is also at aposition intermediate between that of the in situ formed MeOH adduct (2.95 ppm,in CDCI3) and that of the precursor complex Ia (3.22 ppm, in CDC13). TheseNMR observations show that the exchange of MeOH between the coordinated andfree state is dependent on the concentration of free MeOH in the medium.5.2.4 Reaction of Ia with EthanethiolWhen RuC12(PMA)(PPh3)la was reacted with 2-3 equivalents of CH3-CH2S , a rapid reaction was observed, with a green to red color change similar tothat of the CH3O reaction. The 31P{1H} NMR spectrum of the in situ reactionmixture is consistent with the presence of two products, each with an AX spinpattern (Figure 5.13); the 2Jpp values are within the range for cis-phosphines.’6The major product (ca. 80%) with 31P resonances at 56.27 and 47.85 ppm with a180cis-12cis-1200trans-I 2TitICCIrTT1yrrrr-r-r-rrri-TF11rFT1—rTT-1-—[rT1rLrrriCi111i60706050403020PPMFigure5.13:31P{1H}NMRspectrum(121.4MHz,20°C)ofinsitugeneratedRUCI2(PMA)(PPh3)(EtSH),12,inC6D.CFI3H2SHFigure5.14:111 NMRspectrum(300 MHz,20°C)ofinsitugeneratedRuCI2(PMA)(PPh3)(EtSH),12, inC6D;*-N(Me)ofcis-12,x=-N(Me)2ofirans-12.00 1%)*‘“T‘‘•Tr_rt—rrrr-IIf*CFI3H2SHIIIIIIrpp,42Jpp value of 29.74 Hz is formulated as the ethanethiol adduct with cis-chiorides,cis-RuC1(PMA)(PPh3)(EtSH) 12 (Equation 5.10). The minor product (ca. 20%)(55.56 (d), 51.62 (d) ppm, 2Jpp 35.70 Hz) is assigned as an isomer of 12 withtrans-chlorides (see Section 5.2.5).C6F1RuC12(PMA)(PPh3)+ CH32S RiiCI2(PMAXPPh3XCHCHS )(la) (12)(5.10)The ‘H NMR spectrum (300 MHz, C6D 20 °C) of 12 (Figure 5.14)consists of two singlets of equal intensity at 3.74 and 3.18 ppm, assignable to theN-CH3 resonances of aminophosphine ligand of the major product (cis-12), andthe single peak of lesser intensity at 3.06 ppm assignable to the N-CH3 resonanceof the minor product (irans-12). The rationale behind such assignments isexplained in Section 5.2.5. Assignment of the rest of the signals in the 1H NMRspectrum of 12 is made difficult by the presence of uncoordinated EtSH in thereaction mixture; the ethanethiol resonances appear at 2.08 (in, 2H), 1.06 (t, 1H),and 0.95 (t, 3H) ppm, and overlap with some of the resonances of coordinatedethanethiol. The upfield region of the 1H NMR spectrum above 0 ppm did notcontain any signals, confirming the absence of any hydrides; oxidative addition ofRSH resulting in M(H)(SR) species is common for thiol reactions with transitionmetal complexes.24’401No attempts were made to isolate compound 12 because of the obnoxioussmell of EtSH; 12 was made only in situ in order to compare its extent of183formation and spectral characteristics (3 1P{1H} and ‘H NMR spectra) with thoseof the H20, CH3O , and H2S adducts of la.5.2.5 Correlation Between the Molecular Structure and the N-CH31H NMR Resonances of Complexes 1, 9, and 10In complexes 1, 9, 10, 11, and 12, an interesting trend is observed for the1H NMR resonances of the aminophosphine ligand. In the 111 NMR spectra of thestructurally characterized trans-RuCl(PMA)(P(p-tolyl)3) ib, and trans-RuC12-(PMA)(P(p-tolyl)3)(0H29b, the N-(CH3)2resonances appear as a single peak(6H), whereas in cis-RuC12(PMA)(P(,p-tolyl))(SHlOb, the N-CH3 resonancesappear as two signals of equal intensity each integrating to 3H. In light of theseobservations, a correlation between the structure and the N-methyl resonance isproposed, namely that 1H NMR spectra of the cis complexes consist of twosignals, and the spectra of the trans complexes have one signal for the N-methylresonance. Assuming that the solid state structure prevails in solution, such adifference in the NMR spectra is probably explained by the orientation of the N-methyl groups as depicted by their molecular structures. In lb and 9b, a fast ringflip of the PMA chelate (in envelope conformation) in solution, together with thetrans-dichloro arrangement (Figures 3.2 and 5.3, respectively), would render theN-methyls equivalent. However, the presence of cis-chiorides in lOb (Figure 5.4)would make the N-methyls non-equivalent, even with such a fast ring flip of thePMA chelate in solution. Such stereochemical effects on the nonequivalency ofmethyl substituents on the PMA ligand have been shown previously for cis- andtrans-[Rh(PMA)2(Y)Z] complexes where (Y)Z = (Me)I, (Cl)2, (CN)2, or 02ligands.42184By extrapolating the above results to the CH3O and EtSH complexeswhich are not structurally characterized, it is proposed that the CH3O adduct, 11,has a trans configuration in accordance with the single N-methyl resonanceobserved in the 1H NMR spectrum (Figure 5.12). In contrast, the major product ofthe EtSH reaction appears to be the cis-dichioro adduct with two N-methylresonances, while the minor product is the trans-dichloro adduct with a single N-methyl resonance.As all the complexes contain cis-phosphines as evident by the 2Jppvalues,16 the geometry of a irans-dichioro complex is unambiguous (Figure 5.15).The cis-dichloro complexes could have four possible structures (Figure 5.16);however, the crystallographically deduced structure (I) for the H2S adduct lOb isfavored for all other complexes of the type cis-RuC12(PMA)(PR3)(L)(see Section5.4 for an explanation).Figure 5.15: Structure of trans-RuC12(PMA)(PR3)(L)complexes.Ck.J_PCl PRL(I) (II) (III) (IV)Figure 5.16: Possible structures for cis-RuC12(PMA)(PR3)(L)complexes.c1ClL1855.2.6 Reactions of Ia and lb with SO2When solutions of 1 (in CHC13,CH21,or C6H)were reacted with SO2gas (1 atm, ambient temperature), a rapid reaction occurred within seconds, withan accompanying color change from green to red-brown. The 31P{ ‘H} NMRspectrum of the resulting red-brown solution (121.4 MHz, CDC13 20 °C; Figure5.17) consists of a AB spin pattern, and is indicative of quantitative formation of asingle product (Equation 5.11). Addition of hexanes to a CHC13 solution of theSO2 adduct afforded a yellow-orange solid, which was isolated and analyzedcorrectly for the formulationRuC12(PMA)(PR3)(S0,13 (see Section 2.2.4.6).RuCI2(PMA)(PR3)+ SO2 RuC12(PMAXPR3)(S0(1) (13)la RPh 13a RPhlb R = p-tolyl 13b R ptolyl (5.11)The in situ product 13 remained unchanged when the system was subjectedto a vacuum, even when all the solvent was removed and when the residue,redissolved under an atmosphere of argon, was examined by NMR spectroscopy,indicating essentially an irreversible reaction (Equation 5.11), as opposed to thereversible reaction observed with H2S (Equation 5.2).Both complexes 13a and 13b were synthesized, and the 31P{ lH} NMRdata (Table 5.10) show little variation between the phenyl and the p-tolylanalogues, with 2Jpp values again within the range found for cis-phosphines.’6186lIIilI I 11111111111111111111111 I I I I 111111111 II j50 40 30 20 iOPPM 0Figure 5.17: 31P{IH} NMR spectrum (121.4 MHz, 20 °C) ofRuCI2(PMA)(P(p-to1y1)3)(SO), 13b, in CDCI3.Figure 5.18: ‘H NMR spectrum (300 MHz,to1y1)3)(SO), 13b, in CDC13.20°C) of RuC1(PMA)(P(p-8 5J4 3 2 1 0ppm187Table 5.10: 31P{1H} NMR data (121.4 MHz, CDC1320 °C) for thecomplexesRuC12(PMA)(PR3)(S0,13;a the values inbrackets are for the corresponding precursor complex, 1.Complex, R= PP” 3B ppm 2AB,13a, Ph 39.02 (85.17) 37.88 (52.55) 24.77 (36.67)13b,p-tolyl 37.90 (87.22) 35.90 (50.51) 24.60 (36.72)a Based on the discussion in Section 5.2.2, A and B are assigned as thephosphorus atoms of the PMA and PR3 ligands, respectively.The 1H NMR spectrum of 13b (300 MHz, CDC13 20 °C; Figure 5.18), with twosignals of 3H each (ö, 3.50 and 3.28) for the N-methyl group of theaminophosphine, suggests a cis configuration for the SO2 adduct (see Section5.2.5). The CH3 resonances of the p-tolyl phosphine appear as a single peak at2.26 ppm. The corresponding values for 13a in CDC13 are ö: 3.33 (s, 3H,-N(CH3)), 3.47 (s, 3H, -N(CH3))and 6.6-8.0 (m, Ph protons).The JR spectra (CHCI3 solution, in a 0.1 ruin KBr cell) of both 13a and 13bshow two strong absorptions at 1287 and 1122 cm1, assignable to SO stretchingmodes (vso).44 The vso values are lower than those of free S02 (1340 and 1146cm1 in CDC13), and are indicative of SO2 coordination with some M—*S02backit-donation. The presence of two SO stretches, with a frequency separation of 165cm1 in the frequency ranges 1300-1250 and 1130-1087 cm4, suggests a co188planar bonding mode for the SO2 ligand in 13, as is common for other Ru(II)-S02complexes.43 The irreversibility of the SO2 reactions further implies the coplanarbonding mode. The complexes with the pyramidal bonding mode are known thusfar to react with SO2 in a reversible manner, and exhibit vso stretches in the1237-1150 and 1065-990 cm1 ranges; complexes with q2-S,O bonded SO2exhibit SO stretches in the 1157-1107 and 948-873 cm’ ranges with a frequencyseparation greater than 190 cm - 143,44oSooo—SOI \/M M Mr1-pIanar rl-pyramida1 ri2-O,S-bondedFigure 5.19: Common coordination modes of tenninal SO2 complexes.5.2.7 Reactions of la and lb with N2The reaction with dinitrogen was first evident by the lighter green color ofthe solutions of 1 prepared under a nitrogen atmosphere, as opposed to the intensedark green color obtained under an argon atmosphere. Formation of a new productwas evident from the new AX spin pattern observed in the 31P{1H} NMRspectrum (121.4 MHz, CDC13 20 °C, Figure 5.20); the species is formulated asthe end-on bound dinitrogen complex (a-N2)RuClPMA)(PR3),14. The reaction,carried out at a total pressure of 1 atm of N2, resulted in formation of thedinitrogen adduct in - 25% yield, and when the dinitrogen pressure was increased189Ia• I,, • •I ‘ •III III I liii 1111111 III I I I 11111 I IlIjIl 111190 80 70 60 50 40 30 PPMFigure 5.20: 31P{ ‘H) NMR spectrum (121.4 MHz, 20 °C) of la, under 3 atmnitrogen in C6D.I II I II I I I IIJ 1111411 Ii I II I II 11 lIJ 1 I I I IlT I I I I IIII I 14 I I I 11111 1 II 11 1 Ii liii [TTFIdFIrFFigure 5.21: ‘H NMR spectrum (300 MHz, 20 °C) of la, under 3 atmnitrogen inC6D.la 14a14a-N(Me)2,la-N(Me), 14a -N(Me), 14a190to 3 atm the yield of the product was increased to ca. 65%. When the N2atmosphere was replaced by argon, the yield decreased essentially to 0%. Thus,the reaction is reversible (Equation 5.12) and lies in favor of the N2-adduct athigher dinitrogen pressures.RuCI2(PMA)(PR3)+ N2 - RuC(PMAXPR3) N2(1) (14)la R=Ph 14a RPhlb R =p-tolyl 14b R =p-tolyl (5.12)When the reaction was carned out in benzene over a period of 24 h under —3 atm N2, a red-brown suspension was formed, and this is thought to be thedimtrogen adduct. However, when the solid was collected and dried under astream of nitrogen, a color change from red to green was observed, indicating lossof the bound nitrogen; poor results were always obtained for attempted elementalanalyses of the dinitrogen adduct. Of the several attempts made to crystallize theN2-adduct, only one was successful, this leading to orange-red crystals. However,the single crystal X-ray structural analysis could not be performed due to the poorX-ray scattering by these crystals.The 31P{1H} NMR data (Table 5.11) of 14a and 14b are similar to eachother, and closely resemble those of the H2S adducts, 10, with 2Jpp values againwithin the range found for cis-phosphines.’6In the ‘H NMR spectrum of the insitu reaction mixture of la in CDCI3 under - 3 atm of N2 (Figure 5.21), theN-methyl resonances of the dimtrogen adduct appeared as two singlets (3.70 and191Table 5.11: 31P{1H} NMR data (121.4 MI-Iz, CDC13 20 °C) for thecomplexesRuC12(PMA)(PR3)(a-N,14;a the values inbrackets are for the corresponding precursor complexes.Complex, R = 6A ppm 6x ppm 2AX,14a, Ph 53.06 (85.17) 43.25 (52.55) 27.32 (36.67)14b,p-tolyl 53.30 (87.22) 41.80 (50.51) 27.30 (36.72)a Based on the discussion in Section 5.2.2, A and X are assigned as thephosphorus atoms of the PMA and PR3 ligands, respectively.3.09 ppm, 3H), and those of the five-coordinate precursor complex, RuC12(PMA)-(PPh3), were observed at 3.25 ppm as a single peak (6H). The corresponding datafor lb under - 3 atm of N2 are 6 (CDC13): 2.15 (s, 9H, CH3 of p-tolyl), 2.90 (s,3H, -N(CH3)), 3.60 (s, 3H, -N(CH3)), 6.6-7.8 (m, Ph protons). As discussed inSection 5.2.5, the N-methyl resonance pattern suggests a cis-dichioro configuration for the dmitrogen adduct.The presence of the a-N2 ligand in 1 4a and 1 4b was confirmed by the vN2JR stretch observed at 2161 cml(s, CHCI3 solution, in a 0.1mm KBr cell undernitrogen), which is absent in the JR spectrum of 1 under an argon atmosphere. ThevN2 frequency is at the upper limit of the range expected when the precursorspecies forms a stable dihydrogen complex at room temperature. The (q2-H)complexes formed by la and lb at room temperature under 1 atm of H2 areunstable with respect to H2-elimination (see Section 4.3). The data thus supportthe proposal of Morris et al. that a stable dihydrogen complex should exist when192the vN2 of the corresponding dinitrogen adduct is in the frequency range 2060-2150 cm1. The 2161 cm1 value is significantly lower than that of free nitrogenRaman = 2330 cm -1)46, and is somewhat higher than those found for somerelated mononuclear Ru(ll)-(a-N2) complexes. Complex, ‘N2: [Ru(NH3)5-(N2)], 2l20;’ [Ru(H2O)5()],2156 ;48 Ru(N2)(H)(P(p-tolyl3)2147; Ru(H)(N)(PPh3,2147;° and Ru(H)(N)(Cyttp), 2100, (Cyttp =PhP{CHCH(c-C6H1)2}2)•’ As lower v2 frequencies are indicative ofstronger dic-pit back-bonding that stabilizes the dimtrogen complex, the relativelyhigher value of 2161 cm1 further reflects the relatively weaker interactionbetween the metal and the duutrogen ligand in complex 14.5.2.8 Reactions of la and lb with 02When a solution (C6H or CHC13)of la or lb was reacted with 02 gas(1 atm), a rapid reaction was observed, with a color change from bright green todark blue-green (close to black). As in the other reactions discussed above, thecolor change was evident within a few seconds of exposure to the dioxygenatmosphere. The 31P{’H} NMR spectrum (121.4 MHz, CDC13 20°C; Figure5.22) of the in situ reaction mixture of lb under 1 atm of 02 showed a new AXspin pattern, along with the resonances for the oxides of P(p-tolyl)3 (at 34.70 ppm)and of PMA ligand (at 31.90 ppm); the spectrum of Ia under similar conditionsconsists of resonances at 43.74 (d) and 40.33 (d), 2Jpp = 10.79 Hz (15a, Table5.12), 34.5 (s, OPPh3), and 31.8 (s, PMA oxide). The identity of the oxides wasconfirmed by comparing the chemical shifts with those of authentic samples (seeSection 2.1.4). The resonances due to the five-coordinate precursor complex werenot observed, indicating its complete consumption.193free OP(p-tolyl)3III’III’II,II’II’I’II’lI’IIIIII42.04i.541.040.540.039.5PPMfreePMAoxide--LI111111liii1111111IIII111111IIIIl1111111111111111100806040200PPMFigure5.22:31P{1H)NMRspectrum(121.4MHz,20°C)oflbunder1atm02inCDC13;theINSETshowsresonancesof15bexpanded.-N(Me)2of free PMA oxide2ppmFigure 5.23: 1H NMR spectrum (200 MHz, 20°C) of la under 1 atm 02in C6J);the INSET shows the N-methyl region expanded.8 7195Table 5.12: 31P{1H} NMR data (121.4 MHz, CDC13 20°C) for thecomplexes “[RuCl2(PMA)(PR3)]t-O”,15; the values inbrackets are for the corresponding precursor complex 1.Complex, R 6A. ppm 6x ppm 2Jaj, Hz15a, Ph 43.74 (85.17) 40.33 (52.55) 10.79 (36.67)15b,p-tolyl 41.40 (87.22) 40.20 (50.51) 10.32 (36.72)The 3lP{1H} NMR data (Table 5.12) of the product fonned, which isproposed to be a peroxy-bridged dimer of the form [RuCl(PMA)(PR3)].t-O(see below), are distinctly different from those of the corresponding precursorcomplex (values in brackets) and the rest of the six-coordinate ligand adducts 9-14. Of special note is the distinctly low value of the 2Jpp coupling constant (-- 10-11 Hz)inboth 15a and 15b.However, of particular interest are the 1H NMR spectra of these complexes.The spectrum of la in C6D under 1 atm of 02 is shown in Figure 5.23 wherefour signals of equal intensity are observed at 3.31, 2.90, 2.15, and 2.04 ppm,which are attributed to the N-methyl resonances of the aminophosphine ligands.The signal at 2.40 ppm is due to the N-methyl resonance of the free ligand oxide(see Section 2.1.4.3). The corresponding spectrum of in situ formed 15b consistsof N-methyl resonances integrating to 3H each at 2.03, 2.12, 2.90, and 3.32 ppm.The N-methyls of free PMA oxide and the CH3 resonances of free OP(p-tolyl)3196are observed at 2.40 and 1.96 ppm, respectively. In addition, two smglets eachintegrating for - 9H are observed at 2.00 and 1.91 ppm which are assigned to CH3ofp-tolylphosphine.The band of both terminal and bridging peroxo complexes is known tobe in the 790-950 cm’ range.52 The JR spectrum of la under 1 atm of 02 (CHCI3solution, in a KBr cell, Figure 5.24 B) contains many bands in this region. Assome of these bands could arise from other reaction products (OPPh3 and PMAoxide) and traces of i.mreacted la, the spectrum in Figure 5.24 B is matched withthe spectra of la under argon, OPPh3 and PMA oxide in CHC13 solutions (Figure5.24 A, C, and D, respectively). By a close examination of these spectra(especially by overlaying all of them on one illuminated screen), the band at 908cm’ is tentatively assigned to the vo2 of 15a. By use of a similar procedure, aband at 904 cm1 is tentatively assigned to the v02 of 15b.Based on the JR data, and the presence of four signals for the N-methylresonances in the 1H NMR spectrum, the dioxygen adduct 15 is tentativelyproposed to have a peroxo-bridged dinuclear structure as shown in Figure 5.25.Although a c/s or trans arrangement of chlorides is possible, the presence of tworesonances in the 1H NMR spectrum for each N-(methyl) group favors the c/sform (see Section 5.2.5), and the presence of two such N-(methyl)2 groups perdimer (Figure 5.25) could explain the four N-methyl resonances in the ‘H NMRspectrum. Alternatively, the dioxygen adducts iSa and iSb could be monomericRuC12(0)(PMA)(PR3species with a terminal peroxo ligand. Formation of sucha seven-coordinate dioxygen adduct with a concominant Ru(II) —* Ru(JV)197launder I atmO2Figure 5.24: JR spectra (in CHC13 solution, 0.1 mm KBr cell) of la, Ia under1 atm 02, OPPh3 and PMA oxide.PMA oxidea’DCBAOPPh3t.a’C)C):1 CCa’Ca’la under argonc4a’946 922 898 874 850 cm1198oxidation is rare but is not unknown; e.g. [RuH(DIPPE)2]BPh4—+ [RuH(O)(DIPPE)2]B h453,[Cp*Ru(DPPE)]PF6—+ [Cp*Ru(0)(DPPE)]PF654For such amonomeric formulation, the presence of two isomers of a cis-dichloro complex ina 1:1 proportion has to be invoked to explain the 1H NMR spectrum. However, thesingle AX spin pattern observed in the 131P NMR spectrum tends to disfavor sucha formulation.Cl-.---Cl—o-.—oCH3Cl- NCH3Figure 5.25: Proposed stri.icture for the dioxgen adduct,[RuCl(PMA)(PR3)].t-O,15, with P indicating themonodentate phosphine PPh3, 15a, or P(p-tolyl)3, 15b.The presence of “relatively sharp” signals in the NMR spectra stronglysuggests the product to be diamagnetic (cf the 31P NMR spectra of RuCl3-(PMA)(PR3)complexes for which no observable signals are obtained); this may199be due to long range spin-coupling of the unpaired electrons within the dimer, asobserved in peroxo-bridged iron(Ill) porphyrin complexes.55 Although the 31PNMR signals are relatively sharp (Figure 5.22), the ‘H NMR signals are somewhatbroadened (Figure 5.23). This may be due to some other species produced duringthe reaction; precipitation of an unidentified green-black material was observedwithin few hours of introducing 02 to benzene or chloroform solutions of 1 a or lbcomplexes.The in situ formed dioxygen adducts 15 were unstable in C6D or CDC13,and decomposed to OPR3 and PMA oxide over a 24 h period at room temperature.Formation of oxides was evident even immediately after exposure of precursor 1to °2 Several attempts were made to minimize the amount of oxides formedduring the reaction, such that isolation of 15 might be feasible. Such experimentsincluded reaction of 1 with Ca. an equivalent amount of 02 (syringe techniques),and carrying out the reaction at lower temperatures (-40 to 0 °C range). However,all such reactions also produced oxides as the major product, and in theexperiments at lower temperatures the reaction was incomplete, precursor complexalso being seen in the reaction mixture as evidenced by 31P{ lH} NMR spectroscopy. The fmdings suggest that the oxides are formed either in a parallel reactionwith formation of 15, or in a fast reaction following formation of the dioxygenadduct 15.2005.2.9 Reactions of la and lb with CO5.2.9.1 Formation of the bis-CO adduct Ru(CO)2C1(PMA), 16When a benzene or chloroform solution of la reacts with CO (1 atm,ambient temperature), an initial color change from dark green to olive-green wasobserved within a few seconds; the color then gradually changed to yellow over aperiod of 15-20 miii. The3lP{1H} NMR spectrum (121.4 MHz, CDC13 20°C,Figure 5.26 F) of this yellow solution showed two low field sunglets (41.60 and31.71 ppm) along with the resonance of free PPh3 at 0 ppm, the latter indicatingdissociation of the monodentate phosphune in the course of the reaction (Equation5.13). The resonances at 41.60 and 31.71 ppm are assigned to cis, trans (minorproduct) and cis, cis (major product) isomers of Ru(CO)2C1(PMA), 16, respectively (Figure 5.27). The 1H, 31P{1H}, and 13C{1H} NMR spectra obtained fromthe reaction with 13C0 were used to assign the above formulations (see below).RuC12(PMA)(PR3) Rii(CO)2C1(PMA + PR3(1) (16)la R=Phlb R=p-tolyl (5.13)The CO reaction products of the p-tolyl analogue lb showed identical31P{1H} NMR chemical shifts along with the free P(p-tolyl)3 resonance at -2.59ppm. The 1H NMR spectrum for the la reaction (Figure 5.28 F) showed twosignals of equal intensity (3.68 and 2.98 ppm, major product) and another singleresonance of lesser intensity (3.25 ppm, minor product) assignable to the N-methyl201free PPh38 31.71Cis, cis..j 6F 20°C6 41.60(after overnight)cis, trans-I 6E 20°C- -—--D 0°CC -20°C1JB -30°CJL_.A-50°CJL70 60 50 40 30 20 iO OppmFigure 5.26: Variable temperature 31P{ li-i } NMR spectra (121.4 MHz, CDCI3)ofla under 1 atm CO.202P____ I_— co I .,.-ciN N COCis, trans-i 6 Cis, cis- 16Figure 5.27: Cis, trans and cis, cis isomers ofRu(CO)2C1(PMA), 16.resonances of the cis, cis and cis, trans isomers, respectively. The presence of twoN-methyl resonances for the cis-dichioro complex (cis,cis-16) and a single one forthe trans-dichloro complex (cis, trans-16) conforms with the 1H NMR spectralgeometry correlation for the other ligand adducts (see Section 5.2.5).To confirm further the formulation of 16, the reaction of la was carried outwith 13C0. The 31P{1H} NMR spectrum (202.5 MHz, CDC13 20 °C, ca. 2 atm13C0; Figure 5.29) of the in-situ reaction mixture showed two doublets ofdoublets centered at 41.59 and 31.69 ppm, each of which shows a trans 2Jpvalue (114.90 and 123.50 Hz, respectively) and a cis 2Jp value 14.0 Hz. The2Jp coupling pattern56 establishes the cis-(CO)2 arrangement in the two isomersof the bis-CO adduct 16. Of interest is the difference in the ratio of the major andthe minor isomers in the CO and 13C0 reactions; the minor product (cis, transisomer 31P 3 41.60, Figure 5.26) formed in the reaction with 1 atm CO is themajor product with the 13CO reaction (— 2 atm, Figure 5.29), and this is evidentfrom the 1H NMR spectra as well. This difference could be due to the higherpressure used in the 13CO reaction(13C0 gas was obtained from a break-sealflask equipped with a Teflon valve. The NMR tube containing la in CDC13 wasattached to the flask via a T-joint and the gas was transferred to the NMR sample203FEDCBA20°C(after overnight)20°C0°C-20 °C-30 °C-50 °CppmFigure 5.28: Variable temperature ‘H NMR spectra (300 MHz, CDC13)of la under 1 atm CO; * = -N(Me)2of 17a, . = -N(Me) ofcis,cis-16, x = -N(Me)2of cis,trans-16.i8 7 6 5 4 iÔ204cis, trans-i 6cis, cis-16IJx 79—.ppm 55 50 45 40 35 30 25 20Figure 5.29: 31P{1H} NMR spectrum (202.5 MHz, 20 °C) of la under 2 atm13C0 in CDC13;? = unidentified products, x = OPPh3. free COA IB A’JB, 77 777ppm 202 200 198 196 194 192 190 188 186 184Figure 5.30: 13C{1H} NMR spectrum (125.8 MHz) of Ia under — 2 atm 13C0 inCDCI3;? = unidentified products.205with cooling of the solution in liquid nitrogen). Similar observations have beenobserved in the analogous RuCI2(CO)PR3)complexes; the kinetic, all trans(lit) product is thermally isomerized to the cis, cis, trans isomer at ambientconditions, but the isomerization was inhibited at higher CO concentrations andthus requires more vigorous conditions.56’7In the 13C NMR spectrum (125.8 MHz, CDC13 20 °C, Ca. 2 atmFigure 5.30) of the in-situ reaction mixture, the doublet of doublet spin patternscentered at 196.41 and 194.41 ppm (B and B’), each consisting of a cis P-Ccoupling constant (2pC = 14 Hz), and a cis C-C coupling constant 5Hz),56 are assigned to the CO ligand cis to the P-arm of the aminophosphine, ineach of the two isomers. The multiplets centered at 189.60, and 187.23 ppm (Aand A’) arise from the CO ligand trans to the P-ann of the aminophosphine in thetwo isomers; the resonances from CO(A) and CO(A’) consist of a trans 2PC valueof 115 or 123.7 Hz, respectively, with further coupling to the cis CO ligand ineach of the two isomers with an associated cis 2CC value of 5.80 or 5.03 Hz,respectively.The reaction ofRuC12(PMA)(PR)3,1, with CO, leading to the productionof the bis-CO adduct Ru(CO)C1(PMA with the loss of PR3, closely resemblesthat observed between RuC12(PPh3)and CO, where the bis-CO adduct, all transRu(CO)2C1(PPh3),is produced and this readily undergoes isomerization toproduce the more stable cis, cis, trans isomer under ambient conditions.58The IR spectrum of 16 (CHC13 solution, in a KBr cell, Figure 5.31 F)shows sharp signals (2078, 2010(sh), 1999, and 1967 cm1) attributed to the206FFigure 5.31: JR spectra (in CHCI3,0.1 mm KBr cell) of Is, and launder 1 atmCO. at different temperatures: (A) is under argon, (B)-(F) Ia underCO at different temperatures, (B) -50 °C, (C)-(E) between —. -50and 20 °C, (F) at 20 °C.207-7[----VC.)EDCBA001 -2095 1995 1895 1795 1695 cm1stretches of the two isomers. Such an JR spectral pattern, with a v band in eachof the frequency ranges 2000-2100 and 1900-2000 cm, agrees well with thoseobserved for the analogous complexes with cis-disposed CO ligands.575.2.9.2 Formation of mono-CO adduct,RuC12(PMA)(PR3)CO,17The reaction of 1 with CO was carried out at reduced temperatures (downto -50 °C) with the aim of forming the mono-CO adduct akin to the other six-coordinate ligand adducts; this implies prevention of dissociation of the PR3ligand. The 31P{1H} NMR spectrum (121.4 MHz, CDCI3 -50 °C, 1 atm CO,Figure 5.26 A) of the resulting olive-green solution showed quantitative formationof a single product, with an AX spin pattern, attributed to the mono-CO adduct,RuC12(PMA)(PR3)(CO), 17 (Equation 5.14).RuC12(PMAXPR3) I trflCO RuC12(PMA)(PR3XCO)below -20 C(1) (17)la R=Ph 17a R=Phlb R p-tolyl 17b R —p-tolyl (5.14)The data for 17 (Table 5.13) were significantly different from those of thefive-coordinate precursor complex 1 (values in brackets in Table 5.13), but were inline with those observed for other ligand adducts 9-15. The mono-CO adduct wasmonitored by 31P{1H) NMR spectroscopy at different temperatures and, asshown in Figure 5.26, it was stable upto about -20 °C. At higher temperatures,208formation of the bis-CO adduct 16 with accompanying loss of PPh3 was observed(Figure 5.26, spectra A-F).The 1H NMR spectrum (300 MHz, CDC13 -50 °C, Figure 5.28 A) of 17a(or 17b) showed a single resonance (3.30 or 2.29 ppm) for the N-methyls of theammophosphine ligand, suggesting a trans-dichloro geometry for the complexesRuC12(PMA)(PR3)(CO), 17 (see Section 5.2.5). When the temperature wasincreased, the 1H NMR spectrum of the mono-CO adduct transformed to that ofbis-CO adduct, 16 (Figure 5.28, spectra A-F). The spectrum in Figure 5.28 Eclearly shows the N-methyl resonances of the mono-CO adduct and of the twoisomers of the bis-CO adduct present together in solution. The 1H NMR spectrumof 17b (in CDC13) consists of & 2.29 (6H, -N(Me)2), 2.27 (9H, Me of p-tolyl),6.7-7.6 (m, Ph protons).Table 5.13: 31P{1H} NMR data (121.4 MHz, CDCI3 -50 °C, 1 atm CO)for the complexes RuC1(PMA)(PR3)CO, 17; the values inbrackets are for the corresponding precursor complex 1.Complex: R= 6A. ppm ppm 2J, Hz17a,Ph 51.68 (85.17) 18.56 (52.55) 25.74(36.67)17b,p-tolyl 49.80 (87.22) 18.41 (50.51) 25.15 (36.72)209The mono-CO adduct I 7a was also characterized by JR spectroscopy.However, because of the instability of 17a, the JR spectrum had to be taken attemperatures below -20 °C. This was difficult due to the absence of a temperatureregulator in the JR spectrometer; this was circumvented by preparing the mono-COadduct at -60 °C, and transferring a sample by using a syringe into the JR cellimmediately at that temperature, and running the JR spectrum as quickly aspossible. Sampling of this solution at different time intervals, while it is warmingupto room temperature, resulted in a series of JR spectra (Figure 5.31), whichclearly show the transition from the mono-CO adduct 17a (Figure 5.31 B) to thebis-CO adduct 16 (Figure 5.31 F). The JR spectrum of 17a (CHC13 solution, KBrcell, below -20 °C, Figure 5.31 B) showed a single VCO stretch at 1985 cm’,which is absent in the JR spectrum of the precursor complex la under argon(Figure 5.31 A). The JR spectrum of the p-tolyl analogue, 17b, was the same asthat observed for the Ph complex, 17a. The VCO value of 1985 cm compareswell with those found for similar complexes of the type trans-RuCl2(CO)-(phosphine)3 (Phosphine, VCO cm1: PPh2Me, 1991; PPhMe2, 1979; PMe3,198 1).56The mono-CO adducts were also obtained by the solid state reaction ofRuC12(PMA)(PR3), 1, with 1 atm CO at room temperature. A fast reactionoccurred with lb within a few seconds of exposure to CO, while the reaction tooka few minutes with la; both were accompanied by a color change from green topale brown-grey. The products obtained were characterized by JR spectroscopy (vCO 1962 cm’, Nujol, for both 17a and 17b), and mass spectroscopy (17a [M] =767, [M-CO] = 739; 17b [M] = 809, [M-CO] = 781). The elemental analysisresults agreed well with the RuCl2(PMA)(PR3)(CO) formulation (see Section2.2.4.9.2). The formation of the mono-carbonyl complex in the solid state closely210resembles the solid state reaction observed by Bresson and Rigo,59 where the1 atm CO reaction of the five-coordinate complex [RuCI2(DPPB)]ji-D PB)resulted in the binding of one CO at each Ru to give [RuC1(CO)(DPPB)]j.t-DPPB).5.2.9.3 Proposed mechanism for the solution reaction ofRuCI2(PMA)(PR)with COThe reaction ofRuCl2(PMA)(PR3),1, with CO is envisaged to occur by amechanism of the form shown in Scheme 5.1, where formation of the mono-COadduct, 17, is the first step. Phosphine dissociation would then lead to theformation of the five-coordinate intermediate, which reacts with CO to give the cisand trans isomers of the bis-CO adduct, 16.5.3 Reactions ofRuCI2(PAN)(P(p-tolyl)3),2, and RuCI(AMPHOS)(P(p-tolyl)3)with small moleculesThe reactions of RuC12(PAN)(P(p-tolyl)3),2, with H2, H2S, SO2, andCH3O were investigated under conditions identical to those used for theRuC12(PMA)(PR),1, complex. The reactions were monitored for upto four days.However, no reaction was evident by NMR spectroscopy, and the color of the darkgreen solution remained unchanged. This is in marked contrast to theinstantaneous reactions observed with complex 1. Of interest, green solutions ofthe relatedRuCl2(AMPHOS)(P(p-tolyl)3)complex (which could not be isolatedanalytically pure in reasonable yield to study the reactions with various ligands ingreater detail) react with SO2 with a color change to red within a few seconds.211Co C1RuCoCis trans-i 6R3P-R’C1 N(1)(17)+ PR3]I—PR3Scheme 5.1: Proposed mechanism for the reaction ofRuC12(PMA)(PR3)with CO; only the species in parentheses was not observed.CO(1 aim)[ CO ]CI—Cis, cis-i6CO212Formation of the corresponding SO2 adduct was evident from the 31P NMRspectrum of the reaction mixture (the 31P resonances of the SO2 adduct in CDC13appear at & 22.73 (d), 27.86 (d) 2Jpp = 25.62 Hz); many other signals werepresent due to the impurity of the precursor complex. Based on these findings, theinability to obtain analogous six-coordinate ligand adducts of the typeRuCl(PAN)(P(p-tolyl)3)(L) from the five-coordinate RuCl2(PAN)(P(p-tolyl)3)precursor complex, 2, is attributed to steric effects, where the bulky phosphinoaminonapthyl ligand likely hinders access of the central metal atom to theincoming ligand L.5.4 Summary of Results and ConclusionsAs discussed in detail in the preceding sections, the five-coordinate Ru(II)complex RuC12(PMA)(PR3),1, has proven to be extremely useful for the bindingof a wide range of small molecules (Scheme 5.2, Tables 5.14 and 5.15). Inparticular, the formation of the H2S and ethanethiol adducts reveals novelreactivity of this five-coordinate Ru(II) complex, and adds new dimensions to itschemistry. Of particular interest is the formation of stable, fhlly characterizedH2S-adducts 10 at ambient conditions, relative to the extreme conditions that areused in making Sellinan’s H25 complex (see Section 5.2.2.1), the only other H2Scomplex structurally characterized to-date. The availability of 10 allows for futureinvestigation of the chemistry of coordinated H2S, while its reversible formationshould allow for a study of the thermodynamics of the process, including anestimation of the Ru-S bond energy.213c-(iH2)RuC1PMAXPR3transc-(.N2)RuC1 PMA)(PR3N2// c,t& c,c-RiiCO)2C(PMAt- RucWMA)(PR3)(CO)Nb. no reactionc1—PR3C’sC-RuC12(PMAXPR3)(HS)Scheme 5.2 Summary of reactions ofRuC12(PMA)(PR3),1, toward smallmolecules (L); c = cis, I = Irans; see text for a discussion onthe proposed structure of the cis complex for whichother structures are possible (Section 5.2.5).c-[RuC12(PMA)(PR3)]0H2t-R(PMA)(PR3) F120R12(PMAXPR3)t-RuC12(PMAXPR3)(CHOH)C & t-R(PMA)(pR)(EtSH)so2C-RuCI2(PMA)(PR3XSO)Cl NL214Table 5.14: 31P{1H} (121.4 MHz, CDC13 20 °C)and1HNMR(300 MHz, CDCI3 20 °C) data for trans-RuC1(PMA)(PR3)(L)complexes.abcdL 31P{1H} dataöÃ 2JftJ(8NMe2 3MeH20 3.10 (3.09) (2.28) 69.32 (69.33) 53.40 (52.10) 38.36 (38.51)CH3O 2.95 (2.97) (2.22) 67.36 (68.97) 52.51 (51.47) 38.88 (38.98)EtSH 3.06 (-) (-) 55.56 (-) 51.62 (-) 35.69 (-)CO 3.30 (2.29) (2.27) 51.68 (49.80) 18.56 (18.41) 25.74 (25.15)a) Values in parentheses refer to the P(p-tolyl)3 systems; the non-bracketed data refer to thePPh3 system; J values in Hz.b) The phenyl resonances and ligand L resonances are not listed.c) The corresponding values for precursor complexes, RuC12(PMA)(PR3)are:R Ph: ‘H 5 3.22 (6H); 31P{’H}, 8 85.17, 52.55 (36.67 Hz).R =p-tolyl: 1H8 2.30 (9H), 3.25(6H); 31P{1H}, 87.22, 50.51 (36.72 Hz).d) A and X are proposed to be the phosphorus atoms of the PMA and PR3 ligands,respectively; with L=CO, the reverse is proposed (see page 217).Both the p-tolyl and phenyl analogues of 1 in solution show similarreactivity toward the small molecules investigated, and in each of the systems thereaction was fast, and complete within a few seconds. The solid state reactions of1 with H2S were unusual in that no reaction was observed with la over a period of215Table 5.15: 31P{1H} (121.4 MHz, CDC13 20 °C)and1HNMR(300 MHz, CDC13 20 °C) data for cis-RuCl(PMA)(PPh3)(L)complexes.abCdL 1H 31P{1H}6NMe2 Me 2jH2S 3.42, 3.21 (3.41, 3.05) (2.15) 54.50(55,90) 48.41(46.50) 30.11 (30.30)EtSH 3.74, 3.18 (-) (-) 56.27 (-) 47.85 (-) 29.74 (-)SO2 3.47, 3.33 (3.50, 3.28) (2.26) 39.02 (37.90) 37.88 (35.90) 24.77 (24.60)N2 3.70, 3.09 (3.60, 2.90) (2.15) 53.06 (53.30) 43.25 (41.80) 27.32 (27.30)H2 3.56, 3.07 (3.57, 3.03) (2.13) 53.24 (53.51) 49.44 (47.60) 26.87 (27.00)a) Values in parentheses refer to the P(p-tolyl)3 systems; the non-bracketed data refer to thePPh3 system; J values in Hz.b) The phenyl resonances and ligand L resonances are not listed.c) The corresponding values for precursor complexes, RuC12(PMA)(PR3)are:R = Ph: ‘H 6 3.22 (6H); 31P{1H}, 6 85.17, 52.55 (36.67 Hz).R =p-tolyl: ‘H 82.30 (9H), 3.25(6H); 31P{’H}, 87.22, 50.51 (36.72 Hz).d) A and X are proposed to be the phosphorus atoms of the PMA and PR3 ligands,respectively; with L= SO2, an AB system is obtained.few days whereas lb reacts within a few seconds under similar conditions. Thesolid state reaction of la with CO was slower (within a few minutes) compared tothe reaction of lb (within a few seconds) under similar conditions.With the exception of the reaction with dioxygen, and the room temperaturesolution reaction of CO, all the other reactions led to the formation of six-216C1%JPci PR3L(II) (ifi)coordinate complexes of the formRuCl2(PMA)(PR3)(L). Combined 1H NMR andstructural data (Section 5.2.5) showed the possible formation of either trans (Table5.14) or cis (Table 5.15) or both isomers in solution. As discussed in Section 5.2.2(Table 5.8) the downfield 31P{1H) NMR resonance in each spectrum (except inthe case ofRuCl2(PMA)(PR3)(CO)) is assigned to the aminophosphine, and thatat higher field is assigned to the monodentate phosphine. In transRuC12(PMA)(PR3)(CO), the chemical shift of the downfield signal is comparableto that of the monodentate phosphine in other complexes (Table 5.14). Thus, theupfleld signal 6x is assigned to the aminophosphine; such a upfield shift of theaminophosphine may be related to the strong trans-influence of the CO ligand.As discussed in Section 5.2.5 (Figure 5.15) and noted in Scheme 5.2, thestructure of the trans-dichloro complexes is unambiguous. The cis-diehlorocomplexes can in principle have four possible structures: (I), (II), (III), or (IV), seeabove. From an examination of the 31P NMR data of the cis-dichioro complexes(Table 5.15), it is clear that the type of ligand L generally has little effect on thechemical shifts of the P atoms of the aminophosphine and monodentate phosphineamong the different ligand adduct complexes (the exception is where L = SO2,when both 6A and x are significantly different from values for the othercomplexes). This is in marked contrast to the data for the trans complexes (Table5.14), where the chemical shift öA of the aminophosphine trans to ligand L shows(1)PR3L(lV)217significant variation in the different ligand adduct complexes. Based on thesefmdings, structures (III) and (IV) with L trans to PMA or PR3 are disfavored.Although (I) and (II) are both possible, based on the similarity of the NMR data ofthe ligand adducts to those of the structurally characterized H2S complex,structure (I) is proposed for the cis-dichioro complexes.The inability to obtain analogous six-coordinate ligand adducts of the typeRuCl2(PAN)(PR3)(L) from the five-coordinate RuC12(PAN)(P(p-tolyl)3)precursor complex, 2, is attributed to steric effects, where the bulky phosphinoaminonapthyl ligand likely hinders access of the central metal atom to the incomingligand L. Concerning RuCl2(PAN)(P(p-tolyl)3),2, and RuCl2(PMA)(PR3), 1,each being five-coordinate, 16-electron complexes, their different reactivitytoward small molecules demonstrates the importance of a proper choice ofparticularly steric and electronic factors in dictating such chemistry. In thisrespect, the RuC12(PMA)(PR3)complex is remarkable, and its full potential is yetto be discovered.2185.5 References - Chapter 5I a) Joshi, A. M., Ph.D. Dissertation, The University ofBritish Columbia, Vancouver,Canada, 1990, and references therein.b) Joshi, A. M.; Thorburn, I. S.; Rettig, S. J.; James, B. R. Inorg. Chim. Acta1992, 198-200, 283.2 a) Hampton, C. R. S. M., Ph.D. Dissertation, The University of British Columbia,Vancouver, Canada, 1989.b) Hampton, C. R. S. M.; Butler, I. R.; Cullen, W. R.; James, B. R.; Charland, 3-P.;Simpson, J. Jnorg. Chem. 1992, 31, 5509, and references therein.3 a) Vahrenkamp, H. Angew. Chem., In!. Ed Engi. 1975, 14, 322.b) Seilman, D. Angew. Chem., In!. 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Inorg. Chem. 1975, 14, 2286.224Chapter 6225General Conclusions and Suggestions for Future WorkThe original objective of the present thesis work was to study the activationof 112 by Ru(P-N) complexes, with special attention to possible involvement of theN-arm of the P-N chelate in heterolytic H2 cleavage; related to this was thepossibility of generating molecular hydrogen complexes. Further, it was of interestto evaluate the potential of Ru(P-N) complexes for catalytic hydrogenation ofunsaturated organic substrates. In addition to the above general H2-theme, thework was extended to study the interaction of Ru(II)-(P-N) complexes with smallmolecules other than H2.The complexes RuC13(P-N)(PR)and RuC12(P-N)(PR3),where (P-N)PMA, PAN or (R)-AMPHOS, and R = Ph or p-tolyl, were synthesized viaphosphine exchange reactions with RuC13(PR)2DMA) and RuC12(PR3),respectively; with PAN, only the Ru(II) complex with R = p-tolyl was synthesized, and the Ru(II)-AMPHOS complexes were obtained only in poor yields usingan alternate method via decomposition of a hydrido species in CHCI3. Thestructures of (R)-AMPHOS, RuC13(PMA)(PPh3),RuC13(R-AMPHOS)(PPh),andRuC12(PMA)(P(p-tolyl)3),were determined by X-ray crystallography.The reaction ofRuCl2(PMA)(PR3)with 1 atm of H2 at room temperaturein the presence and absence of PS led to the formation of Ru(H)Cl(PMA)(PR3and(12-H)RuC1PMA)(PR3,respectively. The presence of the 2-H moietyfor the p-tolyl complex was demonstrated by the short 111 NMR T1 relaxationtime (Tl() = 13.4 ± 0.2 ms at 232 K and 300 MHz) and the relatively largeH-D coupling for ther12-HD isotopomer(1JHD = 30 Hz). The H-H distance wasestimated to be 0.87 ± 0.03 A from the T1 data. The presence of excess PS (6226equivalents) was essential to give exclusive formation of the monohydride species;with 1-3 equivalents of PS, a mixture of the molecular hydrogen complex and themonohydride was formed. Further experiments with RuC12(PMA)(PR3)and H2 inthe presence of PS should be carried out at higher H2 pressures as this might leadto formation of a complex of the form(q-)Ru(H)Cl(PMA)(PR. Highpressure NMR experiments with a mixture ofH2/D and RuC12(PMA)(PR3mayeven permit detection of the species()(RuC1PMA)(PR3,which is theintermediate postulated in the H21D exchange reactions. Reaction of RuCl2-(PAN)(P(p-tolyl)3)with 1 atm of H2 in the presence of PS (4-6 equivalents) atroom temperature resulted in— 60% formation of the monohydride species, whileno reaction was observed in the absence of PS. This behavior parallels the non-reactivity of the Ru(II)-(PAN) complex with the other small molecules investigated, and is attributed to the steric bulk of the PAN ligand; experiments should beextended to RuC12(AMPHOS)(PR3)complexes and other Ru(P-N) species.Reaction ofRuC13(P-N)(PR)(P-N = PMA and AMPHOS) with 1 atm H2at room temperature in the presence of PS afforded Ru(H)Cl(P-N)(PR3complexes. In the case of AMPHOS, the available evidence could not distinguishbetween the presence in solution of diastereomeric forms of Ru(H)Cl(AMPHOS)(PR3)or a dimeric form [Ru(H)Cl(AMPHOS)(PR3)]2.Based onkinetic studies of the reaction ofRuC1(AMPHOS)(P(p-tolyl) with H2 at 30 °Cin DMA, a mechanism involving “Ru(H)C12” and “RuC12” intermediates isproposed for the formation of the “Ru(H)Cl(AMPHOS)(P(p-tolyl)3) product.Further kinetic experiments at different temperatures may resolve some of thecomplexities observed at 30 °C (see Section 4.6), and would also yield informativeactivation parameters; experiments with varying higher concentration of PS arealso needed to determine the effects of the [PS] on the observed kinetic data.227The potential of RuCI3(PMA)(PR) and RuCI3(AMPHOS)(PR)ascatalyst precursors in hydrogenation was studied using styrene as the substrate.The reactions, carried out at 30 °C and 1 atm of H2 in the presence of 6equivalents of PS, revealed that the corresponding monohydride complexesRu(H)Cl(P-N)(PR3are probably the catalytically active species, but these weremuch less effective compared to the well known Ru(H)Cl(PPh3)system. Thecatalytic asymmetric hydrogenation of the prochiral alkenes ct-acetamidocinnamicand tiglic acids, with RuC13(AMPHOS)(PPh)as the catalyst precursor, requiredhigher H2 pressures (17-68 atm). Although the minimal chiral inductions obtainedwith these substrates ( 6% e.e.) are not promising, more work on relatedsubstrates, including prochiral ketones and ketimines, and use of different reactionconditions will help in drawing more defmite conclusions regarding the potentialof Ru(AMPHOS) systems as asymmetric hydrogenation catalyst precursors.The potential of the RuC12(P-N)(PR3)complexes for binding smallmolecules was studied, and much of the work was conducted on the PMAderivative. The RuC12(PMA)(PR3)complex in solution at room temperaturecoordinates a range of small molecules resulting in a series of adducts of the formRuC12(PMA)(PR3)(L)which contain either cis-dichiorides (L = H2,N2, SO2, andH2S) or trans-dichlorides (L = H20, MeOH, and CO). With L = EtSH, a mixtureof cis- and trans-dichloro adducts was obtained. The solution reaction of theprecursor five-coordinate species with 1 atm of CO at room temperature resultedin a mixture of cis-cis and cis-trans isomers of Ru(CO)2C1(PMA), while themono-CO adduct RuC12(PMA)(PR3)(CO) was obtained when the reaction wascarried out in solution at sub-zero temperatures, or in the solid state at roomtemperature. The adduct formed under 1 atm of 02 was tentatively proposed to bea peroxo-bridged dimer of the form [RuCl2(PMA)(PR3)]2(t-O2). More studies,228mcludmg the use of 1802, are needed in order to confirm the formulation. Theseries of ligand adducts formed by the RuC12(PMA)(PR3)complexes were eitherisolated or studied in situ by spectroscopic methods. The crystal structure of theH2S and the H20 adducts were determined, and that of the former is the secondexample known for a transition metal-H2Scomplex. The formation of a stableH2S complex at ambient conditions deserves special attention. The availability ofthe H2S adduct allows for future investigations into the chemistry of coordinatedH2S, while its reversible formation should allow for a study of thethermodynamics of the process, including an estimation of the Ru-S solution bondenergy. Of equal interest is the reaction with EtSH, which should be extended toinclude other less obnoxious thiols, thioethers, and sulfur itself. The reactionshown with methanol is also of interest and studies should be extended to use of 2-propanol; the potential of RuC12(PMA)(PR3)for transfer hydrogenation ofunsaturated organic substrates using 2-propanol as the hydrogen source should beevaluated. As there was no reaction of RuCl(PMA)(PR3)with 1 atm of CO2.experiments perhaps should be carned out at higher CO2 pressures. Also ofinterest would be extension of the studies to other small molecules including NH3,PR3 (where R= H or Me), CS2, CH4 and silanes.The PAN complex RuC12(PAN)(P(p-tolyl)3)did not react with H2,H2S,SO2 or CH3O . The reaction of an impure sample of RuCl2(AMPHOS)(P(p-tolyl)3) with SO2 shows adduct formation, and so improved synthetic pathways tothe RuCl2(AMPHOS)(PR complexes should be sought because extensive ‘smallmolecule’ chemistry, akin to that observed for the PMA analogue, should berealized.229Appendix230Appendix A-iX-ray Crystallographic Analysis of RuC1(PMA)(P(,p-to1yI)3).benzene,lb.benzeneStereoview of the molecular structure of lb.CS C4C27C.Z 7231Experimental DetailsA. Crystal DataEmpirical FormulaFormula WeightCrystal Color0 HabitCrystal Dimensions (mm)Crystal SystemNo. Reflections Used for UnitCell Determination (2e range)Omega Scan Peak Widthat Half—heightLattice Parameters:Space GroupZ valueDcalcF000(MoKc)DiffractometerRadiationTemperatureTake—off AngleDetector ApertureC47 H 47C12NPRu859.82Green, irregular0.250 X 0.300 X 0.350Monoclinic25 ( 20.5 — 26.8°)0.37a — 12.874 (3)Ab — 11.088 (4)Ac 30.198 (6)AS — 96.35 (2)°V — 4284 (3)AP21/c (*14)41.333 g/cm317765.89 cmB. Intensity MeasurementsRigaku AFC6SMoKcc (X — 0.71069 A)21°C6.006.0 mm horizontal6.0 mm vertical232Scan WidthNo. of Reflections MeasuredCorrectionsStructure SolutionRefinementFunction MinimizedLeast—squares Weightsp—factorAnomalous DispersionNo. Observations (I>3.OOa(I))No. VariablesReflection/Parameter RatioResiduals: R;Goodness of Fit IndicatorMax Shift/Error in Final CycleMaximum Peak in Final Diff. NapMinimum Peak in Final Diff. Map285 mm(*316.0°/mm (in omega)(8 rescans)(0.91 + 0.35 tanG)°60.0°Total: 13607Unique: 13049 (Rmt — .041)Lorentz—polari zationAbsorption(trans. factors: 0.82— 1.0)Decay (—18.00% decline)Secondary Extinction(coefficient: 0.129(7) E—06RefinementPatterson MethodFull—matrix least—squaresE w (IFol — IFcI)24Fo2/aC Fo)0.00All non—hydrogen atoms563747911.770.036; 0.0311.540.250.29 e/A3—0.29 e/A3Crystal to Detector DistanceScan TypeScan RateC. Structure Solution and233Table A-i. 1: Bond Lengths (A) with estimated standard deviations inparentheses.atom atom distance atom atom distanceRu(1) C1(1) 2.387(1) C(16) C(17) 1.358(6)Ru(1) C1(2) 2.379(1) C(17) C(18) 1.379(5)Ru(1) P(1) 2.170(1) C(21) C(22) 1.380(5)Ru(1) P(2) 2.290(1) C(21) C(26) 1.375(5)Ru(1) N(1) 2.238(3) C(22) C(23) 1.386(5)P(1) C(1) 1.836(3) C(23) C(24) 1.368(6)P(1) C(7). 1.828(3) C(24) C(25) 1.366(7)P(1) C(13) 1.840(3) C(24) C(27) 1.511(6)P(2) C(21) 1.831(4) C(25) C(26) 1.375(6)P(2) C(28) 1.823(3) C(28) C(29) 1.381(5)P(2) C(35) 1.832(4) C(28) C(33) 1.372(5)N(1) C(2) 1.464(4) C(29) C(30) 1.384(5)N(1) C(19) 1.483(4) C(30) C(31) 1.373(5)N(1) C(20) 1.500(4) C(31) C(32) 1.365(5)C(1) C(2) 1.395(4) C(31) C(34) 1.507(5)c(1) C(6) 1.386(5) C(32) C(33) 1.388(5)C(2) C(3) 1.386(4) C(35) C(36) 1.368(5)C(3) C(4) 1.371(5) C(35) C(40) 1.387(5)C(4) C(S) 1.361(5) C(36) C(37) 1.400(6)C(S) C(6) 1.393(5) C(37) C(38) 1.34S(S)C(7) C(S) 1.376(4) C(38) C(39) 1.359(6)C(7) C(12) 1.390(4) C(38) C(41) 1.522(6)C(8) C(9) 1.390(5) C(39) C(40) 1.388(6)C(9) C(10) 1.364(5) C(42) C(43) 1.33(1)C(10) C(11) 1.365(5) C(42) C(47) 1.26(1)C(11) C(12) 1.381(5) C(43) C(44) 1.37(1)C(13) C(14) 1.376(5) C(44) C(45) 1.41(2)C(13) C(18) 1.371(5) C(45) C(46) 1.35(1)C(14) C(15) 1.380(5) C(46) C(47) 1.30(1)C(15) C(16) 1.354(6)234Table A-1.2:BondAngles(deg)withestimatedstandarddeviationsinparentheses.atomatomatomangleatomatomatomangleC1(l)Ru(l)Cl(2)156.58(3)C(7)C(12)C(ll)120.6(3)Cl(l)Ru(1)PU)92.59(4)P(1)C(13)C(14)121.3(3)Cl(l)Ru(1)P(2)92.99(4)P(l)C(13)C(18)120.8(3)Cl(1)Ru(1)N(1)86.71(8)C(14)C(13)C(18)117.8(3)Cl(2)Ru(l)P(l)109.75(4)C(13)C(14)C(15)120.7(4)Cl(2)Ru(l)P(2)88.16(4)C(14)C(15)C(16)120.3(4)Cl(2)Ru(l)N(l)89.53(8)C(l5)C(16)C(17)120.1(4)P(1)Ru(1)P(2)104.74(4)C(16)C(17)C(18)119.6(4)P(1)Ru(l)N(1)81.81(8)C(13)C(18)C(17)121.5(4)P(2)Ru(1)N(1)173.45(8)P(2)C(21)C(22)119.5(3)Ru(1)P(1)C(1)101.1(1)P(2)C(21)C(26)123.9(3)VRu(1)P(1)C(7)121.2(1)C(22)C(2l)C(26)116.5(4)Ru(1)P(1)C(13)121.9(1)C(21)C(22)C(23)121.5(4)C(1)P(1)C(7)104.5(2)C(22)C(23)C(24)121.6(4)C(1)P(1)C(13)104.8(2)C(23)C(24)C(25)116.5(4)C(7)?(1)C(13)101.1(1)C(23)C(24)C(27)121.2(5)Ru(1)P(2)C(21)104.6(1)C(25)C(24)C(27)122.3(5)flu(1)P(2)C(28)115.6(1)C(24)C(25)C(26)122.7(5)Ru(1)P(2)C(35)126.2(1)C(21)C(26)C(25)121.2(4)C(21)P(2)C(28)104.9(2)P(2)C(28)C(29)118.4(3)C(21)P(2)C(35)102.7(2)P(2)C(28)C(33)124.1(3)C(28)P(2)c(35)100.5(2)C(29)C(28)C(33)117.4(3)Ru(1)N(l)C(2)109.2(2)C(28)C(29)C(30)121.3(4)Ru(1)N(1)C(19)105.0(2)C(29)C(30)C(31)121.0(4)Ru(l)N(l)C(20)115.4(2)C(30)C(31)C(32)117.6(4)C(2)N(1)C(19)113.6(3)C(30)C)31)C(34)120.9(4)C(2)N(1)c(20)106.9(3)C(32)C(31)c(34)121.4(4)C(19)N(1)C(20)106.9(3)C(31)C(32)C(33)121.8(4)P(1)C(1)C(2)116.0(3)C(28)C(33)C(32)120.8(4)P(1)C(l)C(6)125.5(3)P(2)C(35)C(36)121.0(3)C(2)C(l)C(6)118.4(3)P(2)C(35)C(40)122.0(3)N(1)C(2)C(1)116.7(3)C(36)C(35)C(40)116.9(4)N(1)C(2)C(3)122.8(3)C(35)C(36)C(37)120.7(4)C(1)C(2)C(3)120.4(3)C(36)C(37)C(38)121.9(4)C(2)C(3)C(4)119.8(4)C(37)C(38)C(39)118.1(4)C(3)C(4)C(5)121.0(4)C(37)C(38)C(41)120.5(4)C(4)C(S)C(6)119.5(4)C(39)C(38)C(41)121.4(5)C(l)C(6)C(S)120.9(3)C(38)C(39)C(40)121.1(4)P(1)C(7)C(8)122.0(3)C(35)C(40)C(39)121.3(4)P(l)C(7)C(12)120.0(3)C(43)C(42)C(47)122.1(9)C(8)C(7)C(12)117.9(3)C(42)C(43)C(44)123(1)C(7)C(8)C(9)121.3(3)C(43)C(44)C(45)111(1)C(8)C(9)C(l0)119.7(4)C(44)C(45)C(46)123(1)C(9)C(10)C(11)120.2(4)C(45)C(46)C(47)119(1)C(10)C(11)C(12)120.3(4)C(42)C(47)C(46)122(1)TableA-l.3:Final atomiccoordinates(fractional)andB(eq).atomxY2u(l)0.38323(2)0.18502(2)0.145976(9)2.60(1)C(24)—0.0340(4)0.1028(5)0.17614(15)5.6(3)C1(i)0.35809(7)0.31647(9)0.20646(3)3.83(4)C(2S)—0.0380(4)0.2167(5)0.1588(2)7.6(3)c1(2)0.36761(8)0.00399(8)0.10347(3)3.98(4)C(26)0.0401(3)0.2636(4)0.1364(2)6.2(3)0.51098(7)0.29288(8)0.12620(3)2.54(4)C(27)—0.1214(4)0.0508(5)0.1998(2)8.5(3)P12)0.23780(7)0.25530(9)0.10321(3)3.15(4)C(28)0.2172(3)0.1964(3)0.04656(11)3.2(1)0.5131(2)0.1014(2)0.19106(9)3.1(1)C(29)0.2861(3)0.2300(4)0.01686(13)4.6(2?Cli)0.6030(3)0.2886(3)0.17717(10)2.8(1)C(30)0.2769(3)0.1855(4)—0.02619(12)5.1(2)C(2)0.5887(3)0.1950(3)0.20675(10)3.1(1)C(31)0.1992(3)0.1054(4)—0.04076(12)4.3(2)C(3)0.6492(3)0.1889(4)0.24763(11)4.2(2)C(32)0.1320(3)0.0710(4)—0.01122(13)4.6(2)C(4)0.7232(3)0.2757(4)0.25914(12)4.8(2)C(33)0.1398(3)0.1162(3)0.03188(12)4.0(2)C(S)0.7399(3)0.3670(4)0.23064(13)4.7(2)C(34)0.1915(4)0.0541(4)—0.08722(13)6.1(2)C(6)0.6797(3)0.3736(3)0.18946(12)3.7(2)C(35)0.2025(3)0.4138(3)0.09326(13)3.8(2)C(7)0.4942(3)0.4534(3)0.11358(11)2.8(1)C(36)0.2300(3)0.4999(4)0.12482(14)5.3(2)C(8)0.4858(3)0.5378(3)0.14636(12)3.9(2)C(37)0.1970(4)0.6195(4)0.1182(2)5.9(2)C(9)0.4686(4)0.6589(3)0.13601(14)4.9(2)C(38)0.1374(3)0.6546(3)0.0810(2)5.2(2)C(10)0.4581(4)0.6948(4)0.09255(15)5.4(2)C(39)0.1101(4)0.5703(4)0.0492(2)6.3(3)C(i1)0.4661(4)0.6127(4)0.0S944(13)5.5(2)C(40)0.1425(4)0.4513(4)0.05477(14)5.8(2)C(12)0.4837(3)0.4925(3)0.06959(12)4.1(2)C(41)0.1008(4)0.7848(4)0.0755(2)7.6(3)C(13)0.5882(3)0.2446(3)0.08159(11)3.0(2)C(42)0.2405(7)0.1989(7)0.3164(5)9.5(5)Clii)0.5507(3)0.1601(3)0.05051(12)4.1(2)C(43)0.2364(9)0.1574(10)0.3573(5)11.7(6)C(1S)0.6065(4)0.1304(4)0.01557(13)5.2(2)C(44)0.146(2)0.1138(11)0.3719(4)16(1)C(16)0.6999(4)0.1832(5)0.01175(14)5.8(2)C(45)0.0619(11)0.1172(12)0.3376(6)17(1)C(17)0.7394(4)0.2657(5)0.0424(2)6.5(3)C(46)0.0706(9)0.1632(12)0.2969(4)16.0(8)C(18)0.6836(3)0.2957(4)0.07720(13)5.3(2)C(47)0.1612(13)0.2006(10)0.2871(3)12.4(6)C(19)0.4614(3)0.0444(4)0.22729(13)4.9(2)C(20)0.5729(3)0.0039(3)0.17054(13)4.5(2)C(21)0.1278(3)0.1974(3)0.13043(11)3.5(2)C(22)0.1321(3)0.0824(4)0.14808(15)4.9(2)C(23)0.0530(4)0.0364(4)0.1704(2)5.7(2)Appendix A-2X-ray Crystallographic Analysis of mer-RUCI3(PMA)(PPh3),6aC9Stereoview of the molecular structure of 6a.C4 C4 C9C22237Experimental DetailsA. Crystal DataEmpirical Formula CsH3sClNP2RuFormula Weight 775.08Crystal Color, Habit Red, prismCrystal Dimensions 0.30 X 0.40 X 0.45Crystal System OrthorhombicLattice Type PNo. of Reflections Used for UnitCell Determination (28 range) 25 ( 45.3 - 49.7° )Omega Scan Peak Widthat Half-height 0.37°Lattice Parameters a = 19.615(3) Ab = 17.538(2) Ac = 10.152(1) AV = 3492(1) A3Space Group Pna21 (#33)Z value 4Dcalc 1.474 g/cm3F000 1580p(MoKa) 789 cm1B. Intensity MeasurementsDiffractometer Rigaku AFC6SRadiation MoKc (A = 0.71069 A)graphite monochromatedTake-off Angle 6.0°238Detector Aperture 6.0 mm horizontal6.0 mm verticalCrystal to Detector Distance 285 mmTemperature 21.0°CScan Type w-29Scan Rate 32.0°/mm (in omega) (8 rescans)Scan Width (1.26 + 0.35 tan 6)°26ma 70.00No. of Reflections Measured . Total: 8446Unique: 8446Corrections Lorentz-polarizationAbsorption(trans. factors: 0.95 - 1.00)C. Structure Solution and RefinementStructure Solution Direct Methods (SHELXS86)Refinement Full-matrix least-squaresFunction Minimized Ew(IFoI — FcI)2Least Squares Weights= a(F:2)p-factor 0.00Anomalous Dispersion All non-hydrogen atomsNo. Observations (I>3.00o(I)) 5038No. Variables 405Reflection/Parameter Ratio 12.44Residuals: R; Rw 0.028 ; 0.038Goodness of Fit Indicator 1.03Max Shift/Error in Fina) Cycle 0.001Maximum peak in Final Duff. Map 0.76 e/A3n1 I4SMinimum peak in Final Duff. Map -u. i C239Table A-2. 1: Bond Lengths (A) with estimated standard deviations inparentheses.atom atom distance atom atom distanceRu(1) C1(1) 2.3338(9) Ru(1) CI(2) 2.3264(9)Ru(1) C1(3) 2.4005(9) Ru(1) P(1) 2.3606(9)Ru(1) P(2) 2.3565(9) Ru(1) N(1) 2.338(3)P(1) C(1) 1.808(4) P(1) C(7) 1.826(4)P(1) C(13) 1.841(4) P(2) C(19) 1.837(4)P(2) C(25) 1.832(4) P(2) C(31) 1.826(4)N(1) C(2) 1.470(5) N(1) C(37) 1.508(5)N(1) C(38) 1.482(6) C(1) C(2) 1.398(5)C(1) C(6) 1.403(5) C(2) C(3) 1.385(5)C(3) C(4) 1.373(6) C(4) C(5) 1.379(7)C(5) C(6) 1.381(6) C(7) C(8) 1.395(6)C(7) C(12) 1.393(6) C(8) C(9) 1.391(7)C(9) C(10) 1.372(10) C(10) C(11) 1.386(8)C(11) C(12) 1.391(6) C(13) C(14) 1.388(5)C(13) C(18) 1.395(6) C(14) C(15) 1.404(6)C(15) C(16) 1.351(7) C(16) C(17) 1.365(8)C(17) C(18) 1.394(6) C(19) C(20) 1.395(5)C(19) C(24) 1.393(6) C(20) C(21) 1.393(7)C(21) C(22) 1.367(9) C(22) C(23) 1.346(8)C(23) C(24) 1.392(6) C(25) C(26) 1.395(6)C(25) C(30) 1.369(6) C(26) C(27) 1.395(7)C(27) C(28) 1.342(8) C(28) C(29) 1.379(8)C(29) C(30) 1.383(6) C(31) C(32) 1.399(6)C(31) C(36) 1.408(5) C(32) C(33) 1.392(7)C(33) C(34) 1.383(9) C(34) C(35) 1.375(9)C(35) C(36) 1.398(6)240TableA-2.2:BondAngles(deg)withestimatedstandarddeviationsinparentheses.atomatomatomangleatomatomatomangleatomatomatomangleatomatomatomangleCl(l)Ru(1)Cl(2)175.25(4)C1(1)Ru(1)C1(3)92.12(3)C(9)C(10)C(1l)119.1(5)C(10)C(11)C(12)121.1(5)C1(1)Ru(1)P(1)90.06(3)C1(1)Ru(1)P(2)88.35(3)C(7)C(12)C(11)119.5(5)P(1)C(13)C(14)120.8(3)Cl(1)Ru(1)N(1)93.54(9).Cl(2)Ru(1)Cl(3)91.77(3)P(1)C(13)C(18)120.1(3)C(14)C(13)C(18)119.1(4)C1(2)Ru(1)P(1)85.68(3)CI(2)Ru(1)P(2)94.76(3)C(13)C(14)C(15)119.9(4)C(14)C(15)C(16)120.5(4)Cl(2)Ru(1)N(1)83.63(9)C1(3)Ru(1)P(1)170.81(3)C(15)C(16)C(17)120.1(4)C(16)C(17)C(18)121.2(4)C1(3)Ru(1)P(2)84.04(3)C1(3)Ru(1)N(1)91.70(8)C(13)C(18)C(17)119.2(4)P(2)C(19)C(20)124.7(3)P(1)Ru(1)P(2)104.96(3)P(1)Ru(1)N(1)79.25(8)P(2)C(19)C(24)116.5(3)C(20)C(19)C(24)118.8(4)P(2)Ru(1)N(1)175.40(8)Ru(1)P(1)C(1)101.4(1)C(19)C(20)C(21)119.5(4)C(20)C(21)C(22)320.1(4)Ru(1)P(1)C(7)115.6(1)Ru(1)P(1)C(13)125.3(1)C(21)C(22)C(23)121.4(5)C(22)C(23)C(24)120.0(5)C(1)P(1)C(7)104.1(2)C(I)P(1)C(13)103.2(2)C(19)C(24)C(23)120.2(4)P(2)C(25)C(26)120.1(3)1%)C(i)P(1)C(13)104.4(2)Ru(1)P(2)C(19)113.5(1)P(2)C(25)C(30)122.6(3)C(26)C(25)C(30)117.3(4)Ru(1)P(2)C(25)117.3(1)Ru(l)P(2)C(31)114.5(1)C(25)C(26)C(27)120.0(5)C(26)C(27)C(28)121.8(5)C(19)P(2)C(25)100.9(2)C(19)P(2)C(31)106.9(2)C(27)C(28)C(29)118.9(4)C(28)C(29)C(30)120.0(4)C(25)P(2)C(31)102.2(2)Ru(1)N(1)C(2)112.1(2)C(25)C(30)C(29)122.1(4)P(2)C(31)C(32)121.5(3)Ru(1)N(1)C(37)109.2(2)Ru(1)N(1)C(38)110.8(3)P(2)C(31)C(36)119.6(3)C(32)C(31)C(36)118.7(4)C(2)N(1)C(37)109.7(3)C(2)N(1)C(38)108.2(3)C(31)C(32)C(33)119.6(5)C(32)C(33)C(34)121.0(5)C(37)11(1)C(38)106.6(3)P(1)C(1)C(2)118.7(3)C(33)C(34)C(35)120.3(4)C(34)C(35)C(36)119.6(5)P(1)C(l)C(6)122.3(3)C(2).C(1)C(6)119.0(3)C(31)C(36)C(35)120.6(4)N(1)C(2)C(l)119.1(3)N(1)C(2)C(3)122.2(3)C(1)C(2)C(3)118.7(3)C(2)C(3)C(4)121.6(4)C(3)C(4)C(5)120.6(4)C(4)C(S)C(6)118.9(4)C(1)C(6)C(5)121.3(4)P(1)C(7)C(S)121.9(3)P(1)C(7)C(12)118.6(3)C(S)C(7)C(12)119.3(4)C(7)C(8)C(9)119.9(5)C(S)C(9)C(10)121.0(5)TableA-2.3:Finalatomiccoordinates(fractional)andB(eq).atomyzB,,atomxyzB,,Ru(1)-0.10999(1)-0.14794(1)-0.00422.055(3)C(18)-0.2369(2)-0.2834(3)0.2203(6)4.4(1)C1(1)-0.14941(5)-0.07092(5)-0.17547(10)3.25(2)C(19).0.0885(2)-0.3430(2).0.0736(4)2.73(6)CI(2)-0.07748(4)-0.22002(6)0.17765(10)3.01(2)C(20)-0.1251(2).0.4111(2).0.0762(6)4.26(10)C1(3)0.00544(4).0.14061(5)-0.0818(1)3.00(2)C(21).0.0982(3).0.4756(3)-0.0152(9)6.0(1)P(1).0.21789(4).0.14101(5)0.09811(9)2.31(1)C(22)-0.0353(3).0.4725(3)0.0428(7)5.7(1)P(2).0.11731(4)-0.25310(5)-0.14795(9)2.33(1)C(23)0.0018(2)-0.4080(3)0.0426(6)4.7(1)N(1)-0.0932(2).0.0450(2)0.1386(3)2.85(6)C(24)-0.0241(2)-0.3423(2)-0.0155(7)3.73(8)C(1).0.1971(2).0.0924(2)0.2499(4)2.65(6)C(25)-0.0649(2).0.2505(2).0.2972(4)2.84(7)C(2).0.1369(2).0.0498(2)0.2560(4)2.63(6)C(26).0.0331(3)-0.3167(3).0.3424(5)4.6(1)C(3)-0.1215(2).0.0117(2)0.3717(4)3.58(8)C(27)0.0038(4).0.3155(4).0.4597(6)6.3(2)C(4)-0.1633(2)-0.0157(2)0.4799(4)3.93(9)C(28)0.0099(3).0.2518(3)-0.5320(5)4.7(1)C(5).0.2221(2)-0.0587(3)0.4766(4)4.01(9)C(29).0.0205(2).0.1856(3)-0.4879(4)4.15(10)C(6).0.2391(2).0.0962(3)0.3616(4)3.53(8)C(30)-0.0569(3).0.1858(2)-0.3712(4)3.74(9)C(7)-0.2798(2)-0.0785(2)0.0185(4)2.91(7)C(31)-0.2024(2)-0.2705(2).0.2145(4)2.81(7)C(8)-0.2972(2).0.0076(3)0.0710(5)4.11(9)C(32)-0.2202(3).0.2478(3).0.3421(5)4.07(9)C(9)-0.3414(2)0.0402(3)0.0028(8)5.3(1)C(33)-0.2874(3)-0.2553(4).0.3842(6)5.4(1)C(10)-0.3683(3)0.0190(3)-0.1165(7)5.3(1)C(34)-0.3368(2).0.2858(3).0.3026(7)5.1(1)C(11)-0.3517(2).0.0518(3).0.1680(6)5.0(1)C(35)-0.3198(2).0.3113(3).-0.1788(6)4.17(10)C(12)-0.3072(2)-0.1005(3).0.1024(5)3.74(8)C(36)-0.2529(2)-0.3029(2).0.1334(4)3.28(7)C(13)-0.2685(2).0.2233(2)0.1541(4)2.68(6)C(37).0.0194(2).0.0425(3)0.1798(5)4.21(9)C(14)-0.3382(2).0.2264(2)0.1320(5)3.43(8)C(38)-0.1077(3)0.0282(2)0.0711(5)4.12(10)C(15)-0.3758(2).0.2898(3)0.1749(5)4.06(9)C(16)-0.3447(2).0.3477(3)0.2388(5)4.31(10)C(17)-0.2762(3)-0.3451(3)0.2618(7)5.1(1)Appendix A-3X-ray Crystallographic Analysis of mer-RuCI3(AMPHOS)(PPh3), 7aC33 C3ZStereoview of the molecular structure of 7a.c33 C3ZCa243Experimental DetailsA. Crystal DataEmpirical FormulaFormula WeightCrystal Color, HabitCrystal Dimensions (mm)Crystal SystemNo. Reflections Used for UnitCell Determination (2 range)Omega Scan Peak Widthat Half—heightLattice Parameters:Space GroupZ valueF00011(MoKcL)Di ffractometerRadiationTemperatureTake—off AngleDetector ApertureCrystal to Detector DistanceC40H391NP2Ru803.13red, prism0.120 X 0.250 X 0.250orthorhombic25 ( 20.1 — 28.7°)a 13.311 (3)Ab — 20.649 (3)Ac — 13.187 (4)AV — 3624 (1)A3P212 (*19)41.472 g/cm316440.367.63 cmB. Intensity, MeasurementsRigaku AFC6SMoKcz (X — 0.71069 A)21°C6.006.0 may horizontal6.0 mm vertical285mm244Scan Width28maxNo. of Reflections MeasuredCorrectionsStructure SolutionRefinementFunction MinimizedLeast—squares Weightsp—factorAnomalous DispersionNo. Observations (I>3.00(I))No. VariablesReflection/Parameter RatioResiduals: R;Goodness of Fit IndicatorMax Shift/Error in Final CycleMaximum Peak in Final Diff. MapMinimum Peak in Final Diff. Map16.0°/mm (in omega)(8 rescans)(1.00 + 0.35 tane)°50.00Total: 3601Lorentz—polarizationAbsorption(trans. factors: 0.92— 1.03)RefinementPatterson MethodFull—matrix least—squarest w (IFol — IFcI)24Fo2/()0.02All non—hydrogen atoms23564245.560.030; 0.0301.250.010.26 e/A3—0.32 e/A3Scan TypeScan Rate— 26C. Structure Solution and245Table A-3. 1: Bond Lengths (A) with estimated standard deviations inparentheses.atom atom distance atom atom distanceRu(1) C1(1) 2.398(2) C(13) C(14) 1.36(1)Ru(1) C1(2) 2.319(2) C(14) C(15) 1.35(1)Ru(1) C1(3) 2.356(2) C(15) C(16) 1.39(1)Ru(1) P(1) 2.401(2) C(17) C(18) 1.37(1)Ru(1) P(2) 2.374(2) C(17) C(22) 1.40(1)Ru(1) N(1) 2.355(6) C(18) C(19) 1.38(1)PCi) C(1) 1.835(7) C(19) C(20) 1.37(1)P(i) C(1i) 1.834(7) C(20) C(21) 1.38(1)P(1) C(17) 1.827(7) C(21) C(22) 1.40(1)P(2) C(23) 1.831(7) C(23) C(24) 1.40(1)P(2) C(29) 1.849(7) C(23) C(28) 1.390(9)P(2) C(35) 1.846(7) C(24) C(25) 1.40(1)N(1) C(7) 1.522(9) C(25) C(26) 1.37(1)N(i) C(9) 1.484(9) C(26) C(27) 1.34(1)Nd) C(10) 1.483(9) C(27) C(28) 1.39(1)C(1) C(2) 1.41(1) C(29) C(30) 1.39(1)Cdi) C(6) 1.38(1) C(29) C(34) 1.41(1)C(2) C(3) 1.407(9) C(30) C(31) 1.39(1)C(2) C(7) 1.54(1) C(31) C(32) 1.38(1)C(3) C(4) 1.36(1) C(32) C(33) 1.32(1)C(4) C(S) 1.37(1) C(33) C(34) 1.38(1)C(S) C(6) 1.364(9) C(35) C(36) 1.40(1)C(7) C(8) 1.515(9) C(35) C(40) 1.39(1)C(1i) C(12) 1.37(1) C(36) C(37) 1.40(1)C(11) C(16) 1.39(1) C(37) C(38) 1.37(1)C(12) C(13) 1.41(1) C(38) C(39) 1.38(1)C(39) C(40) 1.42(1)246TableA-3.2:BondAngles(deg)withestimatedstandarddeviationsinparentheses.atomatomatomangleatomatomatomangleatomatomatomangleatomatomatomangleC1(1)Ru(1)Cl(2)99.15(7)C(29)P(2)C(35)99.4(3)c(14)C(15)C(16)121.6(8)p(2)C(35)C(36)119.0(6)C1(1)Ru(l)C1(3)88.53(7)Ru(1)N(1)C(7)111.4(4)C(l1)C(16)C(lS)119.8(8)P(2)C(35)C(40)123.6(6)C1(1)Ru(1)P(1)170.08(7)Ru(1)N(1)C(9)107.3(4)P(1)C(17)C(18)119.5(6)C(36)C(35)C(40)117.3(6)C1(1)Ru(1)P(2)85.73(7)Ru(1)N(1)C(10)111.1(5)P(l)C(17)C(22)122.2(6)C(35)C(36)C(37)121.2(7)C1(1)Ru(1)N(1)86.5(2)C(7)N(1)C(9)108.1(6)C(18)C(17)C(22)118.3(7)C(36)C(37)C(38)120.5(7)C1(2)Ru(1)C1(3)171.61(8)C(7)N(1)C(10)111.2(6)C(17)C(18)C(19)120.2(8)C(37)C(38)C(39)120.3(7)C1(2)Ru(1)PCi)89.87(7)c(9)N(1)C(10)107.5(6)C(18)C(19)C(20)122.5(8)C(38)C(39)C(40)119.3(7)Cl(2)Ru(1)P(2)86.00(7)P(1)C(1)C(2)118.3(5)C(19)C(20)C(21)118.0(8)C(35)C(40)C(39)121.3(7)C1(2)Ru(1)N(1)87.2(1)P(1)C(1)C(6)121.4(6)C(20)C(21)C(22)120.6(8)C1(3)Ru(1)P(1)82.24(7)C(2)C(l)C(6)120.1(7)C(17)C(22)C(21)120.4(8)C1(3)Ru(1)P(2)98.01(7)C(1)C(2)C(3)116.7(7)P(2)C(23)C(24)124.0(6)C1(3)Ru(1)N(1)90.0(1)C(1)C(2)C(7)121.3(6)P(2)C(23)C(28)117.8(6)—3P(1)Ru(1)P(2)99.09(7)C(3)C(2)C(7)121.9(7)C(24)C(23)C(28)117.6(7)P(1)Ru(1)N(1)89.9(2)C(2)C(3)C(4)121.4(7)C(23)C(24)C(25)121.3(8)P(2)Ru(1)N(1)168.7(2)C(3)C(4)C(S)121.0(7)C(24)C(25)C(26)119.3(8)Ru(1)P(1)C(1)107.4(2)C(4)C(5)C(6)119.3(8)C(25)C(26)C(27)119.7(9)Ru(1)P(1)C(11)118.4(3)C(1)C(6)C(S)121.4(8)C(26)C(27)C(28)122.4(8)Ru(1)P(1)C(17)118.9(2)N(1)C(7)C(2)110.4(6)C(23)C(28)C(27)119.6(7)C(1)PU)C(11)104.1(3)N(1)C(7)C(S)114.5(6)P(2)C(29)C(30)123.2(6)C(1)PCi)C(17)103.0(3)C(2)C(7)C(8)111.2(6)P(2)C(29)C(34)121.0(6)C(ii)P(1)C(17)103.1(4)P(1)C(11)C(12)121.2(6)C(30)C(29)C(34)115.6(7)Ru(1)P(2)C(23)117.3(2)PCi)C(11)C(16)120.0(6)C(29)C(30)C(31)121.1(8)Ru(1)P(2)C(29)115.1(2)C(12)C(11)C(16)118.8(7)C(30)C(31)C(32)120.0(7)Ru(1)P(2)C(35)115.1(2)C(11)C(12)C(13)119.8(7)C(31)C(32)C(33)120.8(8)C(23)P(2)C(29)100.3(3)C(12)C(13)C(14)121.3(8)C(32)C(33)C(34)120.2(9)C(23)P(2)C(35)107.3(3)C(13)C(14)C(1S)118.8(8)C(29)C(34)C(33)122.3(7)xyzTableA-3.3:Finalatomiccoordinates(fractional)andB(eq).00atomBegatomxzBegRu(1)0.08455(5)0.11353(3)0.17301(4)2.33(2)c(18)0.2023(6)0.2920(4)0.2470(6)3.4(4)C1(1)—0.0356(2)0.0505(1)0.0802(2)3.7(1)C(19)0.2370(7)0.3532(4)0.2235(6)4.2(4)C1(2)0.0668(1)0.21132(8)0.0884(1)3.07(9)C(20)0.3322(8)0.3642(4)0.1883(7)5.2(5)C1(3)0.1263(1)0.01963(8)0.2654(1)3.31(9)c(21)0.3962(6)0.3119(4)0.1800(7)5.2(5)PCi)0.2183(2)0.1590(1)0.2723(2)2.5(1)C(22)0.3638(6)0.2497(4)0.2063(6)4.1(4)P(2)—0.0541(1)0.1475(1)0.2730(1)2.5(1)C(23)—0.0934(6)0.0941(3)0.3764(5)2.9(3)N(1)0.2010(5)0.0842(3)0.0466(5)2.9(3)C(24)—0.1318(6)0.1161(4)0.4689(6)3.9(4)C(1)0.3289(5)0.1072(4)0.2S47(5)2.7(3)C(25)—0.1739(8)0.0733(5)0.5393(6)5.2(5)C(2)0.3558(5)0.0892(3)0.1551(6)2.9(4)C(26)—0.1773(8)0.0083(5)0.5171(7)5.2(5)C(3)0.4377(6)0.0467(4)0.1449(6)4.0(4)C(27)—0.1379(7)—0.0134(4)0.4297(7)4.6(5)C(4)0.4868(6)0.0228(4)0.2275(7)4.3(4)C(28)—0.0990(6)0.0281(4)0.3566(5)3.6(4)C(S)0.4600(6)0.0411(4)0.3234(7)3.8(4)C(29)—0.1741(5)0.1560(3)0.2036(5)2.8(4)C(6)0.3817(6)0.0830(3)0.3363(6)3.4(4)C(30)—0.1799(6)0.1770(4)0.1036(6)3.5(4)C(7)0.3016(5)0.1178(4)0.0625(5)3.0(3)C(31)—0.2724(7)0.1899(4)0.0582(6)3.8(4)C(8)0.3693(6)0.1182(4)—0.0299(6)4.3(4)C(32)—0.3597(6)0.1823(4)0.1127(6)3.9(4)C(9)0.1594(6)0.1060(4)—0.0521(5)3.7(4)C(33)—0.3574(6)0.1617(5)0.2073(7)4.7(5)C(10)0.2133(6)0.0130(4)0.0414(6)3.9(4)C(34)—0.2666(6)0.1472(4)0.2532(6)3.7(4)C(11)0.2027(5)0.1632(4)0.4103(S)2.5(3)C(35)—0.0437(5)0.2301(3)0.3257(6)2.6(3)C(12)0.1476(6)0.1179(4)0.4613(5)3.0(3)C(36)—0.0732(6)0.2827(4)0.2661(6)3.7(4)C(13)0.1337(7)0.1240(4)0.5670(6)4.2(4)C(37)—0.0585(6)0.3466(4)0.2990(6)4.2(4)C(14)0.1734(7)0.1745(4)0.6193(6)4.4(5)C(38)—0.0190(6)0.3588(4)0.3926(7)4.4(4)C(1S)0.2275(7)0.2195(4)0.5684(6)4.4(5)C(39)0.0091(6)0.3085(4)0.4550(6)4.3(5)C(16)0.2442(6)0.2146(4)0.4644(6)3.6(4)C(40)—0.0030(5)0.2437(3)0.4207(6)3.0(4)C(17)0.265S(6)0.2395(3)0.2400(5)2.9(4)Appendix A-4X-ray Crystallographic Analysis of RuCI(PMA)(P(p-to1yl)3)(OH2,9bStereoview of the molecular structure of 9b.C4249Experimental DetailsA. Crystal DataEmpirical FormulaFormula weightCrystal Color, HabitCrystal Dimensions (mm)Crystal SystemNo. Reflections Used for UnitCell Determination (28 range)Omega Scan Peak Widthat Half—heightLattice Parameters:Space GroupZ valueF000‘1(CuK)DiffractometerRadiationTemperatureTake—off AngleC41H32NOPRu799.72red, prism0.100 X 0.180 X 0.200triclinic25 ( 22.3 — 56.2°)1.429 g/cm38240.33a=cv11.232 (3)A15.717 (4)A11.056 (2)A102.22 (2)°102.91 (2)°86.30 (3)01858.9 (9)A3P1 (2)259.26 cmB. Intensity MeasurementsRigaku AFC6SCuK (X — 1.54178 A)21°C6.0°250Detector ApertureCrystal to Detector DistanceScan TypeScan RateScan Width2emaxNo. of Reflections MeasuredCor rections0.00All non—hydrogen atoms496444211.230.035; 0.0341.610.090.34 e/A3—0.45 e7A36.0 mm horizontal6.0 mm vertical285 mmw— 2 e16.0°/mm (in omega)(8 rescans)(0.94 + 0.20 tane)°155.4°Total: 7989Unique: 7573 (Rt — .039)Lorentz—polarizationAbsorption(trans. factors: 0.68— 1.00)Secondary Extinction(coefficient: 0.86(5) E—06)RefinementPatterson MethodFull—matrix least—squaresE w (FoI— IFcI)24Fo2/a( Fo2)C. Structure Solution andStructure SolutionRefinementFunction MinimizedLeast—squares Weightsp—factorAnomalous DispersionNo. Observations (I>3.OOa(I))No. VariablesReflection/Parameter RatioResiduals: R; RGoodness of Fit IndicatorMax Shift/Error in Final CycleMaximum Peak in Final Diff. MapMinimum Peak in Final Diff. Map251Table A-4. 1: Bond Lengths (A) with estimated standard deviations inparentheses.atom atom distance atom atom distanceRu(1) C1(1) 2.418(1) C(13) C(14) 1.387(6)Ru(I) C1(2) 2.385(1) C(13) C(18) 1.387(5)Ru(1) P(1) 2.220(1) C(14) C(1S) 1.382(6)Ru(1) P(2) 2.284(1) C(15) C(16) 1.363(7)Ru(1) 0(1) 2.252(4) C(16) C(17) 1.361(7)Ru(1) N(1) 2.326(4) C(17) C(18) 1.386(6)P(1) C(I) 1.830(4) C(21) C(22) 1.398(5)P(1) C(7) 1.822(4) C(21) C(25) 1.391(5)PCi) C(13) 1.859(4) C(22) C(23) 1.390(6)P(2) C(21) 1.835(4) C(23) C(24) 1.387(6)P(2) C(28) 1.861(4) C(24) C(26) 1.385(6)P(2) C(35) 1.831(4) C(24) C(27) 1.506(6)N(1) C(2) 1.474(5) C(25) C(26) 1.383(5)N(1) C(19) 1.477(5) C(28) C(29) 1.344(6)MCi) C(20) 1.475(5) C(28) C(33) 1.385(6)C(1) C(2) 1.390(5) C(29) C(30) 1.397(6)C(i) C(6) 1.389(5) C(30) C(31) 1.365(6)C(2) C(3) 1.383(6) C(31) C(32) 1.351(6)C(3) C(4) 1.386(6) •C(31) C(34) 1.512(6)C(4) C(S) 1.368(7) C(32) C(33) 1.382(6)C(5) C(6) 1.376(6) C(35) C(36) 1.393(6)C(7) C(8) 1.395(6) C(35) C(40) 1.383(6)C(7) C(12) 1.381(6) C(36) C(37) 1.380(6)C(8) C(9) 1.386(6) C(37) C(38) 1.387(6)• C(9) C(10) 1.362(7) C(38) C(39) 1.377(6)C(10) C(11) 1.371(7) C(38) C(41) 1.507(6)C(11) C(12) 1.396(6) C(39) C(40) 1.385(6)252TableA-4.2:BondAngles(deg)withestimatedstandarddeviationsinparentheses.C(28)C(29)C(30)121.7(4)atomatomatomangleatomatomatomangleC1(1)Ru(1)Cl(2)162.91(4)C(S)C(7)C(l2)119.8(4)C1(1)Ru(1)P(l)90.73(4)C(7)C(S)C(9)119.3(5)dli)Ru(l)P(2)96.26(5)C(S)C(9)C(10).120.9(5)dli)Roll)0(1)82.2(1)C(9)C(i0)C(1i)120.0(5)dli)Roll)N(1)83.73(9)C(l0)C(i1)C(12)120.5(5)Ci(2)Roll)P11)104.30(5)C(7)C(12)C(11)119.4(5)Cl(2)Ru(1)P12)89.74(5)P(l)C(13)C(14)119.8(3)Cl(2)Ro(1)0(1)81.6(1)PU)C(l3)C(18)121.4(3)C1(2)Ru(1)N(1)90.76(9)C(14)C(13)C(18)118.5(4)PCi)Roll)P12)98.04(5)C(13)C(14)C(15)120.2(5)P(1)Ru(1)0(1)168.8(1)C(14)C(15)C(16)120.8(5)PU)Ru(1)N(l)80.20(9)C(15)C(16)C(17)119.5(5)P(2)Ru(1)0(1)91.4(1)C(16)C(17)d(18)121.0(5)P12)Roll)NIl)178.24(9)C(13)C(18)C(17)119.9(5)0(1)Ru(1)NIl)90.3(1)P(2)C(21)C(22)121.6(3)Ru(1)PCi)C(1)101.1(1)P(2)C(21)C(25)121.1(3)Ro(1)P(1)C(7)120.1(1)C(22)C(21)C(25)117.2(4)Ru(l)P11)C(13)127.2(1)C(2l)C(22)C(23)120.5(4)C(1)P(1)C(7)104.5(2)C(22)C(23)C(24)122.1(4)Cli)P(i)C(13)99.3(2)C(23)C(24)C(26)117.0(4)C(7)PCi)C(13)100.6(2)C(23)C(24)C(27)121.2(4)Ro(1)P12)C(21)116.7(1)C(26)C(24)C(27)121.8(5)Ru(1)P(2)C(28)111.9(1)C(21)C(25)C(26)121.5(4)Ru(1)P(2)C(35)121.2(2)C(24)C(26)C(25)121.6(4)C(21)P12)C(28)104.8(2)P12)C(28)C(29)124.8(3)C(21)P(2)C(35)102.7(2)P(2)C(28)C(33)118.6(3)C(28)P(2)C(35)96.7(2)C(29)C(28)C(33)116.6(4)Ru(1)NIl)C(2)107.7(2)Ru(1)NIl)C(19)107.8(3)C(29)C(30)C(31)121.4(S)Ru(1)N(1)C(20)115.3(3)C(30)C(31)C(32)117.0(4)C(2)N(1)C(19)112.1(3)C(30)C(31)C(34)120.7(5)C(2)NIl)C(20)106.9(3)C(32)C(31)C(34)122.3(5)C(19)N(1)C(20)107.1(3)C(31)C(32)C(33)121.7(5)P11)C(l)C(2)116.7(3)C(28)C(33)C(32)121.4(5)P11)C(1)C(6)124.3(3)P12)C(35)C(36)120.0(3)C(2)C(i)C(6)119.0(4)P(2)C(35)C(40)122.4(3)NIl)C(2)C(1)118.1(4)C(36)C(35)C(40)117.3(4)NIl)C(2)C(3)121.7(4)C(35)C(36)C(37)121.4(4)CU)C(2)C(3)120.2(4)C(36)C(37)C(38)121.0(5;C(2)C(3)C(4)119.7(4)C(37)C(38)C(39)117.6(4)C(3)C(4)C(S)120.4(4)C(37)C(38)C(41)121.3(5)C(4)C(S)C(6)120.1(4)C(39)C(38)C(41)121.1(5)C(i)C(6)C(S)120.6(4)C(38)C(39)C(40)121.6(4)P11)C(7)C(S)119.5(3)C(35)C(40)d(39)121.0(4)PU)C(7)C(12)120.6(3)TableA-4.3:Final atomiccoordinates(fractional)andB(eq).atomyz‘-I’BegatomxyzRu(1)0.05149(3)0.21639(2)0.07921(3)3.03(1)C(19)0.2486(4)0.1256(3)—0.0651(4)5.0(2)C1(1)0.11309(10)0.08469(7)0.15857(10)4.01(4)c200.2802(4)0.2781(3)—0.0138(4)4.8(2)C1(2)—0.01142(11)0.31700(8)—0.05781(9)4.51(5)C(21)—0.1550(4)0.1776(3)0.2571(4)3.3(2)P(1)0.15569(10)0.29625(7)0.25700(9)3.07(4)c22—0.1800(4)0.2259(3)0.3706(4)3.8(2)P(2)—0.13618(10)0.23037(7)0.12966(10)3.22(4)C(23)—0.1880(4)0.1850(3)0.4681(4)4.0(2)0(1)—0.0200(4)0.1202(3)—0.1012(3)4.5(2)C(24)—0.1733(4)0.0956(3)0.4572(4)4.1(2)N(1)0.2451(3)0.2047(2)0.0340(3)3.6(1)c25—0.1375(4)0.0883(3)0.2477(4)3.5(2)C(1)0.3072(3)0.2444(3)0.2659(4)3.3(2)c26—0.1481(4)0.0483(3)0.3447(4)3.9(2)c(2)0.3346(4)0.2000(3)0.1524(4)3.5(2)C(27)—0.1831(5)0.0524(4)0.5638(4)5.9(3)C(3)0.4456(4)0.1565(3)0.1517(4)4.3(2)c(28—0.2590(4)0.1849(3)—0.0081(4)3.5(2)C(4)0.5279(4)0.1551(3)0.2653(5)4.9(2)c29—0.3052(5)0.1050(3)—0.0301(5)5.3(2)C(5)0.5014(4)0.1985(4)0.3774(5)5.2(2)C(30)—0.3957(5)0.0743(3)—0.1372(5)6.0(2)C(6)0.3926(4)0.2440(3)0.3781(4)4.6(2)C(31)—0.4413(4)0.1244(3)—0.2246(4)4.3(2)C(7)0.1182(4)0.2938(3)0.4083(3)3.4(2)C(32)—0.3949(5)0.2047(4)—0.2030(5)5.8(2)C(8)0.0559(4)0.3644(3)0.4675(4)4.4(2)C(33)—0.3042(5)0.2349(3)—0.0981(5)5.7(2)C(9)0.0256(5)0.3616(4)0.5814(5)5.7(3)C(34)—0.5408(5)0.0906(4)—0.3388(5)6.4(3)c(10)0.0541(5)0.2904(4)0.6350(4)5.7(3)C(35)—0.2082(4)0.3375(3)0.1691(4)3.6(2)C(11)0.1135(5)0.2202(4)0.5762(4)5.4(2)C(36)—0.3287(4)0.3439(3)0.1836(5)4.5(2)C(12)0.1436(4)0.2204(3)0.4604(4)4.4(2)C(37)—0.3892(4)0.4233(3)0.2016(5)5.1(2)C(13)0.1996(4)0.4119(3)0.2841(4)3.7(2)C(38)—0.3323(5)0.4996(3)0.2047(5)5.0(2)C(14)0.2715(5)0.4508(3)0.3994(4)5.2(2)C(39)—0.2134(5)0.4933(3)0.1896(5)4.7(2)C(15)0.3124(5)0.5345(4)0.4170(5)6.1(3)C(40)—0.1514(4)0.4140(3)0.1739(4)4.0(2)C(16)0.2862(5)0.5791(3)0.3209(7)6.3(3)C(41)—0.3986(6)0.5864(4)0.2219(7)7.8(3)C(17)0.2152(5)0.5418(3)0.2076(6)5.5(2)C(18)0.1718(4)0.4583(3)0.1874(4)4.2(2)Appendix A-5X-ray Crystallographic Analysis of RuC1(PMA)(P(p-tolyI)3)(SH2),lObStereoview of the molecular structure of lOb.255Experimental DetailsA. Crystal DataEmpirical Formula 43H782CI2NPRuSO091Formula Weight 859.22Crystal Color, Habit Red-brown, octahedronCrystal Dimensions 0.20 X 0.20 X 0.20Crystal System TetragonalLattice Type INo. of Reflections Used for UnitCell Determination (29 range) 21(10.6 - 17.2° )Omega Scan Peak Widthat Half-height 0.37°Lattice Parameters a = 20.587(7) Ac = 38.51(1) AV = 16322(9) ..kaSpace Group 14/a (#88)Z value 16DcaIc 1.398 g/cm3F000 7105.60p(MoKa) 6.78 cm1.B. Intensity MeasurementsDiffractometer Rigaku AFC6SRadiation MoNa (A = 0.71069 A)graphite monochromatedTake-off Angle 6.0°256Detector Aperture 6.0 mm horizontal6.0 mm verticalCrystal to Detector Distance 285 mmTemperature 21.0°CScan Type wScan Rate 8.0°/nun (in omega) (8 rescans)Scan Width (1.15 + 0.35 tan 0)026mar 5490No. of Reflections Measured Total: 6194Unique: 5829 (R = 7.54)Corrections Lorentz-polarizationAbsorption(trans. factors: 0.88- 1.00)Decay (-23.66% decline)C. Structure Solution and R.eflnementStructure Solution Patterson Methods (SAPI)Refinement Full-matrix least-squaresFunction Minimized Ew(jFo— Fcl)2Least Squares Weights 2(Fo) = c2(Fo3)p-factor 0.00Anomalous Dispersion All non-hydrogen atomsNo. Observations (I>2.OOcr(I)) 2365No. Variables 459Reflection/Parameter Ratio 5.15Residuals: R; Rw 0.048 ; 0.057Goodness of Fit Indicator 1.31Max Shift/Error in Final Cycle 0.008Maximum peak in Final Duff. Map 0.38 r/A3Minimum peak in Final Duff. Map -0.33 e/A257Table A-5. 1: Bond Lengths (A) with estimated standard deviations inparentheses.atom atom distance atom atom distanceRu(1) C1(1) 2.469(4) Ru(1) C1(2) 2.429(3)Ru(1) 5(1) 2.330(4) Ru(1) P(1) 2.256(4)Ru(1) P(2) 2.304(3) Ru(1) N(1) 2.371(10)P(1) C(1) 1.84(1) P(1) C(7) 1.81(1)P(1) C(13) 1.85(1) P(2) C(19) 1.85(1)P(2) C(26) 1.84(1) P(2) C(33) 1.85(1)N(1) C(2) 1.45(1) N(1) C(40) 1.48(2)N(1) C(41) 1.51(2) C(1) C(2) 1.38(1)C(1) C(S) 1.40(1) C(2) C(3) 1.39(2)C(3) C(4) 1.36(2) C(4) C(5) 1.37(2)C(5) C(6) 1.37(2) C(7) C(8) 1.42(2)C(7) C(12) 1.39(2) C(8) C(9) 1.33(2)C(9) C(1O) 1.37(2) C(10) C(11) 1.36(2)C(11) C(12) 1.39(2) C(13) C(14) 1.32(1)C(13) C(18) 1.40(2) C(14) C(15) 1.40(2)C(15) C(16) 1.38(2) C(16) C(17) 1.35(2)C(17) C(18) 1.42(2) C(19) C(20) 1.37(2)C(19) C(24) 1.37(2) C(20) C(21) 1.39(2)C(21) C(22) 1.34(2) C(22) C(23) 1.41(2)C(22) C(25) 1.49(2) C(23) C(24) 1.38(2)C(26) C(27) 1.38(2) C(26) C(31) 1.37(2)C(27) C(28) 1.37(2) C(28) C(29) 1.38(2)C(29) C(30) 1.37(2) C(29) C(32) 1.52(2)C(30) C(31) 1.39(2) C(33) C(34) 1.38(2)C(33) C(38) 1.42(2) C(34) C(35) 1.38(2)C(35) C(36) 1.30(2) C(36) C(37) 1.43(2)C(36) C(39) 1.50(2) C(37) C(38) 1.40(2)258TableA-5.2:BondAngles(deg)withestimatedstandarddeviationsinparentheses.atomatomatomangleatomatomatomangleatomatomatomangleatomatomatomangleCl(1)Ru(l)Cl(2)94.3(1)Cl(1)R.u(1)S(1)83.1(1)C(9)C(10)C(11)119(1)C(l0)C(11)C(12)120(1)Cl(1)Ru(l)P(1)170.0(1)Cl(1)Ru(1)P(2)88.0(1)C(7)C(12)C(I1)120(1)P(1)C(13)C(14)119(1)Cl(l)Ru(1)N(1)89.1(3)Cl(2)Ru(1)S(1)174.6(1)P(1)C(13)C(18)120.7(9)C(14)C(13)C(18)119(1)Cl(2)Ru(1)P(1)88.0(1)C1(2)Ru(1)P(2)91.9(1)C(13)C(14)C(15)122(1)C(14)C(15)C(16)119(1)Cl(2)Ru(1)N(1)85.4(2)S(1)Ru(l)P(1)93.8(1)C(15)C(16)C(17)118(1)C(16)C(17)C(18)121(1)S(1)Ru(1)P(2)927(1)S(l)Ru(l)N(1)89.8(2)C(13)C(18)C(17)118(1)P(2)C(19)C(20)122.9(10)P(1)Ru(1)P(2)101.7(1)P(1)Ru(1)14(1)81.3(3)P(2)C(19)C(24)117.8(9)C(20)C(19)C(24)118(1)P(2)Ru(1)N(1)175.9(3)Ru(1)P(1)C(1)103.9(4)C(19)C(20)C(21)120(1)C(20)C(21)C(22)122(1)Ru(1)P(1)C(7)113.3(4)Ru(1)P(l)C(13)127.9(4)C(21)C(22)C(23)116(1)C(21)C(22)C(25)125(1)C(1)P(1)C(7)103.5(5)C(1)P(1)C(13)998(5)C(23)C(22)C(25)117(1)C(22)C(23)C(24)121(1)C(7)P(1)C(13)105.0(6)Ru(1)P(2)C(19)119.5(4)C(19)C(24)C(23)120(1)P(2)C(26)C(27)124(1)Ru(1)P(2)C(26)113.3(4)Ru(1)P(2)C(33)118.9(4)P(2)C(26)C(31)118.6(10)C(27)C(26)C(31)116(1)C(19)P(2)C(26)99.7(5)C(19)P(2)C(33)962(6)C(26)C(27)C(28)123(1)C(27)C(28)C(29)120(1)C(26)P(2)C(33)106.4(6)Ru(1)N(1)C(2)112.7(7)C(28)C(29)C(30)116(1)C(28)C(29)C(32)121(1)Ru(1)N(1)C(40)108.8(8)Ru(1)N(1)C(41)112.0(7)C(30)C(29)C(32)121(1)C(29)C(30)C(31)122(1)C(2)N(1)C(40)111.4(9)C(2)N(1)C(41)105(1)C(26)C(31)C(30)120(1)P(2)C(33)C(34)114.8(10)C(40)N(1)C(41)105(1)P(1)C(1)C(2)118.8(9)P(2)C(33)C(38)125(1)C(34)C(33)C(38)119(1)P(1)C(1)C(6)120.5(10)C(2)C(1)C(6)120(1)C(33)C(34)C(35)118(1)C(34)C(35)C(36)127(1)N(1)C(2)C(1)120(1)N(1)C(2)C(3)121(1)C(35)C(36)C(37)113(1)C(35)C(36)C(39)125(1)C(1)C(2)C(3)118(1)C(2)C(3)C(4)121(1)C(37)C(36)C(39)120(1)C(36)C(37)C(38)124(1)C(3)C(4)C(S)120(1)C(4)C(5)C(6)119(1)C(33)C(38)C(37)116(1)C(1)C(6)C(S)119(1)P(1)C(7)C(8)122(1)P(1)C(7)C(12)122.1(10)C(S)C(7)C(12)115(1)C(7)C(S)C(9)123(1)C(S)C(9)C(10)120(1)TableA-5.3:Finalatomiccoordinates(fractional)andB(eq).s.t.omxYB.0CC.RtomXyB.1ocr.Ru(1)0.13973(5)0.52755(5)0.20458(3)3.61(3)C(21)0.3242(8)0.6139(7)0.1247(4)6.2(4)CI(1)0.1499(2)0.6444(2)0.19117(9)5.57(10)C(22)0.3888(9)0.6115(8)0.1289(4)6.6(5)CI(2)0.1494(2)0.4936(2)0.14438(7)4.72(8)C(23)0.4119(7)0.5864(7)0.1608(5)6.9(5)S(1)0.1217(2)0.5655(2)0.26074(9)5.31(10)C(24)0.3696(7)0.5623(7)0.1854(3)5.2(4)P(1)0.1119(1)0.4245(2)0.21771(8)3.55(8)C(25)0.4379(8)0.6344(9)0.1034(5)11.2(7)P(2)0.2507(2)0.5250(2)0.21217(8)3.74(8)C(26)0.2777(5)0.5660(7)0.2521(3)3.9(3)0(1)0.50000.25000.108(1)33.1(8)0.41C(27)0.2765(6)0.5384(6)0.2847(4)4.6(3)N(1)0.0268(5)0.5345(5)0.1931(2)4.3(3)C(28)0.2871(6)0.5729(7)0.3146(3)4.9(4)C(1)0.0295(5)0.4161(6)0.1999(3)3.7(3)C(29)0.3021(7)0.6383(8)0.3133(4)5.7(4)C(2)-0.0040(6)0.4713(6)0.1906(3)3.7(3)C(30)0.3011(7)0.6665(6)0.2812(5)6.5(5)C(3)-0.0680(6)0.4647(7)0.1798(3)4.8(4)C(31)0.2896(7)0.6316(7)0.2510(3)5.1(4)C(4).0.0962(7)0.4054(9)0.1772(3)5.7(4)C(32)0.3143(8)0.8778(8)0.3459(4)8.7(5)C(5)-0.0618(7)0.3500(8)0.1848(3)5.7(4)C(33)0.2928(6)0.4458(6)0.2111(4)4.5(3)C(6)0.0000(6)0.3548(6)0.1977(3)4.4(3)C(34)0.2863(6)0.4120(8)0.1804(3).4.0(3)C(7)0.1007(6)0.4111(5)0.2637(3)3.9(3)C(35)0.3227(6)0.3562(7)0.1757(3)4.6(4)C(8)0.1538(6)0.4094(6)0.2874(4)5.1(4)C(36)0.3844(6)0.3308(6)0.1971(3)3.8(3)C(9)0.1464(9)0.4055(7)0.3217(3)8.0(5)C(37)0.3684(6)0.3641(6)0.2295(4)5.0(4)C(10)0.0854(9)0.4048(7)0.3360(3)5.9(5)C(38)0.3346(6)0.4213(6)0.2372(3)4.4(3)C(11)0.0324(8)0.4077(7)0.3149(4)5.9(4)C(39)0.4040(7)0.2711(6)0.1907(4)7.0(5)C(12)0.0393(6)0.4108(6)0.2790(4)5.0(4)C(40)0.0189(7)0.5730(7)0.1612(4)7.1(5)C(13)0.1486(6)0.3487(6)0.2013(3)3.9(3)C(41)-0.0090(7)0.5703(7)0.2213(5)8.2(5)C(14)0.1453(6)0.3345(6)0.1679(3)4.2(3)C(42)0.00000.25000.484(2)13.7(9)0.28C(15)0.1723(7)0.2777(7)0.1542(4)5.9(4)C(43)-0.031(3)0.260(5)0.547(2)13.9(9)0.39C(16)0.2031(6)0.2343(7)0.1758(4)5.0(4)C(44)0.028(2)0.199(2)0.524(1)14(1)0.60C(17)0.2043(6)0.2466(6)0.2102(4)5.1(4)C(45).0.042(3)0.224(3)0.528(2)13(1)0.44C(18)0.1771(6)0.3041(8)0.2242(3)4.9(4)C(46)0.005(2)0.204(2)0.5006(9)13.9(10)0.81C(19)0.3038(6)0.5658(6)0.1803(3)3.5(3)C(20)0.2810(6)0.5911(6)0.1498(4)5.6(4)Appendix A-6X-ray Crystallographic Analysis of (R)-AMPHOSCIAStereoview of (R)-AMPHOS showing the two independent molecules in theasymmetric unit.COdoC”C9C20cliC5C15Ci4C15C5C2OBC9BCOBC1OBC2OBCOBCOBC48CI6BC168261Experimental DetailsA. Crystal DataEmpirical FormulaFormula WeightCrystal Color, HabitCrystal Dimensions (mm)Crystal SystemNo. Reflections Used for UnitCell Determination (2 range)Omega Scan Peak Widthat Half—heightLattice Parameters:Space GroupZ valueDcalcF000‘‘(MoKa)Di ffractometerRadiationTemperatureTake—off AngleC22H4NP333.41colorless, prism0.250 X 0.350 x 0.400triclinic25 ( 34.1 — 39.1)0.37a — 10.484 (2)Ab — 12.486 (2)Ac — 8.582 (1)A— 96.09 (2)°— 103.74 (1)°Y — 114.79 (1)°V — 963.3 (3)AP1 (*1)21.149 g/cm33561.40 cmB. Intensity MeasurementsRigaku AFC6SMOKa (X — 0.71069 A)21°C6.0°262Detector ApertureCrystal to Detector DistanceScan TypeScan RateScan WidthNo. of Reflections MeasuredCorrectionsC. Structure Solution andStructure SolutionRefinementFunction MinimizedLeast—squares Weightsp—factorAnomalous DispersionNo. Observations (I>3.00(I))No. VariablesReflection/Parameter RatioResiduals: R;Goodness of Fit IndicatorMax Shift/Error in Final CycleMaximum Peak in Final Diff. MapMinimum Peak in Final Diff. Map6.0 mm horizontal6.0 mm vertical285 mm— 2 e32.0°/mm (in omega)(8 rescans)(1.57 + 0.35 tane)°55.0°Total: 4663Unique: 4418 (Rmt — .017)Lorentz—polarizationAbsorption(trans. factors: 0.95 — 1.00)Secondary Extinction(coefficient: 0.13081E—05)RefinementDirect MethodsFull—matrix least—squaresE w (IFol— IFcI)24Fo2/(Fo2)0. 01All non—hydrogen atoms27414316.360.033; 0.0321.850.170.12 e/A3—0.16 e/A3263Table A-6.l: Bond Lengths (A) with estimated standard deviations inparentheses.atom atom distance atom atom distanceP(1) C(1) 1.840(6) P(1B) C(1B) 1.839(6)P(1) C(7) 1.837(5) P(1B) C(7B) 1.824(5)PU) C(13) 1.835(5) P(1B) C(138) 1.827(5)N(1) C(19) 1.475(5) N(1B) C(19B) 1.453(5)N(].) C(21) 1.459(6) N(1B) C(21B) 1.477(7)N(1) C(22) 1.449(7) N(1B) C(22B) 1.450(7)C(1) C(2) 1.403(7) C(1B) C(2B) 1.401(7)C(1) C(6) 1.387(8) C(1B) C(6B) 1.402(7)C(2) C(3) 1.406(8) C(2B) C(3B) 1.379(8)C(2) C(19) 1.495(7) C(2B) C(19B) 1.554(7)C(3) C(4) 1.386(8) C(38) C(4B) 1.373(9)C(4) C(S) 1.373(7) C(4B) C(58) 1.372(7)C(5) C(6) 1.399(8) C(5B) C(6B) 1.354(7)C(7) C(8) 1.409(7) C(7B) C(8B) 1.369(7)C(7) C(12) 1.387(7) C(7B) C(12B) 1.389(7)C(8) C(9) 1.391(8) C(8E) C(9B) 1.372(9)C(9) C(10) 1.353(9) C(9B) C(1OB) 1.379(9)C(10) C(11) 1.39(1) C(1OB) C(11S) 1.34(1)C(11) C(12) 1.366(8) C(11B) C(12B) 1.386(8)C(13) C(14) 1.376(7) V C(13B) C(14B) 1.399(7)C(13) C(18) 1.390(7) C(13B) C(18B) 1.383(7)C(14) C(15) 1.385(7) C(14B) C(15B) 1.384(7)C(iS) C(16) 1.368(7) C(15B) C(16B) 1.378(7)C(16) C(17) 1.365(7) C(168) C(17B) 1.385(8)C(17) C(18) 1.389(7) C(17B) C(18B) 1.360(8)C(19) C(20) 1.529(7) C(19B) C(20B) 1.540(6)264Table A-6.2: Bond Angles (deg) with estimated standard deviations inparentheses.atom atom atom angle atom atom atom angleC(l) P(l) C(7) 100.9(2) C(lB) P(1B) C(7B) 102.5(2)C(l) PCi) C(13) 102.8(2) C(1B) P(1B) C(13B) 102.7(2)C(7) PCi) C(13) 101.6(2) C(7B) P(1B) C(138) 102.0(2)C(19) N(i) C(21) 112.0(3) C(19B) N(iB) C(21B) 111.7(4)C(19) N(l) C(22) 111.1(4) C(i9B) N(iB) C(228) 109.8(4)C(21) N(l) C(22) 108.3(4) C(218) N(1B) C(22B) 108.5(5)P(i) C(1) C(2) 119.2(4) P(1B) C(1B) C(2B) 118.9(4)PCi) CU) C(6) 121.8(4) P(1B) C(1B) C(6B) 122.7(4)C(2) C(l) C(6) 118.7(5) C(2B) C(iB) C(6B) 118.2(5)C(l) C(2) C(3) 118.3(5) C(1B) C(2B) C(3B) 119.0(5)C(1) C(2) C(l9) 122.7(5) C(1S) C(28) C(19B) 122.5(5)C(3) C(2) C(19) 118.8(5) C(38) C(2B) C(19B) 118.5(5)C(2) C(3) C(4) 121.9(6) C(2B) C(3B) C(4B) 121.5(6)C(3) C(4) C(5) 119.8(6) C(3B) C(4B) C(58) 119.6(6).C(4) C(S) C(6) 118.8(5) C(4B) C(SB) C(6E) 120.2(5)C(i) C(6) C(5) 122.4(5) C(15) C(6B) C(5B) 121.5(5)P(l) C(7) C(8) 116.4(5) P(lB) C(7B) C(8B) 119.1(4)P(l) C(7) C(12) 125.4(5) P(1B) C(7B) C(12B) 123.7(5)C(8) C(7) C(l2) 118.2(5) C(8B) C(7B) C(12B) 117.2(5)C(7) C(8) C(9) 119.4(6) C(78) C(88) C(98) 121.8(6)C(8) C(9) C(1O) 121.2(6) C(8B) C(9B) C(1OB) 119.9(7)C(9) C(iO) C(l1) 119.8(6) C(9B) C(i0B) C(11B) 119.5(6)C(l0) C(11) C(12) 120.0(6) C(lOB) C(11B) C(12B) 120.8(7)C(7) C(12) C(il) 121.4(6) C(73) C(12B) C(11B) 120.7(6)PCi) C(13) C(14) 124.7(4) P(1B) C(13B) C(148) 125.5(4)PCi) C(13) C(18) 116.9(5) P(1B> C(138) C(182) 118.2(5)C(14) C(13) C(18) 118.4(5) C(14B) C(138) C(18B) 116.3(5)C(13) C(14) C(15) 120.9(5) C(13B) C(148) CC15B) 121.5(5)C(14) C(i5) C(16) 119.4(5) C(14B) C(15B) C(16B) 120.8(5)C(15) C(16) C(17) 121.4(5) C(15B) C(16B) C(17B) 117.6(6)C(16) C(17) C(18) 118.8(5) C(16D) C(17B) C(18B) 121.5(5)C(13) C(18) C(17) 121.1(6) C(138) C(18B) C(17B) 122.3(6)N(i) C(l9) C(2) 111.3(4) N(1B) C(198) C(2B) 109.1(4)N(1) C(19) C(20) 112.5(4) N(1B) C(19B) C(20B) 110.3(4)C(2) C(19) C(20) 109.5(4) C(2B) C(198) C(20B) 108.7(4)265TableA-6.3:Final atomiccoordinates(fractional)andB(eq).atomxyz1’P1.1)04311009fl.6O.5619421(5)N(1B)0.1670(4)—0.4033(3)0.4007(4)5.9(1)N(1)0.7669(4)0.4597(3)0.6615(4)5.1(1)C(1B)0.5087(5)—0.2254(5)0.7359(7)3.8(2)C(1)0.5006(6)0.2354(5)0.2801(7)3.8(2)C(28)0.3913(6)—0.3347(6)0.6349(7)4.2(2)C(2)0.6290(6)0.3394(5)0.3776(7)3.9(2)c3E0.3336(7)—0.4318(6)0.7043(8)5.1(2)C(3)0.6821(7)0.4411(5)0.3100(8)5.1(2)C(4B)0.3898(7)—0.4242(6)0.8691(9)6.0(3)C(4)0.6124(7)0.4402(5)0.1506(8)5.6(2)C(58)0.5073(7)—0.3183(6)0.9674(8)5.3(2)C(S)0.4882(8)0.3377(7)0.0540(8)5.8(2)C(6B)0.5660(6)—0.2212(5)0.9028(7)4.5(2)C(6)0.4345(6)0.2359(5)0.1199(7)4.8(2)C(78)0.6880(5)—0.1162(5)0.5373(7)3.9(2)C(7)0.3177(6)0.1282(5)0.4732(7)4.5(2)C(8a)0.7232(6)—0.0520(5)0.4210(8)5.3(2)C(8)0.2816(6)0.0596(5)0.5906(8)5.0(2)c9B0.8125(7)—0.0654(7)0.3351(8)6.9(3)C(9)0.1938(7)0.0770(7)0.6789(7)6.5(2)C10B0.8636(7)—0.1496(8)0.3595(9)7.2(3)C(10)0.1407(7)0.1576(7)0.653(1)6.8(3)c11B0.8314(8)—0.2134(6)0.473(1)6.7(3)C(11)0.1754(7)0.2256(6)0.536(1)6.2(3)C1280.7429(6)—0.1989(5)0.5620(8)5.4(2)1%)C(12)0.2611(6)0.2097(5)0.4480(8)5.2(2)C(138)0.7079(6)0.0289(5)0.8288(7)4.3(2)C(13)0.2934(6)—0.0182(5)0.1791(7)4.1(2)C(148)0.8588(7)0.0613(5)0.8839(8)5.1(2)C(L4)0.1458(6)—0.0470(5)0.1304(8)5.4(2)Cu580.9556(7)0.1572(6)1.0175(8)6.4(2)C(15)0.0473(6)—0.1375(5)—0.0087(8)5.6(2)C(168)0.9048(7)0.2203(5)1.1061(7)5.9(2)C(16)0.0969(6)—0.2014(5)—0.0957(7)6.1(2)C(178)0.7556(8)0.1889(6)1.051(1)6.7(3)C(17)0.2426(7)—0.1751(6)—0.0519(8)6.1(2)C(188)0.6613(7)0.0967(6)0.9168(8)5.6(2)C(18)0.3409(7)—0.0838(6)0.0873(8)5.8(2)C(19E)0.3270(6)—0.3522(4)0.4459(6)5.0(2)C(19)0.7166(5)0.3436(4)0.S4SS(6)4.8(2)C(20B)0.3705(7)—0.4386(5)0.3558(8)6.8(2)C(20)0.8448(7)0.3182(5)0.5327(8)6.9(2)c21B0.0984(7)—0.4273(6)0.2209(8)8.8(2)C(21)0.8614(7)0.4689(5)0.8227(7)8.6(2)C(22B)0.1274(7)—0.31.98(7)0.483(1)9.1(3)C(22)0.6424(8)0.4750(6)0.6844(8)7.1(2)P(18)0.5713(1)—0.0910(1)0.6489(1)4.19(5)

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