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Synthesis, characterisation and reactivity of phosphide and methylidene complexes of iridium Joshi, Kiran 1990

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SYNTHESIS, CHARACTERISATION AND REACTIVITY OF PHOSPHIDE AND METHYLIDENE COMPLEXES OF IRIDIUM By K I R A N JOSHI B.Sc. (Hons.), University of British Columbia, 1985 M . S c , University of British Columbia, 1987 A THESIS SUBMITTED IN T H E REQUIREMENTS DOCTOR OF P A R T I A L F U L F I L M E N T OF FOR T H E D E G R E E OF PHILOSOPHY in THE F A C U L T Y OF G R A D U A T E STUDIES D E P A R T M E N T OF C H E M I S T R Y We accept this thesis as conforming to the required standard THE UNIVERSITY OF BRITISH C O L U M B I A August 1990 © Kiran Joshi, 1990 In presenting this thesis in partial fulfilment of the requirements for an advanced degree at the University of British Columbia, I agree that the Library shall make it freely available for reference and study. I further agree that permission for extensive copying of this thesis for scholarly purposes may be granted by the head of my department or by his or her representatives. It is understood that copying or publication of this thesis for financial gain shall not be allowed without my written permission. The University of British Columbia Vancouver, Canada Department DE-6 (2/88) A B S T R A C T The iridium(III) methyl diarylphosphide complexes, I r ( C H 3 ) P R 2 -[N(SiMe2CH2PPh2)2l (2a: R = phenyl, 2b: R = meta-tolyl) had been prepared previous to this work. The iridium(III) dimethylphosphide complex, Ir(CH3)PMe2-[N(SiMe2CH2PPh.2)2]> 2c, is readily prepared in situ by transmetallation of the I r ( C H 3 ) I [ N ( S i M e 2 C H 2 P P h 2 ) 2 ] with K P M e 2 at -30°C. The synthesis of the phenylphosphide complex I r ( C H 3 ) P H P h [ N ( S i M e 2 C H 2 P P h 2 ) 2 L 2d, involves deprotonation of the six-coordinate iridium(III) phenylphosphine complex, Ir(CH3)I-(PH 2Ph)[N(SiMe2CH 2PPh 2)2], with K O l B u . Thermolysis of 2a and 2b yields the six-coordinate iridium(III) cyclometallated hydride complexes / a c - I r ( r i 2 - C H 2 P R 2 ) H [ N ( S i M e 2 C H 2 P P h 2 ) 2 ] , 3a and 3b. The dimethylphosphide complex 2c undergoes the same rearrangement to afford 3c but more rapidly. Thermolysis of 3a-3c yields the square planar iridium(I) phosphine complexes of the formula, Ir(PCH3R2)[N(SiMe2CH2PPh 2 ) 2 ] , 4a-4c. Some of the intermediates proposed in the thermolysis of 2a are synthesised independently by the reaction of iridium methylidene complex, I r=CH 2 [N(S iMe 2 CH 2 PPh2)2 ] . 10, with P H P h 2 . The complex/ac-Ir(ri2-CHPhPMe2)H[N(SiMe2CH2PPh2)2] is generated from the reaction of I r (CH 2 Ph)Br[N (S iMe2CH2PPh 2 )2 ] with KPMe2 without intermediacy of the corresponding phosphide complex. The photolysis of 2a-2c also yields species 4a-4c; however, no intermediacy of the cyclometallated hydride complexes 3a-3c is observed during this transformation. Upon thermolysis of the phenylphosphide complex 2d, only the corresponding iridium(I) phosphine complex, Ir(PHCH3Ph)[N(SiMe2CH2PPh 2)2], 4d, is obtained, which is also the photolysis product of 2d. ii Ir(CH 3 )PPh 2 [N(SiMe 2 CH 2 PPh 2 )2], 2a, reacts at -78°C with dimethyl-acetylenedicarboxylate to yield an octahedral iridium(III) complex in which the alkyne has bridged between the phosphide ligand and the phosphine group of the chelating ligand. In addition, one of the phenyl groups from the chelating phosphine has migrated to the metal. On the other hand, Ir(CH3)PMe2[N(SiMe2CH2PPh2)2], 2c, reacts with the same alkyne to yield a product in which the alkyne has bridged between the phosphide group and the iridium centre. The reaction of 2a with diphenylacetylene affords Ir(PhC=CPh)[N(SiMe2CH2PPh2)2] and free methyl-diphenylphosphine. Complex 2a reacts with terminal alkynes (RC=CH; R = H, Ph, lBu) to yield acetylide complexes of formula Ir(CH3)PHPh2(C=CR)[N(SiMe2CH2-PPh2)2]-The methylidene complex, lr=CH2[N(SiMe2CH2PPh2)2L 10, prepared by the reaction of Ir(CH 3)I[N(SiMe 2CH 2PPh2)2] with KO lBu, reacts with phosphines PHR2 (R = Ph, lBu) to afford the cyclometallated hydride complexes, /ac-Ir(r| 2-CH 2 PR 2 )H[N(SiMe 2 CH 2 PPh 2 ) 2 ] , v ia a five-coordinate methylidene phosphine intermediate. The reaction of 10 with PH2Ph yields similar cyclometallated hydride product, but in this case the five-coordinate intermediate is not observed. The methylidene complex 10 reacts with the electrophiles Mel and AlMe3 to yield Ir(Ti2-C 2H4)H(I)[N(SiMe 2CH 2PPh2)2] and Ir((i-AlMe2)H[N(SiMe2CH2PPh2)2], respectively. Reaction of 10 with H O C H affords an r|3-allyl acetylide complex Ir(r|3-C3H5)(C=CH)[N(SiMe2CH2PPh2)2]. A trimethylenemethane complex, fac-Ir{ri4-C(CH2)3}[N(SiMe2CH2PPh2)2], is obtained readily upon exposing 10 to 1,2-propadiene. The reaction of 10 with 1,3-butadiene affords a pentenyl product, Ir(c-r|3-C5H8)[N(SiMe2CH2PPh2)2]. In previous studies, the iridium(I) r]2-cyclooctene species, \r{r\^-C%rl\^)-[N(SiMe 2CH 2PPh 2) 2], 25, has served as a useful starting material in the preparation of a number of iridium(I) and iridium(III) amide complexes. This complex is thermally iii stable, but upon photolysis, it yields Ir(H)2[N(SiMe2CH2PPh.2)2] and a mixture (2:1) of free 1,3-and 1,5-cyclooctadiene. This dehydrogenation process proceeds through anr|3-allyl hydride intermediate, Ir(ri3-C8Hi3)H[N(SiMe2CH2PPh2)2]- The cyclo-octene ligand in 25 can be replaced by 1,3-butadiene and. 1,2-propadiene. The products obtained from these reactions are Ir(ri4-C4H6)[N(SiMe2CH2PPh2)2] and Ir(r)2-C3H4)tN(SiMe2CH2PPh2)2]. respectively. The reaction of 25 with A l M e 3 affords Ir(u-AlMe2)Me[N(SiMe2CH2PPh2)2]-i v T A B L E OF CONTENTS Page ABSTRACT ....ii TABLE OF CONTENTS : v LIST OF TABLES xi LIST OF FIGURES xiii LIST OF ABBREVIATIONS '. xvi ACKNOWLEDGEMENTS xix CHAPTER 1 INTRODUCTION 1 1.1 General Introduction ;1 1.2 Hybrid Ligand Design in Organometallic Chemistry 2 1.3 Transition Metal Phosphide Complexes 3 1.3.1 Synthesis of Transition Metal Phosphide Complexes ...4 1.3.1.1 Metathesis with Lithium Phosphides ..4 1.3.1.2 Oxidative Addition of Phosphines 5 1.3.1.3 Deprotonation of Primary and Secondary Phosphines 6 1.3.2 Structure and Bonding of the Phosphide Ligand ..6 1.4 Intramolecular Carbon-Hydrogen Bond Activation-Cyclometallation 8 1.5 Transition Metal Carbene Complexes 12 1.5.1 Synthesis of Transition Metal Carbene Complexes 14 1.5.1.1 Heteroatom substituted Carbene Complexes 14 1.5.1.2 Alkylidene Complexes 16 1.5.2 Reactivity of Transition Metal Carbene Complexes 20 1.6 Scope of the Thesis 22 1.7 References 24 v CHAPTER 2 Synthesis and Characterisation of the Iridium(III) Phosphide Complexes and Their Thermolytic and Photolytic behaviour 32 2.1 Introduction 32 2.2 Solid-State Structure of Ir (CH 3 )PPh 2 [N(SiMe 2 CH 2 PPh 2 ) 2 ] , 2a 33 2.3 Synthesis and Characterisation of the Iridium Dimethylphosphide Complex, I r (CH 3 )PMe 2 [N(S iMe 2 CH 2 PPh 2 ) 2 ] , 2c 36 2.4 Synthesis and Characterisation of the Iridium Phenylphosphide Complex, I r (CH 3 )PHPh[N(SiMe 2 CH 2 PPh 2 ) 2 ] , 2d 38 2.5 Thermolysis of the Phosphide Complexes, 2a-2c 42 2.6 Kinetic and Mechanistic Studies of the Thermolysis of I r (CH 3 )PPh 2 [N(S iMe 2 CH 2 PPh 2 ) 2 ] , 2a, and / a c - I r ( r i 2 - C H 2 P P h 2 ) H [ N ( S i M e 2 C H 2 P P h 2 ) 2 ] , 3a 49 2.6.1 Kinetic Data 49 2.6.2 Mechanistic Considerations 54 2.6.3 Discussion of the Kinetic and Mechanistic Experiments ..66 2.7 Photolysis of I r ( C H 3 ) P R 2 [ N ( S i M e 2 C H 2 P P h 2 ) 2 ] , 2a-2c 69 2.8 Thermolysis of I r (CH 3 )PHPh[N(SiMe 2 CH 2 PPh 2 ) 2 ] , 2d 69 2.9 Kinetic and Mechanistic Experiments on the Thermolysis of 2d ..70 2.9.1 Kinetic Experiments 70 2.9.2 Mechanistic Considerations 73 2.9.3 Discussion on the Kinetics and the Mechanism 75 2.10 Photolysis of I r (CH 3 )PHPh[N(SiMe 2 CH 2 PPh 2 ) 2 ] , 2d 76 2.11 Synthesis of Other Cyclometallated Hydride complexes 77 2.11.1 Reaction of I r=CH 2 [N(SiMe 2 CH 2 PPh 2 ) 2 ] , 10, with H P i B u 2 77 2.11.2 Limitations of the Reactions of I r (R)X[N(SiMe 2 CH 2 PPh 2 ) 2 ] with M P R ' 2 77 2.12 References 83 C H A P T E R 3 Reactivity of the Iridium(III) Phosphide Complexes with Alkynes 86 3.1 Introduction..; 86 vi 3.2 Reaction of of Ir(CH3)PPh2[N(SiMe2CH2PPh2)2], 2a, with D M A D 89 3.3 Reaction of of Ir(CH3)PMe2[N(SiMe2CH2PPh2)2], 2c, with D M A D „ ..96 3.4 Reaction of of Ir(CH3)PPh2[N(SiMe2CH2PPh2)2L 2a, with P h O C P h 103 3.5 Reactions of of Ir(CH3)PPh2[N(SiMe2CH2PPh2)2L 2a, with RC=CH (R = H , Ph, tBu) 104 3.6 Summary 106 3.7 References 108 C H A P T E R 4 Synthesis and Reactivity of an Iridium Methylidene Complex 110 4.1 Introduction 110 4.2 Improved Synthesis of Ir=CH 2[N(SiMe2CH 2PPh 2) 2], 10 110 4.3 Reactivity of Ir=CH 2[N(SiMe2CH2PPh2)2], 10 115 4.3.1 Reactivity with AlMe3 and Mel 116 4.3.1.1 Reaction with Trimethylaluminum 118 4.3.1.2 Reaction with Methyl Iodide 123 4.3.2 Reactions with Unsaturated Hydrocarbons 126 4.3.2.1 Reaction with Acetylene 126 4.3.2.2 Reaction with 1,3-Butadiene 130 4.3.2.3 Reaction with Allene 134 4.4 Summary 142 4.5 References.... 143 C H A P T E R 5 Reactivity of the Iridium(I) ri2-Cyclooctene Complex 146 5.1 Introduction 146 5.2 Photochemical Carbon-Hydrogen Bond Activation of the Coordinated Cyclooctene in Ir(ri2-C8Hi4)[N(SiMe2CH2PPh2)2], 25 148 5.3. Reactions with Unsaturated Hydrocarbons 153 5.3.1 Reaction with 1,3-Butadiene 153 5.3.2. Reaction with Allene 158 vii 5.4. Reaction with Trimemylaluminum 159 5.5 Summary 163 5.6 References 164 C H A P T E R 6 General Conclusions and Recommendations for Future Studies ...167 C H A P T E R 7 Experimental Procedures 170 7.1 Materials 170 7.1.1 Solvents 170 7.1.2 Gases 170 7.1.3 Reagents , 171 7.1.4 Instrumentation 171 7.2 Synthesis and Characterisation of New Complexes 173 7.2.1 Ir(CH3)PMe2[N(SiMe2CH2PPh2)2], 2c 173 7.2.2 Ir(CH3)I(PHPh2)[N(SiMe2CH2PPh2)2], 9 174 7.2.3 Ir(CH3)PHPh[N(SiMe2CH2PPh2)2L 2d 174 7.2.4 /ac-Ir(Ti 2-CH 2PR 2)H[N(SiMe 2CH 2PPh 2) 2], (3a: R = Ph,3b: R = mera-tol): General Procedure 175 7.2.4.1 /ac-Ir(ri2-CH2PPh2)H-[N(SiMe2CH2PPh2)2], 3a 175 7.2.4.2 /ac-Ir[ri2.CH2P(mera-tol)2]H-[N(SiMe2CH2PPh2)2], 3b 176 7.2.5 /ac-Ir(ri 2-CH 2PMe 2)H[N(SiMe 2CH 2PPh 2) 2], 3c ....176 7.2.6 Ir(PCH3R2)[N(SiMe2CH2PPh2)2], (4a: R = Ph,4b: R = mera-tol, 4c: R = Me) 177 7.2.6.1 Method I: Thermolysis, General Procedure 177 7.2.6.1a Ir(PCH3Ph2)[N(SiMe2CH2PPh2)2],4a 178 7.2.6.1b Ir[PCH3(/nera-tol)2]-[N(SiMe2CH2PPh2)2], 4b 178 7.2.6.1c Ir(PMe3)[N(SiMe2CH2PPh2)2], 4c 178 7.2.6.2 Method II: Photolysis, General Procedure 179 7.2.6.2a Ir(PCH3Ph2)[N(SiMe2CH2PPh2)2], 4a 179 7.2.6.2b Ir[PCH3(mera-tol)2]-viii [N(SiMe 2 CH 2 PPh 2 ) 2 ] , 4b ..179 7.2.6.2c I r (PMe 3 ) [N(SiMe 2 CH 2 PPh 2 ) 2 ] , 4c 179 7.2.7 Ir(PHMePh)[N(SiMe 2 CH 2 PPh 2 ) 2 ] , 4d 179 7.2.8 I r=CH 2 [N(SiMe 2 CH 2 PPh 2 ) 2 ] + P H R 2 (R = Ph,tBu) ReactionsGeneral Procedure 180 7.2.8.1 I r=CH 2 (PHPh 2 ) [N(SiMe 2 CH 2 PPh 2 ) 2 ] , 5a.... 180 7.2.8.2 /ac-Ir(Ti2-CH 2 PPh 2 )H-[N(SiMe 2 CH 2 PPh 2 ) 2 ] , 6a 181 7.2.8.3 /ac-Ir(r i2-CH 2 PPh 2 )H-[N(S iMe 2 CH 2 PPh 2 ) 2 ] , 3a 181 7.2.8.4 I r=CH 2 (PHtBu 2 ) [N(SiMe 2 CH 2 PPh 2 ) 2 ] , 5e 181 7.2.8.5 /ac-Ir(Ti2-CH 2 PtBu 2 )H-[N(SiMe 2 CH 2 PPh 2 ) 2 ] , 6e 182 7 .2 .8 .6 / ac - I r(Ti2 -CH 2 PtBu 2 )H-[N(SiMe 2 CH 2 PPh 2 ) 2 ] , 3e 182 7.2.9 /ac-Ir(r i2-CH 2 PHPh)H[N(SiMe 2 CH 2 PPh 2 ) 2 ] , 6d 183 7.2.10 /ac-Ir(r]2-CHPhPMe 2 )H[N(SiMe 2 CH 2 PPh 2 ) 2 ] , 6f 183 7.2.11 I r (PMe 2 CH 2 Ph) [N(S iMe 2 CH 2 PPh 2 ) 2 ] , 4f 184 7.2.12 I r ( r i l -CH 2 PPh 2 )H(CO)[N(S iMe 2 CH 2 PPh 2 ) 2 ] , 7a 184 7.2.13 /ac - I r (CH 3 ) ( r i2 -CH 2 PMe 2 ) [N(S iMe 2 CH 2 PPh 2 ) 2 ] 185 7.2.14 I r ( C H 3 ) P P h 2 { C 2 ( C 0 2 M e ) 2 } -[N(S iMe 2 CH 2 PPh 2 ) 2 ] , 12. 185 7.2.15 I r ( C H 3 ) P M e 2 { C 2 ( C 0 2 M e ) 2 } -[N(SiMe 2 CH 2 PPh 2 ) 2 ] , 13 186 7.2.16 I r ( C H 3 ) I { C 2 ( C 0 2 M e ) 2 ) [ N ( S i M e 2 C H 2 P P h 2 ) 2 ] , 14 187 7.2.17 Ir(PhC=CPh)[N(SiMe 2CH 2PPh 2) 2], 15 .....187 7.2.18 I r (CH 3 )PHPh 2 (C=CR)[N(SiMe 2 CH 2 PPh 2 ) 2 ] , 16-18 (R = H , Ph, lBu): General Procedure...... 188 7.2.18.1 Ir(CH 3 )PHPh 2 (C=CH)-[N(SiMe 2 CH 2 PPh 2 ) 2 ] , 16 188 7.2.18.2 Ir(CH 3)PHPh 2(C=CPh)-[N(SiMe 2 CH 2 PPh 2 ) 2 ] , 17 189 7.2.18.3 Ir(CH 3 )PHPh 2 (C=C'Bu)-[N(SiMe 2 CH 2 PPh 2 ) 2 ] , 18 189 7.2.19 I r=CH 2 [N(SiMe 2 CH 2 PPh 2 ) 2 ] , 10 189 7.2.20 /ac-Ir(r i2-CH 2 NHtBu)H[N(SiMe 2 CH 2 PPh 2 ) 2 ] , 19 190 ix 7.2.21 Ir(u-AlMe2)H[N(SiMe2CH2PPh2)2], 20 190 7.2.22 Ir(Ti2-C2H4)H(I)[N(SiMe2CH2PPh2)2]. 21 191 7.2.23 Ir(Ti3.C3H5)(CsCH)[N(SiMe2CH2PPh2)2]. 22 191 7.2.24 Ir(a--n3-C5H8)[N(SiMe2CH2PPh2)2], 23 192 7.2.25 /ac-Ir{Ti4-C(CH2)3}[N(SiMe2CH2PPh2)2], 24 192 7.2.26 Ir(Ti3-C8Hi3)H[N(SiMe2CH2PPh2)2]. 27 .193 7.2.27 Ir(Ti4-C4H6)[N(SiMe2CH2PPh2)2],28 193 7.2.28 Ir(Ti2-C3H4)[N(SiMe2CH2PPh2)2], 29 194 7.2.29 Ir(H-AlMe2)Me[N(SiMe2CH2PPh2)2], 30 195 7.2.30 Rh(^-AlMe2)Me[N(SiMe2CH2PPh2)2], 31 ....195 7.3 Kinetic Experiments 196 7.3.1 Thermolysis Experiments 196 7.3.2 Carbonylation Experiment 196 7.4 References ..197 APPENDIX 198 A l X-ray Crystallographic Analyses 198 A2 Raw Data for the Kinetic Studies of the Thermolysis and Carbonylation Processes 248 x LIST OF TABLES Table Title Page 2.1 Selected Bond Lengths (A) for Ir(CH3)PPh 2-[N(SiMe 2 CH 2 PPh 2 ) 2 ] , 2a 35 2.2 Selected Bond Angles (deg) for Ir(CH3)PPh 2-[N(SiMe 2 CH 2 PPh 2 ) 2 ] , 2a 35 2.3 Selected Bond Lengths (A) for /ac-Ir(Ti 2 -CH 2 PPh 2 )H-[N(SiMe 2 CH 2 PPh 2 ) 2 ] , 3a 47 2.4 Selected Bond Angles (deg) for /ac-Ir(Ti 2 -CH 2 PPh 2 )H-[N(SiMe 2 CH 2 PPh 2 ) 2 ] , 3a 47 2.5 First-Order Analysis of the Absorption Spectral Changes for the Conversion of I r (CH3)PPh 2 [N(SiMe 2 CH 2 PPh 2 ) 2 ] , 2a, to/ac-Ir(ri 2-C H 2 P P h 2 ) H [ N ( S i M e 2 C H 2 P P h 2 ) 2 ] , 3a, at 83°C in Toluene 51 2.6 Observed Rate Constants and Activation Parameters for the Conversion of I r (CH3)PPh 2 [N(SiMe 2 CH 2 PPh 2 ) 2 ] , 2a, to /ac- I r(Ti 2-C H 2 P P h 2 ) H [ N ( S i M e 2 C H 2 P P h 2 ) 2 ] , 3a 52 2.7 First-Order Analysis of the Absorption Spectral Changes for the Conversion of /ac - I r ( r i 2 -CH 2 PPh 2 )H[N(SiMe 2 CH 2 PPh 2 ) 2 ] , 3a, to I r (PCH 3 Ph 2 ) [N(SiMe 2 CH 2 PPh 2 ) 2 ] , 4a, at 112°C in Toluene 53 2.8 Observed Rate Constants and Activation Parameters for the Conversion of /ac - I r ( r i 2 -CH 2 PPh 2 )H[N(SiMe 2 CH 2 PPh 2 ) 2 ] , 3a, to I r (PCH 3 Ph 2 ) [N(SiMe 2 CH 2 PPh 2 ) 2 ] , 4a, in Toluene 54 2.9 First-Order Analysis of the Absorption Spectral Changes for the Isomerisation of 6a to 3a at 46°C in Toluene 61 2.10 Observed Rate Constants and Activation Parameters for the Isomerisation of 6a to 3a in Toluene ; 62 2.11 First-Order Analysis of the Absorption Spectral Changes for the Thermolysis of Ir(CD3)PHPh[N(SiMe 2 CH 2 PPh 2 ) 2 ] , 2d-CD 3 , to I r (PHCD 3 Ph)[N(SiMe 2 CH 2 PPh 2 ) 2 ] , 4d-CD 3 , at 74°C in Hexanes 71 2.12 Observed Rate Constants and Activation Parameters for the Conversion of I r (CH 3 )PHPh[N(SiMe 2 CH 2 PPh 2 ) 2 ] , 2d, to xi Ir(PHCH 3Ph)[N(SiMe2CH 2PPh2)2].4d 72 3.1 Selected Bond Lengths (A) for Ir(CH3)PPh2{C2(C02Me)2}-[N(SiMe2CH2PPh2)2], 12 91 3.2 Selected Bond Angles (deg) for Ir(CH 3)PPh 2{C 2(C02Me) 2}-[N(SiMe2CH2PPh2)2], 12 91 3.3 Selected Bond Angles (deg) for Ir(CH 3)I{C2(C0 2Me) 2}-[N(SiMe 2 CH 2 PPh 2)2]. 14 100 3.4 Selected Bond Angles (deg) for Ir(CH3)I{C2(C02Me)2}-[N(SiMe 2 CH 2 PPh 2)2], 14 100 4.1 Chemical Shift and Coupling Constants for the Pentenyl Ligand Protons in Ir(a-rj3-C5H8)[N(SiMe2CH2PPh2)2]. 23 133 4.2 1 3 C { ] H ) N M R Data for the Pentenyl Ligand in Ir(a-Ti3-C5H8)[N(SiMe2CH2PPh2)2], 23 134 4.3 Chemical Shift and Coupling Constants for the Trimethylenemethane Ligand Protons and Carbons in /ac-Ir{ri4-C(CH2)3}[N(SiMe2CH2PPh2)2], 24 137 4.4 Selected Bond Lengths (A) for /ac- I r{Ti 4 -C(CH 2 ) 3 }-[N(SiMe 2CH 2PPh2)2], 24 139 4.5 Selected Bond Angles (deg) for /ac-I r{r , 4 -C(CH 2 ) 3 }-[N(SiMe 2CH 2PPh2)2], 24 139 5.1 Selected Bond Lengths (A) for Ir(r|4-C4H6)-[N(SiMe 2 CH 2 PPh 2)2], 28 157 5.2 Selected Bond Angles (deg) for Ir(rj4-C4H6)-[N(SiMe2CH 2PPh 2) 2], 28 157 xii LIST OF FIGURES Figure Title Page 1.1 Mixed hard soft donor ligands by Sacconi and co-workers 2 1.2 Tridentate amido-phosphine ligand bound to a metal centre 3 1.3 A transition metal complex containing (A) a pyramidal phosphide ligand (B) a planar phosphide ligand 7 1.4 Example of a Fischer carbene (A), and a Schrock carbene (B) 13 1.5 Chem-3D™ view of Ir=CH2[N(SiMe2CH2PPh2)2] 20 2.1 X-ray crystal structure of I r (CH3)PPh2 [N(SiMe 2 CH 2PPh2) 2], 2a 34 2.2 *H N M R spectrum (300 MHz, CyDg, -30°C) of I r (CH3)PMe 2 [N(SiMe 2 CH 2 PPh 2)2], 2c 37 2.3 *H N M R spectrum (300 MHz) of Ir(CH3)PHPh[N(SiMe2CH2PPh2)2], 2d (a) at RT in C6D6, (b) at -50°C in C 7 D g 41 2.4 *H N M R spectrum (300 MHz, C6D 6 ) of / a c - I r ( r i 2 - C H 2 P P h 2 ) H [ N ( S i M e 2 C H 2 P P h 2 ) 2 ] , 3a 44 2.5 X-ray crystal structure of /ac-I r (Ti 2 -CH 2 PPh 2 )H [N(SiMe 2 CH 2 PPh 2 ) 2 ] , 3a 46 2.6 *H N M R spectrum (400 MHz, C 6 D 6 ) of Ir(PCH3Ph2)[N(SiMe2CH2PPh2)2], 4a . ..49 2.7 Absorption spectral changes upon thermolysis of 2a at 83°Cin toluene 51 2.8 Eyring plot for the conversion of 2a to 3a in toluene and hexanes 52 2.9 Absorption spectral changes upon thermolysis of 3a at 112°C in toluene 53 2.10 Eyring plot for the conversion of 3a to 4a in toluene 54 2.11 *H N M R spectrum (300 MHz, C 7 D 8 ) of I r=CH 2 [N(SiMe 2 CH 2 PPh 2 ) 2 ] + P H P h 2 (a) at -78°C in CyDg, (b) at RT in Q D 6 59 2.12 3 1 P { J H} N M R spectrum (121.4 MHz, C7D8) of Ir=CH2[N(SiMe2CH2PPh2)2] + PHPh 2 (a) at -78°C, (b) at -20°C (c) at RT after 48 hours 60 xiii 2.13 Absorption spectral changes for the thermolysis of 6a at 46°C in toluene 61 2.14 Eyring plot for the conversion of 6a to 3a in toluene ..62 2.15 J H N M R spectrum (400 M H z , C6D 6 ) of Ir(ril-CH2PPh2)H(CO)[N(SiMe2CH2PPh2)2], 7a 65 2.16 Absorption spectral changes upon thermolysis of 2d-CD3 at 74°C in hexanes 71 2.17 Eyring plot for the conversion of 2d to 4d in toluene and hexanes 72 2.18 *H N M R spectrum (300 MHz, C6D 6 ) of /ac-Ir(Ti2-CH2PHPh)H[N(SiMe2CH2PPh2)2], 6d 74 2.19 3 1 P { !H} N M R spectrum (121.4 MHz, C 7Ds) of Ir=CH 2[N(SiMe 2CH2PPh 2)2] + P H l B u 2 (a) at -78°C, (b) at -10'C (c) at RT after 48 hours 79 2.20 ] H N M R spectrum (300 MHz, C 6 D 6 ) of /ac-Ir(ri2-CHPhPMe2)H[N(SiMe2CH2PPh2)2], 6f 82 3.1 X-ray crystal structure of Ir(CH3)PPh2{C2(C02Me)2) [N(SiMe 2 CH 2PPh2)2], 12 90 3.2 ! H N M R spectrum (400 MHz, C6D 6 ) of I r (CH 3 )PPh 2 { C 2 ( C 0 2 M e ) 2 } [N(SiMe 2CH2PPh 2) 2], 12 93 3.3 *H N M R spectrum (300 M H z , C 6 D 6 ) of Ir(CH3)PMe2{C2(C02Me)2}[N(SiMe2CH2PPh2)2], 13 98 3.4 X-ray structure of Ir(CH 3)I{C2(C0 2Me)2} [N(SiMe 2 CH 2PPh2)2], 14 99 3.5 *H N M R spectrum (300 MHz, C6D 6) of Ir(CH3)I{C2(C02Me)2}[N(SiMe2CH2PPh2)2], 14 101 4.1 X-ray crystal structure of Ir(u-AlMe2)[C(=CH2)CH3] [N(SiMe2CH2PPh2)2] 117 4.2  lll N M R spectrum (300 MHz, C6D 6 ) of I r ( u - A l M e 2 ) H [ N ( S i M e 2 C H 2 P P h 2 ) 2 ] , 20 120 4.3 ] H N M R spectrum (300 M H z , CoD 6 ) of Ir(Ti 2-C 2H 4)H(I)[N(SiMe 2CH2PPh2)2], 21 124 4.4 ] H N M R spectrum (300 MHz, C6D 6 ) of Ir(Ti3-C3H 5)(C=CH)[N(SiMe 2CH 2PPh 2) 2], 22 128 4.5 1 3 C - ] H HETCOR spectrum (300 M H z , C6D 6 ) of Ir(a-ri 3-C5H8)[N(SiMe 2CH 2PPh 2)2], 23 132 xiv 4.6 *H NMR spectrum (300 MHz, C6D6) of /ac-Ir{Ti4-C(CH2)3}[N(SiMe2CH2PPh2)2], 24 136 4.7 X-ray crystal structure of /ac-Ir{Ti4-C(CH2)3}[N(SiMe2CH2PPh2)2],24 ..138 5.1 1H NMR spectrum (300 MHz, C6D6) of Ir(Ti3-C8H1 3)H[N(SiMe2CH2PPh2)2], 27 151 5.2 Bonding modes of 1,3-butadiene 154 5.3 13c-lH HETCOR spectrum (300 MHz, CgD6) of Ir(Ti4-C4H6)[N(SiMe2CH2PPh2)2L 28 155 5.4 X-ray crystal structure of Ir(r|4-C4H6)[N(SiMe2CH2PPh2)2], 28 156 5.5 Modes of allene coordination at a metal centre 158 5.6 lH NMR spectrum (300 MHz, C 6 D 6 ) of Ir(ri2-C3H4)[N(SiMe2CH2PPh2)2], 29 160 5.7 *H NMR spectrum (300 MHz, C 6 D 6 ) of Ir(ji-AlMe2)Me[N(SiMe2CH2PPh2)2],30 162 xv LIST OF ABBREVIATIONS The following list of abbreviations, most of which are commonly used in the chemical literature, wil l be employed in this thesis: At absorbance at time t (UV-Vis) A angstrom, 10~8 centimeter APT attached proton test (NMR) atm atmosphere; 1 atm = 760 mm Hg br broad Bu butyl, CH 2(CH 2)2CH 3 lBu tertiary butyl, C(CH 3 ) 3 Bz benzyl, CH 2 C6H 5 1 3 C carbon-13 cm centimeter . COD cyclooctadiene COE cyclooctene Cp cyclopentadienyl, r|5-C5H5 Cp* pentamethylcyclopentadienyl, ri5-C5Me5 °C degree Celsius d doublet (NMR) DBU l,8-diazabicyclo[5.4.0]undec-7-ene dd doublet of doublets (NMR) DMAD dimethylacetylenedicarboxylate dt . doublet of triplets deg degree xvi deg fac gem 1H Hz HETCOR IR 'Pr J k L 1 M m M e mer meta-\o\ min mL mmol mol nm N M R NOEDIFF obs degree facial geminal proton-1 Hertz, cycles per second heteronuclear correlation (NMR) infra-red iso-propyl, ( C H 3 ) 2 C H coupling constant, in Hz rate constant ligand litre path length central metal atom in a complex multiplet (NMR) moderate intensity (IR) methyl, CH3 meridional mera-tolyl, ( ^ ( C g H O o minute(s) millilitre millimole(s) mole(s) nanometer(s) nuclear magnetic resonance nuclear Overhauser effect difference observed xvii 3 1 P phosphorus-31 Ph phenyl, C6H5 ppm parts per million r.d.s. rate determining step RT room temperature s singlet (NMR), strong (IR) T temperature t triplet ten tertiary U V - V i s ultraviolet-visible W Watt w weak intensity (IR) A heat e extinction coefficient (in mol" 1 L cm - 1 ) X wave length 8 chemical shift (in ppm downfield from T M S ) v frequency (cm - 1) r) descriptor for hapticity (I descriptor for bridging xviii ACKNOWLEDGEMENTS I would like to thank Professor M . D. Fryzuk for his guidance, encouragement, and patience throughout the duration of this work. I am also indebted to members of the Fryzuk group (past and present) for their friendship and support. I wish to express my gratitude to the proof-readers for their excellent criticism. The assistance of the various departmental services is gratefully acknowledged. Finally, I would like to thank my family for their encouragement and support over the years. xix CHAPTER 1 Introduction 1.1 General Introduction The last three decades have witnessed a tremendous growth in the field of organometallic chemistry. Organometallic compounds, particularly those of the transition metals, are becoming increasingly important in many stoichiometric and catalytic transformations; for example, the speciality chemicals, L-dopa 1 and naproxen,2 are synthesised via highly specific and selective transformations. Interest in such processes has also provided the impetus for synthesis and reactivity of new organometallic compounds. This thesis deals with the transformations of a number of iridium complexes that contain phosphide (-PR2), alkyl (-CR3) or alkylidene (=CR2) ligands. Before this work is presented, some background in hybrid ligand strategy, phosphide and carbene chemistry, and cyclometallation process is appropriate to put the thesis work in perspective. 1 1.2 Hybrid Ligand Design in Organometallic Chemistry The chemistry of transition metal complexes is largely governed by the electronic and steric properties of the ligands. 3 Even a subtle variation in ligand design can dramatically influence the reactivity of transition metal complexes. Therefore, a considerable effort has been directed towards the synthesis of new ligands.4 Sacconi and co-workers have synthesised multi-dentate, neutral ligands with mixed hard (e.g. N) and soft donors (e.g. P, As) (Figure 1.1).5 According to the hard-soft acid-base theory, "hard acids prefer to bind to hard bases and soft acids prefer to bind to soft bases."6 Transition metal complexes often follow this rule as evidenced from the fact that soft late transition metals form a large number of complexes with the soft tertiary phosphines.7 In contrast, few phosphine derivatives of the hard early transition metals have been reported.8 CH 2 CH 2 NE t 2 (1) Y = NEt2; Z = PPh 2 / (2) Y = Z = PPh 2 : N " C H 2 C H 2 Y (3) Y=NEt 2 ; Z = AsPh2 \ C H 2 C H 2 Z (4)Y = Z = AsPh 2 Figure 1.1 Mixed hard-soft donor ligands by Sacconi and co-workers4 The anionic amido-phosphine tridentate ligand, "[N(SiMe2CH2PR-2)2] (R = Me, Ph, 'Pr, lBu), was first synthesised in our laboratory (Figure 1.2).9 The impetus for the design of this ligand originated from the aforementioned fact that soft tertiary phosphines formed relatively few derivatives of the hard early transition metals, while the hard amide donors provided only a few stable, late transition metal complexes. 1 0 Thus, it was thought that incorporation of the amide donor "NR.2 into a chelating array 2 of phosphines might allow coordination to a wide range of transition metals. This indeed was the case as a variety of amide phosphine complexes of both the early and the late transition metals have been prepared with this tridentate ligand system. 1 1 Recently, this work has been extended to lanthanides.12 Figure 1.2 Tridentate amido-phosphine ligand bound to a metal centre In most cases, the tridentate ligand acts as an ancillary (innocent) ligand. Recent studies have shown that it can become involved in certain reactions. 1 3 Some of these reactions are mentioned in this thesis (Chapters 3-5). 1.3 Transition Metal Phosphide Complexes Tertiary phosphine complexes of the transition metals ( L n M - P R 3 ) are numerous due to the fact that they are easily prepared and quite stable. These complexes serve as catalyst precursors for such industrially important processes as hydrogenation, hydroformylation and polymerisation. 1 4 In addition to the well-known trivalent phosphines, other valencies of phosphorus are known but less studied. These include metallated phosphoranes ( - P R 4 ) , 1 5 terminal phosphides ( - P R 2 ) 1 6 and phosphinidenes (=PR). 1 7 Although phosphorane and phosphinidene complexes are rare, the chemistry of the transition metal phosphide complexes has become a rapidly 3 growing research area. Now terminal phosphide complexes have been synthesised for most of the transition metals. 1.3.1 Synthesis of Transition Metal Phosphide Complexes There are many ways to synthesise transition metal phosphide complexes. The following examples highlight the primary synthetic methods used to generate this class of compounds. 1.3.1.1 Metathesis with Lithium Phosphides A variety of phosphide complexes of group 4 transition metals have been prepared via metathesis of the bis(cyclopentadienyl)dihalide complexes of zirconium or hafnium with two equivalents of the lithium phosphide reagents (Equation 1.1).1 8 The extensive use of this preparative method is due to the easy accessibility of the required alkali phosphides; in particular, lithium dialkyl and diaryl phosphides are readily prepared from the corresponding secondary phosphines and BuLi (Equation 1.2). Most of the dialkyl and diaryl lithium phosphides can be isolated as solids which are stable at room temperature under an inert atmosphere for extended periods of time. CP2MCI2 + 2LiPR 2 * - C p 2 M ( P R 2 ) 2 + 2 LiCI M = Hf, Zr R = Et, Ph, Cy Equation 1.1 HPR 2 + BuLi • LiPR2 + BuH Equation 1.2 4 A recent publication 1 9 makes use of a similar metathetical reaction (Equation 1.1) involving the complexes, Cp*2HfCl2 and Cp*2ZrCl2, but with one equivalent of the secondary lithium phosphide salt, L iPHR (Scheme 1.1). These phosphide complexes were tested as possible precursors of the corresponding phosphinidene complexes via dehydrohalogenation reactions; however, it is believed that a polymeric species containing phosphinidene units was produced. Cp* 2MX 2 + LiPHR • Cp*2M(X)(PHR) + LiX M = Hf, Zr •X-CI.I BuLi R = Ph, Cy [Cp*2M=PR]x Scheme 1.1 1.3.1.2 Oxidative Addition of Phosphines The first six-coordinate rhodium(III) and iridium(III) complexes containing PX2 (X = F, CI, H) ligands were prepared by the oxidative addition of a PX2Y species to a low-valent Vaska-type rhodium(I) and iridium(I) complexes (Equation 1.3).20 The rhodium phosphides reported in the abovementioned study still remain the only phosphide complexes known for this metal. trans -M(CO)CI(PEt3)2 + PX 2Y • trans -M(PX2)(CO)CI(Y)(PEt3)2 M = Rh,lr X = F; Y = CI, Br, L H X = CI;Y = CI X = H; Y = H Equation 1.3 5 1.3.1.3 Deprotonation of Primary and Secondary Phosphines Primary and secondary phosphine complexes can be deprotonated readily in the presence of strong nucleophilic bases such as l,8-diazabicyclo[5.4.0]undec-7-ene (DBU), KCKBu, NaN(SiMe3)2 or BuLi , to yield terminal phosphide complexes.2 1 An example of this preparative method is shown in Equation 1.4. M = Ru, Os Equation 1.4 1.3.2 Structure and Bonding of the Phosphide Ligand A terminal phosphide ligand in a mononuclear transition metal complex can either be pyramidal or planar (Figure 1.3).22 A simple bonding scheme distinguishing these two conformations is shown in A and B. In the case of pyramidal geometry, the PR.2~ ligand is a two-electron donor and is bound to the metal via a G-bond; in the planar geometry, the ligand is a four-electron donor and must involve 7t-bonding with the metal. 6 R LnM P.. LnM '"R R A B Figure 1.3 A transition metal complex containing (A) a pyramidal phosphide ligand A distinguishable feature of the two configurations is the metal-phosphorus bond length: complexes containing planar phosphide group possess a shorter M-P bond compared to that of complexes containing pyramidal group. In addition, a difference is noted in the metal-phosphorus-substituent bond angles: the ranges are reported to be 127-140° for planar and 106-114° for pyramidal phosphide complexes.2 1 These two types of complexes can also be distinguished by 3 1 P N M R spectroscopy. In complexes of type B, the 3 1 P N M R resonances are usually shifted to low field as compared to complexes of type A . The 3 1 P chemical shifts for pyramidal and planar phosphide complexes reported in the literature range from -270 to +420 ppm and +200 to +400 ppm, respectively.1 6 The iridium(III) methyl diarylphosphide complexes of formula, Ir(CH3)PR2-[N(SiMe2CH2PPh2)2] (R = phenyl, meta-tolyl), were synthesised via metathesis of the iridium(III) methyl halide complex, Ir(CH3)I[N(SiMe2CH2PPh2)2L with the appropriate lithium phosphide, LiPR2, as a part of my M.Sc. thesis. 1 6 a > 6 5 The synthesis and characterisation of the dimethylphosphide complex, Ir(CH3)PMe 2-[N(SiMe2CH2PPh2)2l, and of the phenylphosphide complex, Ir(CH3)PHPh-[N(SiMe2CH2PPh2)2], are described in this thesis (Chapter 2). (B) a planar phosphide ligand 7 1.4 Intramolecular Carbon-Hydrogen Bond Activation — Cyclometallation Alkanes are major constituents of natural gas, petroleum and coal liquefaction processes. Their use as feedstocks for large-scale catalytic synthesis of organic molecules by activation of C - H bonds and subsequent functionalisation is of industrial importance. 2 3 However, the C - H bonds in alkanes are relatively unreactive. This apparent lack of reactivity is partly a consequence of the high C - H bond energies (-400 K J mol" 1 ) . 2 4 Some soluble transition metal systems have been found which are capable of activating such C - H bonds. 2 5 Carbon-hydrogen bond activation by transition metal complexes can be achieved intermolecularly 2 6 (Equation 1.5) or intramolecularly 2 7 (Equation 1.6). Related to the intramolecular C - H activation is the cyclometallation of tertiary phosphines which is described in this thesis work. 2 8 R I (n + 2) M<n) + R-H _ H M Equation 1.5 Equation 1.6 One of the earliest structurally well-defined examples of an intramolecular C -H activation involving the formation of ruthenium dimer complexes was reported by Chatt and Davidson in 1965 (Equation 1.7).29 Later, Tolman and co-workers studied the activation of C - H bonds in CH3X (X = C N , CO2EO by some iron and ruthenium 8 compounds (Equation 1.8). 3 0 In these reactions, the reductive elimination of naphthalene to form the corresponding M(0) species was found to be the rate-determining step. In contrast, some alkyl hydride complexes of ruthenium and osmium, ci"s-(PMe3)4Ru(H)Me 3 1 and c/s-(dmpe)20sH(CioH7), 3 0 are stable toward thermal reductive elimination. H \ / P (dmpe)2Ru / H 150°C - CioH 8 (dmpe)Ru j_ drA2 P - C H 2 - p Ru (dmpe) dmpe = Me 2 PCH 2 CH 2 PMe 2 (dmpe)2M H Equation 1.7 CH 3X, A -CTQHS (dmpe)2M \ H CH 2X dmpe = Me 2 PCH 2 CH 2 PMe 2 M = Fe, Ru X = CN, C0 2Et Equation 1.8 However, the complex c/s-(PMe3)40sH[CH2C(CH3)3] undergoes intra-molecular activation of one of the C - H bonds of the bound P M e 3 ligand to form the cyclometallated hydride complex/ac-(PMe3)30s(ri 2-CH2PMe2)H at 80°C (Equation 1.9), presumably via the intermediate "(PMe3)40s". 3 2 A similar cyclometallation reaction is observed upon the reduction of ruthenium and osmium complexes with sodium amalgam (Equation 1.10).33 9 V *PMe3 \ CH2 Me3P_Os'-^ ^ 04—>Me2 / \ \ - (-CMe4) (PMe3)3 Me3P PMe3 Equation 1.9 ? ^ P M e 3 | CH2 Me 3P_ M-lpMe 3 N a / H9 , M < l ^ M e 2 y\ (-2 NaCl) (PMe3)3 Me3P ci M = Ru, Os Equation 1.10 Irradiation of rhenium(I) complex, CpRe(PMe3)3, at 5-10°C in cyclohexane yielded two products originating from intramolecular C-H activation of the PMe3 ligand (Scheme 1.2). However, when the complex was photolysed in a solvent such as benzene (which is more prone to intermolecular C-H activation compared to cyclohexane), the complex CpRe(Ph)H(PMe3)2 was produced.34 Me3P R'e „CH 2 R'e Jl . / VMe2 Me3P / PMe3 + PMe3 CeH6 h v R'e P M e 3 H / \ ^ P M e 2 PMe3 R ' e P M e 3 Scheme 1.2 Ph PMe3 10 The synthesis of cyclometallated complexes via metathetical reactions has also been reported. The use of a lithiating reagent such as LiCH2PR.2 (R = Me, lBu) with CoCl(PMe3)3 generates Co(ri2-CH2PR2)(PMe3)3 (Equation l . l l ) . 3 5 The treatment of RuCl2(PMe3)4 with LiCH2(=CH2)PMe2 gives a complex containing both three and four-membered rings (Equation 1.12).3 6 The reaction of mer-IrCl3(PMe2Ph)3 with Li(CH2)sLi generates the three-membered iridacycle shown in Equation 1.13.33 CoCI(PMe3)3 + LiCH 2PR 2 • Co(t|2-CH2PR2)(PMe3)3 (-LiCI) R = Me,-Bu Equation 1.11 RuCI2(PMe3)4 + Me 2P(=CH 2)CH 2Li (-LiCI) Equation 1.12 mer-lrCI3(PMe2Ph)3 + Li(CH2)5Li • lrCI2(r|2-CH2PMePh)(PMe2Ph)2 (-LiCI) Equation 1.13 Attempts to prepare some ruthenium amide complexes by treating ruthenium halide species with lithium amide salts resulted instead in the metallation of the PMe3 ligand to give the corresponding three-membered metallacyclic complexes (Equation 1.14). 3 7 Similar cyclometallation was observed when the iridium system mer-IrCl 3{P(Me)(CH2Ph) 2b was reacted with LiN(iPr)2 (Equation 1.15).36 H 2 C PMe 3 I ^ C H 2 Me2P<J J ^ R u C I • C * ^ I ^ P M e 2 H 2 I PMe 3 11 Cp*(PMe3)2RuCI + LiNHlE3u (-tBuNH2) (-LiCI) Cp*(PMe3)Ru(r,2-CH2PMe2) Equation 1.14 /ner-lrCl3[PMe(CH2Ph)2l3 + LiN'Pr2 (-LiCI) (-'Pr2NH) Me(CH 2Ph) 2P Me(CH 2Ph) 2P •Ir CI CI CI "^-CH 2Ph Ph Equation 1.15 In this thesis, cyclometallated hydride complexes of formula Ir(r|2-CH2PR2)H-[N(SiMe2CH2PPh2)2l are described. These' species were synthesised (i) via the thermal rearrangement of the phosphide complexes Ir(CH3)PR2[N(SiMe2CH2-PPh2hL (ii) by the reactions of the alkylidene species Ir=CH2[N(SiMe2CH2PPh2)2] with free phosphines PHR2 and PH2R (Chapter 2). 1.5 Transition Metal Carbene Complexes The ability of transition metal complexes to stabilise very reactive organic fragments, such as carbenes, 3 8 vinylidenes, 3 9 benzynes 4 0 and thiocarbonyls, 4 1 constitutes a basic facet of organometallic chemistry. Carbenes OCR2) are short-lived chemical species which can only be isolated by entrapment in low temperature matrices. 4 2 However, they can also be stabilised by coordination to a metal centre. 12 Indeed, much has been reported on the formation of transition metal carbene complexes (M=CR.2) and the reactivity of the coordinated carbene uni t . 3 8 The importance of metal carbene complexes in a variety of different processes such as olefin metathesis,43 cyclopropanation,4 4 ethylene polymerisation (propagation step in the Ziegler-Natta mechanism) 4 5 and alkyne co-cycl isa t ion 4 6 is now well appreciated. 4 7 Also, surface bound carbenes have been postulated as intermediates in Fischer-Tropsch chemistry. 4 8 The first example of a stable transition metal carbene complex was reported by Fischer and Maasbol in 1964. 4 9 Since then a vast number of carbene complexes have been reported. In these complexes, one or both of the substituents on the carbene carbon are heteroatom (other than C and H) substituents (Figure 1.4 A ) . These complexes are common among the late transition metals, and are generally referred to as "Fischer carbenes". A series of early transition metal complexes without a heteroatom substituent on the carbene carbon was reported by Schrock (Figure 1.4 B ) . 5 0 These complexes are often called alkylidenes or "Schrock carbenes". OMe H Me A B Figure 1.4 Example of a Fischer carbene (A), and Schrock carbene (B) 13 1.5.1 Synthesis of Transition Metal Carbene Complexes Since the pioneering work of Fischer's group and Schrock' group, hundreds of transition metal carbene complexes have been prepared by many different synthetic methods. (From this point in the thesis, Fischer and Schrock complexes wi l l be known as transition metal carbene complexes). Examples of some of these routes are mentioned below. 1.5.1.1 Heteroatom Substituted Carbene Complexes These carbene complexes are still prepared by the method of Fischer and Massbol. This reaction involves the external attack of a carbanionic nucleophile such as R~ in L i R at the carbon atom of a coordinated carbonyl ligand to give an anionic metal acyl complex (Scheme 1.3); subsequent attack of an electrophilic reagent at the acyl oxygen atom converts it into the corresponding carbene complex. 5 1 Cr(CO)6 + LiR -R = Me, Ph Li + (CO) 5Cr-c; Me 3 OBF 4 R (- LiBF4) (- Me 20) OMe (CO)5Cr=C Scheme 1.3 An ce-hydroxyalkyne reacts with an iridium(III) complex and affords an iridium(III) bis(oxacyclopentylidene) complex (Equation 1.16). 5 2 A variety of ruthenium carbene complexes have also been generated in a similar manner. 5 3 14 dBF 4 R | ^NCCH 3 | R OH •1 ( - 2 N C C H 3 ) -NCCH3 R = CO2CH3 L = PPh 3 Equation 1.16 Electron-rich olefins such as A in Equation 1.17 have been used in the synthesis of a large number of mono-, bis-, tris- and tetracarbene complexes of ruthenium, osmium, rhodium and iridium. 5 4 Me I lrCI(CO)(PPh3)2 + [ ) = ( ^ N a B F 4 > CO(PPh3)2lr = / ^ 1 (-NaCl) \y I Me Me . Me A Equation 1.17 A variety of late transition metal dihalocarbene complexes have also been reported in recent years. These complexes were prepared by halide abstraction from a trihaloalkyl ligand with Lewis acids such as BF3 (Equation 1.18).55 15 P P h 3 P P h 3 Equation 1.18 1.5.1.2 Alkylidene Complexes Alkylidene complexes are generally prepared by the removal of an a-hydrogen from an alkyl ligand. In many cases, steric crowding induces the alkane loss, and affords alkylidene formation from group 5 and 6 transition metal dialkyl complexes (Equation 1.19).56 M (CH 2CMe 3) 3 C l 2 + 2LiCH 2CMe 3 ^ ( M ^ C O ^ M = C f + CMe 4 (-2LiCI) ^ C M e 3 M = Nb, Ta Equation 1.19 The reactions of low-valent Ru, Os and Ir complexes with diazoalkanes provide the most general route to d 8 alkylidene species. 5 5 The osmium complex, Os(Cl)NO(PPh3)3, for example, reacted with diazomethane or diazoethane at room temperature to form the stable methylidene or ethylidene complex (Equation 1.20). Diazomethane addition to Ir(CO)I(PPh 3) 2 at -50°C yielded Ir=CH2(I)CO(PPh 3)2. 5 5 This methylidene complex rearranged to the orthometallated ylide complex (Scheme 1.4) when its solution was warmed to room temperature. 16 N 2 OsCI(NO)(PPh3)3 H' (-PPh 3, -N 2 ) CI(NO)(PPh 3) 2Os=C Equation 1.20 I r (CO)I(PPh3)2 + CH 2 N 2 -50 'C (-N2) Scheme 1.4 R = H, Me l r=CH 2 (CO)I (PPh3) 2 RT H PPh 2 OC — I r — C H 2 PPh 3 The synthesis of stable cationic rhenium methylidene complexes has been reported by Gladysz and co-workers. 5 7 The complex, [Cp*Re=CH2(NO)(PPh3)3]+, was prepared by treating the rhenium alkyl complex, Cp*Re(CH3)NO(PPh3)3, with trityl hexafluorophosphate (Equation 1.21). ON Ph 3C+PF 6~ PPh 3 (- HCPh3) ON Re + —|PF6 \ PPh 3 C H 3 H H Equation 1.21 17 The synthesis of an iridium(L) alkylidene species using IrHCl-[tBu2P(CH2)2CH(CH2)2PtBu2] as precursor has been described by Shaw's group. Elimination of H2 from the precursor complex by thermolysis afforded the desired Ir(I) alkylidene complex (Equation 1.22).58 Although this is considered to be a text book example,59 poor yields and the irreproducibility of the reaction have prevented any detailed study of this compound. 200°C / — P B u 2 1 5 mmHg > — P B u 2 <T i <-"*>. < j H — C — I r — c i _ C = l r — C I A / ' I ( + h 2 ) / I ^ — P'Bu 2 ^ — P B u 2 Equation 1.22 A recent example of a cyclopentadienyl iridium alkylidene species is shown in Equation 1 .23. 6 0 The complex Cp*Ir=CH2(PMe3) was prepared by the photoextrusion of acetone from a 2-oxametallacyclic complex at -60°C. At temperatures higher than -40°C, the methylidene complex decomposed. Equation 1.23 In 1985, the preparation of an iridium(I) methylidene complex, Ir=CH2-[N(SiMe2CH2PPh2)2]> via photochemical a-hydrogen abstraction (or elimination) from the iridium(III) dialkyl complex, Ir(CH3)(CH2CMe3)[N(SiMe2CH2PPh2)2] (Scheme 1.5) was reported by Fryzuk and co-workers.6 1 This complex was the first example of a stable sixteen-electron square-planar late metal-alkylidene species. 18 The complex Ir=CH2[N(SiMe2CH2PPh2)2] was isolated in low yields (15-20%), and was characterised by X-ray crystallography (Figure 1.5). The stability of this complex compared to the above mentioned iridium alkylidene complexes is attributed to the tridentate ligand on the metal centre. The phenyl substituents on the phosphine centres of the tridentate ligand seem to provide a "pocket" which protects the methylene unit. The major product of the reaction was the iridium(III) dihydride species, Ir(H)2[N(SiMe2CH2PPh2)2]». (Scheme 1.5). An in-depth study of the reactivity of the iridium-alkylidene complex was prevented by the difficulty in obtaining it in good yield. 6 2 h v , 1 8 h o u r s N Ir + H2C=CHCMe3 P h 2 P h 2 55 % * Lil LiCH 2 CMe 3 + C H 2 + CMe 4 45 % * * in situ yield Scheme 1.5 19 Figure 1.5 Chem-3DTM v i e w of Ir=CH2[N(SiMe2CH2PPh2)2] 1.5.2 Reactivity of Transition Metal Carbene Complexes A traditional view regarding the reactivity of transition metal carbene complexes suggests that Fischer carbene complexes display electrophilic reactivity at the carbene carbon. In these complexes, replacement of a methoxy group by an amide group, for example, is initiated by the attack of the nucleophile at the carbene carbon (Equation 1.24).63 In contrast, the alkylidene carbon of Schrock carbenes generally displays nucleophilic behaviour. The nucleophilicity of the methylene ligand in Cp 2(CH3)Ta=CH 2 was illustrated by complexation with the electrophile AlMe3 (Equation 1.25).56a (CO)5Cr = C(OMe)Ph RNH 2 (CO)5Cr = C(NHR)Ph (- MeOH) Equation 1.24 C H 3 C H 3 Equation 1.25 20 However, such a sharp distinction between the electrophilic versus the nucleophilic nature of the metal-carbon double bond does not always ho ld . 5 5 For example, an alkylidene ligand can easily become electrophilic when it is part of a cationic species (Equation 1.26).55 In addition, there are complexes reported in the literature in which the carbene carbon shows amphiphilic (both nucleo- and electrophilic) behaviour. 6 4 The rhenium alkylidene complex, Cp(CO)2Re=C[(D)(CH2CH2CMe3)], undergoes protonation at the alkylidene carbon upon reaction with HC1 at -80°C and affords the corresponding alkyl rhenium species (Scheme 1.6). 6 4 a It also reacts with the nucleophile PMe3 to produce the zwitterionic complex (A, Scheme 1.6). [Cp(NO)(PPh3)Re = CH 2 ] + MeLi ^ Cp(NO)(PPh 3)Re-CH 2CH 3 Equation 1.26 PMe 3 '•- D + A Scheme 1.6 21 A new and improved synthesis of the methylidene complex, I r=CH 2 -[N(SiMe2CH2PPh2)2L is reported in this thesis (Chapter 4). Reactions of this complex with some electrophiles and with some unsaturated hydrocarbons are described. 1.6 Scope of the Thesis The iridium(III) methyl diarylphosphide complexes, Ir(CH3)PR2-[N(SiMe2CH 2 PPh 2 )2L (2a: R = phenyl, 2b: R = meta-tolyl) were prepared. The photolysis and the reactivity of complex 2a with small molecules such as H2, CO and Mel were studied as part of my M.Sc. thesis. 6 5 These complexes were proposed to be square pyramidal, with the methyl ligand in the apical position (from NOE-DIFF experiments). Furthermore, although inconclusive, the geometry at the phosphide phosphorus nucleus was assigned as pyramidal (from 3 1 P NMR spectral data). 6 5 Chapter 2 describes the results of a crystallographic study on complex 2a. In addition, the syntheses of the dimethylphosphide complex, Ir(CH3)PMe2-[N(SiMe2CH 2 PPh 2 )2], 2c, and the phenylphosphide complex, I r ( C H 3 ) P H P h -[N(SiMe 2CH2PPh2)2l, 2d, are discussed. Complexes 2a-2c undergo thermal rearrangement to yield cyclometallated hydride species of formula Ir(rj 2 -CH 2PR2)H[N(SiMe2CH 2PPh2)2]- The results of this process along with the kinetic and mechanistic details constitute the major part of this chapter. Some of the intermediates proposed in the mechanism of the thermolysis reaction of 2a were prepared via a different synthetic route involving the reaction of the iridium methylidene complex, I r = C H 2 [ N ( S i M e 2 C H 2 P P h 2 ) 2 ] , and PHPh.2. The characterisation of other cyclometallated hydride complexes prepared by the reaction of Ir=CH2[N(SiMe2CH2PPh2)2] with PHtBu 2 and PH 2 Ph is also described. Complex 22 2d shows thermal reactivity different than that of 2a-2c. The kinetic and mechanistic details of this reaction are presented. Photolytic behaviour of 2a-2d is also described in this chapter. Chapter 3 consists of the reactivity of complex 2a with various alkynes such as diphenylacetylene, phenylacetylene, rerr-butylacetylene, acetylene, and dimethyl-acetylenedicarboxylate (DMAD) . The reaction of complex 2c with D M A D is also discussed. A n improved synthesis of the iridium methylidene complex, Ir=CH2-[N(SiMe2CH2PPh2)2L is reported in chapter 4. The reactivity of this alkylidene complex with electrophiles such as trimethylaluminum and methyl iodide is described. Furthermore, some interesting reactions were observed on reacting the methylidene complex with 1,3-butadiene, 1,2-propadiene (allene) and acetylene. They are also discussed in chapter 4. The iridium(I) cyclooctene complex, Ir(ri 2-C8Hi4)[N(SiMe 2CH2PPh2)2L serves as a usefull starting material in a variety of reactions leading to iridium(I) and iridium(III) amide complexes. Chapter 5 consists of a study of the photochemical versus thermal reactivity of this complex, along with its reactions with dienes such as 1,3-butadiene and 1,2-propadiene (allene). The reaction with trimethylaluminum is also mentioned. Chapter 6 outlines some general conclusions and recommendations for future work. The experimental procedures used in this thesis work are described in chapter 7. 23 1.7 References 1 Knowles, W. S. Aces. Chem. Res. 1983,16, 206. 2 Haggin, J. Chem. Eng. News May 7,1990, 58. 3 McAuliffe, C. A. Compr. Coord. Chem. 1987,2, 989. 4 Collman, J. P.; Hegedus, L . S.; Norton, J. R.; Finke, R. G. Principles and Applications of Organotransition Metal Chemistry; University Science Books: M i l l Valley, C A , 1987, Chapter 3. 5 (a) Bertini, I.; Dapporta, P.; Fallani, G.; Sacconi, L . Inorg. Chem. 1971,10, 1703. (b) Sacconi, L . ; Morassi, R. / . Chem. Soc. (A) 1969, 2904. 6 Pearson, R. G. J. Chem. Ed. 1968, 45, 581 and 643. 7 (a) Levason, W.; MacAuliffe, C. A . Phosphine, Arsine, and Stibine Complexes of Transition Elements; Elsevier: Amsterdam, 1979. (b) Tolman, C. A . Chem. Rev. 1977, 77,-313. 8 (a) Fryzuk, M . D.; Haddad, T. S.; Berg, D. J. Coord. Chem. Rev. 1990, 99, 137. (b) Datta, S.; Fisher, M . B.; Wreford, S. S. J. Organomet. Chem. 1980, 188, 353. (c) Parshall, G .W.; Schrock, R. R. Chem. Rev. 1976, 76, 243. 9 Fryzuk, M . D.; MacNeil, P. A . / . Am. Chem. Soc. 1981,103, 3592. 10 (a) Fryzuk, M . D.; Montgomery, C. D. Coord. Chem. Rev. 1989, 95, 1. (b) Bryndza, H. E.; Tarn, W. Chem. Rev. 1988, 88, 1163. (c) Lappert, M . F.; Power, P. P.; Sanger, A . R.; Srivastava, R. C. Metal and Metalloid Amides; Horwood-Wiley: Chichester, New York, 1980. 11 (a) Fryzuk, M . D.; MacNeil, P. A. ; Rettig, S. J.; Secco, A . S.; Trotter, J. Organometallics 1982, 7,918. (b) Fryzuk, M . D.; MacNeil, P. A . Organometallics 1983,2, 682. 24 (c) Fryzuk, M . D.; MacNeil, P. A. ; Rettig, S. J. Organometallics 1986, 5, 2469. (d) Fryzuk, M . D.; Rettig, S. J.; Westerhaus, A . ; Williams, H . D. Inorg. Chem. 1985,24, 4316. (e) Fryzuk, M . D.; Williams, H . D. Organometallics 1983, 2, 162. (f) Fryzuk, M . D.; Haddad, T. S.; Rettig, S. J. Organometallics 1988, 7, 1224. (g) Fryzuk, M . D.; Haddad, T. S. / . Am. Chem. Soc. 1988,110, 8263. 12 Fryzuk, M . D.; Berg, D. J.; Haddad, T. S. unpublished results, 1989. 13 Fryzuk, M . D.; MacNeil, P. A . Organometallics 1982,1, 1540. 14 Alyea, E . C ; Meek, D. W. Catalytic Aspects of Metal Phosphine Complexes; Advances in Chemistry, 196; American Chemical Society, Washington, D.C., 1982. 15 Ebsworth, E. A . V . ; Holloway, J. H. ; Pilkington, N . J.; Rankin, D. W. H . Angew. Chem., Int. Ed. Engl. 1984, 8, 630. 16 (a) Fryzuk, M . D.; Joshi, K . Organometallics 1989, 8, 722. (b) Crisp, G. T.; Salem, G.; Wild, S. B. Organometallics 1989, 8, 2360. (c) Montllo, D.; Svades, J.; Torres, M . R.; Perales, A. ; Mathieu, R. J. Chem. Soc, Chem. Commun. 1989, 97. (d) Hey, E.; Lappert, M . F.; Atwood, J. L . ; Bott, S. G. Polyhedron 1988, 7, 2083. (e) Fryzuk, M . D.; Bhangu, K . / . Am. Chem. Soc. 1988,103, 961. (f) Buhro, W. E.; Zwick, B . D.; Georgiou, S.; Hutchinson, J. P.; Gladysz, J. A . J. Am. Chem. Soc. 1988,110, 2427. (g) Buhro, W. E.; Chisholm, M . H. ; Folting, K. ; Huffmann, J. C. / . Am. Chem. Soc. 1987,109,905. (h) Jorg, K. ; Malisch, W.; Reich, W.; Meyer, A. ; Schubert, U . Angew. Chem., Int. Ed. Engl. 1986,25, 92. (i) Bohle, D. S.; Jones, T. C ; Rickard, C. E. F.; Roper, W. R. Organometallics 1986,5, 1612. (j) Baker, R. T.; Whitney, J. F.; Wreford, S. S. Organometallics 1983, 2,1049. 25 (j) Baker, R. T.; Whitney, J. F.; Wreford, S. S. Organometallics 1983, 2, 1049. (k) Day, V . W.; Tavanaiepour, I.; Abdel-Meguid, S. S.; Kirner, J. F.; Goh, L . Y . ; Mutterties, E. L . Inorg. Chem. 1982, 21, 657. (1) Rocklage, S. M . ; Schrock, R. R.; Churchill, M . R.; Wasserman, H . J. Organometallics 1982, 7, 1332. (m) Domaille, P. J.; Foxman, B. M . ; McNeese, T. J.; Wreford, S. S. J. Am. Chem. Soc. 1980,102, 4114. (n) Malisch, W.; Alsmann, R. Angew. Chem., Int. Ed. Engl. 1976, 15, 769. (o) Buhro, W. E.; Georgiou, S.; Hutchinson, J. P.; Gladysz, J. A . / . Am. Chem. Soc. 1985,107, 3346. (p) Dobbie, R. C ; Hopkinson, M . J.; Whittaker, D. / . Chem. Soc, Dalton Trans. 1972, 1030. 17 (a) Cowley, A . H.; Barron, A . R. Aces. Chem. Res. 1988, 21, 81. (b) Arif, A . M . ; Cowley, A . H.; Norman, N . C ; Orpen, A . G.; Paulski, M . Organometallics 1988, 7, 309. (c) Charrier, C ; Maigrot, N . ; Mathey, F. Organometallics 1987, 6, 586. (d) Hitchcock, P. B. ; Lappert, M . F.; Leung, W. P. / . Chem. Soc, Chem. Commun. 1987, 1282. (e) Flynn, K . M . ; Bartlett, R. A. ; Olmstead, M . M . ; Power, P. P. Organometallics 1986,5, 813. (f) Marinetti, A. ; Mathey, F. / . Am. Chem. Soc. 1982,104, 4484. 18 Baker, R. T.; Krusic, P. J.; Tulip, T. H.; Calabrese, J. C ; Wreford, S. S. J. Am. Chem. Soc 1983,105, 6763. 19 Vaughan, G. A. ; Hillhouse, G. L. ; Rheingold, A . L . Organometallics 1989, 8, 1760. 20 (a) Ebsworth, E. A . V . ; Holloway, J. H. ; Pilkington, N . J.; Rankin, D. W. H . Angew. Chem., Int. Ed. Engl. 1984, 8, 630. (b) Ebsworth, E. A . V. ; Mayo, R. Angew. Chem., Int. Ed. Engl. 1985, 24, 68. 26 21 Bohle, D. S.; Roper, W. R. Organometallics 1986,5,1607. 22 Reference 18 describes a hafnium phosphide complex containing both a pyramidal and a planar phosphide ligand. The structural parameters (M-P bond length and angle) along with the 3 1 P N M R data typical for a pyramidal versus planar phosphide geometry are discussed. 23 Crabtree, R. H . Chem. Rev. 1985, 85, 245, and references therein. 24 Benson, S. W. Thermochemical Kinetics; Wiley, New York, 1976, p. 309. 25 Bergman, R. G. Science 1984, 223, 902 and references 26-32. 26 (a) Shilov, A . E.; Shteinman, A . A . Coord. Chem. Rev. 1971,24,97. (b) Shilov, A . E. Activation of Saturated Hydrocarbons by Transition Metal Complexes; D. Reidel: Hingham, M A , 1984. (c) Halpern, J. Inorg. Chim. Acta 1985,100, 41. (d) Deem, M . L . Coord. Chem. Rev. 1986,10, 9. 27 (a) Ryabov, A . D. Chem. Rev. 1990, 90, 403, and references therein. (b) Evans, D. W.; Baker, G. R.; Newkome, G. R. Coord. Chem. Rev. 1989, 93, 155. (c) Omae, I. Organometallic Intramolecular-coordination Compounds; . Elsevier Scince Publishers: Amsterdam, New York, 1986. (d) Rothwell, I. P. Acc. Chem. Res. 1988,21, 153. (e) Parshall, G. W. Acc. Chem. Res. 1970, 3, 139. 28 In addition to cyclometallation, intramolecular C - H activation is known as orthometallation when an ortho aromatic C - H bond is activated. Examples of orthometallation process can be located in: Collman, J. P.; Hegedus, L . S.; Norton, J. R.; Finke, R. G. Principles and Applications of Organotransition Metal Chemistry; University Science Books: M i l l Valley, C A , 1987, p. 298. 29 Chatt, J.; Davidson, J. M . / . Chem. Soc. 1965, 843. The correct structure of the dimer was assigned by: Cotton, F. A. ; Hunter, D. L. ; Frenz, B . A . Inorg. Chim. Acta 1975,15, 155. 27 30 Tolman, C. A. ; Ittel, S. D.; English, A . D.; Jesson, J. P. / . Am. Chem. Soc. 1978,100,4080. 31 Statler, J. A. ; Wilkinson, G.; Thornton-Pett, M . ; Hursthouse, M . B . / . Chem. Soc, Dalton Trans. 1984, 1731. 32 (a) Shinomoto, R. S.; Desrosiers, P. J.; Harper, T. G. P.; Flood, T. C. J. Am. Chem. Soc. 1990,112,704. (b) Desrosiers, P. J.; Shinomoto, R. S.; Flood, T. C. J. Am. Chem. Soc. 1986,108,7964. 33 (a) Werner, H ; Werner, R. / . Organomet. Chem. 1981,209, C60. (b) Werner, H ; Gotzig, J. Organometallics 1983, 2, 547. 34 Wenzel, T. T.; Bergman, R. G. / . Am. Chem. Soc. 1986,108, 4856. 35 (a) Karsch, H. H.; Schmidbaur, H. Z. Naturforsch. 1977, B(32), 762. (b) Karsch, H . H. ; Klein, H . F.; Schmidbaur, H . Angew. Chem., Int. Ed. Engl. 1975, 637. 36 Schmidbaur, H. ; Blaschke, G. Z. Naturforsch. 1980, B(75), 584. 37 (a) Bryndza, H . E.; Fong, L . K. ; Paciello, R. A. ; Tarn, W.; Bercaw, J. E. J. Am. Chem. Soc. 1987,109, 1444. (b) Mainz, V . V. ; Andersen, R. A . Organometallics 1984,3, 675. 38 (a) Erker, G. Angew. Chem., Int. Ed. Engl. 1989,28, 397. (b) Dotz, K . H . ; Fischer, H . ; Hoffmann, P.; Kreissel, F. R.; Schubert, U . ; Weiss, K . Transition Metal Carbene Complexes; Verlag Chemie, Weinheim 1983. 39 (a) Fryzuk, M . D.; McManus, N . T.; Rettig, S. J.; White, G. S. Angew. Chem., Int. Ed. Engl. 1990,29, 73. (b) Duran, R. P.; Amorebieta, V . T.; Colussi, A . J. J. Am. Chem. Soc. 1987,709,3154. 40 (a) Buchwald, S. L. ; Neilsen, R. B . Chem. Rev. 1988, 88, 1047. (b) Bennett, M . A. ; Schwemlein, H . Angew. Chem., Int. Ed. Engl. 1989,10, 1349. 28 (c) Hartwig, J. F.; Andersen, R. A. ; Bergman, R. G. J. Am. Chem. Soc. 1989,7/7,2717. 41 (a) Butler, I. M . Acc. Chem. Res. 1977,10, 359. (b) Yaneff, P. V . Coord. Chem. Rev. 1977,23, 183. 42 (a) Nefedov, O. M . ; Maltsev, A . K. ; Mikaelyan, R. G. Tet. Lett. 1971, 44, 4125. (b) Trozzolo, A . M . ; Gibbons, W. A . / . Am. Chem. Soc. 1967, 89, 239. 43 (a) Schrock, R. R.; Murdzek, J. S.; Bazan, G. C ; Robbins, J.; DiMare, M . ; O'Regan, M . / . Am. Chem. Soc. 1990,112, 3875. (b) Feldman, J.; Murdzek, J. S.; Davis, W. M . ; Schrock, R. R. Organometallics 1989, 5, 2260. (c) Schrock, R. R.; De Pue, R.; Feldman, J.; Schaverien, C. J.; Dewan, J. C.; Liu, A . H . J. Am. Chem. Soc. 1988,110, 1423. (d) Horton, A . D.; Schrock, R. R. Polyhedron 1988, 7, 1841. (e) Grubbs, R. H . In Comprehensive Organometallic Chemistry; Wilkinson, G.; Stone, F. G. A . ; Abel, E. W.; Eds., Pergamon: New York, 1982; Vol . 8. 44 (a) Wulff, W. D.; Dragisich, V. ; Huffman, J. C.; Kaesler, R. W.; Yang, D. C. Organometallics 1989, 8, 2196. (b) Wulff, W. D.; Yang, D. C.; Murray, C. K . Pure Appl. Chem. 1988, 60,137. (c) Fischer, E. O.; Dotz, K . H . Chem. Ber. 1972,105, 3966. 45 Soto, J.; Steigerwald, M . L . ; Grubbs, R. H . / . Am. Chem. Soc. 1982, 104, 4479. 46 (a) McKinney, R. J.; Tulip, T. H . ; Thorn, D. L . ; Coolbaugh, T. S.; Tebbe, F. N . / . Am. Chem. Soc. 1981,103, 5584. (b) Meinhart, J. D.; Anslyn, E. V. ; Grubbs, R. H. Organometallics 1989,5, 583. (c) Straus, D. A. ; Grubbs, R. H . J. Mol. Catal. 1985,28, 9. (d) Straus, D. A. ; Grubbs, R. H. J. Am. Chem. Soc. 1981,103, 7358. 29 47 Also see: Collman, J. P.; Hegedus, L . S.; Norton, J. R.; Finke, R. G. Principles and Applications of Organotransition Metal Chemistry; University Science Books: M i l l Valley, C A , 1987, Chapter 16. 48 (a) Brady, R. C ; Pettit, R. / . Am. Chem. Soc. 1981,103, 1287. (b) Brady, R. C ; Pettit, R. J. Am. Chem. Soc. 1980,102, 6181. (c) Herrmann, W. A . Angew. Chem., Int. Ed. Engl. 1982, 21, 117. (d) Steinmetz, G. R.; Morrison, E. D.; Geoffroy, G. L . J. Am. Chem. Soc. 1984,106, 2559. 49 Fischer, E. O.; Maasbol, A . Angew. Chem., Int. Ed. Engl. 1964, 3, 580. 50 Schrock, R. R. / . Am. Chem. Soc. 1974, 96, 6796. 51 Fischer, E. O. Adv. Organomet. Chem. 1976,14, 1. 52 O'Connor, J. M . ; Pu, L.; Rheingold, A . L . J. Am. Chem. Soc. 1989, 111, 4129. 53 (a) Chisholm, M . H. ; Clark, H. C. Acc. Chem. Res. 1973, 6, 202. (b) Bruce, M . I.; Swincer, A . G.; Thomson, B . J.; Wallis, R. C. Aust. J. Chem. 1980, 33, 2605. 54 Hermann, W. A. ; Hubbard, J. L. ; Bemal, I.; Korp, J. D.; Haymore, B. L. ; Hillhouse, G. L . Inorg. Chem. 1984,23, 2978. 55 Gallop, M . A. ; Roper, W. R. Adv. Organomet. Chem. 1986, 25, 121. 56 (a) Schrock, R. R. Acc. Chem. Res. 1979,12, 98. (b) Brow, F. J. Prog. Inorg. Chem. 1980,27, 1. 57 (a) Wong, W. K. ; Tam, W.; Gladysz, J. A . / . Am. Chem. Soc. 1979, 101, 5440. (b) Kie l , W. A . ; L in , G. Y . ; Constable, A . G.; McCormick, F. B. ; Strouse, C. E.; Eisenstein, O.; Gladysz, J. A . J. Am. Chem. Soc. 1982, 104, 4865. 58 Crocker, C ; Empsall, H . D.; Errington, R. J.; Hyde, E. M . ; McDonald, W. S.; Markham, R.; Norton, M . C ; Shaw, B . L. ; Weeks, B. J. Chem. Soc, Dalton Trans. 1982, 1217. 30 59 Collman, J. P.; Hegedus, L . S.; Norton, J. R.; Finke, R. G. Principles and Applications of Organotransition Metal Chemistry; University Science Books: M i l l Valley, C A , 1987, p. 382. 60 Klein, D. P.; Bergman, R. G. J. Am. Chem. Soc. 1989, 777, 3079. 61 Fryzuk, M . D.; MacNeil, P. A. ; Rettig, S. J. J. Am. Chem. Soc. 1985, 707,6709. 62 Preliminary reactivity of the methylidene complex were attempted by a previous graduate student in our laboratory. The results of this work are described in chapter 4. Massey, R. L . M. Sc. Thesis, University of British Columbia, Vancouver, Cananda, 1989. 63 Dotz, K . H . Angew. Chem., Int. Ed. Engl. 1984,23, 58. 64 (a) Casey, C. P.; Vosejpka, P. C ; Askham, F. R. / . Am. Chem. Soc. 1990,772,3713. (b) Brothers, P. J.; Roper, W. R. Chem. Rev. 1988, 88, 1293. (c) Clark, G. R.; Hoskins, S. V. ; Jones, T. C ; Roper, W. R. J. Chem. Soc, Chem. Commun. 1983, 719. 65 Bhangu, K . M. Sc. Thesis, University of British Columbia, Vancouver, Canada, 1987. 31 CHAPTER 2 Synthesis and Characterisation of the Iridium(III) Phosphide Complexes and Their Thermolytic and Photolytic behaviour 2.1 Introduction As noted in chapter 1, the preparation and spectral characterisation of the iridium(III) diarylphosphide complexes, I r ( C H 3 ) P R 2 [ N ( S i M e 2 C H 2 P P h 2 ) 2 ] , (R = phenyl, wefa-tolyl, 2a-2b), have been reported previously.1 The geometry at the phosphide phosphorus atom was suggested to be pyramidal from the 3 1 P { 1 H ) N M R data. On the basis of NOE-DIFF experiments, the structure of these complexes in solution was proposed to be intermediate between trigonal bipyramidal and square pyramidal with the methyl ligand in the apical position. However, results of an X-ray crystal study show that the structure in the solid-state is different from the previously reported solution structure. The results of this study are discussed in this chapter. The synthesis and characterisation of Ir(CH3)PMe2[N(SiMe2CH2PPh2)2], 2c, and of I r ( C H 3 ) P H P h [ N ( S i M e 2 C H 2 P P h 2 ) 2 ] , 2d, are described here. Under thermal and photolytic conditions, complexes 2a-2c rearrange to give new products arising from C -H bond cleavage and P - C bond formation.2 However, for the complex 2d, only P - C bond formation is observed both upon thermolysis and photolysis. This intriguing 32 difference is explored in more detail in this chapter. The kinetic and mechanistic results of some of the thermal processes are also discussed. 2.2 Solid-State Structure of I r (CH 3 )PPh2[N(SiMe 2 CH2PPh2)2] , 2a Diffraction quality crystals of the methyl-diphenylphosphide complex, Ir(CH 3)-PPh2[N(SiMe2CH2PPh.2)2]> 2a, were finally obtained after many earlier attempts. Some pertinent bond lengths and bond angles are listed in Tables 2.1 and 2.2, respectively. Figure 2.1 shows that the overall geometry at the iridium centre is best described as a distorted square pyramid. The tridentate hybrid ligand is arranged in a quasi-meridional fashion (P(l)-Ir-P(2) = 166.68°). The angle between the methyl carbon (C(43)) and the phosphide phosphorus atom (P(3) = 87.4°) is close to the expected 90° angle for a square pyramidal geometry. However, the angle between the phosphide group and the amide ligand (N-Ir-P(3) = 113.2°) is greater by -23° from the expected 90° for an apical phosphide. Interestingly, the methyl ligand is out of the square pyramid base plane by 21° (C(43)-Ir-N = 159.0°) which is very close to the 23° distortion observed for the phosphide ligand. This apparent rotation of the phosphide-iridium-methyl unit around the phosphine-iridium-phosphine bonds of the tridentate ligand may be ascribed to the steric bulk of the diphenylphosphide moiety and/or repulsion between the amide and phosphide lone pairs of electrons. Crystal packing effects might also be contributing to the distortion. The magnitude of Ir-P(3)-C(31) (108.4°) and Ir-P(3)-C(37) (117.7°) seems to indicate that the geometry at the phosphorus in the PPh 2 ligand is pyramidal. The solution data have been reinterpreted in terms of the solid-state structure. An N O E - D I F F experiment conducted on a benzene solution of ,2a showed a small enhancement of the methyl (IT-CH3) resonance upon irradiation of one of the two sets of methylene proton (PCH2Si) resonances. No enhancement of the methyl proton 33 resonance was observed upon irradiation of the other set of the methylene signals. This result suggests that the methyl ligand is not in the apical position, but a distortion from the square pyramid base plane may still account for the observed enhancement. Although the solid-state geometry for 2a is a distorted square pyramid, in this thesis this molecule wil l be drawn as a square pyramid with the methyl ligand trans to the amide centre and the phosphide ligand in the apical position. Figure 2.1 X-ray crystal structure of Ir(CH3)PPh2[N(SiMe2CH2PPh2)2], 2a 34 Table 2.1 Selected Bond Lengths (A) for Ir(CH3)PPh2[N(SiMe2CH2PPh2)2], 2a a Ir—P(l) 2.309(2) Ir—P(2) 2.312(2) Ir—P(3) 2.297(2) Ir—C(43) 2.126(9) Ir—N 2.126(6) Table 2.2 Selected Bond Angles (deg) for Ir(CH3)PPh2[N(SiMe2CH2PPh2)2], 2a a C(43)—Ir—N 159.0(3) C(43)—Ir—P(l) 91.2(2) C(43)—Ir—P(2) 90.3(2) C(43)—Ir—P(3) 87.4(2) N—Ir—P(l) 87.4(2) N—Ir—P(2) 86.5(2) N—Ir—P(3) 113.2(2) P(l)—Ir—P(2) 166.68(2) P(3)—Ir—P(l) 105.35(9) P(3)—Ir—P(2) 87.95(8) Ir—P(3)—C(31) 108.4(3) Ir—P(3)—C(37) 117.7(3) a. A complete list of the bond distances and the bond angles is compiled in Appendix 35 2.3 Synthesis and Characterisation of the Iridium Dimethylphosphide Complex, Ir(CH3)PMe2[N(SiMe2CH2PPh2)2],2c The iridium(III) methyl dimethylphosphide complex, Ir(CH3)PMe2-[N(SiMe2CH2PPh2)2], 2c, was synthesised by a transmetallation reaction of the square pyramidal iridium(III) methyl-iodide complex, Ir(CH3)I[N(SiMe2CH2PPh2)2], 1, with stoichiometric amounts of potassium dimethylphosphide (Equation 2.1). The reaction proceeded over an hour at -30°C with the deep green colour of the methyl iodide derivative changing slowly to the characteristic1 dark purple of the phosphide complex. The phosphide complex, 2c, is thermally unstable (vide infra) at temperatures higher than -30°C, and, therefore, has been prepared only in situ. Ph 2 I r ' C H 3 I •P Ph 2 2C Equation 2.1 Spectral characterisation of 2c was carried out at -30°C and the proposed structure was found to be very similar to that of the diarylphosphide complexes 2a-2b. Its ! H N M R spectrum is shown in Figure 2.2. The Si(CH3)2 resonances consist of two sharp singlets of equal intensity at -0.03 and 0.26 ppm indicating inequivalent environments above and below the metal tridentate plane, in keeping with the earlier work on five coordinate complexes stabilised by this tridentate ligand. 3 An A B quartet of virtual triplets at 1.99 and 2.12 ppm ( J g e m = 12.0, J a p p = 4.9 Hz) for the CH2P protons is indicative of a trans orientation of the chelating phosphines. Me 2Si Ph 2 •P \ N I r .*CH3 — I Me 2 Si ' KPMe 2 \ Me 2Si -P Ph 2 toluene -30°C (-KI) N Me 2S 1 36 SiMe2 Figure 2.2 *H N M R spectrum (300 MHz, C 7 D 8 , -30°C) of Ir(CH3)PMe2[N(SiMe2CH2PPh2)2], 2c (* indicates solvent hexanes protons) Brookes and Shaw have demonstrated that virtual coupling arises in such AA'BB'XX' spin systems when Jxx' is very large.4 In the complex 2c, because the phosphines are strongly coupled, this spin system simplifies to an (AB)2X2 pattern for the CH2P protons. The resonances for the para and meta phenyl protons are observed as a multiplet and are separated from the ortho protons' resonances by 0.67 ppm. A chemical shift difference of 0.6 and 1.0 ppm between the ortho and para/meta protons of the phosphine phenyl groups (in deuterated aromatic solvents) is also indicative of the trans orientation of the chelating phosphines.5 As pointed out earlier (Chapter 1, Section 1.2), the phosphide ligand can possess either a pyramidal geometry or a planar geometry. The 3 1P{ 1H} chemical shifts are usually reliable, although not conclusive, in distinguishing the geometry at the phosphide phosphorus. The respective phosphorus chemical shifts for pyramidal and planar phosphide complexes reported in the literature range form -270 to +420 ppm and +200 to +400 ppm.6 The 31p{lH} shift of 94.30 ppm (t, 2 J P ( P = 25.1 Hz) for the dimethylphosphide ligand points to the presence of a pyramidal phosphide donor in this complex. Because the spectral data for the dimethylphosphide complex 2c are similar to those of the crystallographically characterised diphenylphosphide analogue 2a, complex 2c has been assigned as having square-pyramidal geometry with the methyl ligand trans to the amide centre and the dimethylphosphide moiety at the apical site of the pyramid. 2.4 Synthesis and Characterisation of the Iridium Phenylphosphide Complex, Ir(CH3)PHPh[N(SiMe2CH2PPh2)2],2d The synthesis of the phenylphosphide derivative Ir(CH3)PHPh-[N(SiMe 2CH2PPh2) 2], 2d, was achieved by the deprotonation of an octahedral 38 iridium(III) phenylphosphine complex, Ir(CH3)PH2Ph(I)[N(SiMe2CH2PPh2)2], 9 with potassium rm-butoxide, KO l Bu, (Scheme 2.1). The reaction proceeded within minutes at room temperature as the yellow colour of the octahedral phosphine complex changed to a brick red colour. The phenylphosphide complex 2d was isolated as brick red crystals from hexanes at -30°C in good yield (80%). The synthesis of complex 2d was also attempted by the abstraction of HI from 9 using the base, 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU), but no reaction was observed. Me 2Si PH 2 Ph toluene RT Me 2Si Me 2 Sl p P H 2 KO'Bu toluene, RT Scheme 2.1 Me 2Sf 2d Alternatively, the complex 2d could be prepared by reacting freshly prepared in situ LiPHPh or Mg(PHPh)2-TMEDA with the iridium(III) methyl iodide complex, Ir(CH3)I[N(SiMe2CH2PPh2)2L 1, but there were problems associated with these metathetical reactions. Along with the formation of the desired iridium(III) 39 phenylphosphide complex, 2d , there was a competitive reaction of the free phenylphosphine with 1 regenerating 9. The free PH2Ph may arise from the slow hydrolysis of the lithium and magnesium phenylphosphide reagents. The complex Ir(CH3)PHPh[N(SiMe2CH2PPh2)2], 2d, exhibits simple lH and 3 1 P{ 1 H) NMR spectra. The lH NMR spectrum (Figure 2.3) consists of a sharp singlet at 0.37 ppm and a broad peak at -0.10 ppm for the silyl methyl protons at room temperature. As the temperature of the solution is lowered, the peak at -0.10 ppm broadens and then splits into two singlets which are observed at -0.05 and 0.14 ppm (T c = 280 K, AG* = 58 ± 4 KJ mol - 1 ). In addition, the broad methylene resonance (2.00 ppm) and the phenyl resonance (7.80 ppm) split into multiplets. The different orientations of the substituents on the chiral phosphide ligand with respect to the tridentate ligand protons on the same side of the phosphide may result in different environments for those particular ligand protons (for example, the silyl methyls marked a and b in Scheme 2.2 and Figure 2.3): The silyl methyl protons on the side opposite to the phosphide ligand (labelled c and d in Scheme 2.2 and Figure 2.3) remain relatively unaffected by the different orientations of the phosphide ligand, and therefore, only single coincidental resonance is observed. The spectral data can be explained by invoking inversion at the chiral phosphide phosphorus in the pyramidal phenylphosphide ligand (Scheme 2.2). In complexes CpRe(PHPh)NO(PPh3)7 and CpFe(PHPh){ l,2-C6H4(PMePh)2},8 the inversion barriers reported for the pyramidal phenylphosphide ligand are 48 and 60 KJ mol"1, respectively. Thus, the activation barrier of 58 KJ mol"1 for the phosphide inversion mecahnism in 2d seems reasonable. 40 TT| I I I I I I I I I j I I I I I I I If I I I I I I I 1 ITTTTTTT 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 1 I | I I I I | I I I I | I I 1 1 | I I I I | P 7 A 3 2 1 0 P P M - 1 Figure 2.3 ! H NMR spectrum (300 MHz) of Ir(CH3)PHPh[N(SiMe2L'H2PPh2)2J, 2d, (a) at RT in C 6 D 6 , (Dj at -50°C in C 7 D 8 (* indicates toluene peak) a M e Scheme 2.2 In solution, the phenylphosphide complex 2d is less stable thermally than its diphenylphosphide analogue 2a but more stable compared to the dimethylphosphide complex 2c. Details of this difference are described in the following sections (Section 2.5 for the complexes 2a-2c, Section 2.8 for 2d). 2.5 Thermolysis of the Phosphide Complexes 2a-2c The diphenyl and di-mera-tolyl phosphide complexes, I r ( C H 3)PR2-[N(SiMe2CH2PPh2)2], 2a-b, are quite stable thermally in the solid form and can be stored at room temperature for months under an inert atmosphere without any noticeable decomposition. However, when thermolysed in hydrocarbon solvents, typically benzene, toluene or hexanes (50°C in the dark for about five hours), complexes 2a and 2b were converted cleanly and quantitatively to the cyclometallated hydride species /tfc-fr(ri2-CH2PR2)H[N(SiMe2CH2PPh2)2], 3a-b (Equation 2.2). The dimethylphosphide complex Ir(CH3)PMe2[N(SiMe2CH2PPh2)2], 2c, is less stable than 2a and 2b, and, as mentioned before, has been prepared only in situ at -30°C. When the sample was warmed from -30°C to room temperature, it cleanly converted to the cyclometallated hydride derivative / a c - I r ( r | 2 - C H 2 P M e 2 ) H -[N(SiMe2CH2PPh.2)2]> 3c. The complexes 3a-3c were isolated in > 80% yield as 42 pale yellow crystalline solids which were stable under inert atmosphere for months at room temperature. These complexes have been characterised by various N M R spectral techniques and X-ray diffraction (for the T| 2 -CH2PPh2 complex). Me 2 Me 2 ^ S i Si ^ Ph 2 M e 2 S i '  P\ / R 2 P h 2 P / y / I % % %PPh 2 \ N Ir C H 3 Me 2 / I toluene / , \ . P H 2C j PR 2 Ph 2 2a R = phenyl H 2b R = mete-tolyl 3a-3c 2c R = methyl Equation 2.2 The *H and 3lp{lH} N M R spectra of the complex 3a wil l serve to illustrate the typical spectral behaviour of these complexes. In the *H N M R spectrum (Figure 2.4), four singlet resonances at -0.22, 0.65, 0.68 and 0.81 ppm are observed for the silyl methyl groups in the tridentate ligand backbone. Both pairs of the methylene protons of the hybrid ligand backbone display four sets of resonances at 1.40 ppm (t, J a p p = 13.7 Hz), 1.75 ppm (t, J a p p = 13.7 Hz), 2.10 (m) and 2.49 (m). The C H 2 protons of the r | 2 -CH2PPh2 moiety are observed as two diastereotopic multiplets at 1.32 ppm (br) and 2.00 ppm (br, t). The hydride ligand trans to the amide resonates at -19.90 ppm (td, 2 Jp ,H = 16.7 Hz, 2Jp ,H = 9.9 Hz). Hydride chemical shift values are related to the trans influence order (CO > P > N) of the ligand positioned trans to the hydride.9 In octahedral complexes containing the hybrid tridentate l igand, 1 0 a hydride trans to the amide centre typically resonates at -19 to -25 ppm; however, when it is trans to a 43 phosphine, the chemical shift range is -9 to -12 ppm. The hydride trans to a carbonyl moiety is normally observed between -6 to -7 ppm. The 3 1 P { 1 H } N M R spectrum of 3a shows an A M X pattern for this molecule indicating that all three phosphorus centres are non-equivalent. Two of the phosphorus nuclei are strongly coupled to each other, but weakly coupled to the third. The chemical shifts of the phosphorus nuclei belonging to the tridentate ligand [12.39 ppm (dd, 2 J p A ) px = 32.0 Hz, 2 J P M > px = 5.5 Hz) and 15.60 ppm (dd, 2 J P A , PM = 298.2 Hz, 2 J P M , P X = 6.4 Hz)] are well within the expected range; however, the resonance of the phosphorus nucleus in the r i 2 - C H 2 P P h 2 moiety is shifted upfield (-46.80 ppm, dd, 2 J P A , PM = 297.9 Hz, 2 J P A , PX = 30.4 Hz), a phenomenon which has been observed before in other metallacyclic structures.11 The X-ray crystal structure of 3a is shown in Figure 2.5. Selected bond lengths and bond angles are listed in Tables. 2.3 and 2.4 respectively. The structure reveals that the ancillary tridentate ligand has isomerised to the facial coordination mode (P(2)-Ir-P(3) = 104.5°) with the hydride ligand trans to the amide donor; the r i 2 - C H 2 P P h 2 moiety occupies the remaining cis sites of the distorted octahedron. The distortions from true octahedral geometry in the molecule are not unexpected given the steric demands of the tridentate ligand and the r i 2 -CH2PPh.2 metallacyclic ring. The crystallographically determined iridium-hydride bond length of 1.51 A is consistent with other reported Ir-H distances.1 2 The Ir-P(l) bond length in the three-membered ring is 0.03 A and 0.05 A shorter than the other two Ir-P bond lengths of the hybrid tridentate ligand. The shortening of Ir-P(l) bond may be the result of the bridging methylene unit. In the related complex I r C l 2 0 l 2 - C H 2 P M e P h ) ( P M e 2 P h ) 2 the parameters reported for the metallacycle are analogous.1 2 45 Figure 2.5 X-ray crystal structure of/ac-Ir(rj2-CH2PPh2)H[N(SiMe2CH2PPh2)2], 3a 46 Table 2.3 Selected Bond Lengths (A) for/ac-Ir(r) 2-CH2PPh2)H[N(SiMe2CH2PPh2)2], 3a a I r - P ( l ) 2.241(2) Ir—P(2) 2.272(2) Ir—P(3) 2.291(2) Ir—C(l) 2.203(7) Ir—N 2.277(6) Ir—H 1.51(6) P ( D — C ( l ) 1.760(8) Table 2.4 Selected Bond Angles (deg) for/ac-Ir(r| 2-C H 2 P P h 2 ) H [ N ( S i M e 2 C H 2 P P h 2)2], 3a a C(l )—Ir—N 97.6(3) P( l )—Ir—H 70(3) C( l )—Ir—H 87(3) P(2)—Ir—H 157.5(2) C( l )—Ir—P(l ) 46.7(2) P(3)—Ir—H 112(3) C(l)—Ir—P(2) 157.5(2) N—Ir—H 167(3) C(l)—Ir—P(3) 97.9(2) N—Ir—P(l) 103.8(2) N—Ir—P(2) 88.4(2) N—Ir—P(3) 79.7(1) P(l)—Ir—P(2) 110.9(1) P(l)—Ir—P(3) 144.5(1) P(2)—Ir—P(3) 104.5(1) a. A complete list of the bond distances and the bond angles is compiled in Appendix 47 Complexes 3a-3c are stable in the solid-state at room temperature under an inert atmosphere; however, heating benzene or toluene solutions of 3a-3c for 24 hours at 100°C results in the formation of the iridium(I) phosphine complexes, I r ( P R 2 C H 3 ) [ N ( S i M e 2 C H 2 P P h 2 ) 2 ] , 4a-4c (Equation 2.3). Me2 Me? ,Si Si Y ^ P h 2 p , v y p h 2 H 2 C ^ - | — \ R 2 H I r ' ' _ ^ N Ir -PR 2CH 3 toluene Me 2Si 3a-3c 4a-4c Equation 2.3 These complexes were characterised by J H and 3 1 P { 1 H ) N M R spectra. The ! H N M R spectrum of 4a (Figure 2.6) consists of a sharp singlet at 0.20 ppm for the silyl methyl protons indicating an equivalent environment above and below the metal tridentate plane. The ligand backbone methylene proton resonances are observed as a triplet (1.91 ppm, J app = 5.2 Hz) and thus are indicative of the meridional arrangement of the hybrid ligand. The methyl protons of the PPh 2 Me ligand are observed as a doublet at 1.38 ppm (3Jp,H = 7.5 Hz). The phenyl protons are observed at 6.90 -7.10 ppm (m, paralmeta) and 7.53, 7.75 ppm (m, ortho). In summary, the rearrangement of a methyl-phosphide complex L n M ( C H 3 ) P R 2 to L n M ( r i 2 - C H 2 P R 2 ) H is unprecedented. However, as mentioned in chapter 1 (Section 1.4), the cyclometallatibn of coordinated phosphines does lead to complexes with the r ) 2 - C H 2 P R 2 unit, although, as discussed above, this certainly is not occurring in this system. 48 r in C H 2 P P h 2 5 1 ppm Figure 2.6 lH NMR spectrum (C6D 6 , 400 MHz) of Ir(PCH 3Ph 2)[N(SiMe2CH 2-PPh 2) 2], 4a 2.6 Kinetic and Mechanistic Studies of the Thermolysis of Ir(CH3)PPh 2 -[N(SiMe 2 CH 2 PPh 2 ) 2 ] , 2a, and/ac-Ir(r l 2-CH 2PPh 2)H[N(SiMe 2CH 2PPh2)2], 3a 2.6.1 Kinetic Data A kinetic study was undertaken of the thermolytic conversion of Ir(CH3)PPh2-[N(SiMe 2CH 2PPh 2)2l, 2a, to/ac-Ir(ri2-CH2PPh2)H[N(SiMe2CH2PPh2)2], 3a, and of 3a toIr(PMePh2)[N(SiMe2CH2PPh2)2L 4a, in order to elucidate some mechanistic details for these transformations. Because the phosphide complex 2a is coloured ( l m a x = 538 nm, e = 2850 mol" 1 L cm"1), presumably due to d-d transitions, its rearrangement to 3a in toluene was conveniently studied by following the decrease in the intensity of the band at 538 nm with time using UV-Vis spectroscopy (Figure 2.7, Table 2.5). Analysis of the spectral changes showed that the thermolysis rates were first order in the concentration of 2a (data taken for at least three half-lives or more), 49 as demonstrated by the linear plot of ln(A t-Aoo) versus time (Figure 2.7). Measurements of the reaction rates were carried out at four different temperatures between 73 and 1 0 8 ° C (Table 2.6). The plot of ln(k0bs/T) versus 1/T yielded a straight line, from which the following activation parameters were calculated: A H * = 52 ± 15 K J mol"1 , A S * = -163 ± 4 0 J K ' 1 mol"1 (Figure 2.8). The A S * value was found to be a rather large negative number in toluene, suggesting an ordered transition state. A reaction pathway involving solvation of the phenyl rings of "PPh2" by the solvent toluene is an attractive possibility. To test this, the thermolysis was performed in hexanes. It was found that the activation parameters were remarkably different in hexanes [AH* = 103 ± 20 K J mol"1 , AS* = -16 ± 3 J K ' 1 mol"1 (Figure 2.8, Table 2.6)]. The activation enthalpy was almost doubled but this was now offset by a less negative activation entropy value, thus suggesting that the solvation effects were contributing to the overall activation parameters when the solvent was toluene. The kinetic isotope effect ( k n / k o ) for this process was also determined. Thermolysis of 2a -CD3 in hexanes at 6 7 ° C was followed by UV-Vis spectroscopy, and the k n / k o was found to be 1.6 ± 0.1, which indicated that C - H bond breaking was involved in the transition state. The cyclometallated hydride complex, /ac-Ir(ri2-CH2PPh2)H[N(SiMe2CH2-PPh2)2], 3a, shows an absorption band at 360 nm (e = 5425 m o H L cnr 1 ) in the UV-Vis spectrum. The freshly prepared samples of 3 a were thermolysed in toluene, and decrease in the absorption band at 3 6 0 nm was followed as 3 a converted to the corresponding phosphine complex, Ir(PCH3Ph2)[N(SiMe2CH2PPh2)2], 4 a (Figure 2.9, Table 2.7). - Again, the reaction was first order in the concentration of 2 a with kobs = 6.59 x 1 0 - 5 s"1 at 112°C. The transformation rates, determined at four temperatures 9 1 - 1 1 2 ° C , yielded the following activation parameters: AH* = 107 ± 2 K J mol - 1 and AS* = -49 ± 6 J K - 1 mol"1 (Figure 2.10, Table 2.8). The kinetic isotope effect was 50 Table 2.5 First-Order Analysis of the Absorption Spectral Changes for the Conversion of Ir(CH3)PPh2[N(SiMe2CH2PPh2)2], 2a, to/ac-Ir(ri2-CH2PPh2[N(SiMe2CH2PPh2)2], 3a at 83°C a in toluene [2a] = 3.26 xlO" 4 mol L - 1 Time (s) A t (538 nm) ln(At-Aoo) 0 0.881 -0.196 200 0.824 -0.268 400 0.765 -0.348 700 0.658 -0.512 1000 0.573 -0.665 1300 0.509 -0.798 1800 0.388 -1.110 2300 0.298 -1.430 4000 0.127 -2.290 Aoo 0.059 — k p b s = 0.84 x 10-3 s - l a. Temperature deviation + 1°C X (nm) Figure 2.7 Absorption spectral changes upon thermolysis of 2a at 83°C in toluene 51 determined by heating 3a-CD2 deuteride complex at 112°C in toluene. Comparison of the observed rate constants yields kn/ko to be 1.6 ± 0.1 which coincidently is the same as the kn/kD value observed for the thermolysis of 2a to 3a at 67°C in hexanes. Table 2.6 Observed Rate Constants and Activation Parameters for the Conversion of Ir(CH3)PPh 2[N(SiMe2CH 2PPh2)2], 2a, to/ac-Ir(ri 2-CH 2PPh2)H[N(SiMe 2CH2PPh2)2], 3a in Toluene in Hexanes Temp CC) kobsxlO 3 , s"1 Temp CC) k 0 b s x 10 3, s"1 73 0.54 60 0.06 83 0.84 67 0.14 9 7 b 1.04 78 0.42 108 1.90 87 1.10 A H * = 52 ±15 K J mol" 1 AS* = - 1 6 3 ± 4 0 J K - 1 m o H AH* = 103 ± 20 K J mol ' 1 AS* = -16 ± 3 J K ^ m o F a. The data for each run are given in Appendix A2. b. The run at 97"C was repeated, k0bs = 1.07 x 10"3 s - 1 . Thus the uncertainty of 0.03 x 10 - 3 in the kobs values was used to determine the error in the A H * and AS* values. • Toluene • Hexanes 0.0026 0.0027 0.0028 0.0029 0.0030 0.0031 1/T(K"1) Figure 2.8 Eyring plot for the conversion of 2a to 3a in toluene and hexanes • i t -13--14- RA2 = 1.000 £ -15--16- RA2 = 0.997 -17' 52 Table 2.7 First-Order Analysis of the Absorption Spectral Changes for the Conversion of/ac-Ir(Ti2-CH2PPh2)H[N(SiMe2CH2PPh2)2], 3a, to Ir(PCH3Ph2)[N(SiMe2CH2PPh2)2], 4a at 112°Ca in Toluene [3a] = 2.04 x IO"4 mol L ' 1  Time (s) 0 4000 8000 12550 16550 20550 38270 A t (360 nm) 1.066 0.928 0.810 0.697 0.621 0.584 0.454 0.400 ln(A t -Aoo) -0.406 -0.639 -0.892 -1.214 -1.509 -1.693 -2.919 . kpbs = 6.59 x 10-5 s-1 a. Temperature deviation ± 1°C Figure 2.9 Absorption spectral changes upon thermolysis of 3a at 112°C in toluene 53 Table 2.8 Observed Rate Constants and Activation Parameters for the Thermolytic Conversion of/ac-Ir(Ti2-CH2PPh2)H[N(SiMe2CH2PPh2)2L 3a, to Ir(PCH3Ph)[N(SiMe2CH2PPh2)2], 4a in Toluene3 Temp (°C) k0bs x 10 5, s"1 91b 0.87 94 1.03 102 2.31 112 6.59 AH* = 107 ± 2 K J mol" 1 AS* = -49 ± 6 J K - 1 mol" 1 a. The data for each run are given in Appendix A2. b. The run at 91°C was repeated and k0bs = 0.94 x IO"5 s'1. An error of 0.07 x 10"5 was used in all the kobs values in calculating the errors in the activation parameters. -19 H 1 1 1 — 0.0026 0.0027 0.0028 1A"(K"1) Figure 2.10 Eyring plot for the conversion of 3a to 4a in toluene 2.6.2 Mechanistic Considerations A possible mechanism put forth for the aforementioned thermolysis transformations is shown in Scheme 2.3. The first step involves a-hydr ide 54 abstraction 1 3 by the phosphide group from the coordinated methyl ligand yielding Ir=CH2(PHR2)[N(SiMe2CH2PPh2)2], 5. The six-coordinate hydride-phosphide intermediate A then forms via oxidative addition of the phosphine P - H bond at the metal centre. This is followed by the migratory insertion of the methylene ligand into the iridium-phosphide bond thus yielding the intermediate B. The lone pair on the uncoordinated phosphine of B can then bind to the coordinatively unsaturated iridium(III) centre to generate the species 3 or 6. As proposed in Scheme 2.3, the conversion of 3 to 4 proceeds via an intermediate involving C - H bond formation. During the thermolytic transformation of 2a to 3a and 3a to 4a, none of the proposed intermediates in Scheme 2.3 were observed by the and 3 1 P { 1 H } N M R spectroscopy; however, the mechanism was supported via some independent experiments. The addition of one equivalent of diphenylphosphine to a toluene solution of Ir=CH2-[N(SiMe2CH2PPh2)2], 10, 1 4 at -78°C caused the purple colour of 10 to change to wine red (Scheme 2.4). This colour persisted up to -30°C, above which it started to fade away to light yellow. The reaction was monitored by ^ P p H } and ] H N M R spectroscopy. The complex formed at -78°C was characterised as the d i p h e n y l - p h o s p h i n e adduct of the m e t h y l i d e n e c o m p l e x , Ir=CH2(PHPh2)[N(SiMe2CH2-PPh2)2], 5a. The methylidene protons in this complex are observed as a four line pattern at +12.08 ppm ( 3 J P ) H = 15.0 Hz) in the lH N M R spectrum (Figure 2.11 a), because of similar coupling to three phosphorus nuclei, whereas in the starting complex, a triplet at +16.44 ppm (3Jp,H = 14.4 Hz) is observed. 1 4 The silyl-methyl protons are observed as two singlets, indicating inequivalent environments above and below the Ir-P-N-P plane. The PHPY12 proton would be expected to resonate as a doublet of triplets. One part of this resonance, was observed at 5.90 ppm but the other half was presumably obscured by the PPh2 resonances. 55 P h 2 •P Me 2Si' \ / R 2 N — I r C H 3 Me2Si P h 2 k-1 h (r.d.s) P h 2 •P -Me2Si^ PHR2 N I r, M e 2 ^ H 2 , 5 P P h 2 k2 P h 2 P I H N —.1 r ' — PR2 rv C H 2 I Me2sr C H 2 -P A P h 2 M e 2 Me 2 ^Si ,Si r Y ^ P h 2 p P P h 2 I r 1 H PR 2 3 Me 2Sr \ P h 2 •P N I r PCH3R2 / - s . F h 2 M e 2 S M e 2 s r j ^ . H N 1 / M e 2 s ( / I ^ C H 2 P R 2 -P B P h 2 -P 4 P h 2 Me 2 .Si M e 2 Si Y ^  P h 2 p P P h 2 R2P. \ C H 2 Scheme 2.3 56 P H P h 2 Me 2 Si PHPh 2 toluene, 1 -78°C to -30'C Me 2Si toluene -30'C to RT Me 2 Me 2 >Si Si Y ^ Me 2 Me 2 .Si Si Ph?P toluene p p h 2 "•• I r •' '• Ir •' H 2 C 1 — — * ^ P h 2 H 3a RT y ^ 24 - 48 hours S >w P h 2 P v H \ C H 2 6a Scheme 2.4 The 3 1P{ 1H} NMR spectrum (Figure 2.12 a) shows two singlets at 13.45 ppm (for the phosphorus nuclei belonging to the tridentate ligand) and 3.90 ppm (for the PHPh2 ligand) in the integral ratio of 2:1. No coupling is observed between the coordinated diphenylphosphine and the tridentate ligand phosphine donors. There are only two other examples of iridium methylidene phosphine complexes reported in the literature. 1 5 As mentioned in chapter 1 (Section 1.5), the complexes Cp*Ir=CH2(PMe3) and Ir=CH2(I)CO(PPh3)2 have been prepared in situ at low temperatures only. The former complex decomposed above -40°C, whereas the latter species yielded the corresponding ylide complex at temperatures higher than -50°C via intramolecular cyclometallation. With the hybrid tridentate ligand system, the 57 t r i m e t h y l p h o s p h i n e a d d u c t of the m e t h y l i d e n e c o m p l e x , Ir=CH2 (PMe3)-[N(SiMe2CH2PPh2)2]» was f o u n d to be stabl e o n l y b e l o w 0 ° C . 1 6 T h i s s p e c i e s c o n v e r t e d to Ir(PMe3)[N(SiMe2CH2PPh2)2] a b o v e 0 ° C l o s i n g ethylene. T h e s o l u t i o n o f Ir=CH 2 (PHPh2)[N(SiMe2CH2PPh2)2L 5a, w h e n w a r m e d a b o v e -30°C, s l o w l y r e a r r a n g e d to/ac-Ir(Ti 2 -CH2PPh2)H[N(SiMe2CH 2 PPh2)2]. 6 a , i n w h i c h the h y d r i d e l i g a n d w a s trans to o n e o f the p h o s p h o r u s n u c l e i . T h e tr a n s f o r m a t i o n was c l e a n a n d n o other s p e c i e s were d e t e c t e d d u r i n g this process. T h e 3 1 P { 1 H } NMR s p e c t r u m c o n s i s t s o f a n A M X pattern i n d i c a t i n g a l l three p h o s p h o r u s n u c l e i are n o n e q u i v a l e n t ( F i g u r e 2.12 b). In the * H NMR s p e c t r u m ( F i g u r e 2.11 b) f o u r s i n g l e t s f o r the s i l y l - m e t h y l p r o t o n s , f o u r m u l t i p l e t s f o r the l i g a n d b a c k b o n e m e t h y l e n e p r o t o n s are o b s e r v e d . O n e o f the m o s t i n f o r m a t i v e features i s the h y d r i d e r e s o n a n c e w h i c h is o b s e r v e d as a d o u b l e t o f d o u b l e t o f d o u b l e t s at -11.88 p p m (trans to a p h o s p h o r u s n u c l e u s ) that s h o w s a la r g e trans c o u p l i n g ( 2Jp , H (trans) - 133.3 Hz) to o n e o f the p h o s p h o r u s n u c l e i a n d cis c o u p l i n g s to the other t wo p h o s p h o r u s centres ( 2Jp , H (cis) - 19.8 Hz, 2 J P ) H (cis) = 11.8 Hz). T h e c o m p l e x 6 a was stable i n s o l u t i o n o n l y f o r a f e w h o u r s at r o o m tem p e r a t u r e but it c o u l d be i s o l a t e d as p a l e y e l l o w c r y s t a l s w h i c h w e r e s t o r e d u n d e r an in e r t a t m o s p h e r e at r o o m temperature f o r l o n g p e r i o d s o f time. W i t h i n 48 hours i n s o l u t i o n , however, it c o m p l e t e l y i s o m e r i s e d to the c o m p l e x 3a, i n w h i c h the h y d r i d e l i g a n d was trans to the a m i d e d o n o r ( o b s e r v e d b y *H a n d 3 1 P { 1 H } NMR s p e c t r o s c o p y ) . F o r the c o n v e r s i o n o f 6 a to 3 a , s t a n d a r d f i r s t - o r d e r k i n e t i c s w a s o b s e r v e d ( F i g u r e 2.13). T h e appearance o f c o m p l e x 3 a was f o l l o w e d b y U V - V i s s p e c t r o s c o p y at 3 6 0 n m ( F i g u r e 2.13, T a b l e 2.9). T h e o b s e r v e d rate c o n s t a n t s at v a r i o u s temperatures (36-59°C) are l i s t e d i n T a b l e 2.10. A n E y r i n g p l o t o f the data, l n ( k / T ) v e r s u s 1/T ( F i g u r e 2.14), y i e l d e d the a c t i v a t i o n e n t h a l p y a n d entropy, A H * = 95 ± 10 K J m o l " 1 , A S * = -3 + 2 J K _ 1 m o l " 1 , r e s p e c t i v e l y : 58 1 1 . & 1 1 . 8 - 1 2 . & 1 2 . 2 - 1 2 ..4-1I2RI8 I | I I I I | I I I I | I I I I | I 11 I | I I I I | I I I I | I I I I | I I I I | I I I I | I I I I | I I I I | I I I I | I I I I | I I I 8 7 6 " ' 5 4 3 2 i P!PM 8 (a) Ir=CH2 llll|llll|llll|llll|llll|!IH[ll!l|llll|llll|llll|ll!!|ll!l|llll|ll! 1 2 . 6 1 2 . 4 1 2 . 2 1 2 . 0 1 1 . 8 1 1 . 6 IRR MI 1111 I I 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 i 1 1 111 1 1 1 . 1 1 1 1 111 1 1 1 1 1 1 1 111 1 8 7 6 5 4 3 2 l | l l l l | l l I I | I I M j I I I I | I 1 0 PPM Figure 2.11 l H N M R spectrum (300 MHz) of Ir=CH2[N(SiMe2CH2PPh2)2] + PHPh 2 (a) at -78°C in C 7 D 8 , (b) at RT in C 6 D 6 (* indicates toluene protons) (c) (b) Ph 2 P o 1 (a) P P h 2 PPh 2 PHPh 2 P h 2 P P P h 2 / n 2-CH 2pph 2 ;j I T ] -]- 7 T r-prrrrp-Tr r_r T "T~ 20 10 - p ' T T r | i i - | -T~| T T T r y v T T r }~r r r r p r 0 -10 -20 "(-]•"J"T r r r r i i : | i i I i T n T T y r T T T T n i i j i i i i -30 -40 -50 -60 PPM Figure 2.12 31p{lH] NMR spectrum (121.4 MHz, C 7 D 8 ) of Ir=CH2[N(SiMe2CH2PPh2)2] + PHPh2 (a) at -78°C, (b) at -20°C, (c) at RT after 48 hours Table 2.9 First-Order Analysis of the Absorption spectral changes for the isomerisation of 6a to 3a at 46° C in toluene [6a] = 2.08 x 10-4 mol Lr*  Time (s) A t (360 nm) ln(A t -Aoo) 0 0.458 -0.443 600 0.528 -0.559 1200 0.581 -0.656 1800 0.633 -0.761 2400 0.678 -0.863 3200 0.732 -1.000 4200 0.792 -1.178 5200 0.840 -1.347 6200 0.883 -1.528 8200 0.963 -1.988 9700 0.992 -2.226 Aoo 1.100 k o b s = 1.84 x 10-4 s-1 a. Temperature deviation ± 1°C o !,500 X (nm) Figure 2.13 Absorption spectral changes for the thermolysis of 6a at 46°C in toluene 61 Table 2.10 Observed Rate Constants and Activation Parameters for the Isomerisation of 6a to 3a in Toluene3 Temp CC) 36 46 56 59 kobs x 10 4, S ' 1 0.50 1.84 4.87 7.15 AH* = 95 ± 1 0 K J mol" 1 AS* = - 3 ± 2 J K - 1 m o l - 1 a. The data for each run are given in Appendix A2. -12 -17 H 1 1 . , . 1 1 0.0030 0.0031 0.0032 0.0033 1/T (K"1) Figure 2.14 Eyring plot for the thermolytic conversion of 6a to 3a in toluene A five-coordinate iridium(III) hydride complex B is proposed as an intermediate in the isomerisation of 6a to 3a. There exists indirect evidence for the involvement of B via a trapping experiment. Exposing the benzene solution of 6a or 3a to one atmosphere of CO gas at room temperature for 48 hours afforded a six 62 c o o r d i n a t e i r i d i u m ( I I I ) h y d r i d o c a r b o n y l s p e c i e s 7 a c o n t a i n i n g the r ^ - C F I ^ P P h ^ l i g a n d ( S c h e m e 2.5). T h i s c o m p l e x was i s o l a t e d as p a l e y e l l o w c r y s t a l s . T h e r e a c t i o n o f 6 a w i t h C O gas was f o l l o w e d b y U V - V i s s p e c t r o s c o p y at 4 6 ° C a n d the koD S (1.82 x 1(H s _ 1 ) was f o u n d to be e s s e n t i a l l y i d e n t i c a l w i t h the k 0 D S v a l u e f o r the i s o m e r i s a t i o n o f 6 a to 3 a at this temperature ( T a b l e 2.10). Me2 Me2 Si Si r Y i Me2 Me? >Si Si PPhj Ir Ph2P, \ H >CH2 6a CO (1 a t m ) toluene Me2Si^ 48 hours RT Ph2 •P ry^ P h 2 p pp h 2 Ir H2C r — P P h 2 3a H N Me2Si I ^ C H o P Me2Si Me2S CH2 Ph2 CH2PPh2 toluene 1 week R T Me2Si (- PCH3Ph2) S c h e m e 2.5 T h e !H N M R s p e c t r u m o f 7 a ( F i g u r e 2.15) c o n s i s t s o f t w o sharp s i n g l e t s f o r the s i l y l m e t h y l protons, two sets o f d o u b l e t s o f v i r t u a l triplets f o r the S i C F P i P p r o t o n s 63 of the ligand backbone thus indicating trans disposition of the chelating phosphines. Most informative is the hydride region which is comprised of a triplet of doublets at -6.50 ppm ( 2 J P ) H = 18.0 Hz, 3 J P J H = 9.0Hz). The 2 J H , c coupling (54.0 Hz) observed in the *H N M R spectrum of 1 3 C O enriched complex helped to determine the trans disposition of the hydride and carbonyl ligands. The iridium-carbonyl stretching frequency is at 1965 c m - 1 in its infrared spectrum in toluene solution, and the Vi r .H band is at 1925 cm" 1. In the ^ C O H } N M R spectrum, the 1 3 C O ligand is observed as a doublet of triplets at 179.88 ppm ( 2 J P ) c = 11.0 Hz, 3 J P > C = 5.9 Hz). This chemical shift and the above mentioned IR data are quite typical for a late transition metal carbonyl functionality.17 Examples of transition metal complexes containing r | 1 -CH 2 PR2 ligand are rare. 1 8 The complex CpRe(ri1-CH2PMe2)H(PMe3)2 could be prepared only in situ at temperatures below 1 0 ° C . 1 8 b At room temperature in benzene solution, it converted to CpRe(Ph)H(PMe3)2 and generated one equivalent of free trimethylphosphine. Similarly, the hydrido carbonyl species, Ir(T| 1-CH2PPh2)H(CO)[N(SiMe2CH 2-PPh 2)2l» 7a, reductively eliminated methyldiphenylphosphine in solution (benzene) over a period of a week at room temperature and converted to a previously reported iridium(I) carbonyl complex, Ir(CO)[N(SiMe 2CH 2PPh2)2], 8. 3 a Another piece of evidence for the involvement of the intermediates similar to B in the formation of the metallacyclic species such as 3 involves the reaction of L iCH 2 PPh 2 «TMEDA with Ir(CH3)I[N(SiMe 2 CH 2 PPh 2 )2], 1. The species Ir(CH 3 )-(rj2-CH2PPh2)[N(SiMe2CH2PPh2)2] was produced, in which the tridentate ligand had facial geometry (as indicated by the *H and 3 1 P { 1 H } N M R spectroscopy). The reaction presumably proceeds via a five coordinate complex containing the 64 Figure 2.15 lH NMR spectrum (400 MHz, C 6 D 6 ) of Ir(Ti1-CH2PPh2)H(CO)[N(SiMe2CH2PPh2)2], 7a T|1-CH2PPh2 ligand which undergoes ring closure to form the six coordinate r\2-C H 2 P P h 2 complex. The species Ir(CH3)(ri2-CH2PPh2)[N(SiMe2CH2PPh2)2] was found to be unstable in solution as it decomposed within a day. 2.6.3 Discussion of the Kinetic and Mechanistic Experiments The aforementioned kinetic experiments revealed that thermolysis of the methyl diphenylphosphide complex, 2a, in toluene produced the cyclometallated hydride species, 3a, cleanly and quantitatively and that the conversion is first order in 2a. The activation parameters for this process are A H * = 52 ± 15 K J m o l - 1 and AS* = -163 ± 40 J K _ 1 mol" 1 . In hexanes, the cyclometallation occurs with very different parameters: A H * = 103 ± 20 K J mol" 1 and AS* = -16 ± 3 J K " 1 mol" 1 . The activation enthalpy is almost doubled but this is now offset by less negative activation entropy value. While negative entropy of activation may be explained by invoking an ordered transition state, the difference in the AS* values in toluene and hexanes strongly suggests that solvation in the transition state is important, and the solvation effects are likely to be contributing to the overall activation enthalpy value. The formation of complex 3a via thermolysis of the phosphide complex 2a is slower than its production from the reaction of the methylidene complex 10 with diphenylphosphine; therefore, the rate determining step in the thermolysis reaction must be before the formation of the methylidene phosphine adduct 5a. Thus, the above mentioned A H * and AS* values for the thermolysis reaction refer to the k i step (Scheme 2.3). The activated complex is suggested to be C (Scheme 2.6) and resembles closely to the starting material; in other words, the transition state is reactant like. A small primary kinetic isotope effect (1.6 ± 0.1) also supports the transition state C in which only a slight breaking of the C - H bond in the methyl ligand has taken place. 66 E Scheme 2.6 No methylidene phosphine complex 5a can be observed during thermolysis of 2a, which suggests that it gets consumed as quickly as it forms therefore implying that k2 must be much larger than k i (see Scheme 2.3). Furthermore, the complex 5a, prepared by the alternative route, does not convert to the phosphide complex 2 a indicating that the k 2 value should also be much larger than the k_i value. Because k i is the rate-determining step, the activation parameters listed above should have no contribution from the rest of the steps in the mechanism. It is interesting to compare the kinetic parameters obtained from the cyclometallation of the phosphide system 2a with that of the alkoxide complex Zr(OAr')2(CH2Ph)2 where OAr' = 2,6-di-rm-butylphenoxide. This species 67 undergoes intramolecular activation of one of the C - H bonds of the rm-butyl groups when thermolysed in toluene, and affords the corresponding cyclometallated complex, Zr(OC6H3 tBuCMe2CH2)(OAr')(CH2Ph) and one equivalent of toluene.19 Kinetic measurements of the cyclometallation step showed the reaction to be unimolecular with the following activation parameters: AH* = 90 KJ mol"1, AS* = -80 J K"1 mol"1. On the basis of the moderately large and negative activation entropy, a 4-centre transition state is proposed for the activation step analogous to that for the cyclometallation of 2a. The next isolable species in the mechanism is 6a which upon thermolysis isomerises to its more stable form 3a. The isomerisation occurs with a barrier of 95 + 10 KJ mol"1 and is proposed to proceed via the dissociation of the phosphine end of the metallacyclic ring. Thus the 95 KJ mol"1 value represents enthalpy of activation for phosphine dissociation from 6a in toluene solvent. Because the activated complex (D, Scheme 2.6) resembles closely to the five-coordinate intermediate (B, Scheme 2.3), the 95 KJ mol"1 can be approximated to the bond dissociation energy of Ir-P bond, assuming that the solvation effects are negligible. The rearrangement of 3a to 4a takes place by a clean first order process in which AH* = 107 ± 2 KJ mol"1 and AS* = -49 ± 6 J mol"1 K"1. For this conversion, a small primary kinetic isotope effect of 1.6 ± 0.1 was found. The intermediate suggested for this transformation is the five coordinate species, B (Scheme 2.3). An early transition state is proposed (E) (Scheme 2.6). The measured AH* value of 107 KJ mol"1 represents the enthalpy of activation for Ir-P bond dissociation from 3a in toluene. There are limited data available on transition metal-phosphorus bond dissociation energies. During the isomerisation of rra«5-RuCl2(CO)(PPh3)3 to its cis 68 form, dissociation of a phosphine ligand is proposed to be the key step.20 The measured activation parameters for this step in chlorobenzene are: AH* = 129 ± 2 KJ mol"1 and AS* = 33 ± 8 J K"1 mol"1. A AH* value of 128 ± 13 KJ mol"1 is reported for the Ru-P bond dissociation in the hydrogenolysis of the ruthenium acyl complex, RuCl(COC 7H9)(CO) 2(PPh3)2, in toluene.21 Since M - L bond strengths generally increase down a column in the periodic table,22 higher AH* values will be expected for the Ir-P bond compared to that of the Ru-P bond. The measured activation enthalpy values of Ir-P bond (107 ± 10 and 95 + 10 KJ mol"1) in complexes 6a and 3a are lower perhaps because of the strain in the three-membered metallacyclic rings. 2.7 Photolysis of I r ( C H 3 ) P R 2 [ N ( S i M e 2 C H 2 P P h 2 ) 2 ] , 2a-2c The complexes Ir(PCH3R2)[N(SiMe2CH2PPh2)2], 4a-4c, were produced upon photolysis of the corresponding iridium(III) phosphide complexes, Ir(CH3)PR2-[N(SiMe2CH2PPh2)2L 2a-2c. The diarylphosphide complexes 2a and 2b were photolysed in a benzene solution at room temperature for 24 hours, using a 140 W Hg lamp as the light source. However, due to the thermal instability of the dimethylphosphide complex 2c, its photolysis was carried out at -30°C in toluene using a N2 laser. The completion of this photolytic transformation took approximately three hours. Even though the intermediate rj2-cyclometallated hydride, 3a-3c, was not observed during the photolysis process, the transformation could proceed via the same mechanism as proposed for the thermolysis of. 2a-2c. Migration of the phosphide ligand into the iridium-methyl bond is another possibility. 2.8 Thermolysis of I r ( C H 3 ) P H P h [ N ( S i M e 2 C H 2 P P h 2 ) 2 ] , 2d The complex Ir(CH3)PHPh[N(SiMe2CH2PPh2)2], 2d, is thermally sensitive. Heating a benzene solution of 2d at 60°C for one hour resulted in its transformation to the corresponding iridium(I) phosphine complex, Ir(PHPhCH3)[N(SiMe2CH2-69 PPh2)2], 4d (Equation 2.4). No intermediacy of the cyclometallated hydride complex was observed in the * H and 3 1 P { 1 H } N M R spectra during this process in contrast to the thermal transformations of the diaryl and dialkylphosphide complexes 2a-2c. toluene 60°C, 1 hour Me 2S Equation 2.4 2.9 Kinetic and Mechanistic Experiments on the Thermolysis of 2d 2.9.1 Kinetic Experiments Because the phenylphosphide complex, 2d, is coloured ( ? i m ax = 462 nm, e = 1820 m o l - 1 L cm - 1 ) , its thermal conversion to the phosphine complex, 4d, is easily followed by U V - V i s spectrophotometry. The decrease in the band intensity at 462 nm was followed with time. First order kinetics were observed for this conversion. Rates were determined at four temperatures in toluene in the range of 69-93°C (Table 2.12). A typical l n ( A t - A o o ) versus time plot is shown in Figure 2.16. The activation parameters A H * and A S * are 82 ± 10 K J m o l - 1 and -71 ± 7 J K " 1 mol" 1 , respectively (Figure 2.17, Table 2.12). Thermolysis of the phenylphosphide complex was also followed in hexanes (X = 515 nm, e = 1951 m o l " 1 L cm - 1 ) , and the activation parameters ( A H * = 77 ± 8 K J mol" 1 , A S * = -83 ± 8 J K " 1 mol" 1) obtained were similar to the activation data in toluene (Tables 2.11 and 2.12, Figure 2.16); therefore, any involvement of the solvent in the transition state, which might be reflected in the negative A S * value, was precluded. No primary kinetic isotope effect was observed 70 Table 2.11 First-Order Analysis of the Absorption Spectral Changes for the Thermolysis of the Ir(CD3)PHPh[N(SiMe2CH2PPh2)2L 2d-CD 3 , at 74°C a in Hexanes [2d-CD3] = 1.12 x IP' 3 mol L ' 1  Time (s) A t (515 nm) ln(At-Aoo) 0 1.611 0.334 150 1.225 0.011 400 1.185 -0.029 600 1.020 -0.216 800 0.879 -0.408 1000 0.771 -0.585 1200 0.678 -0.768 1400 0.604 -0.942 1700 0.485 -1.306 2000 0.397 -1.698 2500 0.283 -2.674 Aoo 0.214 — kobs = 9.937 x 10-4 s"1 a. Temperature deviation ± 1°C Figure 2.16 Absorption spectral changes upon thermolysis of 2d-CD 3 at 74°C in hexanes 71 for this transformation (kn/ko = 1.0 ± 0.1 at 74°C in hexanes) indicating no carbon-hydrogen bond breaking is involved in the transition state. Table 2.12 Observed Rate Constants and Activation Parameters for the Thermolytic Conversion of Ir(CH3)PHPh[N(SiMe2CH 2PPh2)2], 2d, to Ir(PHCH 3Ph)[N(SiMe 2CH2PPh2)2],4d in Toluene in Hexanes Temp CC) 69 82 86 93 k0bs x 10 3, s"1 0.430 1.600 2.102 2.800 Temp CC) kobs x 10 3, s' 1 54b 0.176 65 0.476 74 1.008 79 1.327 AH* = 8 2 ± 1 0 K J m o l - 1 AS+ = - 7 1 ± 2 0 J K - 1 m o l - 1 AH* = 77 ± 8 K J mol" 1 AS* = - 83 ± 8 J K - 1 mol" 1 a. The data for each run are given in Appendix A2. b. The run at 54°C was repeated and k0bs = 0.178 x 10' 3 s*1. Therefore, an error of 0.002 x 10 - 3 in the k0bs values was used to calculate the uncertainity in the activation parameters. 0 Hexanes • Toluene 0.0027 0.0028 0.0029 0.0030 0.0031 1 / T ( K " 1 ) Figure 2.17 Eyring plot for the thermolysis of 2d to 4d in toluene and hexanes 72 2.9.2 Mechanistic Considerations It is possible that the thermolysis of the phenylphosphide complex, 2d, also proceeds through the same mechanism as the one established above for the diphenyl, di-mera-tolyl and dimethylphosphide complexes, 2a-2c. However, the experimental evidence does not favour it, but points more towards migration of the phosphide ligand into the iridium-methyl bond. The lack of primary kinetic isotope effect is readily explained by this migration process. Furthermore, the fact that an intermediate cyclometallated hydride species is not seen can be either because it never becomes concentrated enough to be observed by N M R spectroscopy, or it does not form at all during the thermolysis process. A separate experiment involving the reaction of free phenylphosphine with the methylidene complex, Ir=CH2[N(SiMe2CH2PPh2)2L 10, was conducted in order to access the cyclometallated hydride species (Equation 2.5). Me2 Me2 Equation 2.5 The reaction proceeded instantaneously at -78°C and the purple colour of the methylidene solution changed to light yellow. The light yellow complex was characterised as /ac-Ir(Ti 2-CH2PHPh)H[N(SiMe2CH 2PPh2)2], 6d, by *H and 31p{!H} N M R spectroscopy (Figure 2.18). In this complex, the hydride ligand is 73 Me 2 Me-2 Figure 2.18 ! H NMR spectrum (300 MHz, C 6 D 6 ) of/ac-Ir(ri2-CH2PHPh)H[N(SiMe2CH2PPh2)2], 6d (* indicates hexanes protons) trans to a phosphine centre of the tridentate ligand (-12.87 ppm, dt, 2Jp,H (trans) = 149.3 Hz, 2Jp,H (cis) = 19.1 Hz). However, the geometry at the chiral phosphorus in ri 2-CH2PHPh ligand could not be ascertained from the NMR data. This complex in solution does not isomerise to the other expected cyclometallated complex in which the hydride ligand is trans to the amide moiety, and neither does it convert to the square planar phosphine complex, Ir(PHCH3Ph)[N(SiMe2CH 2PPh2)2L 4d. Heating the toluene solution of this complex at 80°C for 30 minutes resulted in decomposition. These observations do suggest that the cyclometallated hydride route is not likely to be involved in the thermolysis of 2d. 2.9.3 Discussion on the Kinetics and the Mechanism The formation of the phosphine complex, 4d, from thermolysis of the phosphide complex, 2d, proceeds smoothly with activation parameters A H * = 82 + 10 K J mol" 1 and AS* = -71 ± 7 J mol" 1 K " 1 in toluene. The activation data obtained in hexanes (AH* = 77.0 ± 7 K J mol" 1 , AS* = -83 ± 8 J mol" 1 K " 1 ) are similar to the parameters reported above in toluene; therefore, any involvement of the solvent in the transition state which might be contributing to the activation parameters is precluded. No primary isotope effect was observed in this transformation (kn/ko = 1.0 ± 0.1); therefore, no C-H bond breaking is suggested in the transition state. The transition state is likely to be ordered as indicated by the large negative AS* value and a possibility is shown below (F). The activation enthalpy value A H * then is a combination of Ir-C bond breaking and P-C bond forming energies. 75 Me 2Si Me 2Si P P h 2 F Why does there exist such a drastic change in the kinetic data (kn/ko), and therefore in mechanism, upon going from diphenylphosphide complex 2a to the phenylphosphide complex 2d? The difference is likely not due to the higher basicity of the phenylphosphide ligand as compared to the diphenylphosphide, because even the very basic dimethylphosphide ligand follows the same thermal conversion as the diphenyl and di-mera-tolylphosphide ligands in the corresponding complexes. 2 3 However, the different reactivities can be rationalised in terms of the transition states. A 4-centre transition state (labelled C in Scheme 2.6) might be necessary in the diphenylphosphide complex because of steric strain which only allows access to the C - H bond of the methyl ligand. For the less sterically encumbered phenylphosphide complex, a 3-centre transition state is proposed (labelled F above), where direct C-P bond formation occurs instead. 2.10 Photolysis of Ir(CH3)PHPh[N(SiMe2CH2PPh2)2], 2d The photolysis of the iridium(III) phenylphosphide complex, Ir(CH3)PHPh-[N(SiMe2CH 2PPh 2)2], 2d, (140 W Hg lamp, 18 hours, C6D6) proceeded cleanly to yield the same product, Ir(PHCH3Ph)[N(SiMe2CH2PPh2)2], 4d, as obtained form the thermolysis of 2d. Again, no intermediates were observed during the photolysis process. 76 2.11 Synthesis of Other Cyclometallated hydride complexes 2.11.1 Reaction of Ir=CH 2[N(SiMe 2CH 2PPh 2)2], 10, with HP*Bu 2 The reactivity of Ir=CH2[N(SiMe2CH2PPh2)2] with diphenylphosphine to generate the cyclometallated species 3a and 6a turned out to be a useful synthetic route to access other cyclometallated hydride species which could not be obtained via the phosphide route. The complex Ir(CH3)I[N(SiMe2CH2PPh2)2]» 1, did not react with KP lBu2 even at elevated temperatures (80°C, 5 hours). However, the reaction of Ir=CH2[N(SiMe2CH2PPh2)2] with HP lBu2 at -78°C afforded the phosphine adduct I r = C H 2 ( P H t B u 2 ) [ N ( S i M e 2 C H 2 P P h 2 ) 2 ] , 5e, (Scheme 2.7). Above -30°C, this complex rearranged to the cyclometallated hydride complex, /<3c - I r (n , 2 -CH 2 P t Bu 2 )H-[N(SiMe2CH2PPh2)2l> 6e, with the hydride ligand disposed trans to one of the phosphorus nuclei. Within 24-48 hours, 6e rearranged to its more stable form, 3e, in which the hydride ligand was trans to the amide moiety. The 3 1P{ 1H} N M R spectral changes for this reaction sequence are shown in Figure 2.19. 2.11.2 Limitations of the Reactions of Ir(R)X[N(SiMe 2 CH 2 PPh 2 ) 2 ] with M P R ' 2 There likely exists some steric hindrance between the alkyl ligand on the iridium centre and the substituents on the phosphide precursor. The reaction also seems to be dependent upon the counterion M in the phosphide salt. These observations were made from the following experiments. When the methyl ligand on the iridium centre was replaced by a phenyl group, the starting material, Ir(Ph)I[N(SiMe 2CH2PPh2)2L failed to react with LiPPh2, but the reaction with L i P M e 2 produced Ir(PMe2Ph)[N(SiMe2CH2PPh2)2] without any apparent intermediacy of the desired phosphide complex (by *H and 3 1 P { 1 H } N M R spectroscopy). A variety of different combinations of the iridium halide complexes and 77 the lithium phosphide salts were tried, but in the cases shown below no reaction was observed (Equation 2.6). Ph 2 •P P h 2 •P Me 2Si \ N Ir = C H 2 Me 2Si PH'Bua \ Me2Si, toluene, N Ir. -P Ph 2 -78°C Me2S\ to -30°C 1 0 toluene %PH l Bu 2 -CH 2 -P Ph 2 5e -30*C to RT Me 2 Me 2 •Si Si P h 2 p p p h 2 Me 2 Me 2  kSi Si toluene Ir -H 2 C ^ | ^ P t | RT 24 - 48 hours P l Bu 2 'Bu 2P p h 2 p p p h 2 I ..." '**• Ir •*'' H 3e H C H 2 s e Scheme 2.7 Me 2 SK Ph 2 •P R N — Ir' X LiPR' 2 Me 2Si y toluene No Reaction -P Ph 2 R' C H 3 ortho- tol I C H 3 jPr I Ph Ph | CH 2 Ph Ph Br Equation 2.6 78 Figure 2.19 31p{lH} NMR spectrum (121.4 MHz, C 7 D 8 ) of Ir=CH2[N(SiMe2CH2PPh2)2] + PHtp>u2 (a) at -78°C, (b) at -10°C, (c) at RT after 48 hours Furthermore, the iridium(III) benzyl bromide complex, Ir(CH2Ph)Br-[N(SiMe2CH2PPh2)2L showed no reactivity toward LiPMe2 at room temperature over a week; however, its reaction with K P M e 2 proceeded smoothly at ambient temperature with a noticeable colour change over a period of half an hour (Scheme 2.8). The green colour of the benzyl bromide complex changed to light yellow of /ac-Ir(ri 2-CHPhPMe2)H[N(SiMe2CH2PPh 2)2], 6f, (Scheme 2.8). The product was isolated as pale yellow crystals in good yield (~80%). Me 2Si Me2Si. Me 2 Me 2 Si Si P h 2 P -KPMe 2 " 1 P F h 2 toluene, RT (-KBr) ••c / Ph Ir ' ' H PMe 2 6f toluene, RT 2 Weeks Me?Si Me 2Si PMe 2(CH 2Ph) Scheme 2.8 The 3 1 P { 1 H ) a n d *H N M R spectra provide excellent handles for deducing the stereochemistry at the iridium centre and also the arrangement of the hybrid tridentate ligand. But, the geometry at the chiral carbon of the metallacycle is not apparent from the N M R data. Based on steric considerations, it is assumed that the phenyl ring on 80 the carbon centre is pointing away from the phenyl moieties on the tridentate ligand. The 3 1 P { 1 H } N M R spectrum of this complex exhibits three resonances which are weakly coupled in the integral ratio of 1:1:1. Of these, a simple triplet for the PMe2 ligand (-11.19 ppm, 2Jp,p = 9.0 Hz) appears to arise from coupling to the two cis phosphorus atoms of the hybrid tridentate ligand. The phosphorus nuclei of the hybrid ligand are coupled (cis) to one another and also to the P M e 2 ligand and thus are observed as two sets of four lines (-7.39 ppm, 2.62 ppm, 2Jpj> = 9.5 Hz, 2Jp,p = 9.3 Hz). Complex 6f exhibits a most informative feature in the high field region in the *H N M R spectrum (Figure 2.20). The hydride resonance is a doublet of doublet of doublets at -10.82 ppm and shows a large trans coupling ( 2JpTH = 153.0 Hz) to one of the phosphorus centres and cis couplings ( 2Jp,H = 20.0 Hz, 2 J P > H = 9.0 Hz) to the other two phosphorus nuclei. The CrYPh proton resonance at 2.11 ppm (m) was identified by comparing the *H N M R spectrum of the protiated compound with that of the deuterated sample / a c - I r ( r | 2 - C D C 6 D 5 P M e 2 ) D [ N ( S i M e 2 C H 2 P P h 2 ) 2 ] . The formation of complex 6f proceeds with remarkable stereoselectivity, since only one isomer is observed in the crude reaction mixture (by *H and 3 1 P { ! H } N M R spectroscopy). A reported reaction between m e r - I r C l 3 { P ( M e ) ( C H 2 P h ) 2 ) 3 and L i N . i P r 2 afforded a pair of geometrical isomers of the formula I r { r j 2 - C H P h -(PMeCH 2 Ph)}Cl 2 {P(Me) (CH 2 Ph) 2 } 2 (see Chapter 1, Section 1.4)1 lb This iridium(III) hydride complex, / a c - I r ( r i 2 - C H P h P M e 2 ) H [ N ( S i M e 2 C H 2 -P P h 2 ) 2 ] , 6f, rearranged to the iridium(I) phosphine complex, I r ( P M e 2 C H 2 P h ) -[ N ( S i M e 2 C H 2 P P h 2 ) 2 ] , 4f, in solution at room temperature over a period of two weeks (Scheme 2.6). During this process, no other hydride intermediate was observed in contrast to some of the transformations mentioned above. 81 JL Me 2 Me 2  kSi Si p h 2 P I ,--/ph2 '"• I r "' / Ph H PMe 2 6f Ir-H -10.4 -10.6 -10.B -11.0 -11.2 PPM. 4 I I II | I I I I | I I I I | II I I | I I I I | I I I I | I I I I | I I I I | I ! I I | I I I I | I II I | I I I I | I I I I | I I II | I I I I | -II I I | i I I I | II 1 I | II 8 . 7 6 5 4 3 2 1 P P M 0 Figure 2.20 NMR spectrum (300 MHz, C 6 D 6 ) of/ac-Ir(Ti2-CHPhPMe2)H[N(SiMe2CH2PPh2)2], 6f 2.12 References 1 (a) Fryzuk, M . D.; Joshi, K . Organometallics 1989, 5,722. (b) Fryzuk, M . D.; Bhangu, K . / . Am. Chem. Soc. 1988,110, 961. 2 Fryzuk, M . D.; Joshi, K . J. Am. Chem. Soc. 1989, 111, 4498. 3 (a) Fryzuk, M . D.; MacNeil, P. A. ; Rettig, S. J. Organometallics 1986, 5,2469. (b) Fryzuk, M . D.; MacNeil, P. A . ; Massey, R. L . ; Ball , R. G. / . Organomet Chem. 1989,368, 213. 4 Brookes, P. R.; Shaw, B. L . / . Chem. Soc. A. 1967, 1079. 5 Moore, D. S.; Robinson, S. D. Inorg. Chim. Acta. 1981,53, L171. 6 (a) Montllo, D.; Svades, J.; Torres, M . R.; Perales, A. ; Mathieu, R. J. Chem. Soc, Chem. Commun. 1989, 97. (b) Hey, E.; Lappert, M . F.; Atwood, J. L . ; Bott, S. G. Polyhedron 1988, 7, 2083. (c) Buhro, W. E.; Zwick, B. D.; Georgiou, S.; Hutchinson, J. P.; Gladysz, J. A . J. Am. Chem. Soc 1988,110, 2427. (d) Buhro, W. E.; Chisholm, M . H.; Folting, K. ; Huffmann, J. C. J. Am. Chem. Soc. 1987,109, 905. (e) Jorg, K. ; Malisch, W.; Reich, W.; Meyer, A. ; Schubert, U . Angew. Chem., Int. Ed. Engl. 1986,25, 92. (f) Bohle, D. S.; Jones, T. C.; Rickard, C. E. F.; Roper, W. R. Organometallics 1986,5,1612. (g) Baker, R. T.; Whitney, J. F.; Wreford, S. S. Organometallics 1983, 2,1049. (h) Day, V . W.; Tavanaiepour, I.; Abdel-Meguid, S. S.; Kirner, J. F.; Goh, L . Y . ; Mutterties, E. L. Inorg. Chem. 1982, 21, 657. (i) Rocklage, S. M . ; Schrock, R. R.; Churchill, M . R.; Wasserman, H . J. Organometallics 1982,1,1332. (j) Domaille, P. J.; Foxman, B. M . ; McNeese, T. J.; Wreford, S. S. J. Am. Chem. Soc. 1980,102,4114. 83 (k) Malisch, W.; Alsmann, R. Angew. Chem., Int. Ed. Engl. 1976,15, 769. (1) Buhro, W. E.; Georgiou, S.; Hutchimson, J. P.; Gladysz, J. A . J. Am. Chem. Soc. 1985,107, 3346. (m) Dobbie, R. C ; Hopkinson, M . J.; Whittaker, D. J. Chem. Soc, Dalton Trans. 1972, 1030. (n) Roddick, D. M . ; Santarsiero, B . D.; Bercaw, J. E. / . Am. Chem. Soc. 1985,107,4670. 7 Buhro, W. E.; Gladysz, J. A . Inorg. Chem. 1985,24, 3505. 8 Crisp, G. T.; Salem, G.; Wild, S. B . Organometallics 1989, 8, 2360. 9 Appleton, T. G.; Clark, H . C ; Mazner, L . E. Coord. Chem. Rev. 1973, 10, 335. 10 Fryzuk, M . D.; MacNeil, P. A. ; Rettig, S. J. J. Am. Chem. Soc. 1987, 109, 2803. 11 (a) Mainz, V . V. ; Andersen, R. A . Organometallics 1984, 3, 675. (b) Schimdbaur, H ; Blaschke, G. Z. Naturforsch. B. 1980, 35, 584. (c) Werner, H.; Werner, R. J. J. Organomet. Chem. 1981, C60, 209. 12 Al-Jibori, S.; Crocker, C ; McDonald, W. S.; Shaw, B. L . / . Chem. Soc, Dalton Trans. 1981, 1572. 13 (a) Crocker, C ; Empsall, H . D.; Ernington, R. J.; Hyde, E. M . ; McDonald, W.S.; Markam, R.; Norton, M . C ; Shaw, B . L . / . Chem. Soc, Dalton Trans. 1982,1217. (b) Ling, S. S.; Puddephatt, R. J. / . Chem. Soc, Chem. Commun. 1982, 412. 14 Fryzuk, M . D.; MacNeil, P. A. ; Rettig, S. J. / . Am. Chem. Soc 1985, 107, 6708. 15 (a) Klein, D. P.; Bergman, R. G. J. Am. Chem. Soc. 1989, 111, 3079. (b) Clark, G. R.; Roper, W. R.; Wright, A . H . / . Organomet. Chem. 1984, CI 7,273. 84 16 Massey, R. L . M. Sc. Thesis, University of British Cloumbia, Vancouver, Cananda, 1989. 17 (a) Deutsch, P. P.; Eisenberg, R. Organometallics 1990, 9, 709. (b) Mann, B. E.; Taylor, B. F. 13C NMR Data for Organometallic Compounds; Academic: New York, 1981. 18 (a) Blandy, C ; Locke, S. A. ; Young, S. J.; Schore, N . E. J.Am. Chem. Soc. 1988,110, 7540. (b) Wenzel, T. T.; Bergman, R. G. / . Am. Chem. Soc. 1986,108, 4856. (c) Karsch, H . H. ; Appelt, A . Phosphorus Sulfur 1983,18, 287. (d) Engelhard, L . M . ; Jacobsen, G. E.; Raston, C. L. ; White, A . H . J. Chem. Soc, Chem. Commun. 1984, 220. (e) Chiu, K . W.; Wong, W. K. ; Wilkinson, G.; Galas, A . M . R.; Hursthouse, M . B. Polyhedron 1982,1, 37. 19 Latesky, S. L . ; McMullen, A . K. ; Rothwell, I. P.; Huffmann, J. C. / . Am. Chem. Soc 1985,107, 5981. 20 Krassowki, D. W.; Nelson, J. H . ; Brower, K . R.; Hauenstein, D.; Jacobson, R. A . Inorg. Chem. 1988, 27, 4294. 21 Joshi, A . M . ; James, B. R. Organometallics 1990, 9, 199. 22 Collman, J. P.; Hegedus, L . S.; Norton, J. R.; Finke, R. G. Principles and Applications of Organotransition Metal Chemistry; University Science Books: M i l l Valley, C A , 1987, Chapter 4, p 239. 23 Kosolapoff, G. M . Organophosphorus Compounds; John Wiley: New York, 1950, Chapter 1, p. 24. 85 CHAPTER 3 Reactivity of the Iridium(IH) Phosphide Complexes with Alkynes 3.1 Introduction In the last ten years, several reports on the reactivity of terminal phosphide complexes have been published.1 Due to the presence of a lone pair of electrons on the pyramidal phosphide (See Chapter 1, Section 1.3.2), nucleophilic properties are normally associated with this type of phosphorus centre.2 For example, the complex trans-[Cp(CO)2(PMe3)Mo(PPh2)] reacts with the electrophilic reagents M e l or HC1 to yield products in which the phosphide ligand has been methylated or protonated, respectively (Scheme 3.1).3 On the other hand, the formal charges present in planar phosphide derivatives (Chapter 1, Section 1.3.2) suggest that this phosphorus centre should display electrophilic character. Since complexes containing planar phosphide ligands are rare, little is known about their reactivity patterns.4 However, the following example wil l serve to illustrate the electrophilic nature of this type of phosphorus centre. The complex Cp(CO)2W[P(CMe3)2] undergoes spontaneous reaction with R O H (R = H , Me, Et) to form the derivative in which the alcohol group has added across the metal-phosphorus double bond with the nucleophilic R O ' group adding to the phosphorus (Equation 3.1).5 86 trans -Cp(CO)2(PMe3)Mo — P Mel [Cp(CO)2(PMe3)Mo(PMePh2)]+ I" HCI [Cp(CO)2(PMe3)Mo(PHPh2)]+ CI' Scheme 3.1 Cp(CO)2W = P" \ x CMe 3 CMe 3 ROH Cp(CO)2HW — P., /CMe3 >CMe3 R = H, Me, Et Equation 3.1 To our knowledge, there is no report in the literature describing the reactivity of mononuclear phosphide complexes with alkynes, but some reactions of binuclear complexes containing bridging phosphide ligands with alkynes have been published.6 Relevant to the thesis work is the following example: the complex [Fe(CO)3]2-( | i-PHPh)2, when exposed to one equivalent of dimethylacetylenedicarboxylate (DMAD) in the presence of the base piperidine, undergoes a Michael-type addition reaction 7 with the alkyne to yield two products (Equation 3.2).8 In the product A, the alkyne binds to one of the phosphide ligands; whereas, in the product B, both the carbons of the alkyne are bridged between the two phosphide ligands. 87 Fe(C0)3 H N ^ (CO)3Fe'^- Fe £ 0 2 C 0 2 . (CO) 3 C H 3 C H 3 H H Ph , , P H P h C H 3 0 2 C C e C C 0 2 C H 3 P h H P ^ ^ P _ c _ c _ N ^ A * C 0 2 C H 3 (CO)3Fe - Fe(CO)3 B Equation 3.2 As a part of an ongoing study on the reactivity of iridium(III) phosphide complexes, 9 the reactions of I r ( C H 3 ) P R 2 [ N(SiMe2CH 2PPh2)2] (2a: R = Ph, 2c: R = Me) with various alkynes were investigated in an attempt to generate complexes in which the alkyne has bridged between the nucleophilic phosphide phosphorus and the unsaturated metal centre (in other words to generate metallacyclophosphinobutene-type complexes, shown below as C) . This chapter describes the reactivity of 2a and 2c with D M A D , and the reactions of 2a with the following alkynes: PhC=CPh, R G E C H (R = H, Ph, l Bu). Ph2 /^^>» P M e 2 S i / C ^ 3 \ N l r s — P R 2 Me^i^ | -P R R "Ph2 88 3.2 Reaction of Ir(CH3)PPh2[N(SiMe2CH2PPh2)2], 2a, with DMAD Addition of one equivalent of DMAD to the toluene solution of the iridium(III) diphenylphosphide, Ir(CH3)PPh2[N(SiMe2CH2PPh2)2], 2a, at -78°C resulted in the immediate colour change from purple to burgundy (Equation 3.3); recrystallisation from toluene/hexanes at -30°C afforded the new complex, 12, in good yields (~ 82%). The geometry of the product 12 was not obvious from the available N M R spectral information; however, the X-ray crystal structure (Figure 3.1) revealed that one of the phosphorus phenyl substituents had migrated to the iridium centre. The phosphide group is now part of a tetradentate ligand joined by the D M A D unit, and the newly formed tetradentate ligand is in the cis-$ configuration [P(l)-Ir-P(3) = 96.16°]. The methyl ligand is oriented trans to the amide [C(49)-Ir-N = 173.6°]. The C=C bond length of 1.34 A is the same as reported for several alkenyl complexes. 1 0 Some selected bond lengths and bond angles are listed in Tables 3.1 and 3.2. Ph 2 Ph 2 2a 1 2 Equation 3.3 89 C 1 6 Figure 3.1 X-ray crystal structure of Ir(CH3)PPh2{C2(C02Me)2}-[N(SiMe2CH2PPh2)2],12 90 Table 3.1 Selected Bond Lengths (A) for Ir(CH3)PPh2{C2(C02Me)2}[N(SiMe2CH2PPh2)2], 12a Ir—P(l) 2.352(2) Ir—P(2) 2.288(2) Ir—P(3) 2.335(2) Ir—C(43) 2.145(7) Ir—C(49) 2.119(7) Ir—N 2.281(5) C(38)—C(39) 1.34(1) Table 3.2 Selected Bond Angles (deg) for Ir(CH3)PPh2{C2(C02Me)2}[N(SiMe2CH2PPh2)2], 12a C(43)—Ir—N 89.2(2) C(49> - I r - - N 173.6(2) C(43)—Ir—P(l) 98.8(2) C(49)-- I r - - P ( l ) 90.9(2) C(43)—Ir—P(2) 81.1(2) C(49)-- I r - -P(2) 99.1(2) C(43)—Ir—P(3) 164.5(2) C(49)-- I r - -P(3) 89.2(2) N—Ir—P(l) 84.9(1) C(43)-- I r - -C(49) 86.7(3) N—Ir—P(2) 85.1(1) N—Ir—P(3) 96.1(1) P(l)—Ir—P(2) 169.98(6) P(l)—Ir—P(3) 96.16(7) P(2)—Ir—P(3) 84.88(7) a. A complete list of the bond distances and the bond angles is compiled in Appendix 91 The information provided by various N M R spectra on this complex is consistent with the solid-state data. In the *H N M R spectrum of 12 (Figure 3.2), silyl-methyl groups and the methylene protons of the ligand backbone resonate as four singlets and four sets of multiplets, respectively. Two sharp singlets at 2.92 and 3.05 ppm are observed for the OCH3 protons. In addition, the IR data (KBr disc) are also consistent with the formulation owing to the V(c=o) absorptions at 1711.7 and 1746.9 c m - 1 and V(c=C) absorption at 1620 c m - 1 . 8 The three phosphorus nuclei show an A M X pattern in the 3 1 P { 1 H } N M R spectrum; the chemical shifts of the PPh2 phosphorus nuclei are at 41.25 ppm ( 2JPA, PM = 398.3 Hz, 2JP A , PX = 6.1 Hz) and -17.65 ppm ( 2JPA, PM = 389.8 Hz, 2 J P M , PX = 14.6 Hz). The PPh resonance is observed at 26.85 ppm ( 2JPA, PX = 4.8 Hz, 2JP M , PX = 7.3 Hz). One possible mechanism (Scheme 3.2) for the formation of 12 involves prior coordination of the alkyne to the metal centre to generate an octahedral intermediate A , which then undergoes nucleophilic attack by the phosphide ligand to form the metallacyclobutene complex (B). The alkenyl-phosphine ring in B can be considered as a resonance form of the carbene-ylide form (B'). Such a representation allows for the migratory insertion of the carbene unit 1 1 into one of the tridentate phosphine arms of the ancillary ligand yielding C , which is followed by the phenyl group migration to the metal. 92 Figure 3.2 *H N M R spectrum (400 MHz, C 6 D 6 ) of Ir(CH3)PPh2{C2(C02Me)2}[N(SiMe2CH2PPh2)2], 12, (* indicates hexanes protons, t indicates toluene protons) Me 2 Si ' \ N P h 2 i / • * * lr" ' C H 3 Me 2S' P P h 2 2a EC=CE (E = C0 2 CH 3 ) Ph 2 •P M e 2 S i / C t j 3 N lr Me2s( | y>°E , P CE Ph 2 Ir PPh 2 Me 2S Me2s; 1 2 M e 2 S i / C ^ 3 \ ' N | r Ph 2 P N | r p p h 2 \ — p + b P h / Me 2 S i ' C H 3 \ N Ph 2 •P Ir Me 2Si P E Ph 2 B PPh 2 'E Scheme 3.2 Ph 2 M e 2 S i / c ^ 3 \ \ I N Ir ^ - P P h 2 •P E E Ph 2 B' Examples of binuclear systems involving phenyl migration from a coordinated phosphine ligand have been reported in the literature. 1 2 However, these transformations usually occur at high temperatures. The reaction of [Fe2(CO)7(|i-dppm)] with acetylene produces {Fe2(CO) 5 (u.-CH = C H C O ) -[|i.-PPh2CH2PPh2]} (shown as A in Scheme 3.3) under photolytic conditions. 1 3 The 94 complex A exists in equilibrium with A ' via rapid breaking and reforming of the carbon-carbon bond linking the "alkyne" and CO, thus, exchanging the ketonic and the terminal CO between the two ends of the alkyne. At ~90°C, complex A converts to B, which in turn slowly isomerises to C in which the phenyl group from one of the phosphine ligands has migrated to one of the methylene ligands. Complexes A - C were characterised by X-ray crystallography, but the authors did not comment on how these species were formed. H (CO)3Fe Ph 2P, H I .C -CX H 2 H H Fe(CO)2 I , P P h 2 (CO)2Fe I Ph 2 P Fe(CO) 3 „PPh 2 90°C -CX H 2 A' Ph ? H H 2 C ^ ^ C Ph 2 P (CO)2 F ® H -Fe(CO)3 Ph 2 " 2°\~ P N ^ ^ p H 2 P h PhP (CO)3Fe • Fe(CO)3 O B Scheme 3.3 As mentioned before (Chapter 1, Section 1.2), the amido-diphosphine ligand generally acts as an ancillary ligand. There are few other reports where this rather innocent ligand participated in the reaction.14 One of the examples involved the migratory insertion of CO into nickel(II) carbon bond of Ni(R)[N(SiMe2CH2PPh2)2] (R = CH3, CH=CH 2 , C6H5) and promoted a rearrangement of the tridentate ligand to generate a nickel(O) dicarbonyl derivative of formula N i ( C O ) 2 [ R C O N -95 (SiMe2CH2PPh2)2] (Equation 3.4). The next section describes another example where the tridentate ligand has become involved in the reaction. P h 2 P h 2 P Me 2 M e 2 S i x I / ° ~~ S i \ ^ - ' p " * yC0 \ _ J i _ R C Q ( e x c e s s ) , R - \ ' ">C M e 2 s ( I ^ S i ^ / •P M e 2 P h 2 P h 2 R = CH 3 , CH=CH 2 l C 6 H 5 Equation 3.4 3.3 Reaction of Ir(CH3)PMe2[N(SiMe2CH2PPh2)2], 2c, with DMAD Treatment of the purple-coloured toluene solution of Ir(CH3)PMe2-[N(SiMe2CH2PPh2)2], 2c, with one equivalent of DMAD at -30°C yielded a burgundy-coloured solution within minutes; recrystallisation from hexanes/toluene afforded burgundy crystals of 13 (Equation 3.5). P h 2 Ph 2 Me 2 SK \ / M e 2 M e 2 S K C ^ \ \ I / CH 3 C0 2 C^CC0 2 CH 3 \ \ | N Ir' - C H 3 = — N - | r . p M e 2 / I toluene,-30°C / i > ^ _ J Me 2sf I Me 2s( ' > CO? ' P V ^ . p C 0 2 C 0 2 Ph 2 ^ P h 2 C H 3 C H 3 2c 13 Equation 3.5 The !H and 3 1P{ 1H} NMR spectra of 13 are simpler compared to the spectral features observed for the complex 12. In the *H NMR spectrum (Figure 3.3), two 96 silyl-methyl singlets and the A B quartet of virtual triplets for the CH2P protons protons are two sharp singlets at 3.27 and 3.88 ppm. Further evidence for this structure is the A X 2 pattern in the 3 1 P { 1 H } N M R spectrum: a doublet at 2.99 ppm ( 2 J p , P = 23.8 Hz) for the phosphorus nuclei of the ligand backbone, and a triplet at -106.70 ppm.( 2Jpp = 23.5 Hz) for the P M e 2 phosphorus centre are observed. Such a high shielding of the phosphorus nucleus of the P M e 2 group is consistent with metallacyclic structures.15 From the crude reaction mixture (Equation 3.5), a small amount of burgundy crystals was isolated, which was initially thought to be of the product 13, and therefore analysed by X-ray crystallography. But, the crystals, characterised as I r ( C H 3 ) I { C 2 ( C 0 2 M e ) 2 } [ N ( S i M e 2 C H 2 P P h 2 ) 2 ] , 14, originated from the reaction of D M A D with some left-over starting material I r (CH 3 ) I [N(S iMe 2 CH 2 PPh 2 ) 2 ] , 1, used in preparing the in situ dimethylphosphide complex 2c (see Chapter 2, Section 2.2). In order to analyse the product 14 fully, it was synthesised in larger quantities by reacting pure 1 with D M A D (Equation 3.6). The reaction proceeded rapidly at room temperature as the green colour of 1 turned burgundy due to the formation of 14. indicate the two faces of the iridium complex are inequivalent. In addition, the OCH3 N I r N I r toluene, -30°C Me2Si, 1 Me 2 1 4 Equation 3.6 97 Figure 3.3 lH NMR spectrum (300 MHz, C 6 D 6 ) of Ir(CH3)PMe2{C2(C02Me)2}[N(SiMe2CH2PPh2)2], 13, (* indicates hexanes protons, t indicates toluene protons) The solid-state structure of 14 (Figure 3.4) reveals that the DMAD unit has been incorporated into the backbone of the ligand between the amide and the silicon atoms. The insertion results in the formation of a carbon-nitrogen double bond, based on the N-C(2) distance of 1.28 A (Tables 3.3, 3.4), and a new iridium-carbon bond. The N-C(2) bond length coincides well with other known N=C distances (1.28 A ) . 1 7 Similar to complex 12, the newly formed tridentate ligand is arranged in cis-P Figure 3.4 X-ray structure of Ir(CH3)I{C2(C02Me)2}[N(SiMe2CH2PPh2)2], 14 99 Table 3.3 Selected Bond Lengths (A) for Ir(CH3)I{C2(C02Me)2}[N(SiMe2CH2PPh2)2], 14 a Ir—P(l) 2.278(3) Ir—P(2) 2.433(2) Ir—C(37) 2.146(9) Ir—I 2.6929(9) Ir—N 2.044.(9) Ir—C(3) 2.32(1) C(2)—C(3) 1.51(1) N—C(2) 1.28(1) Table 3.4 Selected Bond Angles (deg) for Ir(CH 3)I {C 2(C02Me)2} [N(SiMe 2CH 2PPh2)2], 14a C(37)—Ir—N 85.1(4) C(3)—Ir—N 64.3(3) C(37)—Ir—P(l) 91.5(3) C(3)—Ir—P(l) 155.2(3) C(37)—Ir—P(2) 172.1(3) C(3)—Ir—P(2) 88.8(2) C(37)—Ir—I 84.7(3) C(3)—Ir—I 104.5(2) N—Ir—P(l) 91.1(2) N—Ir—P(2) 93.7(2) N—Ir—I 165.6(2) P(l)—Ir—P(2) 96.37(9) P(l)—Ir—I 99.24(7) P(2)—Ir—I 95.13(7) a. A complete list of the bond distances and the bond angles is compiled in Appendix A l . The spectral information obtained on this complex is consistent with the solid-state structure. The lH N M R spectrum of 14 (Figure 3.5) consists of four singlet resonances for the silyl-methyl groups, a set of multiplets for the methylene protons of the ligand backbone, and two singlets for the O C H 3 protons. In the ^ P f ^ H } N M R spectrum, the two phosphines being inequivalent show resonances at -20.56 ppm (d, 2Jp,P = 7.4 Hz) and +42.34 ppm (d, 2 J P , P = 11.0 Hz). The IR spectrum (KBr disc) has two moderate intensity bands at 1676.8 and 1732.8 c m - 1 ascribed to the V(c=0) of the acyl ligands. 100 Figure 3.5 lH N M R spectrum (400 MHz, C 6 D 6 ) of Ir(CH3)I{C 2(C0 2Me)2}[N(SiMe2CH 2PPh 2) 2], 14, (* indicates hexanes protons, t indicates toluene protons) Analogous to the mechanism invoked for the formation of the complex 1 2 , the synthesis of 1 4 is thought to involve prior coordination of the alkyne at the iridium centre to afford A (Scheme 3.4). Previous work done on the reactivity of 1 with ligands L = CO or PMe3 has shown that L coordinates trans to the methyl ligand and generates octahedral complexes of formula k(CH3)I(L)[N(SiMe2CH2PPh2)2].17 The nucleophilic attack by the amide nitrogen at the bound alkyne carbon in a pseudo-Michael-type reaction followed by insertion into N-Si bond leads to the product. N l r N Ir 1 Me 2 1 4 E O C E E = C 0 2 C H 3 c N Ir A B Scheme 3.4 102 3.4 Reaction of 2a with P h O C P h The complex Ir(CH3)PPh2[N(SiMe2CH2PPh2)2], 2a, reacted with P h O C P h at room temperature within ten minutes with the purple colour of 2a changing to orange (Equation 3.7). B y lYL and 3 1 P { 1 H } N M R spectroscopy, the product was readily identified as Ir(PhOCPh)[N(SiMe2CH2PPh2)2L 15, because it had been prepared previously by the reaction of the iridium(III) dihydride complex Ir(Ff)2[N(SiMe 2CH2-PPh2)2] with P h O C P h . 1 8 Ph2 Ph2  p P D h . / " p Ph Me 2 Sr I , / P h 2 Me2Si i c \ I .•*** PhC^CPh \ I N Ir' CH3 N Ir / j toluene, RT / I Me 2 s f I (-PCH3Ph2) Me2SlT | -\ ^ - P \ ^ Ph2 Ph2 2a 15 Equation 3.7 The reaction presumably proceeds via the prior coordination of PhC=CPh at the metal centre. Reductive coupling and elimination of PCH 3 Ph2 (observed by lH and 3 1 P { 1 H } N M R spectroscopy) from the metal coordination sphere affords the complex 15. The w o r k done on the reactivity of the diphenylphosphide complex I r ( C H 3 ) P P h 2 [ N ( S i M e 2 C H 2 P P h 2 ) 2 ] , 2a, with C O has shown similar resul ts . 1 9 The reaction of 2a with excess C O afforded two isomers of formula Ir(CH 3)PPh2(CO)-[N(SiMe2CH2PPh2)2] (Scheme 3.5). With in 24 hours in solution, these complexes were converted to the iridium(I) carbonyl species Ir(CO)[N(SiMe2CH2PPh2)2] yielding free methyldiphenylphosphine. 103 Me 2 Si ' \ N Ph 2 | , / P h 2 Ir' C H 3 Me 2Si P Ph 2 2 a Ph 2 •P Me 2 Si ' CO \ N . — Ir y y • — C H 3 Me 2S CO P Ph 2 Me 2 S i ' \ N Me 2S Me 2 Si ' \ + N Ph 2 •P Ir P Ph 2 24 hours (-PCH3Ph2) Ph 2 •P Ir P Ph 2 •CO , x C H 3 — P P h 2 Scheme 3.5 3.5 Reaction of 2a with R O C H (R = H, Ph, B^u) The iridium(III) diphenylphosphide complex Ir(CH3)PPh2[N(SiMe2CH2-PPh2)2l. 2a, reacted with the terminal alkynes RC=CH (R = H, Ph, lBu) over the period of an hour as the purple solution of 2a slowly changed to light yellow (Equation 3.8). By lH and 3 1 P{ 1 H} NMR spectroscopy, the products are formulated as Ir(CH3)PHPh2(C=CR)[N(SiMe2CH2PPh2)2L 16-18. However, none of these species could be isolated because decomposition resulted when solutions of the complexes were left for crystallisation under an inert atmosphere. 104 Ph 2 ^ Ph 2 M e 2 S i X I / P h 2 M e 2 S r | %*CH3 \ I / RC^CH \ I N Ir' C H 3 — N Ir PHPh 2 s I toluene, RT • Si Me2s( | Me 2sf C | \ ^ P R = H,Ph, tBu RNT^-'P X ^ P h 2 R C X ^ P h 2 2 a 16-18 Equation 3.8 The *H NMR spectra of the products are straightforward. The NMR spectral data of 18 will serve to illustrate this point. Once again, the methylene resonances, observed as an AB quartet of virtual triplets, are indicative of the meridional arrangement of the tridentate ligand. The P//Ph2 proton is observed as a doublet of triplets centred at 5.30 ppm l^Jp.H = 360.0 Hz, 3Jp ,H = 7.2 Hz). This large value of *Jp ,H has been observed before in complexes such as Ir(H)2PHPh2-[N(SiMe 2CH 2PPh 2)2] (lJp,u = 334.7 Hz, 3 J P , H = 9.7 Hz). 2 0 The lBu protons resonate as a singlet at 1.72 ppm. There are three possible stereoisomers for the structures of the complexes 16-18 (Scheme 3.6). The isomer 03 was readily ruled out from the NMR data for which the methyl protons of the Ir-CH3 ligand would be expected to resonate as a doublet of triplets because of its larger trans coupling with the phosphorus of the PHPh2 ligand than its cis couplings with the chelating phosphine donors; rather it is observed as a four line pattern (-0.95 ppm, 3Jp ,H = 5.3 Hz). In the complex Ir(CH3)I-(PCH3Ph2)[N(SiMe2CH2PPh2)2l. 1 9 where the methyl and the methyldiphenyl-phosphine ligands are trans oriented, the Ir-CH3 resonance is a doublet of triplets (3Jp,H (trans) = 20.0 Hz, 3 J P , H (cis) = 6-0 Hz). 105 / - \ p h 2 / \ p h * / ^ P h 2 M e 2 S i ' 1 , / H 3 M e 2 S i ^ | ^ P H P h 2 M e 2 s Y P ^ C H 3 N — I x PHPh 2 N — I r ' -CH 3 N — | r' C = CR M e 2 S i ^ M e 2 S i ^ \ M e 2 S i ^ p i ^ , ^ f „ 8 01 0 2 0 3 Scheme 3.6 The isomer 02, in which the acetylide and the phosphine ligands are trans, is unlikely to form from a mechanistic point of view; that is with the assumption that the product forms via an intramolecular proton abstraction by the phosphide ligand from the alkyne, both the ligands would expected to be cz's-oriented. 3.6 Summary The reactivity of 1 and 2a with D M A D is unusual. Some examples of modification of ancillary phosphine ligands are reported in the literature. 1 2 ' 1 3 The results described in this study are the first examples involving the hybrid tridentate ligand where P - C bond formation/cleavage has taken place. Because of the.electron-withdrawing substituents on the D M A D , the alkyne reacts with the electron-rich sites (phosphide and amide) in the complexes 1, 2a and 2c. In the species 2a and 2c, which contain two electron-rich centres, namely phosphide and amide, the alkyne preferentially binds to the phosphide site which suggests that the phosphide is likely more basic than the amide centre. The alkyne PhC^CPh promotes the elimination of the methyldiphenylphosphine from 2a which is pehaps because of the steric bulk of the phenyl substituents. In the case of a terminal alkyne ( R O C H ) , where an acidic proton is present, after being 106 coordinated to the metal centre, the alkyne undergoes a proton abstraction by the phosphide ligand to afford an acetylide phosphine complex. 107 3.7 References 1 Collman, J. P.; Hegedus, L . S.; Norton, J. R.; Finke, R. G. Principles and Applications of Organotransition Metal Chemistry; University Science Books: M i l l Valley, C A , 1987, Chapter 3, p.77. 2 Bohle, D. S.; Jones, T. C ; Rickard, C. E. F.; Roper, W. R. Organometallics 1986,5, 1612, and references therein. 3 Malish, W.; Maisch, R.; Colquhoun, I. J.; MacFarlane, W. J. Organomet. Chem. 1981, 220, C I . 4 Roddick, D. M . ; Santarsiero, B. D.; Bercaw, J. E. / . Am. Chem. Soc. 1985,107, 4670, and references therein. 5 Jorg, K. ; Malish, W.; Reich, W.; Meyer, A. ; Schubert, U . Angew. Chem., Int. Ed. Engl. 1986,25,92. 6 (a) Nucciarone, D.; Taylor, N . J.; Carty, A . J. Organometallics, 1988, 7, 127. (b) Iggo, J. A. ; Mays, M . J.; Raithby, P. R. / . Chem. Soc, Dalton Trans. 1983, 205. 7 For example, see: March, J. Advanced Organic Chemistry; Wiley Interscience: New York, 1985, Chapter 15, p. 665. 8 Seyferth, D.; Wood, T. G. Organometallics 1988,7,714. 9 (a) Fryzuk, M . D.; Joshi, K . Organometallics, 1989, 8, 1722. (b) Fryzuk, M . D.; Bhangu, K . / . Am. Chem. Soc. 1988,110, 961. 10 Balegroune, F.; Braunstein, P.; Carneiro, T. M . ; Grandjean, D.; Matt, D. J. Chem. Soc, Chem. Commun. 1989, 582. 11 Some examples of carbene insertion into iridium-phosphorus bond have been discussed in chapters 1 and 2. Also see Clark, G. R.; Roper, W. R.; Wright, A . H . J. Organomet Chem. 1984, C17,273. 12 (a) Powell, J.; Sawer, J. F.; Shiralian, M . Organometallics, 1989, 8, 577. (b) Chakravarty, A . R.; Cotton, F. A. ; Tocher, D. A . J. Am. Chem. Soc. 1984, 106,6409. 108 (c) Farrugia, L . J.; Miles, A . D.; Stone, F. G. A . J. Chem. Soc, Dalton Trans. 1984, 2415. 13 Hogarth, G.; Knox, S. A . R.; Lloyd, B . R.; Macpherson, K . A . ; Morton, D. A . V. ; Orpen, A . G. J. Chem. Soc, Chem. Commun. 1988, 360. 14 (a) Fryzuk, M . D.; MacNeil, P. A . Organometallics 1982,1, 1540. (b) Fryzuk, M.D . ; McManus, N . T.; Rettig, S. J.; White, G . S. Angew. Chem., Int. Ed. Engl. 1990,29, 73; also see chapters 4 and 5. 15 (a) Mainz, V . V. ; Andersen, R. A . Organometallics 1984, 3,675. (b) Werner, H.; Werner, R. J. J. Organomet. Chem. 1981, C60, 209. 16 Bohme, H . ; Viehe, H . G., Eds. Iminium Salts in Organic Chemistry, Part I. Wiley: New York, 1976, 89. 17 Fryzuk, M . D.; MacNeil, P. A. , Rettig, S. J. Organometallics 1986,5, 2469. 18 Block, G. B. Sc. Thesis, University of British Columbia, Vancouver, Canada, 1986. 19 Bhangu, K . M. Sc. Thesis, University of British Columbia, Vancouver, Canada, 1987. 20 Some examples of proton abstraction by the phosphide ligand from a coordinated ligand have been discussed in chapter 2 of this thesis; also see reference 9b. 109 CHAPTER 4 Synthesis and Reactivity of an Iridium Methylidene Complex 4.1 Introduction The synthesis and characterisation of the iridium methylidene complex, Ir=CH2[N(SiMe2CH2PPh2)2l» 10, have been reported previously.1 However, the usual photochemical preparative route (Chapter 1, Scheme 1.5) gives low isolated yield of the methylidene complex with Ir(H)2[N(SiMe2CH2PPh2)2] formed as the major product. It was found that the reaction of Ir(CH3)I[N(SiMe2CH2PPh2)2]> 1> with KO rBu gave Ir=CH2[N(SiMe2CH2PPh2)2], 10, in higher yield. This chapter describes the synthesis of Ir=CH2[N(SiMe2CH2PPh2)2], 10, its reactivity with the electrophiles, Mel and Me3Al, and with the unsaturated hydrocarbons, 1,2-propadiene (allene), 1,3-butadiene and acetylene. Its reactivity with the nucleophiles, PHPh2, PHlBu2 and PH2Ph, has been discussed in chapter 2. 4.2 Improved Synthesis of I r = C H 2 [ N ( S i M e 2 C H 2 P P h 2 ) 2 ] , 10 The iridium methylidene complex, Ir=CH2[N(SiMe2CH2PPh2)2L 10, was prepared by the reaction of the iridium(III) methyl-iodide derivative, Ir(CH3)I-110 [N(SiMe2CH2PPh.2)2L 1. with excess (~5 equivalents) potassium rm-butoxide in toluene (Equation 4.1). The reaction proceeded over two hours with a noticeable colour change from initial deep green to purple colour due to. the formation of the iridium methylidene species. The isolated yield of the product is ~60%. The methylidene complex 10 is stable toward the by-product ferr-butanol for about 24 hours, beyond which it decomposes as the rerr-butanol presumably reacts with the ligand backbone. The *H NMR spectrum of 10 shows the resonance for the methylidene protons at +16.44 ppm (t, 3Jp ) H = 14.4 Hz). KO lBu toluene , (- HO'Bu, - Kl) r = CH 2 Equation 4.1 In agreement with the iridium(III) methyl-phosphide2 and the dialkyl chemistry,3 it is proposed that the synthesis of 10 might proceed through the formation of the iridium(III) methyl rerf-butoxide intermediate A (Scheme 4.1a). The next step involves an intramolecular cc-hydride abstraction from the methyl ligand by the butoxide group to generate the methylidene butanol intermediate B. The tert-butanol ligand dissociates yielding the product 10. The formation of 10 was followed by *H and 3 1P{ 1H} NMR spectroscopy but no intermediates were observed. An alternative mechanism is shown in Scheme 4.1b which involves intermolecular deprotonation of the oc-proton from the methyl ligand by the butoxide base. The synthesis of the methylidene complex 10 was also attempted by the reaction of the methyl-iodide derivative 1 with LiN(SiMe3)2, BuLi and LiNH lBu. I l l While no reaction was observed with LiN(SiMe3)2, the reaction with BuLi resulted in decomposition. However, the reaction with LiNH lBu yielded Ir(H)2[N(SiMe2CH2-PPfi2)2] quantitatively, presumably by the loss of H2C=NlBu (Equation 4.2). Me 2Si \ Me 2 Si , Me 2Si \ Ph2 •P 0 C H 3 N lr -P Ph2 <OxBu (-KI) Ph2 •P .CH, N — lr O'Bu Me 2 Si . -P Ph2 Scheme 4.1a Me 2 S i ' \ Me 2Si Me 2 S i^ N Me 2 Si , Ph2 •P N | r = C H 2 -P Ph2 1 0 (- HOlBu) Ph2 •P OH'Bu C H 2 -P Ph2 B Me 2Si \ N Ph2 •P O'Bu p y - H lr - r — I Me 2 Si . (- HCfeu, - KI) -P Ph2 Me 2 Si ' \ Ph2 •P N | r = C H 2 Me 2Si •P Ph2 1 0 Scheme 4.1b 112 It was speculated that the dihydride complex might be forming via the iridium(III) methyl rm-butylamide, Ir(CH3)NHtBu[N(SiMe 2CH 2 PPh2)2] ( A ) , and the methylidene amine, Ir=CH2(NH2 tBu)[N(SiMe2CH2PPh2)2] ( B ) , intermediates (Scheme 4.2). To test this hypothesis, one equivalent of l B u N H 2 was added to the toluene solution of the methylidene complex Ir= C H 2[N ( S i M e 2 C H 2PPh 2 ) 2 L 10 (Equation 4 . 3 ) . The reaction proceeded over two hours to yield /ac-Ir(r| 2-CH 2NH tBu)H[N(SiMe 2CH 2PPh 2) 2], 19. No methylidene amine intermediate B was detected by *H and 3 1P{ 1H) NMR spectroscopy. Complex 19 was isolated as pale yellow crystals in good yields ( -75%). The lH NMR spectrocopic features of this complex are similar to its phosphine analogues, /<2c-Ir(ri 2-CH2PR2)H[N(SiMe2CH2-PPh2)2], described in chapter 2. The hydride ligand, being trans to the amide centre of the tridentate ligand, is observed as a doublet of doublets at -20.85 ppm ( 2Jp ) H (cis) = 19.5 Hz, 2Jp ) H (cis) - 9.6 Hz). The complex 19 is stable in solution for extended periods of time and does not convert to Ir(H)2[N(SiMe2CH2PPh2)2]» thus indicating that the formation of the dihydride complex is not proceeding through the intermediates proposed in Scheme 4.2. Ph 2 Ph 2 N Ir LiNH Bu N Ir'. 1 Equation 4.2 113 1 0 Me 2Si Me 2Si LiNH'Bu (-Li!) Me 2St Me?Si lBuNH2 toluene, RT Equation 4.3 NH'BU Me 2 Me 2 ^ S i Si ^ f Y ^  P h 2 P BuHN Ir '•" • C H 2 P P h 2 I H 1 9 Me 2Si Me 2Si f (- CH2=N lBu) Me 2Si Me 2Si NH 2 lBu Scheme 4.2 The aforementioned procedure (Equation 4.1) to synthesise 10 could not be extended to generate other alkylidene species. For example, the reaction of the rhodium methyl-iodide complex, Rh(CH3)I[N(SiMe2CH2PPh2)2L with K O l B u 114 resulted only in decomposition. Furthermore, the reactions of Ir(Ph)I-[N(SiMe 2CH 2PPh2)2], I r ( C H 2 P h ) B r [ N ( S i M e 2 C H 2 P P h 2 ) 2 ] , or I r ( C H 2 C 0 2 M e ) B r -[ N ( S i M e 2 C H 2 P P h 2 ) 2 ] with K O l B u to produce the corresponding benzyne, benzylidene or the carbene complex, respectively, were also unsuccessful as decomposition was observed. 4.3 Reactivity of Ir=CH2[N(SiMe2CH2PPh2)2], 10 Preliminary reactivity patterns of the methylidene complex 10 were investigated by a previous graduate student in our laboratory as a part of her M.Sc. thesis. 4 The reactions of 10 with CO and P M e 3 yielded the iridium(I) complexes of formula I r (L)[N(SiMe 2 CH 2 PPh 2 ) 2 ] (L = CO, PMe 3 ) and free ethylene (Scheme 4.3). In the case of L = P M e 3 , the intermediate I r = C H 2 ( P M e 3 ) [ N ( S i M e 2 C H 2 P P h 2 ) 2 ] was detected below 0°C. The reaction of 10 with ethylene afforded two products: the iridium(I) 7t-bound ethylene species, I r ( r | 2 - C 2 H 4 ) [ N ( S i M e 2 C H 2 P P h 2 ) 2 ] , and the iridium(III) allyl hydride complex, I r ( r i 3 -C 3 H5 )H[N(SiMe 2 CH 2 PPh 2 ) 2 ] in the ratio of 1:2 (Scheme 4.3). Some N M R scale reactions of 10 with methyl iodide and acetylene were also conducted. However, these two latter reactions are re-investigated and are described below along with the reactivity of 10 with trimethylaluminum, 1,3-butadiene and allene. 115 Me2S Me2Si Me2Si CO Me2Si Me2Si | r — PMe 3 Scheme 4.3 4.3.1 Reactivity with AlMe3 and Mel As mentioned before (Chapter 1, Section 1.5), Schrock and co-workers examined the reactivity of Cp2Ta=CH2(CH3) with the electrophiles AlMe3 and M e l which yielded C p 2 T a ( C H 2 A l M e 2)CH3 and Cp2Ta(rj2-C2H4)I, respectively.5 That study along with the reactions with several other substrates pointed towards the nucleophilic nature of the carbene carbon. The following two sections describe the reactions of Ir=CH2[N(SiMe 2CH 2-PPh2)2]» 10, with A l M e 3 and M e l . However, before this work is presented, a brief look at the reactivity of the vinylidene complex, Ir=C=CH2[N(SiMe2CH 2 PPh2) 2 ] with the same reagents is necessary, because both 10 and the vinylidene complex give rise 116 to analogous products apparently via similar mechanisms in the presence of these reagents.6 The complex Ir=C=CH2[N(SiMe2CH2PPh2)2] reacted cleanly with AIR3 (R = Me, Et) at room temperature to yield a complex (shown in Figure 4.1) in which the iridium-carbon double bond has inserted into the R group of AIR3 to generate the isopropenyl ligand, and the A I R 2 moiety has bridged between the iridium-nitrogen bond. The initial step in this reaction is proposed to be the oxidative addition of the A I R 3 reagent at the metal centre in a ds-manner. The reaction of I r = C = C H 2 [ N ( S i M e 2 C H 2 P P h 2 ) 2 ] with M e l afforded the iridium(III) allyl iodide complex, Ir(r| 3 -C3H5)I[N(SiMe2CH2PPh2)2], over the period of 48 hours. The intermediates in this transformation, which are shown in Scheme 4.4, were detected by 1 ! ! and 3 1 P { 1 H } N M R spectroscopy. Figure 4.1 X-ray crystal structure of Ir(HL-AlMe2)[C(=CH 2)CH 3][N(SiMe2CH 2PPh2)2] 117 Ph 2 •P Ph 2 •P Me 2Si Me 2Si N ! r = C = C 'P Ph 2 \ H CH3I Me 2Si \ 48 hours N Ir H Me,S -p Ph 2 Oxidative addition Hydride transfer Ph 2 •P C H 3 Ph 2 •P M e 2 S i N I _/* H N l r = £ = C • / y \ X H Me 2Si \ H Me 2Si Me 2Si N Ir --P Ph 2 •P Ph 2 Migration Ph 2 CH3 p L Me ?Si \ r C H 2 N Ir p-hydride elimination Me 2Si •P Ph 2 Scheme 4.4 4.3.1.1 Reaction with Trimethylaluminum Addition of one equivalent of trimethylaluminum to the toluene solution of the iridium methylidene complex, I r=CH2 [N(SiMe2CH2PPh2)2l . 10, at -78°C resulted in the immediate loss of purple colour and formation of the yellow-orange solution (Equation 4.4); recrystallisation from hexanes at -30"C afforded the new complex 20 in -70% yield. 118 Me 2Si Me 2Si H AIMe3, Toluene \ - 78°C H ( - C 2 H 4 ) 1 0 20 Equation 4.4 In the *H N M R spectrum of 20 (Figure 4.2), the silyl methyl protons are observed as two singlets. The methylene protons resonate as two broad multiplets at 2.47 and 2.65 ppm. One set of the ortho phenyl protons is also a broad resonance (8.15 ppm). The broadening of the certain peaks might be due to the presence of a quadrupolar nucleus [ 2 7 A 1 (I = 5/2)] in the molecule. The methyl protons in the A l M e 2 ligand are observed as a singlet at 0.78 ppm. The iridium-hydride ligand resonance is observed as a triplet at -13.47 ppm (2Jp,H = 16.3 Hz). Free ethylene was detected in the *H N M R spectrum (5.48 ppm, s, C6D6) on conducting the reaction in a sealed N M R tube. The proposal that the A l M e 2 ligand is bridged between the I r -N bond is based upon the above mentioned results obtained from the reactivity of the iridium vinylidene complex, Ir=C=CH2[N(SiMe 2CH2PPh2)2], with AIR3 (R = Me, Et). 119 Figure 4.2 ] H NMR spectrum (300 MHz, C 6 D 6 ) of IrO ri-AlMe2)H[N(SiMe2CH2PPh2)2], 20 (* indicates hexanes protons) A mechanism proposed for the formation of I r ( u . - A l M e 2 ) H [ N ( S i M e 2 C H 2 -PPh2)2], 20, is shown in Scheme 4.5. To keep in line with the vinylidene chemistry, it is proposed that the reaction is likely to involve the oxidative addition of A l M e 3 at the metal centre to generate a transient species having an A l M e 2 ligand, an alkyl and a methylidene ligand (A). Aluminum-alkyl bond cleavage via oxidative addition reaction of trialkylaluminum reagents is rare; however, a recent report by Thorn and Harlow described the oxidative addition of trimethylindium with IrMe(PMe3)4 to yield cz 's-Ir(Me)2lnMe2(PMe3)3. 7 Given that the oxidative addition of AIMC3 reagent at the iridium centre proceeds in a cis manner, another possible isomer of A can be generated (shown as A ' in Scheme 4.5). However, the next step which involves the migration of the methyl unit into the iridium methylidene moiety to form the ethyl ligand (B) wil l prefer A in which the methylidene unit and the methyl ligand are disposed cis to each other, thus excluding the isomer A ' . Insertion reactions of carbene ligands into alkyl ligands are known, 8 and are considered to be analogous to the migratory insertion reactions of carbonyl complexes.9 The next step involves the P-hydride elimination from the ethyl ligand in B thus yielding the iridium ethylene hydride intermediate (C). The elimination of the ethylene moiety from the metal centre followed by the formation of the A l M e 2 bridge between the amide N atom and the A l atom yields the final product. The iridium-aluminum adduct 20 is extremely moisture sensitive in solution. Trace amounts of water from the glassware or the solvents were enough to convert it to I r ( H ) 2 [ N ( S i M e 2 C H 2 P P h 2 ) 2 ] (as observed by lH N M R spectroscopy) and presumably " H O A l M e 2 " . 121 Scheme 4.5 122 4.3.1.2 Reaction with Methyl Iodide The methylidene species 10 reacts faster (10 min) with excess M e l than the vinylidene complex (48 hours). The reaction proceeds with a noticeable colour change from initially purple to green and eventually to yellow due to the formation of octahedral iridium(III) ethylene hydrido iodide complex 21 (Equation 4.5). P h 2 P h 2 M e 2 S i x | H CH 3 l ,10min M e 2 S i N | , N Ir C „ . . *~ N Ir -. . \ RT, toluene ' / Me 2Si | H Me 2Si ^ \ — ^ P h 2 ^ ^ ^ 1 2 1 0 2 1 Equation 4.5 The *H N M R spectrum (Figure 4.3) provides an excellent handle on the identity and the stereochemistry of this hydride complex. Once again, the resonances of the ligand backbone methylene protons are observed as an A B quartet of virtual triplets and thus are indicative of the meridional arrangement of the tridentate ligand. The resonance for the ethylene protons is a triplet centered at 2.26 ppm ( 3 J P ) H = 3.6 Hz). A triplet at -13.14 ppm ( 2Jp,H =8.7 Hz) is due to the I r -H ligand which can exist trans to the amide or the iodide or the ethylene ligand. The former two possibilities are readily ruled out from the J H N M R data available on similar complexes. In the complex I r ( r i 2 - C H 2 P P h 2 ) H [ N ( S i M e 2 C H 2 P P h 2 ) 2 L the hydride ligand, which is oriented trans to the amide donor, is observed at -19.90 p p m ; 1 0 whereas, when the hydride is oriented trans to the iodo ligand in the complex, Ir(H)2l[HN(SiMe2CH2PPh.2)2], the resonance is observed at -19.39 ppm. 1 1 123 * Ir-C2//4 ~T~i • 1 I 1 1 • | 1 • 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 , 111 111111111 j 111111111111 8 7 3 2 1 0 PPM - 1 3 . 0 - 1 3 2 - 1 3 4 Figure 4.3 *H NMR spectrum (300 MHz, C 6 D 6 ) of Ir(Ti2-C2H4)H(I)[N(SiMe2CH2PPh2)2], 21 {t indicates hexanes protons, * indicates impurities from Ir(CH3)I2[HN(SiMe2CH2PPri2)2]} To account for the formation of 21, a mechanism is proposed (Scheme 4.6): it involves the oxidative addition of methyl iodide at the metal centre (to form A), 1 2 followed by migratory insertion of the methylene ligand into the iridium-alkyl bond thus yielding the iridium(III) ethyl iodide intermediate (B). By analogy with other green-coloured square-pyramidal iridium alkyl halide complexes, 1 3 the green colour observed in the early stages of the reaction is suggested to originate from the square pyramidal ethyl iodide complex B. The P-hydride elimination from the ethyl ligand in B would result in the final ethylene hydride complex except that the ethylene and the hydride ligand should be m-oriented to each other. Therefore, hydride abstraction from the ethyl ligand by the amide centre is invoked (which affords C), which following inversion at the amine (D) and N-H oxidative addition to the metal, gives the desired complex. Complexes which contain both the olefin and the hydride ligands cis to each other are rare 1 4 because the intramolecular migration of a hydride to an olefin to yield an alkyl is quite facile. Some compounds containing both the olefin and the hydride ligands are recognised, and as in complex 21, these species possess these two ligands in the trans orientation.1 5 The presence of excess methyl iodide around 21 causes further reaction to give the methyl bis-iodo-amine complex, Ir(CH3)(I)2[HN(SiMe2CH2PPh2)2] and' free ethylene. The same species has also been observed in the reaction of the aforementioned iridium vinylidene complex with excess methyl iodide. From the above mentioned reactions of 10 with AlMe3 ar>d Mel, it is clear that the methylidene complex Ir=CH2[N(SiMe2CH2PPh2)2l does not react in the same manner as the Schrock carbene. Instead, the reactions seem to proceed at the metal first due to the unsaturation at the iridium centre, then this is followed by the products resulting from C - C bond formation. Similar results are apparent from the reactions of 10 with various unsaturated hydrocarbons, as described in the following sections. 125 ho CH 3I Ph 2 •P Me 2Si \ Me,Si N 1 CH3 : C H , M e 2 S i ^ Me 2Si -P Ph 2 A Ph 2 C H 3 P I C H 2 N Ir -P Ph 2 B P h 2 •P Me 2Si \ H — Me 2Si Me 2Si Me,Si -lr ' . -P Ph 2 D Ph 2 N Ir' / I -P Ph 2 C Scheme 4.6 4.3.2 Reactions with Unsaturated Hydrocarbons 4.3.2.1 Reaction with Acetylene The cycloaddition reaction of a transition metal carbene with an alkyne to give a metallacyclobutene complex is a well-known process. 1 6 For example, the titanocene methylidene complex, shown in Equation 4.6, reacted cleanly with diphenylacetylene to form the corresponding metallacyclobutene species. 1 7 126 PMe 3 Ph Cp 2Ti PhC == CPh (-PMe3) Cp 2Ti Ph Equation 4.6 The reaction of the iridium methylidene complex 10 with excess acetylene (~5 equivalents) proceeded over two hours in toluene at room temperature (Equation 4.7). The product obtained is the iridium(III) allylic-acetylide species, I r(r | 3 -e 3 H 5 ) ( C = C H ) [ N ( S i M e 2 C H 2 P P h 2 ) 2 ] , 22. The allylic protons in the *H N M R spectrum (Figure 4.4) of 22 are observed at 3.17 ppm ( H s y n , dd, 3 JP , H = 8.9 Hz, 2JHsyn, Hcentral -5.2 Hz), 3.95 ppm. ( H a nti, d, 2JHanti, Hcentral = 9.3 Hz) and 4.48 ppm (H c e ntral> m ) - 1 8 The acetylide proton is a singlet at 2.12 ppm. The terminal carbon atoms of the allylic ligand resonate at 53.6 and 54.2 ppm in the ^ C ^ H } N M R spectrum. The central carbon resonance is observed at 110.3 ppm. The a-carbon of the acetylide ligand is found at 90.1 ppm, whereas the (3-carbon is observed at 140.0 ppm. The definite assignments of the above mentioned 1 3 C resonances are based on an A P T experiment, and are in agreement with the data reported in the literature. 1 8 b , d 1 0 2 2 Equation 4.7 127 I I I I I I I I I I I I I I I I I I I I I I I I ! I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I 8 7 6 5 4 3 2 1 0 PPM Figure 4.4 *H NMR spectrum (300 MHz, C 6 D 6 ) of Ir(r)3-C3H5)(C=CH)[N(SiMe2CH2PPri2)2], 22 (t indicates hexanes protons, * indicates peaks due to an unknown product) A proposed mechanism for the formation of 2 2 is shown in Scheme 4.7. It is likely that the first step involves the coordination of an acetylene ligand at the metal centre (to generate A) which is followed by cycloaddition with the methylidene ligand to form the metallacyclobutene intermediate (B). Coordination of another acetylene molecule at the empty site on the metal centre (to give C) followed by transfer of a proton from the acetylene ligand to the nearest carbon of the metallacycle generates the product. Scheme 4.7 129 4.3.2.2 Reaction with 1,3-Butadiene The reaction of the methylidene complex 10 with excess 1,3-butadiene (~5 equivalents) in a toluene solution at room temperature afforded a a-T | 3-pentenyl complex (Equation 4.8). The reaction proceeds over an hour with a colour change from purple to light yellow. The complex Ir(o-T|3-C5H8)[N(SiMe2CH2PPh2)2] was isolated in >80% yield. • The carbon-carbon coupling reaction between the Ir=CH2 unit and 1,3-butadiene proceeded with remarkable stereoselectivity. Of two possible diastereomers (characterised by the syn versus anti arrangement of the H(3) and H(4) atoms, Table 4.1), only one product was detected by ! H and 3 1 P { 1 H } N M R spectroscopy. The vicinal coupling constants displayed are for the anti-protons (11-12 Hz, Table 4.1), and are comparable with the known anti-substituted r j 3 -al lyl ic ligands in other complexes. 1 9 The corresponding protons and five 1 3 C resonances for the pentenyl group were identified by the use of 1 3 C - J H heteronuclear correlation maps (Figure 4.5). The orientation of the tridentate ligand (meridional versus .facial) is not apparent from the N M R data. The phenyl region is quite complicated in the lH N M R spectrum, but is similar to that of the phenyl resonances observed for the 1 0 2 3 Equation 4.8 130 crystallographically characterised analogue Ir(ri3-C3H5)I[N(SiMe2CH2PPh2)2] in which the tridentate ligand is arranged meridionally.6b A probable mechanism for the formation of this complex is shown in Scheme 4.8. 1,3-Butadiene first coordinates to the metal centre (A). This is followed by the insertion of the methylidene ligand into one of the double bonds of the coordinated butadiene to generate the metallacyclic isomer (B) which rearranges to the a-r|3-pentenyl product via l,3-o-,7r, shift. Scheme 4.8 131 J L A J L I F 2 (PPM) 140 120 100 BO 6 0 20 Figure 4.5 ^C-^H H E T C O R spectrum (300 M H z , C 6 D 6 ) of Ir(a-T |3-C5H8)-[N(SiMe 2 CH 2 PPh 2 )2] , 23 A series of complexes containing c-T) 3-allyl ligands has been reported by Erker's and Nakamura's groups. 2 0 These complexes were synthesised by the coupling reaction between a transition metal-bound diene and an alkene. For example, the complex Cp2Hf(s-m-diene) reacted with ethylene at -10°C to give the cyclic o-allyl complex which at 25°C rearranged to the isomeric o-T]3-allyl complex (Scheme 4.9) 2 1 CP2W ...|| -10'C Cp2Hf Cp 2Hf 25'C Scheme 4.9 132 Table 4.1 Chemical Shift and Coupling Constants for the Pentenyl Ligand Protons in Ir(o--n3-C5H8)[N(SiMe2CH2PPh2)2],23 Me 2Si Me 2Si Nucleus Chemical Shift (ppm) Coupling Constant (Hz) H(l) H(2) H(3) H(4) H(5) H(6) H(7) H(8) 3.96 2.25 4.15 4.08 2.29 1.31 0.92 -0.85 2j (1,2) = 2.1 3J(1,3) = 7.7 3J(2,3)= 11.3, 3J(3,4) = 11.6 3J(4,6) =11.3 3J(4,5) = 11.3 2j(5,6) = 2.1 3J(6,8) = 10.3 3J(6,7) = 1.9 2J(7,8) = 5.9 133 Table 4.2 ^C^H} N M R Data for the Pentenyl Ligand in Ir(c-ri3-C5H8)[N(SiMe2CH2PPh2)2], 23 Me 2Si Me 2Si Nucleus Chemical Shift (ppm) Coupling Constant (Hz) C(l) C(2) C(3) C(4) C(5) 44.16 (d) 108.35 (s) 54.90 (d) 28.01 (s) -37.26 (s) 2 J(Ci ,P) = 22.3 2 J(C 3 ,P) = 23.5 4.3.2.3 Reaction with Allene Transition metal carbenes react with allene to give either methylene-cyclopropane22 or trimethylenemethane complexes.23 The reaction of benzylidene-pentacarbonyl tungsten species with 1,1-dimethylallene generated the corresponding methylenecyclopropane complex (Equation 4.9). 2 2 The reaction proceeded in a stereoselective manner as the carbene ligand was transferred only to the substituted end of the allene. Another report23 described the synthesis of the trimethylene-methane complexes of chromium and iron by a coupling reaction between allene and the M=C bond of the carbene complexes (Equation 4.10). 134 (CO)5W = c Ph C H 3 CH 3 (CO) 5W„„ # Ph H C H 3 (CO)5M = C \ OEt Ph Equation 4.9 CH 2Y Ph > OEt ' ' 'CH 3 CH 2Y OEt . / M(CO)4 \ Ph M = Cr, Fe Y = OH, CH 2OH, C02Et CH 2Y + (CO)5M = . : + Ph(OEt)C=CH—CH=CH—CH2Y Equation 4.10 The reaction of 10 with allene (-5 equivalents) proceeded at -78°C over a period of an hour. The only product obtained was the trimethylenemethane complex, I r { r i 4 - C ( C H 2 ) 3 } [ N ( S i M e 2 C H 2 P P h 2 ) 2 ] , 24 (Equation 4.11). The product was isolated as colourless crystals in 75% yield. It was apparent from the lH N M R spectrum (Figure 4.6) of 24 that the methylidene unit and allene had coupled to generate a trimethylenemethane moiety because three resonances typical for the trimethylene-methane ligand were observed (see Table 4.3). 2 4 Me 2Si Me 2Si H 2 C = C = C H toluene 1 0 Equation 4.11 135 0 \ I I I | I I I I. | I I I I | I I I I | I I I I | I I I I | I I I I | I I I I | I I I ! | I I I I | I I I I | I I I I | I I I I | I I I ! | I I I I | I I I I 7 6 5 . 4 3 2 1 PPM Figure 4.6 lH NMR spectrum (300 MHz, C 6 D 6 ) of/ac-Ir{r] 4-C(CH2)3}[N(SiMe2CH 2PPh2)2], 24 (* indicates hexanes protons) Table 4.3 Chemical Shift and Coupling Constants for the Trimethylenemethane Ligand Protons and Carbons in /ac-Ir{r|4-C(CFl2)3} [N(SiMe 2CH 2PPh2)2], 24 the complex is viewed along the C(3)-Ir axis Nucleus Chemical Shift (ppm) Coupling Constant (Hz) H ( l ) 1.54 4 J (Hi ,H 3 ) = 3.0, 3j ( H b P ) = 3.0 H(2) 1.45 2 J (H 2 ,H 3 ) = 4.6 3j (H 2 ,P) =9.2 H(3) 2.36 4 J (Hi ,H 3 ) = 3.3 3j( H 3 ,P) = 9.3 Nucleus Chemical Shift (ppm) Coupling Constant (Hz) C ( l ) 31.89 (d) 2 J(Ci ,P) = 4.2 C(2) 47.64 (d) 2 J(C 2 ,P) = 44.3 C(3) 101.00 (s) The trimethylenemethane formulation was also confirmed by a single-crystal X-ray determination; the result is shown in Figure 4.7. Some selected bond lengths and bond angles are listed in Tables 4.4 and 4.5 . The meridional arrangement of the ancillary tridentate ligand in 10 changes to facial in the trimethylenemethane complex 24 as indicated by the P(l)-Ir-P(2) bond angle of 106.49 (5)°. The C - C bond lengths of the trimethylenemethane ligand are quite similar (C(31)-C(32), 1.426 (7) A ; C(31)-C(33), 1.437 (7) A ; C(31)-C(34), 1.441 (7) A). The central carbon, C(31), of the trimethylenemethane ligand is closest to the iridium center (Ir-C(31), 2.055 (5) 137 A) , and the three terminal methylene carbons are all at similar distances (range from 2.19 to 2.22 A ) . This results in the trimethylenemethane unit adopting the characteristic "umbrella" shape. In analogy to the reported iridium trimethylene-methane system, Ir{rj4-C(CH2)3}Cl(CO)PPh3,24 the complex 24 can be considered to possess an octahedral geometry with the r i 4 - C ( C H 2 ) 3 unit and the Ir[N(SiMe2CH2PPh2)2l moiety in a staggered conformation. Figure 4.7 X-ray crystal structure of/ac-Ir{Ti4-C(CH2)3}[N(SiMe2CH2PPh2)2], 24 138 Table 4.4 Selected Bond Lengths (A) for/ac-Ir{t|4-C(CH2)3}[N(SiMe2CH2PPh2)2], 24a Ir—P(l) 2.296 (1) Ir—C(33) 2.222 (5) Ir—P(2) 2.295 (1) Ir—C(34) 2.202 (5) Ir—N 2.198 (4) C(31)—C(32) 1.426 (7) Ir—C(31) 2.055 (5) C(31)—C(33) 1.437 (7) Ir—C(32) 2.189 (5) C(31)—C(34) 1.441 (7) Table 4.5 Selected Bond Angles (deg) for/<2c-Ir{r|4-C ( C H 2 ) 3 ) [N(SiMe 2CH 2PPh2)2], 24* P(l)—Ir- -P(2) 106.49 (5) P(2)—Ir—C(34) 90.4 (2) P(l)—Ir- -N 87.0 (1) N—Ir—C(31) 126.2 (2) P(l)—Ir--C(31) 123.1 (1) N—Ir—C(32) 165.3 (2) P(l)_Ir_ -C(32) 101.9 (2) N—Ir—C(33) 101.1 (2) P(l)—Ir- -C(33) 97.1 (2) N—Ir—C(34) 101.6 (2) P(l)—Ir- -C(34) 161.9 (1) C(31)—Ir—C(32) 39.1 (2) P(2)—Ir--N 83.0 (1) C(31)—Ir—C(33) 39.0 (2) P ( 2 ) _ I r --C(31) 120.7 (1) C(31)—Ir—C(34) 39.4 (2) P(2)—Ir--C(32) 105.3 (2) C(32)—Ir—C(33) 66.4 (2) P(2)—Ir--C(33) 156.3 (2) C(32)—Ir—C(34) 66.7 (2) P(2)—Ir--C(34) 90.4 (2) C(33)—Ir—C(34) 65.8 (2) a. A complete list of the structural parameters is in Appendix A l . 139 There are a few examples of structurally characterised monomeric trimethylenemethane complexes in the literature. 2 5 Parameters obtained for r i 4 -C(CH2)3 ligand in complex 24 are slightly different than those reported in the following example. In the phenylmethylenemethane iron complex Fe{r | 4 -C(CH 2 )2-(CHC6Ff5)}(CO)3, 2 6 carbon-carbon bond distances within the trimethylenemethane moiety are : C(l)-C(2) = 1.405 (±.013) A , C(l)-C(3) = 1.406 (+013) A , C(l)-C(4) = 1.436 (±.012) A . In this complex, the central carbon [C(l)] is closest to the iron centre: Fe-C( l ) = 1.932 (±.010) A , Fe-C(2) = 2.098 (±.010) A , Fe-C(3) = 2.118 (±.010) A , Fe-C(4) = 2.160 (±.009) A . This difference in the bond lengths compared to the parameters observed in complex 24 might be a consequence of the phenyl group on the trimethylenemethane ligand in the iron complex. Similar to other iridium trimethylenemethane complexes, in the complex 24, the rotation of the trimethylenemethane unit about the Ir-centroid bond (Ir-C(3)) is slow on the NMR time scale because its *H NMR spectral parameters remain unchanged between -85°C and +80°C Also, the rotation is slow on the chemical time scale also as observed by the following labelling experiments. The reaction of the 1 3C-labelled material Ir=13CH2[N(SiMe2CH2PPh2)2] with allene generated a material having only the Ci carbon labelled. Furthermore, the exposure of Ir=CD2[N(SiMe2CH2PPh2)2] to allene afforded the product in which only the Hj protons were labelled with deuterium. These results suggest that the transition state for this carbon-carbon coupling process is product like (shown below as A). 140 Me2 Me2 Ph2P„„ 0,PPh2 C H 2 A Trimethylenemethane, which is a structural isomer of 1,3-butadiene, exists only fleetingly under ambient conditions. 2 7 However, as evident from the reactions above (Equations 4.9-4.11), this reactive fragment can be stabilised by coordination to a metal centre. Such complexes have been known for many years.25- 2 8 The parent trimethylenemethane ligand is synthesised from preformed C-4 fragments via three main routes: (i) the ring opening of alkylidenecyclopropane (Equation 4.12), 2 9 (ii) the dehalogenation of oc-a' dihalogen substituted precursors (Equation 4.13), 3 0 and (iii) the thermal extrusion of CH4 (Equation 4.14) 3 1 or Me3SiCl from allyl complexes (Scheme 4 .10) . 3 2 Thus, the coupling reactions (shown in Equations 4.9-4.11) between M=C bond and allene open up another general route to trimethylenemethane complexes. + Equation 4.12 141 Na2[Fe(CO)3] CI CI (- 2NaCI) Equation 4.13 (CO)3Fe Cp*(Me)3Ta — \ ) — Me (-CH4) Equation 4.14 Cp*(Me)2Ta - y LnM + Me 3 SiCH 2 CH2CI CI L n M C H 2 — ^ -nM—j[ (- Me3SiCI) L nM CH 2 SiMe 3 CH 2 SiMe 3 ^ CI l_n M = trans- lrCI(CO)(PPh3)2 Scheme 4.10 4.4 Summary A methylidene complex 10 which is easy to prepare in quantity and pure form has been described. The C - C bond formation reactions between the alkylidene group and the reagents M e l , AlMe3, HC=CH, 1,3-butadiene and allene appear to involve the coordination of the reagents first to iridium, implying that the metal is electron-deficient. The remarkable stereoselectivity observed in the reaction of 1,3-butadiene and allene with 10 may be due to the steric constraints imposed by the tridentate ligand. 142 4.5 References 1 Fryzuk, M . D.; MacNeil, P. A. ; Rettig, S. J. J. Am. Chem. Soc. 1985, 107, 6709. 2 Fryzuk, M . D.; Joshi, K . Organometallics 1989, S, 722. 3 Fryzuk, M . D.; MacNeil, P. A . ; Massey, R. L . ; Ball , R. G. J. Organomet Chem. 1989, 368,213. 4 Massey, R. L . M. Sc. Thesis, University of British Columbia, Vancouver, Canada, 1989. 5 (a) Schrock, R. R.; Sharp, P. R. J. Am. Chem. Soc. 1978,100, 2389. (b) Schrock, R. R. Acc. Chem. Res. 1979,12, 98. 6 (a) AIR3 reactivity: Fryzuk, M . D.; McManus, N . T.; Rettig, S. J; White, G. S. Angew. Chem., Int. Ed. Engl. 1990,29, 73. (b) M e l reactivity: Fryzuk, M . D.; White, G. S.; Paglia, P. L . unpublished results, 1990. 7 Thorn, D. L. ; Harlow, R. L . J. Am. Chem. Soc. 1989, 111, 2575. 8 (a) Thorn, D. L. ; Tulip, T. H. / . Am. Chem. Soc. 1981,103, 5984. (b) Kleitzeir, H. ; Werner, H. ; Serhadli, P.; Ziegler, M . L. Angew. Chem., Int. Ed. Engl. 1983,22,46. (c) Jernakoff, P.; Cooper, N . T. J. Am. Chem. Soc. 1984,106, 3026. 9 Collman, J. P.; Hegedus, L . S.; Norton, J. R.; Finke, R. G. Principles and Applications of Organotransition Metal Chemistry; University Science Books: M i l l Valley, C A , 1987, p. 379-380. 10 Fryzuk, M . D.; Joshi, K . J. Am. Chem. Soc. 1989, 111, 4498. Also see chapter 2 of this thesis. 11 Fryzuk, M . D.; MacNeil, P. A. ; Rettig, S. J. J. Am. Chem. Soc. 1987, 109, 2803. 12 Oxidative addition reaction of alkyl halides at a metal centre proceeds kinetically to generate the trans product: Collman, J. P.; Hegedus, L . S.; 143 Norton, J. R.; Finke, R. G. Principles and Applications of Organotransition Metal Chemistry; University Science Books: M i l l Valley, C A , 1987, p. 280. 13 Fryzuk, M . D.; MacNeil, P. A.; Rettig, S. J. Organometallics 1986,5, 2469. 14 (a) Halpern, J.; Okamoto, T. Inorg. Chim. Acta. 1984,89, L53. (b) Roe, D. C. / . Am. Chem. Soc. 1983,105, 7771. (c) Dohertyi N . M . ; Bercaw, J. E. J. Am. Chem. Soc. 1985,107, 2670. 15 (a) Olgemoller, B. ; Beck, W. Angew. Chem. Int., Ed. Engl. 1980,19, 834. (b) Deeming, A . J.; Johnson, B . F. G.; Lewis, J. / . Chem. Soc, Dalton Trans. 1973, 1848. 16 (a) Tebbe, F. N . ; Parshall, G. W.; Overnall, D. W. / . Am. Chem. Soc. 1979, 707,5074. (b) Tebbe, F. N . ; Harlow, R. L. / . Am. Chem. Soc. 1980,102, 6149. (c) McKinney, R. J.; Tulip, T. H. ; Thorn, D. L. ; Coolbaugh, T. S.; Tebbe, F. N . /. Am. Chem. Soc. 1981,103, 5584. (d) Schlund, R.; Schrock, R. R.; Crowe, W. E. / . Am. Chem. Soc 1989, 111, 8004, and references therein. 17 Meinhart, J. D.; Anslyn, E. V. ; Grubbs, R. H . Organometallics 1989, 8, 583. 18 *H N M R data for an allylic ligand are decribed in these references: (a) Tulip, T. H. ; Ibers, J. A . J. Am. Chem. Soc 1979,101, 4201. (b) McGhee, W. D.; Bergman, R. G. / . Am. Chem. Soc 1988,110, 4246. (c) Batchelor, R. J.; Einstein, F. W. B.; Jones, R. H. ; Zhuang, J. M . ; Sutton, D. J. Am. Chem. Soc 1989, Ul, 3468. (d) Collman, J. P.; Hegedus, L . S.; Norton, J. R.; Finke, R. G. Principles and Applications of Organotransition Metal Chemistry; University Science Books: M i l l Valley, C A , 1987, p. 177. 19 Brown, P. R.; Green, M . L . H. ; Hare, P. M . Bandy, J. A . Polyhedron 1988, 7, 1819. 20 (a) Erker, G . Angew. Chem., Int. Ed. Engl. 1989, 28, 397. (b) Yasuda, H. ; Nakamura, A . Angew. Chem., Int. Ed. Engl. 1988, 7, 1819. 21 Erker, G.; Engel, K. ; Dorf, U. ; Atwood, J. L . ; Hunter, W. E. Angew. Chem., Int. Ed. Engl. 1983,27,914. 144 22 Fisher, H. ; Bidell, W.; Hofmann, J. / . Chem. Soc, Chem. Commun. 1990,12, 858. 23 (a) Aumann, R.; Trentmann, B. Chem. Ber. 1989, 1977. (b) Aumann, R.; Uphoff, J. Angew. Chem., Int. Ed. Engl. 1987,26, 357. 24 The *H and 1 3 C { ] H ) N M R assignments for the {r|4-C(CH2)3} ligand in 24 are based upon the reported N M R analysis of { r | 4 - C ( C H 2 ) 3 } in Ir{ri 4 -C(CH 2 )3}Cl(CO)PPh3: Jones, M . D.; Kemmitt, R. D. W.; Piatt, A . W. G. / . Chem. Soc, Dalton Trans. 1986, 1411. 25 Marr, G.; Rockett, B. W. in Chemistry of the Metal-Carbon Bond; Eds. F. R. Hartley, S. Patai 1982,1, p. 388. 26 Churchill, M . R.; Gold, K. Inorg. Chem. 1969, 8,401. 27 Baseman, R. J.; Pratt, D. W.; Chow, M . ; Dowd, P. / . Am. Chem. Soc. 1976, 98, 5726. 28 (a) Emerson, G. F.; Ehrlich, K. ; Giering, W. P.; Lauterber, P. C. J. Am. Chem. Soc. 1966, 88, 3172. (b) Otsuka, S.; Nakamura, A. Adv. Organomet. Chem. 1975,14, 245. (c) Trost, B . M . Angew. Chem., Int. Ed. Engl. 1986, 25, 1. 29 Pinhas, A . R.; Samuelson, A . G.; Risenberg, R.; Arnold, E. V. ; Clardy, J.; Carpenter, B . K . / . Am. Chem. Soc. 1981,103, 1668. 30 (a) Grosselin, J. M . ; Le Bozece, H ; Moinet, C ; Toupet, L. ; Dixneuf, P. H . / . Am. Chem. Soc 1985,107, 2809. (b) Ehrlich, K. ; Emerson, G. F. / . Am. Chem. Soc. 1972, 94, 2464. 31 Mayer, J. M . ; Curtis, C. J.; Bercaw, J. E. J. Am. Chem. Soc. 1983, 105, 2651. 32 Jones, M . D.; Kemmitt, R. D. W. / . Chem. Soc, Chem. Commun. 1985, 811. 145 CHAPTER 5 Reactivity of the Iridium(I) T)2-Cyclooctene Complex 5.1 Introduction Studies on iridium(I) complexes have greatly contributed to the understanding of some of the basic processes in organometallic chemistry. For example, a number of two-electron oxidative addition reactions at the iridium(I) centre in Vaska's complex, rra^-IrCl(CO)(PPh3)2, have been examined (Scheme 5.1).1 While the reagents O2, H2 and R3S1H undergo c/s-additiori at the metal centre, oxidative addition of M e l proceeds kinetically to generate the trans adduct. In our group, the iridium(I) T] 2-cyclooctene complex, Ir(r | 2-C8H 14)-[N(SiMe2CH2PPh2)2L 25, has been used as a key starting material for the preparation of a wide variety of iridium(I) and iridium(III) amide complexes either via replacement of the cyclooctene moiety by other neutral ligands such as CO, HC=CH, Ff2C=CH2 and PR3 (R = Me, Ph), or by oxidative addition of reagents such as H2 and R X (R = Me, X = CI, Br, I; R = CH 2 Ph, X = Br; R = C H 2 C 0 2 M e , X = Br) at the metal centre (Scheme 5.2).2 146 CI CI -pph 3 CO 02 Me P h3P I CO Ph 3 P ,- - ' Mel ""- ... Ir -« lr I PPh 3 CI PPh 3 R 3SiH Ph 3P CI SiR 3 .H ir PPh 3 CO Scheme 5.1 Ph 3 P H Ir .H CI | ' p p h 3 CO During the course of this thesis work, some interesting chemical properties of Ir(ri2-C8Hi4)[N(SiMe2CH2PPh2)2]i 25, were observed and therefore investigated in detail. This chapter describes the photochemical carbon-hydrogen bond activation of the cyclooctene ligand in 25, and its reactivity with 1,3-butadiene, allene and trimethylaluminum. 147 S c h e m e 5.2 5.2 Photochemical Carbon-Hydrogen Bond Activation of the Coordinated Cyclooctene in Ir(r i 2 -C8Hi4)[N(SiMe2CH 2 PPh2)2], 25 A s d i s c u s s e d i n c h a p t e r 1, s o m e t r a n s i t i o n m e t a l c o m p l e x e s h a v e b e e n f o u n d w h i c h are c a p a b l e o f a d d i n g a l k a n e o r arene C - H b o n d s o x i d a t i v e l y . 3 H o w e v e r , i n o n l y a f e w s y s t e m s has the p r o d u c t o f C - H i n s e r t i o n b e e n c o n v e r t e d i n t o o r g a n i c p r o d u c t s either s t o i c h i o m e t r i c a l l y o r c a t a l y t i c a l l y . 4 In 1979, C r a b t r e e a nd c o - w o r k e r s d e s c r i b e d the d e h y d r o g e n a t i o n o f a n u m b e r o f a l k a n e s b y [ I r H 2 ( M e 2 C O ) 2 ( P P h 3 ) 2 J B F 4 a n d r m - b u t y l e t h y l e n e i n c h l o r i n a t e d 148 solvents (Equation 5.1).5 Anr | 3 -al lyl hydride complex was proposed as one of the intermediates in this transformation. This section describes the photochemical dehydrogenation of the cyclooctene ligand in Ir(rt 2-C8Hi 4)[N(SiMe2CH 2PPh2)2], 25, to yield Ir(H)2[N(SiMe2CH2-PPh2)2]> 26,-and free cyclooctadienes. The reaction proceeded through an ri3-allyl hydride intermediate Ir(r|3-C8Hi3)H[N(SiMe2CH2PPh2)2], 27, which was isolated and characterised. This photochemical activity of 25 was detected during the attempts to make an iridium imide complex of formula, Ir=(NSiMe3)[N(SiMe2CH2PPh2)2L by conducting the reaction of 25 with SiMe3N3 under photolytic conditions. Although the iridium(I) cyclooctene complex 25 is thermally stable even upon heating to 80°C for 24 hours, when photolysed (140 W, Hg lamp) for 6 hours, it rearranges to the iridium(III) T|3-cyclooctenyl hydride derivative, Ir(T|3-C8Hi3)H-[N(SiMe2CH2PPh2)2]» 27 (Scheme 5.3). This transformation proceeded with a noticeable colour change as the orange solution of 25 turned deep red. Complex 27 was isolated as red crystals from hexanes/toluehe solution at -30°C. Some of the important features in the *H NMR spectrum (Figure 5.1) of 27 include the allyl resonances belonging to the cyclooctenyl ring [4.56 ppm (HCentrah U 2 J H , H = 7.6 Hz) and 4.10 ppm (two Usyn, m)] and the hydride resonance [-21.65 ppm (t, 2Jp,H = 16.7 S = Me 2 CO L = PPh 3 + 2S Equation 5.1 Hz)]. 149 hv,6 hours benzene o * o Scheme 5.3 It was noticed that upon continuing the photolysis of 27 for six more hours, the red colour of the solution slowly changed to yellow because of the formation of the iridium(III) dihydride complex, lr(H)2[N(SiMe2CH2PPh2)2]. 26 (as observed by *H N M R spectroscopy). 2 0 A mixture of free 1,3- and 1,5-cyclooctadiene (COD) in the ratio of 2:1 was also detected in the *H N M R spectrum. The iridium(III) dihydride complex 26 and the cyclooctenyl hydride species 27 were found to be in equilibrium in the ratio of 90:10, long after the photolysis process had been stopped. However, addition of five equivalents of 1,5-cyclooctadiene to the benzene solution of this mixture under non-photolytic conditions shifted the equilibrium towards the cyclooctenyl hydride complex 27. 150 I I I I I I I I I I I I I I I I I I I I I I I I I I I I I ! I I I I I I I I I I I I I I I I I I I I I I I I I I I 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 8 7 6 5 4 3 2 1 0 PPM Figure 5.1 ' H NMR spectrum (300 MHz, C6D6) of Ir(Ti 3 -C 8 H ] 3 )H[N(SiMe2CH2PPh2)2], 27 (* indicates hexanes protons, t indicates SiMe2 resonances of the remaining' Ir(r | 2-C8Hi4)[N(SiMe2CH 2 PPh2) 2 ], 25) From these results, it can be seen that I r ( H ) 2 [ N ( S i M e 2 C H 2 P P h 2 ) 2 l is involved in the isomerisation process of 1,3-COD to 1,5-COD presumably through a 1,4-COD intermediate. Such isomerisation of 1,3-COD to 1,5-COD by some rhodium and iridium systems has been reported in the literature.6 It is reasonable to assume that the higher ratio of 1,3-COD observed in Scheme 5.3 might be due to the presence of conjugated double bonds in this isomer. The importance of T] 3-allyl hydride complexes in catalytic processes such as conversion of cyclopropanes to olefins (Scheme 5.4) 7 and alkene isomerisation (Scheme 5.5)8 has long been recognised. However, only a handful examples of stable r | 3 -a l ly l hydride complexes are known. 9 One of the early allyl hydride complexes reported in the literature is Ni(H)(ri 3-C3H5)PPh3. 1 0 This species could only be prepared in situ at low temperatures and decomposed above -40°C. In 1979, a series of stable iridium(III) allyl hydride complexes of formula, I rClH[T | 3 - ( l -Ph ) -C3H4)]-(PR3)2, was reported. 1 1 These species were prepared by the reactions of trans-IrCl(N2)(PR3)2 with phenylcyclopropane. Recently, Sutton and co-workers described the synthesis and crystallographic characterisation of Cp*Re(CO)H(r|3-C3H5) (both the exo and the endo isomers) produced upon the photolysis of the propene complex, Cp*Re(CO) 2(ri 2-C3H 6). 12 H A Scheme 5.4 152 R L N M LNM-ft R R A Scheme 5.5 5.3 Reactions with Unsaturated Hydrocarbons As shown in Scheme 5.2, the cyclooctene moiety can be replaced by a ligand such as ethylene. Thus it would appear that other olefin analogues of 25 should be readily accessible by conducting its reactions with other alkenes and dienes. But to our surprise, complex 25 showed no reactivity toward propene, 4-methyl-l-pentene, 1,4-cyclohexadiene or 2,5-norbornadiene over a period of 24 hours. The only dienes which did substitute the cyclooctene ligand were 1,3-butadiene and allene. 5.3.1 Reaction with 1,3-Butadiene 1,3-Butadiene may coordinate to a transition metal in several ways depending upon the ligands on the metal and the substituents on the diene. Early transition metal butadiene complexes generally assume a o"2-7c geometry with the C - C bond lengths in the diene unit alternating as long-short-long (Figure 5.2 A ) . 1 3 However, the vast majority of the middle and the late transition metal dienes assume the rj 4-7t structure with the carbons of the diene ligand being nearly equally distant from the metal centre (Figure 5.2 B ) . 1 4 Only the more common rt 4-c/s mode of diene coordination is shown below, but recently the r\4-trans form has been observed as the kinetic product in group 4 metallocenes1 5 and the most stable isomer in (r| 5-C5H5)-Mo(NO)(Ti 4-C4H 6). 16 153 A A B Figure 5.2 Bonding modes of 1,3-butadiene The iridium(I) ri4-butadiene complex, Ir(T] 4-C4H 6)[N(SiMe2CH2PPh 2)2], 28 , was synthesised from the reaction of the iridium(I) T[ 2-cyclooctene complex, 2 5 , I r ( r i 2-C8Hi4 ) [ N(SiMe2CH 2PPh2 ) 2 L with excess (~5 equivalents) 1,3-butadiene (Equation 5.2). 1 7 The reaction proceeded at room temperature without any significant colour change of the initial orange solution. Light yellow crystals of the butadiene complex were isolated in >90% yield from toluene/hexanes solution at room temperature. _ P h 2 / -»P Me 2Si . Me 2Si N | r l| \ 1,3-butadiene M e 2 S i / Equation 5.2 Although five-coordinate d 8 complexes have been studied as prototypes for stereochemical non-rigidity, 1 8 the complex 28 has a rigid structure from -80° to +85°C (as observed by lH and 3 1 P { 1 H } N M R spectroscopy). This lack of fluxionality is quite puzzling in contrast to the hafnium analogue, Hf(r]4-C4H6)Ph[N(SiMe2CH2-PPh2)2L which is known to display fluxional behaviour.1 9 The spectral features of this complex are indicative of an asymmetric structure. In the lH N M R spectrum (Figure 5.3), four singlets of equal intensity for the Si(CH3)2 154 protons are observed. The PCH2Si protons are multiplets centred at 1.85 and 2.12 ppm. Hardly any separation of the ortho protons resonance from that of the metalpara protons resonance of the phenyl rings is observed, thus suggesting a facial arrangement of the tridentate ligand. The butadiene moiety shows six resonances at -0.60, -0.20, 2.07, 2.61, 4.00 and 5.37 ppm. The corresponding four 1 3 C resonances for the coordinated diene ligand were identified by the use of ^ C ^ H heteronuclear correlation maps (Figure 5.3). The gated decoupled 1 3 C NMR spectrum shows ^ c - H for C2 and C3 of the diene unit to be 165.5 Hz which is typical of an sp2 bonded carbon centre;20 however, Uc-H f ° r C4 and CI are lower (155.0 and 150.0 Hz, respectively), but are still suggestive of the sp2 character around these carbon centres. Figure 5.3 13CMH HETCOR spectrum (300 MHz, C 6 D 6 ) of I r (T l 4 - C 4 H 6 ) -[N(SiMe 2CH 2PPh 2)2L 28 155 The solid-state structure of k(ii4-C4H6)[N(SiMe2CH2PPh2)2L 28, complex (Figure 5.4; Tables 5.1 and 5.2) complements the solution data. It reveals that the amido-diphosphine tridentate ligand adopts a facial coordination mode as indicated by the Pl-Ir-P2 angle of 107.01(4)°. The metal centre is bonded to each carbon of the butadiene unit with the following bond lengths: Ir-C31, 2.139(4); Ir-C32, 2.167(4); Ir-C33, 2.183(4); and Ir-C34, 2.182(4) A . These metal-carbon bond lengths parallel the fra/is-influence order,21 i.e. P>N, since C31 being trans to the amide posses a stronger bond with iridium than C34 does which is trans to the phosphorus centre. The C-C bond lengths are slightly different and are as follows: C31-C32, 1.430(7); C32-C33,1.409(7); C33-C34,1.421(7) A. c u e ) C(2B) Figure 5.4 X-ray crystal structure of Ir(Ti 4-C4H 6)[N(SiMe 2CH2PPh2)2], 28 156 Table 5.1 Selected Bond Lengths (A) for Ir(Ti 4-C4H 6)[N(SiMe2CH2PPh 2)2], 28 a Ir—P(l) 2.292(1) C(31)—C(32) 1.430(7) Ir—P(2) 2.2879(9) C(32)—C(33) 1.409(7) Ir— C(31) 2.139(4) C(33)—C(34) 1.421(7) Ir—C(32) 2.167(4) Ir—C(33) 2.183(4) Ir—C(34) 2.182(4) Table 5.2 Selected Bond Angles (deg) for Ir(Ti 4 -C 4 H 6 )[N(SiMe2CH2PPh 2 )2], 28 a  P(l)—Ir—P(2) 107.01(4)  a. A complete list of the bond distances and the bond angles is compiled in Appendix A l . Two different methods have been reported in the literature to compare metal-diene interactions, in particular, to gauge the component of TI4-TC versus G 2-7t character of the bonding, from the crystallographic data. 2 2 The first method deals with the dihedral angle,©, (subtended by the C 1 - M - C 4 and the C1-C2-C3-C4 planes) and the difference in the bond distances of the metal from the inner and outer carbons of the diene ligand, Ad, {Ad=[d(M-Cl)+d(M-C4)]-[d(M-C2)+d(M-C3)]/2}. For the vast majority of the middle and the late transition metal diene complexes, which generally assume the r i 4 -m-l ,3-diene structure, the dihedral angle 0 is 75-90° and Ad is between -0.1 and 0.1 A . For the complex 4, the value of 0 is 92.9° and Ad is -0.01 A , thus confirming the T] 4-7t bonding mode of the diene ligand at the iridium centre. The second mode of comparison shows an approximate linear increase in the dihedral angle, 0, with increasing bond lengths, A l , {Al=[l(Cl-C2)+l(C3-C4)]/2-1(C2-C3)]}. For the late transition metals, Al is between -0.1 and 0.0 A ; whereas in the case of early transition metals, Al falls in the range of 0.0-0.2 A . The calculated 157 value of Al in 28 is 0.02 A, indicating that the 1,3-butadiene bonding which, is mainly of rj4-7C character, might have a small contribution from the o2-Jt mode. 5.3.2 Reaction with Allene In analogy with transition metal olefin complexes, an allene ligand can bind to a metal centre in one of two possible ways, namely rj 2-7t (Figure 5.5 A) or Ti 2-a (Figure 5.5 B ) . 2 3 Allene complexes of both types have been prepared and in many cases characterised by X-ray crystallography.2 3 R R L nM jj L n M. v. / \ .R R -R A B Figure 5.5 Modes of allene coordination at a metal centre The reaction of the iridium(I) rj 2-cyclooctene complex, Ir(rj 2-C8Hi4)-[N(SiMe2CH2PPh2)2]> 25, with excess allene (~5 equivalents) proceeded at room temperature to afford the allene derivative, Ir(rj 2 -C3H4)[N(SiMe2CH2PPh2)2L 29 (Equation 5.3). The orange colour of the starting material changed to yellow over 15 minutes period. The complex 29 was isolated as yellow crystals from hexanes at -30°C. Me 2Si Me 2Si Ph; allene toluene (-COE) H Me 2 Si . I n / N — I r / 1 \ H Me2s/ \^c{ -P % — H 2 9 Equation 5.3 158 From ^ C O H } N M R data, it is evident that the allene ligand in 29 is bound to the iridium centre in the r\2-o fashion. In the 1 3 C { lH} N M R spectrum, the resonances for the allene ligand are observed at -3.82 (CI, s), 101.00 (C2, s) and 92.30 ppm (C3, s). Such a high shielding of the CI carbon is consistent with the data reported for methylene carbons bound to an iridium centre via a G-bond. 2 4 In contrast, the olefinic carbons in the iridium(I) r]2-ethylene complex Ir(T|2-C2H4)[N(SiMe2CH2PPh2)2]> and also in many other iridium olefin complexes are observed between 40-60 ppm. 2 5 The ! H N M R spectrum (Figure 5.6) of this complex is straightforward. The resonances of the allene ligand appear at 1.12, 5.20 and 5.44 ppm integrating for the protons in the ratio of 2:1:1. They have been assigned to two protons at CI and two inequivalent protons at C 3 . 5.4 Reaction with T r i m e t h y l a l u m i n u m Alkylaluminum reagents are extensively used in industrial processes like Ziegler-Natta polymerisation. 2 6 Their use as alkylating agents is important in the formation of "Tebbe's reagent" (Equation 5.4). 2 7 Other reactions where a transition metal centre brings about aluminum-alkyl bond cleavage involve alkyl/halide or alkyl/alkoxide exchange, as in Equation 5.5. C H 2 Cp2TiCI2 + AI2Me<3 ^ C p 2 T i ^ ^ c ( ^^AMe2 + CH 4 + 1/2 AI 2Me 4CI 2 Equation 5.4 159 Figure 5.6 l H NMR spectrum (300 MHz, C 6 D 6 ) of Ii{Ti2-C3H4)[N(SiMe2CH2PPh2)2], 29 (* indicates hexanes protons, t indicates toluene protons) MR M'X MX M'R M = main-group metal compound M' = transition-metal compound X = halogen, R = alkyl Equation 5.5 Cleavage of group 13 metal-alkyl bonds via oxidative addition at a transition metal centre is a relatively new process. Recently, Thorn and Harlow described the synthesis of ci'5-Ir(Me)2lnMe2(PMe3)3 from the oxidative addition reaction of InMe 3 with I r M e ( P M e 3 ) 4 . 2 8 Studies on the reactivity of A l M e 3 with I r = C H 2 [ N ( S i M e 2 C H 2 P P h 2 ) 2 ] and I r = C = C H 2 [ N ( S i M e 2 C H 2 P P h 2 ) 2 ] (Chapter 4, Section 4.3) were extended to Ir(rj 2-C8Hi4 ) [ N ( S i M e 2 C H 2 P P h 2 ) 2 ] > 25. In toluene at room temperature, the reaction between trimethylaluminum and the iridium(I) r]2-cyclooctene complex, 25, proceeded smoothly yielding only one product characterised as Ir(Me)( | i -AlMe2)[N(SiMe2CH2-PPh2)2], 30 (Equation 5.6). The orange colour of the cyclooctene complex changed to red within an hour. The reaction was essentially quantitative in situ yield (by ! H N M R spectroscopy). Me 2Si Me,Si Me 2Si AIMe3 2 5 toluene (-COE) Equation 5.6 Me 2S The spectral features (Figure 5.7) of this complex are very similar to those of its hydride analogue I r ( H ) Q i - A l M e 2 ) [ N ( S i M e 2 C H 2 P P h 2 ) 2 ] (see Chapter 4, Figure 4.2). The exclusive trans disposition of the chelating phosphines was once again 161 1111111 111 11111111 11111111111111111111111111111111 11II111111111111111111111111II11111111111 8 7 6 5 4 3 2 1 0 PPM Figure 5.7 *H NMR spectrum (300 MHz, C 6 D 6 ) of Ir(u.-AlMe2)CH 3[N(SiMe2CH2PPh 2)2j, 30 (* indicates hexanes protons) established primarily from *H NMR data, in particular the CH2P and the phenyl resonances. Again, the bridging AlMe 2 ligand protons show a singlet at 0.51 ppm. Because of coupling to the two phosphorus nuclei, the Ir-CH 3 resonance is a triplet (0.76 ppm, 3j p H = 3.1 Hz). As an extension to the iridium(I) r|2-cyclooctene reactivity with AlMe3, reaction between the analogous rhodium complex was briefly investigated. The rhodium(I) r|2-cyclooctene complex, Rh(ri2-C8Hi4)[N(SiMe2CH2PPh2)2L reacted rapidly with AlMe 3 to afford a product similar to that observed above namely Rh(Me)(u,-AlMe2)[N(SiMe2CH2PPh2)2, 31. 5.5 Summary The results discussed above provide further insight into the reactive nature of the iridium(I) ri2-cyclooctene complex, Ir(ri 2-C8Hi4)[N(SiMe2CH2PPh2)2]- The photolytic conversion of the complex to Ir(H)2[N(SiMe2CH2PPh2)2] and free COD through an rj3-allylic hydride intermediate emphasises the importance of such intermediates in dehydrogenation processes. The formation of the iridium(I) olefin complexes via replacement of the cyclooctene ligand by an olefin seems restricted to 1,3-butadiene and allene. The reaction with AlMe 3 indicates that an aluminum-alkyl bond cleavage can be achieved under very mild conditions using transition metal complexes. 163 5.6 References 1 (a) Collman, J. P.; Hegedus, L . S.; Norton, J. R.; Finke, R. G . Principles and Applications of Organotransition Metal Chemistry; University Science Books: M i l l Valley, C A , 1987, p.280. (b) Vaska, L . Acc. Chem. Res. 1968,1, 335. 2 (a) Fryzuk, M . D.; MacNeil, P. A . ; Rettig, S. J. Organometallics 1986, 5, 2469. (b) Fryzuk, M . D.; MacNeil, P. A. ; Rettig, S. J. J. Am. Chem. Soc. 1987,109, 2803. 3 (a) Crabtree, R, H . Chem. Rev. 1985, 85, 245. (b) Shilov, A . E. Activation of Saturated Hydrocarbons by Transition Metal Complexes; D. Riedel Publishing Co.: Dordrecht, 1984. 4 (a) Sakakura, T.; Tanaka, M . J. Chem. Soc, Chem. Commun. 1987, 758. (b) Sakakura, T.; Sodeyama, T.; Tanaka, M . Chem. Lett. 1988,4, 683. (c) Periana, R. G.; Bergman, R. G. J. Am. Chem. Soc. 1986,108, 7332. (d) Fisher, B . J.; Eisenberg, R. J. Am. Chem. Soc. 1986,108, 535. (e) Kunin, A. J.; Eisenberg, R. Organometallics 1983,2,764. (f) Maguire, J. A. ; Boese, W. T.; Goldman, A . S. J. Am. Chem. Soc. 1989, i i i , 7088. 5 (a) Crabtree, R. H. ; Mihelcic, J. M . ; Quirk, J. M . J. Am. Chem. Soc. 1979,101, 7738. (b) Crabtree, R. H. ; Holt, E. M . ; Lavin, M . ; Morehouse, S. M . Inorg. Chem. 1985,24,1986. 6 (a) Rinehart, R. E.; Lasky, J. S. / . Am. Chem. Soc. 1964, 86, 2516. (b) Gargano, M . ; Giannoccaro, M . ; Rossi, M . J. Organomet. Chem. 1975, 84, 389. 7 Bishop, K . C. I l l Chem. Rev. 1976, 76, 461. 8 (a) Crabtree, R. H . The Organometallic Chemistry of the Transition Metals; Wiley- Interscience: New York, 1988, p. 188. 164 (b) Davies, S. G. Organotransition Metal Chemistry: Applications to Organic Synthesis; Pergamon Press: Oxford, 1982, Chapter 7. 9 (a) McGhee, W. S.; Bergman, R. G. J. Am. Chem. Soc. 1988,110, 4246. (b) Siedel, A . R.; Newmark, R. A . ; Brown-Wensley, K . A . ; Skarjune, R. P.; Haddad, L . C. Organometallics, 1988, 7,2078. (c) McGhee, W. S.; Bergman, R. G. / . Am. Chem. Soc. 1985,107, 3388. (d) Baudry, C ; Boydell, P.; Ephritikhine, M . ; Felkin, H . ; Guilhem, J.; Pascard, C ; Dau, E. T. H . / . Chem. Soc, Chem. Commun. 1985, 670. (e) Baudry, C ; Cormier, J. M . ; Ephritikhine, M . ; Felkin, H . J. Organomet. Chem. 1984,227,99. (f) Thorn, D. L . Organometallics 1982,1, 879. (g) Claudert, B . N . ; Cole-Hamilton, D. J.; Wilkinson, G . J. Chem. Soc, Dalton Trans. 1978, 1739. (h) Byrne, J. W.; Blaser, H . U . ; Osborn, J. A . J. Am. Chem. Soc 1975, 97, 3871. 10 Bonnemann, H. Angew. Chem., Int. Ed. Engl. 1970, 9, 736. 11 Tulip, T. H. ; Ibers, J. A . / . Am. Chem. Soc. 1979,101, 4201. 12 Batchelor, R. T.; Einstein, F. W. B.; Jones, R. H. ; Zhuang, J. M . ; Sutton, D. /. Am. Chem. Soc 1989, 111, 3468. 13 (a) Blenkers, J.; Hessen, F.; VanBolhuis, A. ; Wagner, J.; Teuben, J. H . Organometallics 1987,6,459. (b) Yasuda, H. ; Tatsumi, K.; Nakamura, A . Acc. Chem. Res. 1985,18, 120. (c) Yasuda, H . ; Tatsumi, K . ; Okamoto, T.; Mashima, K . ; Lee, K . ; Nakamura, A. ; Kai , Y . ; Kanehisa, N . ; Kasai, N . / . Am. Chem. Soc. 1985,107, 2410. (d) Erker, G.; Kruger, C ; Muller, G. Adv. Organomet. Chem. 1985,24,1. (e) Datta, S.; Wreford, S. S.; Beatty, R. P.; McNeese, T. J. / . Am. Chem. Soc. 1979,101, 1053. 14 See for example: (a) Smith, G. M . ; Suzuki, H. ; Sonnenberger, D. C ; Day, V . W.; Marks, T . J . Organometallics, 1986,5, 549. (b) Erker, G.; Muhlenberd, T.; Benn, R.; Ruflinska, A . Organometallics, 1986,5,402. 165 15 (a) Erker, G.; Wicher, J.; Engl, K . ; Rosenfeldt, F.; Dietrich, W.; Kruger, C. J. Am. Chen. Soc. 1980,102, 6346. (b) Dorf, U . ; Erker, G. Organometallics 1983,2,462. (c) Czisch, P.; Erker, G.; Korth, H. Sustmann, R. Organometallics 1984, 3, 945. 16 (a) Hunter, A . D.; Legzdins, P.: Nurse, C. R.; Einstein, F. W. B. ; Wills, A . C. / . Am. Chem. Soc. 1985,107, 1791. (b) Christensen, N . J.; Hunter, A . D.; Legzdins, P. Organometallics 1989, 8, 930. 17 Fryzuk, M . D.; Joshi, K.; Rettig, S. J. Polyhedron 1989, 8, 2291. 18 Shapley, J. R.; Osborn, J. A . Acc. Chem. Res. 1973, 6, 305. 19 Fryzuk, M . D.; Haddad, T. S.; Rettig, S. J. Organometallics 1989, 8, 1723. 20 Okamoto, T.; Yasuda, H . ; Nakamura, A. ; Kai , Y . ; Kanehisa, N . ; Kasai, N . Organometallics 1988, 7, 2266. 21 Appleton, T. G.; Clark, H . C ; Mazner, L . E. Coord. Chem. Rev. 1973,10, 335. 22 Yasuda, H ; Nakamura, A . Angew. Chem. Int. Ed. Engl. 1987, 26, 723. 23 Otsuka, S.; Nakamura, A . Adv. Organomet. Chem. 1976,14, 265. 24 (a) Fryzuk, M . D.; MacNeil, P. A. ; Massey, R. L. ; Ball, R. G. J. Organomet. Chem. 1989,368, 231. (b) Mann, B. E.; Taylor, B. E. 13C NMR Data for Organometallic Compounds; Academic Press: New York, 1981, p. 45. 25 Mann, B . E.; Taylor, B. E. 13C NMR Data for Organometallic Compounds; Academic Press: New York, 1981, p. 190. 26 (a) Parshall, G. W. Homogeneous Catalysis; Wiley: New York, 1980. (b) Boor, J., Jr. Ziegler-Natta Catalysis and Polymerisation; Academic Press: New York, 1979. 27 Tebbe, F. N . ; Parshall, G. W.; Reddy, G. S. J. Am. Chem.Soc. 1978,100, 3611. 28 Thorn, D. L. ; Harlow, R. E. / . Am. Chem. Soc. 1989, 111, 2575. 166 CHAPTER 6 General Conclusions and Recommendations for Future Studies In this thesis work, the synthesis of the six-coordinate iridium(III) cyclometallated hydride complexes of formula, Ir(ri 2 -CH2PR2)H[N(SiMe2CH2-PPh2)2L has been achieved by two different unprecedented transformations, namely via thermolysis of the iridium(III) phosphide complexes, and by the reaction of the iridium methylidene complex with primary and secondary phosphines. Kinetic studies show that in the thermolysis process, the rate-determining step is the intramolecular a-hydride abstraction of a methyl C-H, presumably by the phosphide group. The cyclometallated hydride species convert to the corresponding square-planar iridium(I) phosphine complexes, Ir(PCH3R2)[N(SiMe2CH2PPh2)2L upon thermolysis. The same iridium(I) phosphine complexes are also produced when the phosphide complexes Ir(CH3)PR2[N(SiMe2CH2PPh2)2] are photolysed. It is possible that the photolytic transformation proceeds either through the cyclo-metallated hydride intermediate, or via the migration of the phosphide ligand into the iridium-methyl bond. The phenylphosphide complex, Ir(CH 3)PHPh[N(SiMe 2CH2PPh2)2], shows dramatically different thermolytic behaviour as compared to its diphenylphosphide 167 analogue. The only species observed upon the thermolysis is Ir(PCH3HPh)-[N(SiMe2CH2PPh2)2l- Mechanistic studies exclude the involvement of the cyclometallated hydride species in this transformation. A 3-centre transition state is proposed where direct C-P bond formation occurs. This is in contrast to the 4-centre transition state assumed for the thermolysis of the diphenylphosphide complex which might be necessary because of steric strain. The reactions of Ir(CH3)PPh2[N(SiMe2CH2PPh2)2] with various alkynes have been conducted. Although the initial goal of obtaining the metallacyclo-phosphinobutene-type complexes could not be achieved (except in the case of the dimethylphosphide complex), some interesting reactivity has emerged from this work. The tridentate ligand undergoes unusual rearrangement when the phosphide complex is exposed to the electron-deficient alkyne DMAD. However, the reactivity with PhC=CPh and terminal alkynes RC=CH is readily explained and is consistent with the previous results involving the reactions of the diphenylphosphide complex with CO. The synthesis of the alkylidene species, Ir=CH2[N(SiMe2CH2PPh2)2]> in relatively good yield has been achieved by the reaction of Ir(CH 3 ) I [N (S iMe 2CH2-PPh2)2] with KO lBu. The reactions of the alkylidene complex with 1,3-butadiene and allene proceed with complete stereoselectivity which might be a consequence of the hybrid tridentate ligand. The photochemical dehydrogenation of the Ti2-cyclooctene ligand in Ir(r|2-C8Hi4)[N(SiMe2CH2PPh2)2] to yield Ir(H)2[N(SiMe2CH2PPh2)2] and free cyclo-octadiene through an isolable Ir(ri3-C8Hi3)H[N(SiMe2CH2PPh2)2] intermediate is interesting. Another notable aspect of the iridium(I) cyclooctene chemistry involves A l - M e bond cleavage of the AlMe3 reagent at the iridium centre to yield Ir(|i-AlMe 2)Me[N(SiMe 2CH 2PPh 2)2] 168 The isolation of and studies on Ir(|i-AlMe 2)Me[N(SiMe2CH2PPh2)2] need to be carried out. In addition, the extension of this work to rhodium analogues and reactivity with other group 13 reagents such as GaR.3 and InR.3 would be of value. The synthesis of Ir=CH 2[N(SiMe2CH2PPh2)2] from the reaction of Ir(CH3)I-[N(SiMe2CH2PPh2)2] with CH2=PR3 or potassium enolate (of acetone, for example) would be worth pursuing. Other alkylidene complexes might be accessible via these routes. A preliminary reactivity study of the l B u N H 2 with Ir=CH 2 [N(SiMe2CH 2 -PPh2)2] has been conducted (Chapter 4) and the product obtained from this reaction is /ac-Ir(ri 2 -CH 2 NH t Bu)H[N(SiMe2CH2PPh 2 )2]. This work can be extended to other amines. The syntheses of the phosphide complexes containing PR2 and PHR ligands have been achieved in this thesis work. Phosphide complexes with a P H 2 ligand, namely I r ( R ) P H 2 [ N ( S i M e 2 C H 2 P P h 2 ) 2 ] , might be prepared from the reaction of Ir(R)I[N(SiMe2CH2PPh2)2] with PH 3 followed by deprotonation with KO lBu. Their reactivity studies, in particular thermolysis and photolysis behaviour, would be of interest. 169 CHAPTER 7 Experimental Procedures 7.1 Materials 7.1.1 Solvents Spectral or reagent grade solvents were obtained from M C B , B D H , Mallinckrodt, Fisher, Eastman or Aldrich Chemical Co. Hexanes and THF were dried by refluxing over C a H 2 and then distilled from sodium benzophenone ketyl under argon. Toluene was dried by refluxing over C a H 2 and distilled from Na under argon. Benzene was dried over activated 4 A molecular sieves for 24 hours, vacuum transferred and freeze-pump-thawed several times before being used. The deuterated solvents (C^D^ and C D 3 C 6 D 5 ) , used in N M R spectroscopy, were purchased from M S D Isotopes, and were dried over activated 4 A molecular sieves overnight, vacuum transferred and freeze-pump-thawed several times before being used. 7.1.2 Gases The gases nitrogen, argon, and carbon monoxide were supplied by Union Carbide of Canada Ltd. The labelled 1 3 C O (90% 1 3 C ) gas was obtained from MSD 170 Isotopes. Acetylene and allene were purchased from Matheson Gas Products and used without further purification. 1,3-Butadiene (obtained from Matheson Gas Products) was condensed into a small gas reactor bomb, and vacuum transferred into a reaction vessel at -10°C. 7.1.3 Reagents The reagent KC^Bu was purchased from Aldrich Chemical Co. and used as received. CH3I and CH2C02MeBr were obtained from Aldrich Chemical Co. CH3I was degassed several times and transferred to a reaction vessel at -10°C. C H 2 C 0 2 M e B r was distilled before being used. BuLi (1.6 M solution in hexanes), A l M e 3 (2 M solution in toluene) and D B U were obtained from Aldrich Chemical Co. The alkynes, D M A D , PhC=CPh, P h C ^ C H , l BuC=CH, were purchased from Aldrich Chemical Co. While P h O C P h was used without any further purification, the other three alkynes were distilled and stored in dark under a N 2 atmosphere. The phosphines, PHPh 2 , P H M e 2 , P H l B u 2 , HP(or//zo-tol)2, HP(wera-tol) 2 and H P i P r 2 , were synthesised by the published procedures.1 PPh 3 and P H 2 P h were purchased from Aldrich Chemical Co., and used without further purification. The literature procedures were followed to synthesise L i P H P h , 2 Mg(PHPh) 2 »TMEDA. 3 K P M e 2 and K P c B u 2 , were prepared from benzylpotassium and the corresponding phosphines. L i P P h 2 , LiP(ori/zo-tol) 2, LiP(mefa-tol) 2, L i P i P r 2 were prepared by a dropwise addition of BuLi (1.6 M solution in hexanes) to a hexanes solution of the respective phosphines. 7.1.4 Instrumentation The *H N M R spectra were recorded in C^D^ or CD3C6D5 on the Varian X L -300 or the Bruker WH-400 spectrometer. With C6D6 as the solvent, the spectra were 171 referenced to the residual solvent protons at 7.15 ppm; when CD3C6D5 was used, the spectra were referenced to the C D 2 H residual proton at 2.09 ppm. The 3 1 P { ^ H) N M R spectra were recorded at 121.421 M H z on the Varian XL-300 and were referenced to external P(OMe)3 set at +141.00 ppm relative to 85% H3PO4. The ^ C p H } and 2 H { *H} were run in C6D6 at 75 M H z and 40 M H z , respectively, on the Varian X L -300. The 1 3 C { 1 H } spectra were referenced at 128.00 ppm (triplet for the solvent), and the 2 H { lH) spectra were referenced at 7.15 ppm, the residual solvent protons. Variable temperature N M R spectral studies and various I D - and 2 D - N M R experiments (e.g. selective decoupling studies, APT and HETCOR experiments) were conducted on the Varian XL-300 spectrometer. Infrared spectra were recorded on a Pye-Unicam SP-1100 or a Nicolet 5DX Fourier Transform spectrophotometer with the samples as K B r pellets or in solution between 0.1 mm NaCl plates. U V - V i s spectra were recorded on a Perkin Elmer 5523 U V / V i s spectro-photometer stabilised at 20°C. The X-ray crystal structure of I r ( r i 2 - C H 2 P P h 2 ) H [ N ( S i M e 2 C H 2 P P h 2 ) 2 ] , 3a, was carried out by Dr. R. K . Chaddha at the University of Manitoba, and the rest of the structures were determined by Dr. S. J. Rettig of this department. Carbon, hydrogen and nitrogen analyses were performed by Mr. P. Borda of this department. 172 7.2 Synthesis and Characterisation of New Complexes A l l synthetic reactions were performed under pre-purified nitrogen in a Vacuum Atmosphere HE-533-2 glove box, equipped with a -30°C freezer, or in standard Schlenk-type glassware,4 as all of the iridium and rhodium complexes prepared in the course of this work were susceptible to oxidation by air. The yields reported for synthetic reactions are generally the average of several repeat preparations. Iridium and rhodium trichloride hydrates were obtained on loan from Johnson-Matthey and used directly in the preparation of [ M ( r i 2 - C 8 H i 4 ) C l ] 2 (M = Ir, R h ) . 5 The starting materials I r ( r i 2 - C 8 H 1 4 ) [ N ( S i M e 2 C H 2 P P h 2 ) 2 ] and Ir(R)X-[N(SiMe 2 CH 2 PPh 2 )2] (1: R = Me, X = I; R = Ph, X = I; 11: R= CH 2 Ph , X = Br; 2a: R = C H 3 , X = PPh2; 2b: R = CH3, X = P(mera-tol)2) were prepared by the published procedures. 6 R h ( r i 2 - C 8 H 1 4 ) [ N ( S i M e 2 C H 2 P P h 2 ) 2 ] and R h ( C H 3 ) I [ N ( S i M e 2 C H 2 -PPh2)2] were also synthesised by the literature procedures.6 ! H , 3 l p { i H } , ! 3c{ iH} N M R d a t a - a n d I R a n d U V - V i s data for the new compounds are listed below following their synthesis. 7.2.1 Ir(CH 3)PMe 2[N(SiMe 2CH 2PPh2) 2], 2c The complex 2c was prepared by adding a 2 mL toluene suspension of KPMe2 (46 mg, 0.47 mmol) at -30°C to the toluene solution (10 mL) of Ir(CFJ.3)I-[N(SiMe2CH 2 PPh2)2], 1, (400 mg, 0.46 mmol) also at -30°C. The reaction took about an hour to go to completion as the green colour of 1 changed to purple. Because the complex 2c is thermally unstable, it was prepared only in situ. lH N M R (300 M H z , C 7 D 8 , -30°C): S iMe 2 , -0.03 (s), 0.26 (s); P C H 2 S i , 1.99, 2.12 (dt, 2 J g e m = 12.0 Hz, J a p p = 4.9 Hz); I r - C H 3 , 1.26 (four line pattern, 3 j P H = 4.0 Hz); PMe 2 , 0.55 (d, 3 j P H = 173 6.7 Hz); PPh 2 , 7.17 (m, para/meta), 7.75 (m, ortho). 31p{*H} NMR ( C 7 D 8 , -30°C): PMe 2 , 94.30 (t, 2 J P ) P = 25.1 Hz); PPh 2, 25.11 (d, 2 J P ) P = 25.0 Hz). 7.2.2 Ir(CH3)I(PH2Ph)[N(SiMe2CH2PPh2)2],9 Preparation of 9 involved dropwise addition of a toluene solution (5 mL) of P H 2 P h (12 mg, 0.11 mmol) to the toluene solution (10 mL) of Ir(CH3)I-[N(SiMe2CH2PPh2)2L 1» (100 mg, 0.11 mmol) at room temperature. The reaction was instantaneous as the green colour of 1 changed to light yellow. The solution was stirred for an hour, and concentrated to ~ 1 mL by pumping off the solvent under vacuum. Addition of ~ 1 mL of hexanes to the reaction mixture afforded light yellow crystals of 9 within few hours. The product was washed with small amounts of hexanes (1/2 mL) and dried in vacuo. Yield: 90%. Anal. Calcd. for C37H4oNP3Si2lr: C, 45.68; H, 4.13; N, 1.44. Found: C, 45.91; H , 4.30; N, 1.20, lH NMR (300 MHz, C 6 D 6 ) : SiMe 2 , 0.39 (s), 0.42 (s); PCH 2 Si , 1.60, 1.95 (dt, J g e m = 12.2 Hz, J a p p = 4.5 Hz); I r - C H 3 , 1.51 (four line pattern, 3 j P H = 4.7 Hz); PtfPh, 5.00 (dt, 2 J P , H = 155.1 Hz, 3 j P H = 6.9 Hz); PPh 2 , 7.00 (m, para/meta), 8.00, 8.17 (m, ortho). 3lp{lH} NMR ( C 6 D 6 ) : PPh 2 , -20.78 (d, 2 J P ( P = 16.6 Hz); PH 2 Ph, -84.57 (t, 2 J P ) P = 15.8 Hz). 13C{1H} NMR ( C 6 D 6 ) : SiMe 2 , 5.83 (s), 7.13 (s); PCH 2 Si , 21.11 (br t); I r - C H 3 , -6.69 (dt, 2 J P i C Qrans) = 90.1 Hz, 2 J P , C (cis) = 5.8 Hz; PPh 2 , 128-136 (m). 7.2.3 Ir(CH3)PHPh[N(SiMe 2CH 2PPh2)2], 2d The synthesis of 2d was achieved by adding KO l Bu (12 mg, 0.10 mmol) to a toluene solution (10 mL) of Ir(CH3)I(PH 2Ph)[N(SiMe2CH 2PPh 2) 2], 9, (100 mg, 0.10 mmol) at room temperature. The reaction proceeded within minutes as the light yellow solution of 9 changed to brick-red due to the formation of 2d. The excess solvent was pumped off under vacuum. The residual powder was dissolved in hexanes (5 mL) and filtered through Celite in order to remove KI. The solution was 174 concentrated to ~ 1 m L and stored at -30°C for recrystallisation. The product was isolated as brick-red crystalline material which was washed with hexanes (1/2 mL) and dried in vacuo. Y ie ld : 80%. Anal . Calcd. for C3 7 H45NP3Si 2 Ir : C, 52.59; H , 5.37; N , 1.66. Found: C, 52.97; H , 5.67; N , 1.49. * H N M R (300 M H z , C 7 D 8 ) : S i M e 2 , -0.10 (s), 0.37 (s); P C H 2 S i , 1.86 (br); I r - C H 3 , 1.19 (four line pattern, 3 j P H = 4.0 Hz) ; P i f P h , 2.83 (dt, l J P f H = 195.0 H z , 3 j P H = 5.4 Hz) ; P P h 2 , 6.81, 6.99, 7.10, 7.29 (m,para/meta), 7.35-7.90 (br, ortho). 3 lp{ lH) N M R ( C 6 D 6 ) : PHPh , 26.95 (t, 2 j P P = 16.8 Hz) ; P P h 2 , 10.85 (d, 2 J P ) P = 16.9 Hz) . U V - V i s : X ( m a x ) (hexanes) = 462 nm, e = 1820 mol" 1 L cm- 1 . 7.2.4 / a c - I r ( r i 2 - C H 2 P R 2 ) H [ N ( S i M e 2 C H 2 P P h 2 ) 2 ] , (3a: R = Ph, 3b: R = meta-to\): General Procedure The complexes 3a and 3b were synthesised by heating a benzene, toluene or hexanes solution (5 m L ) of I r ( C H 3 ) P R 2 [ N ( S i M e 2 C H 2 P P h 2 ) 2 ] , 2a and 2b, respectively, for ~ 5 hours in an o i l bath set at 50°C. The thermolysis was carried out in a reaction vessel sealed under N2 and wrapped with aluminum foil in order to avoid the photolysis reaction (see Chapter 2). During this time, the purple colour of the > phosphide complex discharged to light yellow. The solvent was removed in vacuo and the resultant o i l was crystallised from hexanes/toluene mixture (1 m L ) at room temperature. Light yel low crystals of the product were obtained within few hours which were washed with hexanes (1 mL) and dried in vacuo. 7.2.4.1 / a c - I r ( r i 2 - C H 2 P P h 2 ) H [ N ( S i M e 2 C H 2 P P h 2 ) 2 ] , 3a I r ( C H 3 ) P P h 2 [ N ( S i M e 2 C H 2 P P h 2 ) 2 ] , 2a (150 mg, 0.16 mmol). Y i e l d : 82%. Ana l . Calcd. for C 4 3 H 4 9 N P 3 S i 2 I r : C, 56.07; H , 5.36; N , 1.52. Found: C, 56.28; H , 5.42; N , 1.40. N M R (300 M H z , C 6 D 6 ) : S i M e 2 , -0.78 (s), 0.65 (s), 0.68 (s), 0.81 (s); P C H 2 S i , 1.40 (t, Japp = 13.7 Hz) , 1.75 (t, J a p p = 13.7 Hz) , 2.10 (m), 2.49 (m); r | ? -175 CH 2 PPh 2 , 1.32 (br, m), 2.00 (br, t); PPh2, 6.60-7.25 (m, paralmeta), 7.45-8.05 (m, ortho); Ir-H, -19.90 (td, 2 J P > H = 16.7 Hz, 2 j P H = 9.9 Hz). 3lp{lH} NMR (C 6 D 6 ) : CH 2 PPh 2 , 12.39 (2JPA,PX = 32.0 Hz, 2 j P M ) P X = 5.5 Hz); CH 2PPh 2 , 15.60 ( 2 j P A ) P M = 298.2 Hz, 2 j P M > P X = 6.4 Hz); Tl2-CH 2PPh 2 , -46.80 (2 j P A,PM = 297.9 Hz, 2 j P A ) P X = 30.4 Hz). 13c{lH} NMR (C 7 D 8 ) : SiMe 2 , 4.91 (s), 5.62 (s), 5.81 (s), 7.00 (s); PCH 2 Si, 23.25 (d, lJc,P = 12.3 Hz), 28.90 (d, l j c , p = 21.5 Hz); Ir-CH 2P, -21.62 (m); PPh2, 127-136 (m). UV-Vis: ? i ( m a x ) (toluene) = 360 nm, e = 5425 mol"1 L cm"1. 7.2.4.2 /ac-Ir[ri2.CH2P(me/fl-tol)2]H[N(SiMe2CH2PPh2)2], 3b Ir(CH3)[P(mera-tol)2][N(SiMe2CH2PPh2)2], 2b (200 mg, 0.21 mmol). Yield: 80%. Anal. Calcd. for C45H53NP3Si2lr: C, 56.94; H, 5.63; N, 1.48. Found: C, 57.30; H, 5.80; N, 1.60. *H NMR (400 MHz, C 6 D 6 ) : SiMe 2, -0.90 (s), 0.71 (s), 0.76 (s), 0.90 (s); PCH 2 Si, 1.45 (t, J a p p =11.2 Hz), 1.74 (t, J a p p =11.2 Hz), 2.19 (m), 2.51 (m); Ti2-CH2P(mera-tol)2, 1.30 (br, m), 2.07 (br, overlapped by the tolyl methyl peak); P[CH 3 (C 6 H 4 ) ] , 2.10 (s), 2.39 (s); PPh2, 6.70-8.15 (m); Ir-H, -20.03 (td, 2 J P , H = 17.0 Hz, 2 j P H = 8.7 Hz). 31p{lH} NMR (C 6 D 6 ) : CH 2 PPh 2 , -1.65 ( 2 J P A ( p X = 33.4 Hz, 2 j P M P X = 4.7 Hz); CH 2PPh 2 , 1.82 ( 2 j P A ; P M = 297.1 Hz, 2 J P M,PX = 5.0 Hz); r i 2 -CH2P(mera-tol)2, -61.46 ( 2 J P A ) P M = 297.7 Hz, 2 J P A P X = 33.0 Hz). ^Cf^H} NMR (C 6 D 6 ) : SiMe 2 , 4.97 (s), 5.77 (s), 5.91 (s), 7.21 (s); PCH 2 Si, 23.02 (d, l J C ) P = 12.0 Hz), 29.72 (d, 1J C ,P = 21.7 Hz); Ir-CH 2P, -20.65 (m); P[(CH 3 )C 6 H 4 ] = 21.23 (s), 21.37 (s); PPh2, 128-139 (m). 7.2.5 / cc-Ir ( r i 2 - C H 2 P M e 2 )H[N ( S i M e 2 C H 2 P P h 2 ) 2 ] , 3c Warming the freshly prepared toluene solution (10 mL) of Ir(CH3)PMe2[N(SiMe2CH2PPh2)2], 2c, from -30°C to room temperature resulted in the formation of 3c within five minutes. The solution was stirred for an hour. After this time, the solvent was pumped off under vacuum. The residual light yellow powder 176 was dissolved in toluene (1 mL) and filtered through Celite in order to remove K l generated during the preparation of 2c. The solution was concentrated to 1/2 mL and left for recrystallisation at room temperature. Light yellow crystals of 3c were obtained overnight. Yield: 78% (calculated from the amount of 1 used and its 100% conversion to 2c). Anal. Calcd. for C 3 3 H 4 5 N P 3 S i 2 l r : C, 49.75; H , 5.65; N , 1.77. Found: C, 49.67; H , 5.86; N , 1.66. *H N M R (300 M H z , C 6 D 6 ) : S iMe 2 , 0.10 (s), 0.51 (s), 0.76 (s), 0.85 (s); P C H 2 S i , 1.40 (t, J A P P = 11.2 Hz), 1.71 (t, J A P P =11.2 Hz), 2.18 (m), 2.51 (m); r i 2 - C H 2 P M e 2 , 1.30 (br, m), 2.07 (br); P M e 2 , 1.40, 1.75 (m), 2.39 (s); P P h 2 , 6.70-8.15 (m); I r -H, -20.10 (td, 2 J P ) H = 16.8 Hz, 2 J P > H = 8.5 Hz). 31P{1H} N M R ( C 6 D 6 ) : C H 2 P P h 2 , 12.19 ( 2 J P A , P X = 39.2 Hz, 2 J P M ) P X = 12.2 Hz); C H 2 P P h 2 , 14.14 ( 2 J P A , P M = 300.9 Hz, 2 J P M , P X = 12.0 Hz); r j 2 - C H 2 P M e 2 , -68.15 ( 2JpA , P M = 301.1 Hz, 2 J P A L P X = 39.7 Hz). 7.2.6 I r ( P C H 3 R 2 ) [ N ( S i M e 2 C H 2 P P h 2 ) 2 ] , (4a: R = Ph, 4b: R = meta-tol, 4c: R = Me) 7.2.6.1 Method I: Thermolysis, General Procedure The complexes 4a-4c were synthesised by heating a benzene or toluene solution (5 mL) of 3a-3c, respectively, in a reaction vessel sealed under nitrogen, for 24 h at 100°C. During this time, the light yellow coloured solutions of the species 3a-3c changed to orange. The excess solvent was pumped off under vacuum and the resultant orange oils were crystallised from hexanes at room temperature. 177 7.2.6.1a I r (PCH 3 Ph2 ) [N (S iMe2CH 2 PPh2)2] , 4a /ac-Ir(r]2-CH2PPh2)H[N(SiMe2CH2PPh2)2], 3a (100 mg, 0.11 mmol). Yield: 85%. Anal. Calcd. for C43H49NP3S12I1-: C, 56.07; H, 5.36; N , 1.52. Found: C, 55.80; H, 5.35; N, 1.40. *H NMR (400 MHz, C 6 D6): SiMe 2, 0.20 (s); PCH 2 Si, 1.91 (t, J a p p = 5.2 Hz); PCH3Ph2, 1.38 (d, 3 j P H = 7.5 Hz); PPh 2 , 6.90-7.10 (m, paralmeta), 7.53, 7.62 (m, ortho). 31p{lH} NMR (C 6 D 6 ) : PPh 2 , 25.30 (d, 2 J P > P = 22.8 Hz); PCH 3 Ph 2 , -1.79 (t, 2 J P , P = 22.3 Hz). UV-Vis: k ( m a x) (toluene) = 388 nm, e = 2130 mol"1 L cm - 1 . 7.2.6.1b Ir[PCH 3 (/«^a-tol)2][N(SiMe2CH2PPh2)2], 4b /ac-Ir[ri2-CH2P(mera-tol)2]H[N(SiMe2CH2PPh2)2], 3b (100 mg, 0.10 mmol). Yield: 83%. Anal. Calcd. for C4 5H53NP3Si2lr: C, 56.94; H, 5.63; N, 1.48. Found: C, 56.70; H , 5.62; N, 1.42. l H NMR (300 MHz, C 6 D 6 ) : SiMe 2, 0.22 (s); PCH 2 Si, 1.85 (t, J a p p = 5.1 Hz); PCH 3 , 0.97 (d, 3 J P H = 6.9 Hz); CH3C6H4, 2.45 (s); PPh 2 , 7.13 (m, paralmeta), 8.09 (m, ortho). 31p{lH} NMR (C 6 D 6 ): PPh 2 , 25.56 (d, 2 J P > P = 22.3 Hz); PCH3(mera-tol)2, -2.38 (t, 2 J P > P = 21.9 Hz). 7.2.6.1c I r (PMe 3 ) [N(SiMe2CH 2 PPh2)2] , 4c /ac-Ir(ri2-CH2PMe2)H[N(SiMe 2CH2PPh2)2], 3c (100 mg, 0.13 mmol). Yield: 80%. Anal. Calcd. for C33H45NP3Si2lr: C, 49.75; H, 5.65; N, 1.77. Found: C, 49.74; H, 5.70; N, 1.71. *H NMR (300 MHz, C 6 D 6 ) : SiMe 2, 0.20 (s); PCH 2 Si, 1.88 (t, J a p p = 5.0 Hz); PMe 3 , 0.85 (d, 3 j P H = 7.5 Hz); PPh 2 , 7.15 (m, paralmeta), 8.11 (m, ortho). 31p(lH) NMR (C 6 D 6 ) : PPh 2, 21.51 (d, 2 J P > P = 25.2 Hz); PMe 3 , -59.54 (t, 2 J P , P = 25.2 Hz). 178 7.2.6.2 Method II: Photolysis, General Procedure The preparation of the phosphine complexes 4a and 4b involved the photolysis, using a 140 W Hg lamp, of the diarylphosphide complexes 2a and 2b in a benzene solution (5 mL) at room temperature for 24 h. Because the dimethylphosphide complex 2c was unstable above -30°C, its photolysis was carried out at -30°C using a N 2 laser in order to produce 4c. This transformation took approximately 3 hours. The work up of the final orange solutions of 4a-4c was the same as described above in method I (7.2.6.1). 7.2.6.2a Ir(PCH 3 Ph 2 )[N(SiMe 2 CH 2 PPh 2 ) 2 ] , 4a Ir(CH3)PPh2[N(SiMe2CH2PPh2)2], 2a (50 mg, 0.05 mmol). Yield: 78%. 7.2.6.2b Ir[PCH3(/ne/a-toI)2][N(SiMe2CH2PPh2)2],4b Ir(CH3)[P(meto-tol)2][N(SiMe2CH2PPh2)2], 2b (100 mg, 0.10 mmol). Yield: 82%. 7.2.6.2c Ir(PMe 3 )[N(SiMe 2 CH 2 PPh 2 ) 2 ] , 4c Ir(CH3)PMe2[N(SiMe2CH2PPh2)2], 2c (50 mg, 0.06 mmol). Yield: 85%. 7.2.7 Ir(PHCH 3Ph)[N(SiMe 2CH 2PPh 2) 2], 4d The complex 4d was prepared by heating a benzene, toluene or hexanes solution (5 mL) of the phosphide complex 2d (100 mg, 0.10 mmol) at 60°C for an hour or by photolysing (140 W Hg lamp) its benzene solution (5 mL) for 18 hours at room temperature. The original brick-red solution turned orange as the transformation proceeded. The reaction mixtures were worked up in usual manner which involved the removal of the solvent in vacuo and crystallisation of the orange oil at room 179 temperature. The isolated yields of 4d are similar from both the routes ( ~ 85 %). Anal. Calcd. for C37H45NP3Si2lr: C, 52.59; H, 5.37; N, 1.66. Found: C, 52.39; H, 5.30; N, 1.65. lH NMR (300 MHz, C 6 D 6 ): SiMe2, 0.26 (s), 0.28 (s); PCH 2Si, 1.93 (m); PCT^HPh, 1.07 (dd, 3 j P H = 7.9 Hz, 3 j H H = 3.8 Hz); PCH 3//Ph, 5.00 (dm, l J P f H = 140 Hz); PPh2, 6.90-7.40 (m, para/meta), 7.90 (m, ortho). 31p{lH} NMR (C 6D 6): PPh2, 22.60 (d, 2 J P > P = 18.3 Hz); PHPh, -39.61 (t, 2 J P ) P =18.1 Hz). UV-Vis: X ( m a x) (hexanes) = 390 nm, e = 3000 mol"1 L cm"1. 7.2.8 I r=CH 2 [N(SiMe 2 CH 2 PPh 2 ) 2 ] + P H R 2 (R = Ph, *Bu) Reactions: General Procedure A toluene solution (10 mL) of Ir=CH2[N(SiMe2CH2PPh2)2], 10, was cooled to -78°C in a dry ice/ethanol bath for 15 min. To it was added a 1 mL toluene solution containing PHR 2. The original purple colour of 10 turned wine red immediately. As mentioned in chapter 2, this wine red-coloured compound was characterised as Ir=CH 2(PHR 2)[N(SiMe 2CH 2PPh 2) 2], 5. Warming its solution to -30°C resulted in the formation of/ac-Ir(ri 2-CH 2PR2)H[N(SiMe 2CH 2PPh 2) 2], 6. The solution was stirred for 10 min at room temperature and then the solvent was removed in vacuo. The yellow oil was dissolved in toluene (1 mL) from which pale yellow crystals of 6 were isolated within an hour. The toluene solution of 6 was stirred under an inert atmosphere for 48 hours at room temperature which resulted in its conversion to 3. The solution was pumped to dryness under vacuum The yellow-coloured oil was crystallised from hexanes/toluene mixture (1 mL) at room temperature. 7.2.8.1 Ir=CH 2 (PHPh 2 )[N(SiMe 2 CH 2 PPh 2 ) 2 ] , 5a Ir=CH2[N(SiMe2CH2PPh2)2], 10, (100 mg, 0.14 mmol); PHPh2 (21 mg, 0.15 mmol). lH NMR (300 MHz, C 7 D 8 , -78°C): SiMe2, 0.09 (s), 0.81 (s); PCH 2Si, 1.75 (br); Ir=CH2, 12.08 (four line pattern, 3 j p H = 14.4 Hz); PHPh2, 5.90 (other half 180 obscured by the phenyl resonances); PPh2, 6.70-7.40 (m, para/meta), 8.45 (m, ortho). 31P{1H) N M R ( C 7 D 8 ) : C H 2 P P h 2 , 13.45 (s); P H P h 2 , 3.90 (s). 7.2.8.2 /ac - I r(Ti2 . C H 2 PPh2 ) H [N(SiMe 2 C H 2 PPh2) 2 ] , 6a I r = C H 2 [N ( S i M e 2 C H 2 P P h 2 ) 2 ] , 10, (100 mg, 0.14 mmol); P H P h 2 (21 mg, 0.15 mmol). Y i e l d : 8 5 % . Ana l . Calcd. for C43H 4 9 N P 3 S i 2 I r : C , 56.07; H , 5.36; N, 1.52. Found: C , 5 6 . 5 3 ; H , 5.52; N, 1.50. * H N M R (400 M H z , C 6 D 6 ) : S i M e 2 , 0.52 (s), 0.71 (s), 0.76 (s), 0.82 (s); P C H 2 S i , 1.36 (m), 1.40 (m), 1.60 (t, J a p p = 9.0 Hz) , 2.25 (m); r j 2 - C H 2 P P h 2 , 1.25 (br, m), 1.58 (m); P P h 2 , 6.50-7.49 (m, para/meta), 7.90-8.45 (m, ortho); I r - H , -11.88 (dddd, 2 j p H ( l r a n s ) = 133.3 H z , 2 j p H ( c i s ) = 19.8 H z , 2 j P H r c i s ) = 11.8 Hz) . 31p{l H } N M R ( C 7 D 8 ) : C H 2 P P h 2 , -16.17 (br t, 2 J P P = 12.6 Hz) ; C H 2 P P h 2 , 13.44 ( 2 j P A ) P M = 310.1 H z , 2 J P M P X = 10.3 Hz) ; T i 2 - C H 2 P P h 2 , -58.20 ( 2 JPA,PM = 310.8 H z , 2 j P A P X = 10.3 Hz). 13c{lH} N M R ( C 7 D 8 ) : S i M e 2 , 3.18 (s), 3.59 (s), 3.73 (s), 7.13 (s); P C H 2 S i , 14.38 (br s), 23.08 (br s); I r - C H 2 P , -38.20 (br); P P h 2 , 127-136 (m). U V - V i s : ?i (rnax) (toluene) = 360 nm, e = 2205 moH L cnW. 7.2.8.3 / f lc - I r ( r i 2 -CH2PPh 2 ) H [N(SiMe 2 C H 2 P P h 2 ) 2 ] , 3a / a c - I r ( r i 2 - C H 2 P P h 2 ) H [ N ( S i M e 2 C H 2 P P h 2 ) 2 ] , 6a, (75 mg, 0.08 mmol). Y i e l d : 8 0 % . The spectroscopic data and elemental analysis of this complex are reported in section 7.2.4.1. 7.2.8.4 I r = C H 2 ( P H t B u 2 ) [N(S iMe 2 C H 2 P P h 2 ) 2 ] , 5e I r = C H 2 [ N ( S i M e 2 C H 2 P P h 2 ) 2 ] , 10, (100 mg, 0.14 mmol); P H t B u 2 (17 mg, 0.15 mmol). * H N M R (300 M H z , C 7 D 8 , - 7 8 ° C ) : S i M e 2 , 0.70 (s), 0.74 (s); P C H 2 S i , 2.30 (br); P t B u 2 , 1.10 (s), 1.15 (s); I r = C H 2 , 16.26 (four line pattern, 3 j P H = 18.0 Hz) ; P H t B u 2 , 3.36 (br, d, l J P i H = 216.0 Hz) ; P P h 2 , 6.40-8.15 (m). 31p{lH} N M R ( C 7 D 8 ) : C H 2 P P h 2 , 17.85 (s); P H l B u 2 , 18.71 (s). 181 7.2.8.5 /ac-Ir(ri2-CH2PtBu2)H[N(SiMe2CH2PPh2)2], 6e Ir=CH 2 [N(SiMe2CH 2 PPh 2)2], 10 , (100 mg, 0.14 mmol); PH.tBu 2 (17 mg, 0.15 mmol). Yield: 78%. Anal. Calcd. for C39H 57NP 3Si2lr: C, 53.16; H , 6.52; N , 1.59. Found: C, 53.71; H , 6.61; N , 1.70. lU N M R (300 M H z , C 7 D 8 ) : S iMe 2 , 0.58 (s), 0.70 (s), 0.85 (s), 0.90 (s); P C H 2 S i , 1.49 (m), 1.54 (m), 1.78 (m), 2.46 (m); T i 2 -C H 2 P l B u 2 , 1.28 (br, m), 1.67 (m); P t B u 2 , 1.07 (s), 1.09 (s), 1.12 (s), 1.14 (s); PPh 2 , 6.70-7.85 (m); I r -H, -14.34 (dt, 2 J P , H (trans) = 100.1 Hz, 2 J P ) H (cis) = 15.5 Hz). 31P{lH) N M R ( C 6 D 6 ) : C H 2 P P h 2 , -17.73 ( 2 J P A , P X = 15.9 Hz, 2 J P M , P X = 14.2 Hz); C H 2 P P h 2 , 4.55 ( 2 J P A , P M = 217.9 Hz, 2 J P M , P X = 14.7Hz); T i 2 - C H 2 P t B u 2 , -23.74 ( 2 TPA,PM = 323.6 Hz, 2 J P A , P X = 15.8 Hz). l^C{lH} N M R ( C 7 D 8 ) : S iMe 2 , 3.28 (s), 3.84 (s), 3.98 (s), 7.29 (s); P C H 2 S i , 18.10 (d, 2 J P , C = 13.7 Hz), 25.58 (s); I r - C H 2 P , -38.05 (br); P l B u 2 , 29.54 (s), 31.67 (s); PPh 2 , 128-134 (m). 7.2.8.6 /ac- I r(Ti 2 -CH 2 PtBu 2 )H[N(SiMe 2 CH 2 PPh2) 2 ] , 3e /ac-Ir(Ti 2-CH2P tBu2)H[N(SiMe2CH 2 PPh2)2], 6e, (50 mg, 0.06 mmol). Yield: 86%. Anal. Calcd. for C39H 5 7 N P 3Si2lr: C, 53.16; H , 6.52; N , 1.59. Found: C, 53.32; H , 6.43; N , 1.50. *H N M R (300 M H z , C 7 D 8 ) : S iMe 2 , 0.65 (s), 0.82 (s), 0.96 (s), I. 14 (s); P C H 2 S i , 2.15 (m), 2.35 (m), 2.71 (m); T i 2 - C H 2 P t B u 2 , 1.28 (br, m), 1.67 (m); P l B u 2 , 1.50 (s), 1.62 (s), 1.68 (s), 1.74 (s); PPh 2 , 6.90-8.42 (m); I r -H, -21.62 (dt, 2 Jp,H . ( trans) = 84.0 Hz, 2 J P > H (CJ-,) = 36.0 Hz). 3 1 P { 1 H } N M R ( C 7 D 8 ) : C H 2 P P h 2 , 16.53 ( 2 J P A , P X = 32.8 Hz, 2 J P M , P X = 4.9 Hz); C H 2 P P h 2 , 18.74 ( 2 J P A , P M = 289.8 Hz, 2 J P M , P X = 5.5 Hz); T i 2 - C H 2 P t B u 2 , 3.50 ( 2 J P A , P M = 289.2 Hz, 2 J P A , P X = 32.9 Hz). 13C{lH) N M R ( C 7 D 8 ) : S iMe 2 , 6.43 (s), 6.58 (s), 7.58 (s), 11.07 (s); P C H 2 S i , 22.64 (d, 2 J P ) c = 11-9 Hz), 27.56 (d, 2 J P > C = 21.9 Hz); I r -CH 2 P , -23.00 (br); PtBu 2 , 32.10 (s), 32.28 (s); PPh 2 , 125-136 (m). 182 7.2.9 /ac - Ir(r i2 .CH2PHPh )H[N(SiMe2CH2PPh2)2] , 6d A solution of Ir=CH2[N(SiMe2CH 2PPh 2)2], 10, (150 mg, 0.27 mmol) in toluene (10 mL) was cooled to -78°C in a dry ice/ethanol bath for 15 min. To it was added 1 mL toluene solution of PH^Ph (23 mg, 0.21 mmol). The original purple colour of 10 turned light yellow immediately. The solution was warmed to room temperature and stirred for an hour. The solvent was removed under vacuum, and the residue was recrystallised from hexanes/toluene mixture (1/2 mL) at room temperature. Yield: 75%. Anal. Calcd. for C3 7 H45NP 3 Si2 l r : C, 52.59; H , 5.37; N , 1.66. Found: C, 52.07; H , 5.54; N , 1.70. *H N M R (300 MHz, C6D 6 ) : S iMe 2 , -0.05 (s), -0.20 (s), -0.35 (s), -0.69 (s); P C H 2 S i , 1.95 (m), 2.10 (m); r j 2 -C# 2 PHPh, 1.51 (m), 2.75 (br, m); P//Ph, 3.86 (br, m); PPh 2 , 6.70-7.40 (m, paralmeta), 7.50-7.90 (m, ortho); I r -H, -12.87 (dt, 2h,H(trans) = 149.3 Hz, 2 J P , H ( c;,) = 19.1 Hz). 3 1 P { 1 H } N M R ( C 6 D 6 ) : C H 2 P P h 2 , 5.50 (m); C H 2 P P h 2 , -64.21 (m); r i 2 - C H 2 P H P h , -93.25 (t, 2 J P > P = 9.1Hz). 7.2.10 /ac-I r ( r 1 2 -CHPhPMe 2 )H[N(SiMe 2 CH2PPh2)2],6f The complex 6f was prepared by adding a 2 mL toluene suspension of KPMe2 (10 mg, 0.09 mmol) to the toluene solution (10 mL) of I r ( C H 2 P h ) B r -[N(SiMe2CH2PPh2)2L H , (75 mg, 0.08 mmol) at room temperature. The reaction took about half an hour to go to completion as the green colour of 11 changed to yellow. After this time, the solvent was removed in vacuo. The residue was dissolved in toluene (1 mL) and filtered through Celite in order to remove K B r . Recrystallisation from toluene/hexanes (1 mL) afforded yellow crystals. Yield: 85%. Anal. Calcd. for C39H49NP3Si2lr: C, 53.65; H , 5.66; N , 1.60. Found: C, 53.43; H , 5.80; N , 1.68. l H N M R (300 M H z , C 6 D 6 ) : S iMe 2 , 0.17 (s), 0.51 (s), 0.86 (s), 0.95 (s); P C H 2 S i , 1.30 (m), 1.59 (m), 1.97 (m); r | 2 - C / / P h P M e 2 , 2.09 (m); P M e 2 , 0.35 (d), 1.20 (d, 3 J P ) H = 15.0 Hz); PPh 2 , 6.70-7.75 (m, paralmeta), 8.80 (m, ortho); Ir-H, 183 -10.82 (ddd, 2 J P ,H (trans) = 153.0 Hz, 2 J P ) H (cis) ~ 20.1 Hz, 2 J P ) H (cis) - 9.0 Hz). 31p{lH} NMR (C 6 D 6 ): C H 2 P P h 2 , -7.39 (4 line pattern, 2 J P ) P = 9.5 Hz); C H 2 P P h 2 , -2.60 (4 line pattern, 2 J P > P = 9.5 Hz, 2 J P > P = 9.3 Hz); ri 2-CHPhPMe 2, -11.19 (t, 2 J P ) P = 9.0 Hz). 7.2.11 I r ( P M e 2 C H 2 P h ) [ N ( S i M e 2 C H 2 P P h 2 ) 2 ] , 4f The complex 4f was synthesised by stirring a toluene solution (5 mL) of 6f (50 mg, 0.06 mmol) for two weeks at room temperature (or 48 hours at 80°C) under a N 2 atmosphere. During this time, the light yellow coloured solutions of 6f darkened to orange. The excess solvent was pumped off under vacuum and the resultant orange oil was recrystallised from hexanes at room temperature. Yield: 80%. Anal. Calcd. for C 3 9H49NP 3 Si2lr: C, 53.65; H, 5.66; N, 1.60. Found: C, 53.53; H, 5.72; N, 1.50. !H NMR (300 MHz, C 6 D 6 ) : SiMe2, 0.28 (s); PCH 2 Si , 1.99 (t, J a p p = 6.0 Hz); P C / / 2 P h M e 2 , 2.55 (d, 2 J P , H = 14.5 Hz); PCH 2 PhMe 2 , 0.83 (d, 2 J P j H = 11.5 Hz); PPh 2 , 7.21 (m, para/meta), 8.15 (m, ortho). 31p{lH} NMR (C 6 D 6 ): C H 2 P P h 2 , 20.23 (2Jp,P = 23.8 Hz); CH 2PhPMe 2 , -39.73 ( 2 J P > P = 23.8 Hz). 7.2.12 I r ( r i l - C H 2 P P h 2 ) H ( C O ) [ N ( S i M e 2 C H 2 P P h 2 ) 2 ] , 7a A toluene solution (10 mL) of Ir(r] 2 -CH 2 PPh 2 )H[N(SiMe 2 CH 2 PPh 2 ) 2 ], 2a or 6a (100 mg, 0.11 mmol) was loaded in a thick-walled reactor bomb equipped with a 5 mm Kontes needle valve. The vessel was attached to a vacuum line and degassed. The solution was exposed to excess CO gas (1 atm) and stirred for 48 hours at room temperature. Toluene was removed in vacuo and the faint yellow residual powder was recrystallised from toluene/hexanes mixture (1 mL). Yield: 90%. Anal. Calcd. for C44H49NOP3Si2Ir: C, 55.68; H , 5.20; N, 1.48. Found: C, 55.42; H, 5.36; N, 1.60. *H NMR (400 MHz, C 6 D 6 ) : SiMe2, 0.20 (s), 0.31 (s); PCH 2 Si, 2.10 (dt, J g e m = 13.3 Hz, J a p p = 6.6 Hz); r | l - C H 2 P P h 2 , 1.48 (br); PPh 2 , 7.15 (m, para/meta), 7.79 , 8.00 (m, 184 ortho); I r -H , -6.50 (td, 2 J P ) H = 18.0 Hz, 3 j P H = 9.0 Hz). 31 P{1H} N M R ( C 6 D 6 ) : S i C H 2 P P h 2 , 5.84 (d, 3 j p p = 11.9 Hz); I r C H 2 P P h 2 , 10.51 (t, 3 j p p = H .6 Hz). 13c{lH} N M R ( C 6 D 6 ) : S iMe 2 , 2.81 (s), 3.22 (s); P C H 2 S i , 32.15 (m); I r -CO, 179.88 (dt, 2 J P , c = 11.0 Hz, 3 j P C = 5.9 Hz); PPh 2 , 124-138 (m). IR (toluene): v ( C o ) = 1961 cm" 1 (vs), V(ir-H) = 2095 cm ' 1 (m). 7.2.13 / a c - I r ( C H 3 ) ( r i 2 - C H 2 P P h 2 ) [ N ( S i M e 2 C H 2 P P h 2 ) 2 ] This complex was prepared by adding a toluene solution of L i C H 2 P P h 2 ' T M E D A (40 mg, 0.13 mmol) to the toluene solution (10 mL) of Ir(CH3)I[N(SiMe2CH 2PPh 2)2], 1, (100 mg, 0.11 mmol) at room temperature. The reaction took about an hour to go to completion as the green colour of 1 changed to yellow. The excess solvent was removed in vacuo. The residue was dissolved in toluene (1 mL) and filtered through Celite in order to remove L i l . Several attempts were made to isolate the product, but decompositon resulted over 24 hours as the solution was left for recrystallisation at room temperature under a N2 atmosphere. JH N M R (300 MHz, C 6 D 6 ) : S iMe 2 , -0.50 (s), 0.11 (s), 0.39 (s), 0.51 (s); P C H 2 S i , 2.62 (m), 2.41 (m), 2.10 (m), 1.65 (m); I r - C H 3 , 1.89 (br); PPh 2 , 6.54-7.24 (m, paralmeta), 8.12 (m, ortho). 3lp{lH} N M R ( C 6 D 6 ) : C H 2 P P h 2 , 2.11 ( 2J P A,PX = 35.2 Hz, 2 J P M (PX = 5.1 Hz); C H 2 P P h 2 , 8.59 ( 2 J P A,PM = 326.3 Hz, 2 J P M,PX = 6.0 Hz); r | 2 - C H 2 P P h 2 , -51.23 ( 2J P A,PM = 337.8 Hz, 2 J P A > P X = 36.4 Hz). 7.2.14 I r ( C H 3 ) P P h 2 { C 2 ( C 0 2 M e ) 2 } [ N ( S i M e 2 C H 2 P P h 2 ) 2 ] , 12 A toluene solution (10 mL) of I r (CH 3 )PPri2 [N(SiMe2CH 2 PPh 2 ) 2 ] , 2a, (250 mg, 0.27 mmol) was added to a reactor bomb equipped with a 5 mm Kontes needle valve. The assembly was attached to a vacuum line and cooled to -78°C (dry ice/ethanol). To it was added a toluene solution (1 mL) of D M A D (40 mg, 0.29 mmol) The reaction was instantaneous as the original dark purple colour of the phosphide 185 complex turned burgundy. The reaction mixture was warmed tq room teperature and stirred for an hour. The solvent was removed in vacuo and the resultant powder was recrystallised from hexanes/toluene solution (1 mL) at room temperature. Yield: 82%. Anal. Calcd. for C49H 55N04P3Si 2Ir: C, 55.35; H , 5.21; N, 1.32. Found: C, 55.22; H , 5.37; N , 1.11. *H N M R (400 MHz, C 6 D 6 ) : S iMe 2 , 0.54 (s), 0.71 (s), 0.78 (s), 0.90 (s); P C H 2 S i , 1.78 (t, J g e m = 13.3 Hz), 1.87 (t, J g e m = 11.7 Hz), 2.14 (m), 2.72 (m); I r - C H 3 , 0.22 (four line pattren, 3 j p > H = 4.0 Hz); O C H 3 , 2.92 (s), 3.05 (s); PPh 2 , 7.20 (m, paralmeta), 8.20, 8.45 (m, ortho). 3 l P { l H ) N M R ( C 6 D 6 ) : C H 2 P P h 2 , 41.25 ( 2 J P A , P M = 398.3 Hz, 2 J P A , P X = 6.1 Hz); C H 2 P P h 2 , -17.65 ( 2 J P A , P M = 389.3 Hz, 2 J P M , P X = 14.6 Hz); PPh, 26.85 ( 2 J P A , P X = 4.8 Hz, 2 J P M , P X = 7.3 Hz). 13 C { lH} N M R ( C 6 D 6 ) : S iMe 2 , 5.38 (s), 5.62 (s), 5.82 (s), 8.89 (s); P C H 2 S i , 22.57 (d, l J P i C = 19.2 Hz), 21.30 (d, ijp.c = 12.4 Hz); I r - C H 3 , -17.89 (4 line pattern, 2 J P > C = 7.3 Hz); O C H 3 , 51.13 (s), 51.82 (s); PPh 2 , 126-134 (m). IR (KBr): v ( C 0 ) = 1711.7 (s) and 1746.9 cm" 1 (s). 7.2.15 I r ( C H 3 ) P M e 2 { C 2 ( C 0 2 M e ) 2 } [ N ( S i M e 2 C H 2 P P h 2 ) 2 L 13 A toluene solution (10 mL) of I r ( C H 3 ) P M e 2 [ N ( S i M e 2 C H 2 P P h 2 ) 2 ] , 2c, (100 mg, 0.12 mmol) was prepared at -30°C. To it was added a toluene solution (1 mL, -30°C) of D M A D (20 mg, 0.14 mmol). The reaction was instantaneous as the dark purple-coloured solution turned burgundy. The reaction mixture was warmed to room temperature and stirred for an hour. The solvent was removed in vacuo and the resultant powder was recrystallised from hexanes/toluene (1 mL). Yield: 75%. Anal. Calcd. for C 3 9 H 5 i N 0 4 P 3 S i 2 I r : C, 49.88; H, 5.47; N , 1.49. Found: C, 50.10; H , 5.67; N , 1.21. 1H N M R (300 M H z , C 6 D 6 ) : S iMe 2 , 0.30 (s), 0.61 (s); P C H 2 S i , 2.10 (dt, J g e m = 15.6 Hz, J a p p = 7.1 Hz), 2.38; I r - C H 3 , 0.08 (t, 3 j P H = 4.7 Hz); O C H 3 , 3.27 (s), 3.88 (s); P M e 2 , 1.19 (d, 2 J P , H = 9.5 Hz); PPh 2 , 7.15 (m, paralmeta), 7.66, 7.85 (m, ortho). 3!p{lH} N M R ( C 6 D 6 ) : C H 2 P P h 2 , 2.99 ( 2 J P ) P = 23.8 Hz); P M e 2 , -106.70 186 ( 2 j p P = 23.5 Hz). 13c{lH} N M R ( C 6 D 6 ) : S iMe 2 , 5.96 (s), 7.96 (s); P C H 2 S i , 20.38 (d, ^p.C = 26.1 Hz), 20.64 (d, ijp.c = 19.0 Hz); I r - C H 3 , -15.37 (4 line pattern, 2 J P ) C = 7.0 Hz); O C H 3 , 50.25 (s), 50.84 (s); PPh 2 , 125-132 (m). 7.2.16 I r (CH 3 ) I{C2(C02Me)2}[N (S iMe2CH 2 PPh2)2] , 14 To a rapidly stirred solution of I r (CH 3 ) I [N (SiMe2CH 2 PPh 2 ) 2 ] , 1, (200 mg, 0.25 mmol) in toluene (10 mL) was added a toluene solution (1 mL) of D M A D (35 mg, 0.25 mmol) at -30°C. An instantaneous reaction occured as the green colour of the starting material changed to burgundy due to the formation of 14. The solution was stirred for an hour at room temperature, and then the solvent was removed in vacuo. The resultant oil was crystallised from toluene. Yield: 90%. Anal. Calcd. for C 3 7 H 4 5 N 0 4 P 3 S i 2 I I r : C, 44.22; H, 4.51; N , 1.39. Found: C, 44.17; H , 4.53; N , 1.26. *H N M R (400 M H z , C 6 D 6 ) : S iMe 2 , 0.39 (s), 0.46 (s), 0.62 (s), 0.85 (s); P C H 2 S i , 1.60 (t, obscured by the I r -CH 3 peak), 1.76 (t, J g C m = 8.8 Hz), 1.93 (m); I r - C H 3 , 1.65 (t, 3Jp,H = 3.8 Hz); O C H 3 , 3.39 (s), 3.65 (s); PPh 2 , 6.90 (m, paralmeta), 7.95, 8.05, 8.17 (m, ortho). 31p{lH} N M R ( C 6 D 6 ) : C H 2 P P h 2 , 42.34 (d, 2 J P > P = 11.0 Hz), -20.56 (d, 2 J p p = 7.4 Hz). l3c{lH] N M R ( C 6 D 6 ) : S iMe 2 , 0.18 (s), 0.36 (s), 0.99 (s), 1.25 (s); P C H 2 S i , 14.99 (s), 15.26 (s); I r - C H 3 , -15.15 ( t , 2 J P t C = 7.5 Hz); O C H 3 , 50.45 (s), 52.04 (s); PPh 2 , 126-132 (m). IR(KBr): v ( C 0 ) = 1676.8 (m) and 1732.8 cm" 1 (m). 7.2.17 Ir(PhC=CPh)[N(SiMe 2 CH 2 PPh2)2], 15 A toluene solution (2 mL) of PhC=CPh (50 mg, 0.28 mmol) was added dropwise to the toluene solution (10 mL) of I r (CH 3 )PPh2[N(SiMe2CH2PPh2) 2 ] , 2a, (250 mg, 0.27 mmol). The purple colour of 2a changed to orange over 10 min. After the solution was stirred for an hour, the excess solvent was removed in vacuo. Orange crystals of I r ( P h C = C P h ) [ N ( S i M e 2 C H 2 P P h 2 ) 2 ] , 15, were isolated from 187 hexanes (1 mL). Yield: 75%. Anal. Calcd. for C44H46NP2Si2Ir: C, 58.77; H, 5.16; N, 1.56. Found: C, 59.00; H, 5.16; N , 1.70. The NMR characterisation of 15 is described elsewhere.7 7.2.18 I r (CH 3 )PHPh 2 (C=CR)[N(S iMe 2 CH 2 PPh 2 ) 2 ] , 16-18 (R = H , Ph, *Bu): General Procedure A toluene solution (10 mL) of the phosphide complex Ir(CH 3)PPh 2-[N(SiMe2CH2PPh2)2L 2a, was loaded in a reaction bomb equipped with a 5 mm Kontes needle valve. The assembly was connected to a vacuum line and the solution degassed. In the case of HC=CH, excess alkyne was condensed in the vessel at -78°C (dry ice/ethanol). However, when PhC^CH or lBuC=CH were reacted with 2a, the exact amounts of the alkynes dissolved in toluene (1 mL) were syringed into the reaction vessel. Many attempts were made to isolate these complexes, but decomposition resulted as the solutions were left for crystallisation under an inert atmosphere. 7.2.18.1 Ir(CH 3)PHPh 2(C=CH)[N(SiMe 2CH 2PPh 2) 2], 16 Ir(CH 3)PPh 2[N(SiMe 2CH 2PPh 2) 2], 2a, (100 mg, 0.11 mmol). *H NMR (300 MHz, C 6 D 6 ) : SiMe 2, 0.70 (s), 0.85 (s); PCH 2 Si, 2.21 (dt), 2.45 (dt, J g e r n = 12.3 Hz, J a p p = 7.1 Hz); Ir-CH 3 , -0.10 (four line pattern, 3 j p H = 3.8 Hz); C=CH, 2.10 (s); PHPh 2, 5.01 (dt, lJp > H = 300.1 Hz, 3 j P H = 9 . 5 Hz); PPh2, 6.90 (m,para/meta), 7.95, 8.17 (m, ortho). 3 1 P( 1 H} NMR (C 6 D 6 ) : PPh2, -2.32 (d, 2 J P , P = 15.9 Hz); PHPh2, -21.45 (t, 2 J P ) P =17.8 Hz). 188 7.2.18.2 Ir(CH 3 )PHPh2 (C=CPh)[N(SiMe2CH 2 PPh2)2], 17 Ir(CH3)PPh 2 [N(SiMe2CH 2 PPh2) 2 ] , 2a, (75 mg, 0.08 mmol). P h O C H (10 mg, 0.08 mmol). *H NMR (300 MHz, C 6 D 6 ) : SiMe 2 , 0.56 (s), 0.81 (s); PCH 2 Si , 2.00 (dt), 2.21 (dt, J g e m = 12.1 Hz, J a p p = 6.5 Hz); Ir-CH3, 0.05 (four line pattern, 3 J P < H = 3.0 Hz); PHPh 2 , 5.08 (dt, lJP,H = 310.6 Hz, 3 J P > H = 8.7 Hz); PPh 2 , 6.98 (m, para/meta), 7.65, 8.10 (m, ortho). 3 1 P{ 1 H) NMR (C 6 D 6 ): PPh 2, -2.58 (d, 2 J P ) P = 16.3 Hz); PHPh.2, -23.35 (t, 2 J P ( P =18.1 Hz). 7.2.18.3 Ir (CH 3 )PHPh 2 (C=C t Bu)[N(SiMe2CH 2 PPh2) 2 ] , 18 I r (CH3)PPh 2 [N(SiMe2CH 2 PPh2)2 ] . 2a, (75 mg, mmol). l B u O C H (10 mg, 0.13 mmol). *H NMR (300 MHz, C 6 D 6 ) : SiMe 2, 0.75 (s), 0.90 (s); PCH 2 Si, 2.20 (dt), 2.35 (dt, Jgem = 12.3 Hz, J a p p = 7.1 Hz); Ir-CH 3 , -0.09 (four line pattern, 3 J P > H = 3.8 Hz); O O B u , 1.72 (s); PHPh 2, 5.30 (dt, ! j P ) H = 360.0 Hz, 3 J P > H = 7.2 Hz); PPh2, 6.96 (m, para/meta), 7.91, 8.89 (m, ortho). 3 1 P { ] H ) NMR (C 6 D 6 ) : PPh 2, -3.01 (d, 2 J P , P = 16.5 Hz); PHPh 2, -22.08 (t, 2 J P ) P = 17.9 Hz). 7.2.19 Ir=CH 2[N(SiMe 2CH 2PPh 2)2], 10 To a stirred toluene solution (10 mL) of I r(CH3 ) I [N(SiMe2CH 2 PPh2)2 ] , 1 (250 mg, 0.29 mmol) was added KO lBu (160 mg, 1.4 mmol). The reaction proceeded over two hours as the green-coloured solution of 1 turned purple due to the formation of 10. The reaction mixture was filtered through Celite and pumped to dryness under vacuum. The residue was dissolved in hexanes (2 mL) and recrystallised at -30°C. Yield: 60%. Spectroscopic characterisation of this complex is described elsewhere.8 189 7.2.20 /ac- I r (Ti2 -CH 2 NHtBu)H[N(SiMe 2 CH 2 PPh 2 ) 2 ] , 19 A solution of Ir=CH2[N(SiMe2CH2PPh2)2], 10, (25 mg, 0.03 mmol) in toluene (10 mL) was cooled to -78°C in a dry ice/ethanol bath for 15 min. To it was added a toluene solution (1 mL) of l BuNH 2 (10 mg, 0.09 mmol). The reaction mixture was warmed to room temperature and stirred for two hours. During this time, the initial purple colour of 10 turned light yellow. The solvent was pumped off under vacuum, and the resultant yellow oil was crystallised from hexanes/toluene mixture (1/2 mL) at room temperature. Yield: 75%. Because this study is in its preliminary stages, the product has been characterised only by *H and 3 1P{1H} NMR spectroscopy. lH NMR (300 MHz, C 6 D 6 ) : SiMe2, -0.20 (s), 0.00 (s), 0.33 (s), 0.47 (s); PCH 2Si, 1.40 (m), 2.05 (m); r| 2-C// 2NHtBu, 1.62 (t, 3 j p > H = 3.8 Hz), 2.60 (br); CH 2N//tBu, 2.79 (br); CH 2NHt5u, 0.60 (s), PPh2, 6.30-7.10 (m, para/meta), 7.75 (m, ortho); Ir-H, -20.85 (dd, 2 j P t H (cis) = 19.5 Hz, 2 J P H { c i s ) = 9.6 Hz). 31 P {1 H } NMR (C 6 D 6 ) : PPh2, 10.83 (d, 2 j P P = 27.9 Hz), 5.03 (d, 2 j p p = 19.2 Hz) 7.2.21 Ir(HL-AIMe2)H[N(SiMe 2CH2PPh2)2], 20 A toluene solution (1 mL) of AlMe3 (100 (il, 0.20 mmol) was added dropwise to the cooled toluene solution (10 mL, -78°C) of Ir=CH 2[N(SiMe 2CH 2PPh 2) 2], 10, (100 mg, 0.14 mmol). The reaction was instantaneous as the purple colour of 10 changed to orange. The reaction mixture was warmed to room temperature and stirred for an hour. The removal of excess solvent from the reaction mixture afforded a yellow oil which was crystallised from minimum hexanes (1/2 mL) at -30°C. Yield: 70%. Anal. Calcd. for C32H42NAlP2Si2lr: C, 49.34; H, 5.56; N, 1.80. Found: C, 49.20; H, 5.72; N, 1.69. ] H NMR (300 MHz, C 6 D 6 ) : SiMe 2 , 0.00 (s), 0.31 (s); PCH 2 Si , 2.47 (br, m), 2.65 (br, m); AlMe 2, 0.78 (s); PPh2, 7.40 (m, para/meta), 8.15 (br), 8.50 (m, ortho); Ir-H, -13.47 (t, 2 J P H = 16.3 Hz). 31p{lH) NMR (C 6D 6): PPh2, 31.20 (s). 190 13C{1H} N M R ( C 6 D 6 ) : S iMe 2 , 4.07 (s), 5.55 (s); P C H 2 S i , 24.46 (t, Ucp = 6.8 Hz); A 1 - ( C H 3 ) 2 , -3.66 (s); PPh 2 , 128-140 (m). 7.2.22 Ir(Ti2-C2H4)H(I)[N(SiMe2CH2PPh2)2], 21 This species was prepared by vacuum transfering excess M e l (~ 5 equivalents, -10'C) to the toluene solution (10 mL) of Ir=CH 2[N(SiMe2CH2PPh 2)2], 10, (50 mg, 0.07 mmol). The reaction mixture was warmed up slowly from -78°C to room temperature. Within 10 min, the purple solution turned green and then faded to light yellow. Excess M e l and the solvent were pumped off immediately under vacuum to avoid the production of the side product Ir(CH3)(I)2[HN(SiMe2CH2PPh2)2l (see Chapter 4, Section 4.3.1.2). The yellow residue was recrystallised from hexanes/toluene (1/2 mL) at room temperature. Yield: 70%. Anal. Calcd. for C32H45NP 2SiIIr: C, 43.83; H, 5.17; N , 1.60. Found: C, 43.80; H, 5.11; N, 1.40. J H N M R (300 M H z , C 6 D 6 ) : S iMe 2 , -0.65 (s), 0.51 (s); P C H 2 S i , 1.55 (dt, J g e m = 14.6 Hz, J a p p = 6.6 Hz), 2.88 (dt); C 2 H 4 , 2.56 (t, 3 J P > H = 3.6 Hz); P P h 2 , 7.00 (m, paralmeta), 7.25, 7.85 (m, ortho); Ir-H, -13.14 (t, 2 J P ) H = 8.7 Hz). 3 1 P { 1 H ) N M R ( C 6 D 6 ) : PPh 2 , 6.01 (s). 7.2.23 Ir(ri3-C3H5)(C=CH)[N(SiMe2CH2PPh2)2],22 Excess H C ^ C H (~ 5 equivalents) was condensed (at -196°C, liq. N 2 ) into a reaction vessel containing 10 mL toluene solution of Ir=CH2[N(SiMe2CH2PPh2)2L 10, (50 mg, 0.07 mmol). The reaction proceeded over two hours at room temperature with a gradual colour change from purple to pale yellow. The excess solvent was pumped off under vacuum and the resultant yellow residue was recrystallised from toluene at room temperature. Yield: 85%. Anal. Calcd. for C35H4 2NP 2Si 2Ir: C, 53.41; H , 5.38; N , 1.78. Found: C, 53.30; H , 5.51; N , 1.65. *H N M R (300 M H z , C 6 D 6 ) : S i M e 2 , 0.07 (s), 0.25 (s); P C H 2 S i , 1.60 (m); C=CH, 2.30 (s); r ]3 -C 3 H 5 : H s y n = 3.20 191 (3Jp,H = 8.3 Hz, JHsyn.Hcentral = 5.2 Hz), H a n t i = 3.95 (d, JHanti.Hcental = 9.3 Hz), Hcentral = 4.28 (m); PPh2, 7.00 (m, para/meta), 7.74, 8.38 (m, ortho). 3lp{lH} NMR (C 6 D 6 ): PPh2, -15.2 (s). SiMe2, 6.10 (s), 7.02 (s); PCH 2Si, 25.25 (d, l J P > c = 21.0 Hz); Ti3-C 3 H 5 : C(apical) = 53.61 (s), 54.2 (s), Central) = 110.34 (s); O C H : cx-carbon = 90.15 (s), fj-carbon = 140.02 (s); PPh2, 128-140 (m). 7.2.24 Ir(a-ri3.C5H 8)[N(SiMe 2CH 2PPh 2) 2], 23 Ir=CH 2[N(SiMe 2CH 2PPh 2)2], 10, (100 mg, 0.14 mmol) was dissolved in toluene (10 mL) and loaded into a reactor bomb. An excess of 1,3-butadiene was condensed at -196"C into the reaction vessel and the' reaction mixture warmed gradually to room temperature. Over a one hour period, the purple colour of the reaction mixture changed to light yellow. The excess solvent and 1,3-butadiene were removed in vacuo. The yellow residue was recrystallised from hexanes/toluene solution (1 mL) at room temperature. Yield: 82%. Anal. Calcd. for C35H44NP2Si2Ir: C, 53.28; H.5.62; N, 1.77. Found: C, 53.70; H, 5.73; N, 1.84. J H NMR (300 MHz, C 6 D 6 ) : SiMe2, 0.32 (s), 0.35 (s), 0.38 (s), 0.53 (s); PCH 2Si, 1.98, 2.17 (m); PPh2, 6.70-7.82 (m). 31p{lH) NMR (C 6D 6): PPh2, -4.87 (d, 2 j P P = 7.3 Hz), -7.81 (d, 2 j p p = 6.8 Hz). 13c{lH} NMR (C 6 D 6 ) : SiMe2, 5.23 (s), 5.36 (s), 5.92 (s), 9.04 (s); PCH 2 Si, 24.26 (d, ^p.c = 16.4 Hz), 30.10 (d, = 22.3 Hz); a-T^-CsHg ligand (starting from the o side): CI = 44.16 (d, 2 J C P = 35.1 Hz), C2 = 108.35 (s), C3 = 54.90 (d,2j C P = 23.5 Hz), C4 = 28.01 (s), C5 = -37.29 (s); PPh2, 127-133 (m). 7.2.25 /ac-Ir{Ti4-C(CH2)3}[N(SiMe2CH2PPh2)2], 24 An excess of allene was condensed into a toluene solution (5 mL) of Ir=CH2[N(SiMe2CH2PPh2)2], 10, (100 mg, 0.14 mmol). At -78°C, the purple colour of the methylidene complex faded to light yellow over an hour. At which time, the solution was warmed to room temperatutre. The toluene and excess allene were 192 removed in vacuo. The off-white residue was recrystallised from hexanes/toluene at room temperature. Y i e l d : 75%. Anal. Calcd. for C34H42NP2Si2lr: C, 52.69; H, 5.46; N, 1.81. Found: C, 52.90; H, 5.67; N, 1.71. lH N M R (300 MHz, Q 3 D 6 ) : SiMe 2, 0.36 (s), 0.63 (s); PCH 2 Si, 1.80, 2.10 (m); C(CH 2)3, 1.54 (m), 1.45 (m), 2.38 (m); P P h 2 , 6.70-7.82 (m). 3 1 P { 1 H } NMR (C 6 D 6 ) : P P h 2 , 0.45 (s). ^ C p H } NMR (C 6 D 6 ) : S i M e 2 , 5.35 (s), 6.18 (s); P C H 2 S i , 24.13 (m); T t 4 - C ( C H 2 ) 3 : C H 2 = 31.89 (d, 2 J c , p = 4.2 Hz), 47.64 (d, 2 J c , p = 44.3 Hz) , C = 101.00 (s); P P h 2 , 126-134 (m). 7.2.26 Ir(Ti3 .C8Hi3)H[N(SiMe2CH 2 PPh2)2], 27 A benzene solution (5 mL) of Ir(r i 2 -C8H 14)[N(SiMe2CH 2 PPh2)2] , 25, (100 mg, 0.12 mmol) was sealed under N2 in a reactor bomb. The sample was photolysed using 140 W H g lamp for six hours. During this time, the orange-coloured solution of 25 darkened to red. The solvent was removed under vacuum and the resultant red powder was recrystallised from hexanes (1 mL) at -30°C. Y i e l d : 75%. Anal. Calcd. for C3 8H 5 0NP2Si2lr: C, 54.94; H, 6.02; N, 1.69. Found: C, 55.47; H, 6.28; N, 1.60. *H N M R (300 M H z , C 6 D 6 ) : SiMe 2, 0.47 (s), 0.65 (s); P C H 2 S i , 1.80 (m); T [ 3 - C 8 H i 3 (non allylic protons), 1.25 (br m), 2.15 (br m), T ^ - C g H n (allylic protons), 4.08 ( H s y n , m), 4.56 (Hcentral, 2 J H , H = 7.6 Hz) ; P P h 2 , 6.60-8.00 (m); I r -H, -21.65 (t, 2 J P > H = 16.7 Hz). 3 l p { l H ) N M R (C6D 6): P P h 2 , 4.77 (s). ^CpH} N M R (C 6 D 6 ) : SiMe 2 , 6.95 (s), 8.49 (s); PCH 2 Si, 23.58 (d, l J P , C = 17.9 Hz); T l 3 - C 8 H i 3 : C ( i nner C of the allyl unit) = 102.80 (s), C(outer carbons of the allyl unit) = 37.42 (s), 57.20 (s), C(fi v e octenyl ring carbons) = 37.42 (s), 29.18 (s), 28.34 (s), 26.62 (s), 24.92 (s); P P h 2 , 126-140 (m). 7.2.27 I r ( r i 4 -C 4 H 6 ) [N(SiMe2CH 2 PPh2)2 ] ,28 A solution of Ir(Ti2-C 8Hi4)[N(SiMe2CH2PPh2)2], 25, (100 mg, 0.12 mmol) in toluene (10 mL) was loaded in a reactor bomb. The vessel was attached to a vacuum line, degassed and cooled to l iquid N2 temperature. Excess 1,3-butadiene was 193 condensed in the bomb. The reaction mixture was stirred for one hour at room temperature. Toluene was removed in vacuo and the residue recrystallised from hexanes/toluene at room temperature. Yield: 95%. Anal. Calcd. for C34H42NP2Si2lr: C, 52.70; H, 5.51; N, 1.81. Found: C, 53.27; H , 5.50; N , 1.60. lH N M R (300 MHz, C 6 D 6 ) : S i M e 2 , 0.40 (s), 0.45 (s), 0.50 (s), 0.55 (s); P C H 2 S i , 1.85, 2.12 (m); T i 4 -C 4 H 6 , -0.60 (m, H a i lti), -0.20 (m, H a n t i ) 2.07 (m, H s y n ) , 2.61 (m, H s y n ) , 4.00 (m, Hcentral), 5.37 (m, Hcentral); PPh2, 7.30 (m, paralmeta), 7.90 (m, ortho). 31p{lH) N M R ( C 6 D 6 ) : PPh 2 , 17.82 (s), -5.90 (s). ^Cf^H} N M R ( C 6 D 6 ) : S iMe 2 , 4.40 (d, 3Jp,C = 9.7 Hz), 6.60 (s), 8.40 (s); P C H 2 S i , 23.39 (d, Up.c = 15.2 Hz), 27.85 (d, l J P t C = 18.8 Hz); C i , 14.44 (s), C 2 , 88.93 (d, 2 J P ) C = 2.3 Hz), C 3 , 82.27 (d, 2 J P , C = 6.3 Hz), C 4 , 33.75 (dd, 2 J P , C = 41.6 Hz, 2 J P i C = 3.3 Hz); PPh 2 , 126-135 (m). 7.2.28 I r ( r | 2 . C 3H4 ) [ N ( S i M e 2 C H 2 P P h 2 ) 2 ] , 29 An excess of allene was condensed at -78°C into a reactor vessel containing a toluene solution (10 mL) of Ir(ri 2 -C8Hi 4 )[N(SiMe2CH 2 PPh 2 )2], 25, (50 mg, 0.06 mmol). The reaction mixture was warmed to room temperature and stirred for 15 minutes. During this time, the orange colour of 25 changed to yellow due to the formation of 29. The solvent and allene were pumped off under vacuum. The yellow residue was recrystallised from hexanes at -30°C. Yield: 80%. Anal. Calcd. for C 3 3 H 4 0 N P 2 S i 2 I r : C, 52.08; H , 5.30; N , 1.84. Found: C, 52.07; H , 5.54; N, 1.70. *H N M R (300 M H z , C 6 D 6 ) : S iMe 2 , 0.12 (s), 0.25 (s); P C H 2 S i , 1.79 (m); Ti4-C3H4, 1.12 (m), 5.21 (m), 5.44 (m); PPh 2 , 7.10 (m, paralmeta), 7.78, 7.82 (m, ortho). 31p{lH} N M R ( C 6 D 6 ) : PPh 2 , 20.56 (s). ^ C ^ H } N M R ( C 6 D 6 ) : S iMe 2 , 4.79 (s), 5.08 (s); P C H 2 S i , 23.41 (t, 1 J P > C = 15.5 Hz); Ti 2 -C 3 H4: C H 2 (c-bound) = -3.82 (s), C H 2 = 92.30 (s), C = 101.00 (s); PPh 2 , 125-137 (m). 194 i. 7.2.29 I r ( u , - A I M e 2 ) M e [ N ( S i M e 2 C H 2 P P h 2 ) 2 ] , 30 A toluene solution (1 mL) of A l M e 3 (75 ul, 0.15 mmol) was added dropwise to the toluene solution (10 mL) of Ir(Ti2-C8Hi4)[N(SiMe2CH2PPh2)2], 25, (100 mg, 0.12 mmol). The reaction proceeded over an hour as the orange colour of 25 changed to red. The removal of excess solvent from the reaction mixture afforded red oil . Because this study is in its preliminary stages, the crude product has been characterised only by *H and 3 1 P { 1 H } N M R spectroscopy. *H N M R (300 M H z , C 6 D 6 ) : S iMe 2 , -0.07 (s), 0.05 (s); P C H 2 S i , 1.75 (br, m), 2.40 (br, m); A l M e 2 , 0.48 (s); I r - C H 3 , 0.76 (t, 3 J P > H = 3.1 Hz); PPh 2 , 7.10 (m, paralmeta), 7.90 (m, ortho). 3 1 P { l H } N M R (C 6 D 6 ) : PPh 2 , 23.39 (s). 7.2.30 R h ( ^ - A l M e 2 ) M e [ N ( S i M e 2 C H 2 P P h 2 ) 2 ] , 31 The same procedure was followed as reported above for the synthesis of the iridium analogue, 30. The reaction was instantaneous. Addition of a toluene solution (1 mL) of A l M e 3 (50 u.1, 0.10 mmol) to the toluene solution (10 mL) of the rhodium(I) cyclooctene derivative Rh(r) 2 -C8H 1 4 )[N(SiMe2CH 2 PPh2)2] (50 mg, 0.07 mmol) afforded complex 31. The complex 31 has been characterised only by *H and 3 1 P{ ] H} N M R spectroscopy, because this investigation is in early stages. ! H N M R (300 MHz, C 6 D 6 ) : S iMe 2 , -0.05 (s), 0.06 (s); P C H 2 S i , 1.72 (br, m), 2.45 (br, m); A l M e 2 , 0.50 (s); R h - C H 3 , 0.78 (t, 3 J P ) H = 3.2 Hz); PPh 2 , 7.10 (m, paralmeta), 7.90 (m, ortho). 3 lP{ lH) N M R (C 6 D 6 ): PPh 2 , 26.06 (d, lJRh<? = 145.9 Hz). 195 7.3 Kinetic Experiments 7.3.1 Thermolysis Experiments The details for the kinetic procedures are given in chapter 2. In a typical experiment, a stock solution of known concentration was prepared in an appropriate solvent and stored at -30"C in the glove box. 5 mL aliquots of the solution were placed in a solvent reservoir fused to an anaerobic 1 cm optical cell. During the thermolysis of the light-sensitive phosphide complexes, aluminum foil was wrapped around the vessel. The sample was thermolysed in a temperature-controlled oil bath. As mentioned in chapter 2, the disappearence (or appearence in some cases) of the appropriate absorption band was followed with time using a Perkin Elmer 5523 UV/Vi s spectrophotometer stabilised at 20°C. Treatment of the data is also described in chapter 2. 7.3.2 Carbonylation Experiment A toluene solution of 6a of exact concentration (see Appendix A2) was prepared in the glove box and loaded into a solvent reservoir fused to an anaerobic 1 cm optical cell. The vessel was attached to a vacuum line and degassed once. Then the solution was exposed to CO gas (1 atm). The absorbance of the solution at 360 nm was recorded using a Perkin Elmer 5523 UV/Vi s spectrophotometer stabilised at 20°C. The sample was thermolysed at 46°C in a temperature-controlled oil bath, and the disappearence of the absorption band at 360 nm was followed with time. The data for this run are compiled in Appendix A2. 196 7.4 References 1 (a) Parshall, G. W. Inorg. Synth. 1968,11, 157. (b) Sollot, G. P.; Snead, J. L . Strecker, R. A . / . Am. Chem. Soc. 1973, 95, 210. 2 Issleib, K. ; Kummel, R. J. Organomet. Chem. 1965,3, 84. 3 King, R. B.; Eisch, J. J. (Eds.) Organometallic Syntheses vol. 3; Elsevier: Amsterdam, 1986. 4 Most of the techniques used in this work are described in: Wayda, A . L. ; Darensbourg, M . Y . (Eds.) ACS Symp. Ser. vol. 357; Experimental Organometallic Chemistry; American Chemical Society, Washington, D. C; 1987. 5 Van der Ent, A. ; Onderlinden, A . L . Inorg. Synth. 1973,14, 93. 6 (a) Fryzuk, M . D.; MacNeil, P. A. ; Rettig, S. J. Organometallics 1986, 5, 2469. (b) Fryzuk, M . D.; Joshi, K. Organometallics 1989, 8, 1722. 7 Block, G. B. Sc. Thesis, University of British Columbia, Vancouver, Canada, 1986. 8 Fryzuk, M . D.; MacNeil, P. A. ; Rettig, S. J. J. Am. Chem. Soc. 1985,107, 6709. 197 A P P E N D I X A l X-ray Crystallographic Analyses A l . l X-ray Crystallographic Analysis of I r (CH 3 )PPh2[N(S iMe 2 CH 2 PPh2)2 ] , 2a Experimental Details E m p i r i c a l F o r m u l a F o r m u l a W e i g h t C r y s t a l S y s t e m L a t t i c e P a r a m e t e r s : Space G r o u p 2 v a l u e D c a l c F000 mu(Mo K - a l p h a ) D i f f r a c t o m e t e r R a d i a t i o n T e m p e r a t u r e 2 - t h e t a ( m a x ) No . O b s e r v a t i o n s (I>3 . 0 0 ( s i g ( I ) ) ) No . V a r i a b l e s R e s i d u a l s : R; Rw Goodness o f F i t I n d i c a t o r Maximum S h i f t i n F i n a l C y c l e L a r g e s t Peak i n F i n a l D i f f . Map C ( 4 3 ) H ( 4 9 ) I r ( l ) N ( l ) P ( 3 ) S i ( 2 ) 921.16 M o n o c l i n i c a • 13.506 (3) a n g s t r o m s b - 13.665 (3) a n g s t r o m s c « 22.816 -(7) a n g s t r o m s b e t a - 92.35 (2) d e g r e e s V - 4207 (2) angs troms**3 P21 / c (#14) 4 1.45 g/cm**3 1856 33.59 c m * * - l R i g a k u AFC6 Mo K - a l p h a ( lambda= 0.71069) G r a p h i t e - m o n o c h r o m a t e d 21 d e g r e e s C e n t . 55.0 d e g r e e s 3993 451 0.034; 0.037 1.13 0.05 1.25 e / angs trom**3 198 Table Al.1.1 Bond Lengths (A) with estimated standard deviations in parentheses atom atom d i s t a n c e I r C(43) 2 .126(9) I r N 2 .126(6) I r P (3) 2 .297(2) i r P d ) 2 .309(2) i r P (2) 2 .312(2) P d ) C ( l ) 1 .808(9) P ( l ) C(7) 1 .831(8) P ( l ) C(13) 1 .84(1) P(2) C(2) ,1 .807(9) P(2) C(25) 1 .818(8) P(2) C(19) 1 .824(9) atom atom d i s t a n c e P(3) C(31) 1 .80(1) P(3) C(37) 1 .834(9) S i d ) N 1 .714(7) S i ( l ) C(3) 1 .86(1) S i d ) C(4) 1 .89(1) S i d ) C d ) 1 .91(1) S i ( 2 ) N 1 .729(8) S i ( 2 ) C(6) 1 .85(1) S i ( 2 ) C(5) 1 .85(1) S i ( 2 ) C(2) 1 •87(1) 199 Table Al.l .2 Bond Angles fdeg) with estimated standard deviations in parentheses a t o m a t o m a t o m a n g l e a t o m a t o m a t o m a n g l e C(43) I r N 159.0(3) C(19) P(2) I r 112 .1(3) C(43) I r P(3) 87.4(2) C(31) P(3) C(37) 100 .3(4) C(43) I r P d ) 91.2(2) C(31) P(3) I r 108 .4(3) C(43) I r P(2) 90.3(2) C(37) P(3) I r 117 .7(3) N I r P(3) 113.2(2) N S i d ) C(3) 113 .6(5) N I r P d ) 87.4(2) N S i ( l ) C(4) 115 .6(4) N I r P(2) 86.5(2) N S i ( l ) C ( l ) 105 .9(4) P(3) I r P d ) 105.35(9) C(3) S i ( l ) C(4) 107 .8(5) P(3) I r P(2) 87.95(8) C(3) S i d ) C ( l ) 109 .1(5) P d ) I r P(2) 166.68(8) C(4) S i d ) C ( l ) 104 .3(5) C ( l ) P ( D C(7) 100.9(5) N S i ( 2 ) C(6) 114 .7(5) C ( l ) P d ) C d 3 ) 106.4(5) N S i ( 2 ) C(5). 113 .4(5) C ( l ) P d ) I r 108.8(3) N S i ( 2 ) C(2) 106 .0(4) C(7) P d ) . C U 3 ) 101.3(5) C(6) S i ( 2 ) C(5) 107 .0(6) C(7) P ( l ) I r 111.7(3) C(6) S i ( 2 ) C(2) 105 .2(5) C(13) P ( l ) I r 125.0(3) C(5) S i ( 2 ) C(2) 110 .2(5) C(2) P(2) C(25) 108.8(4) S i d ) N S i (2) 121 .8(4) C(2) P(2) C d 9 ) 104.2(4) S i d ) N I r 119 .2(4) C(2) P(2) I r 105.3(3) S i (2) N I r 118 .9(4) C(25) P(2) C(19) 101.9(4) P d ) C ( l ) S i d ) 106 .3(5) C(25) P(2) I r 123.1(3) P(2) C(2) S i ( 2 ) 107 .1(5) 200 Table Al .1.3 Final Atomic Coordinates (Tractionall and B(eq) atom X y z B ( e q ) l r 0, .28896(2) 0 .24657(3) 0 .17779(1) 2 .83(1) P ( l ) 0, .3295(1) 0 .2494(2) 0 .08048(3) 3 .38(8) P(2) 0 .2825(2) 0 .2239(1) 0 .2780(1) 3 .3(1) P(3) 0 .1359(2) 0 .3194(2) 0 .1802(1) 3 .5(1) S i d ) 0 .3123(2) 0 .0369(2) 0 .1063(1) 4 • 0(1) Si(2) 0 .2512(2) 0 .0239(2) 0 .2313(1) 4 .9(1) N 0 .2815(6) 0 .0916(4) 0 .1706(3) 4 .4(4) C( l ) 0 .2934(8) 0 .1342(7) 0 .0470(4) 4 .1(5) C(2) 0 .2099(7) 0 .1142(7) 0 .2868(4) 4 • 6(5) C( 3) 0 .4427(8) -0 .0072(8) 0 .1066(5) 6 .1(6) C(4 ) 0 .2292(7) -0 .0677(7) 0 .0806(5) 5 .9(6) C(5) 0 .356(1) -0 .0502(8) 0 .2624(5) 8 .3(8) C(6) 0 .145(1) -0 .0602(9) 0 .2190(6) 9 .2(9) C(7) 0 .4638(6) 0 .2464(8) 0 .0725(3) 3 .8(3) C(8) 0 .5025(8) 0 .2259(8) 0 .0181(4 ) 5 .5(6) C(9) 0 .604(1) 0 .2181(8) 0 .0130(5) 6 .4(6) C(l'O) 0 .6671(8) 0 .2293(8) 0 .0593(6) 6 .1(6) C ( l l ) 0 .6306(6) 0 .252(1) 0 .1128(4) 5 .5(4) C(12) 0 .5295(7) 0 .261(1) 0 .1186(4) 5 .2(5) C(13) 0 .2922(8) 0 .3455(7) 0 .0276(4) 4 .0(5) C(14) 0 .2059(8) 0 .3388(7) -0 .0070(4) 4 .9(5) C(15) 0 .1780(8) 0 .4136(8) -0 .0440(4) 5 • 1(5) C(16) 0 .237(1) 0 .4949(8) -0 .0471(5) 5 .8(6) C(17) 0 .3210(8) 0 .5042(7) -0 .0132(4) 4 .8(5) C(18) 0 .3496(8) 0 .4307(7) 0 .0247(4) 4 .8(5) C(19) 0 .4035(6) 0 .1934(6) 0 .3116(4) 3 .5(4) 201 Table (continued). atom X y z B (eq) C(20) 0 .4128(7) 0. 1625(7) 0. 3685(4) 4 .9(5) C(21) 0 .5021(8) 0. 1335(9) 0. 3933(5) 6 .1(6) C(22) 0 .5844(8) 0. 1367(8) 0 . 3612(6) 5 .9(6) C(23) 0 .5771(8) 0 . 167(1) 0 . 3038(6) 7 .1(7) C(24) 0 .4886(8) 0. 195(1) 0. 2801(5) 6 .8(6) C(25) 0 .2389(6) 0. 3172(6) 0. 3275(4) 3 .6(4) C(26) 0 .1445(8) 0. 3156(7) 0. 3484(4) 4 .9(5) C(27) 0 .1126(8) 0. 389(1) 0. 3849(5) 6 .2(6) C(28) 0 .173(1) 0. 463(1) 0. 3997(5) 7 .4(8) C(29) 0 .269(1) 0. 4663(8) 0. 3799(6) 6 .8(7) C(30) 0 .3001(7) 0. 3936(7) 0. 3431(5) 5 .0(5) C(31) 0 .0653(8) 0. 2859(7) 0. 1145(5) 4 .0(5) C(32) 0 .0643(8) 0. 1878(7) 0. 0965(5) 4 .2(5) C(33) 0 .0081(9) 0. 1533(8) 0. 0489(6) 5 .9(7) C(34) -0 .0494(9) 0. 2178(9) 0. 0157(5) 5 .6(6) C(35) -0 .0533(9) 0. 3153(9) 0. 0319(5) 6 .0(7) C(36) 0 .0026(8) 0. 3472(7 ) 0. 0803(5) 5 .0(6) C(37) 0 .1303(6) 0. 4532(6) 0. 1748(4 ) 3 .8(4) COB) 0 .1514(7) 0. 5102(7) 0. 1276(5) 4 .8(5) C(39) 0 .144(1) 0. 6119(8) 0. 1284(6) 6 .8(7) C(40) 0 .114(1) 0. 6572(8) 0. 1770(8) 8 .2(9) C(41) 0 .096(1) 0. 605(1) 0. 2255(7) 8 .3(9) C(42) 0 .1038(8) 0. 5016(8) 0. 2258(5) 5 .7(6) C(43) 0 .3513(6) 0. 3879(6) 0. 1917(4 ) 3 .4(4) 202 C a l c u l a t e d hydrogen atom parameters Atom x y H(l) 0.2237 0.1364 H(2) 0.3349 0.1200 H(3) 0.2211 0.0878 H(4) 0.1393 0.1288 H(5) 0.4537 -0.0550 H(6) 0.4552 -0.0382 H(7) 0.4879 0.0483 H(8) 0.1613 -0.0438 H(9) 0.2530 -0.0943 H(10) 0.2305 -0.1192 H ( l l ) 0.3347 -0.0843 H(12) 0.3756 -0.0982 H(13) 0.4117 -0.0072 H(14) 0.0672 -0.0231 H(15) 0.1621 -0.1102 H(16) 0.1297 -0.0919 H(17) 0.4579 0.2170 H(18) 0.6307 0.2042 H(19) 0.7386 0.2214 H(20) 0.6761 0.2612 H(21) 0.5044 0.2784 H(22) 0.1646 0.2801 H(23) 0.1165 0.4089 H(24) 0.2171 0.5476 H(25) 0.3615 0.5634 z B(iso) 0.0333 4.9 0.0138. " 4.9 0.3264 5.5 0.2800 5.5 0.1362 7.3 0.0689 7.3 0.1128 7.3 0.0742 7.1 0.0438 7.1 0.1105 7.1 0.2976 10.0 0.2333 10.0 0.2728 10.0 0.204i 11.0 0.1902 11.0 0.2560 11.0 0.0165 6.6 0.0255, . 7.7 0.0551 7.3 0.1469 6.6 0.1569 6.2 0.0051 5.9 0.0681 ..6.1 0.0744 7.0 0.0157 5.7 203 Calculated hydrogen atom parameters Atom X y z B( i s o H(26) 0.4100 0.4376 0.0496 5.7 H(27) 0.3539 0.1611 0.3923 - 5.8 H(28) 0.5066 0.1106 0.4340 7.3 H(29) 0.6488 0.1177 0.3789 7.1 H(30) 0.6360 0.1674 0.2801 8.5 H(31) 0.4846 0.2173 0.2393 8.1 H(32) 0.0996 0.2618 0.3373 5.9 H(33) 0.0456 0.3869 0.3998 7.5 H(34) 0.1500 0.5160 0.4248 8.8 H(35) 0.3141 0.5195 0.3920 8.2 H(36) 0.3667 0.3966 0.3278 6.0 H(37) 0.1059 0.1411 0.1189 5.0 H( 38) 0.0091 0.0836 0.0387 7.1 H( 39) •^0. 0874 0.1947 -0.0191 6.7 H( 40 ) -0.0952 0.3613 0.0092 7.2 H(41) -0.0017 0.4163 0.0914 6.0 H(42) 0.1729 0.4783 0.0918 5.8 H(43) 0.1597 0.6502 0.0938 8:2 H(44) 0.1047 0.7283 0.1769 9.8 H(45) 0.0783 0.6394 0.2613 10.0 H(46) 0.0905 0.4644 0.2614 6.8 H(47) 0.4238 0.3831 0.1933 4.1 H(48) 0.3298 0.4313 0.1594 4.1 H(49) 0.3291 0.4145 0.2288 4.1 204 A1.2 X-ray Crystallographic Analysis o f / f l C - I r ( T i 2 - C H 2 P P h 2 ) H [ N ( S i M e 2 C H 2 P P h 2 ) 2 ] , 3a formula mol. wt. (g/mol) crystal size , mm crystal system space group a, A b, k c, A P, deg z Dc, g/cm3 F (000) radiation wavelength (A) [i, cm - 1 transmission factors scan type scan speed, deg/min data collected 26 , deg max total no. of reflections no. of reflcns with I > 3o(7 ) R Rw g.o.f. Experimental Details C 4 3H 4 9 IrNP 3 Si2 920.4 0.14x0.19x0.60 monoclinic Plilc 9.253(2) 21.950(5) 20.081(4) 90.74(2) 4448 4 1.50 1856 M o 0.71069 33.27 0.883-0.959 co-26 3.91-14.65 (variable) +h, +k, ±1 48 7299 4448 0.036 0.037 1.1 205 Table Al.2.1 Bond Lengths (k) with estimated standard deviations in parentheses Ir—P(l) 2.241(2) P(3)—C(61) 1.816(7) Ir—P(2) 2.272(2) Si(l)—N 1.695(6) Ir—P(3) 2.291(2) Si(l)—C(2) 1.897(7) Ir—C(l) 2.203(7) Si(l)—C(4) 1.871(8) Ir—N 2.277(6) Si(l)—C(5) 1.885(9) Ir—H 1.51(6) Si(2)—N 1.684(6) P(D—C(l) 1.760(8) Si(2)—C(3) 1.927(7) P( l )—C(l l ) 1.828(7) Si(2)—C(6) 1.882(9) P(l)—C(21) 1.817(8) Si(2)—C(7) 1.87(1) P(2)—C(31) 1.833(7) P(2)—C(41) 1.831(7). P(3)—C(3) 1.824(8) P(3)—C(51) 1.847(7) 206 Table A l . 2 . 2 Bond Angles (deg') with estimated standard deviations in parentheses C(l)—Ir—N 97.6(3) P(l)—Ir—H 70(3) C(l)—Ir—H 87(3) P(2)—Ir—H 157.5(2) C ( l )_ I r—P( l ) 46.7(2) P(3)—Ir—H 112(3) C ( l ) _ Ir—P(2) 157.5(2) N—Ir—H 167(3) C(l)—Ir—P(3) 97.9(2) Ir—P(l)—C(ll) 123.9(2) N—Ir—P(l) 103.8(2) C( l )—P(l )—C(l l ) 114.6(3) N—Ir—P(2) 88.4(2) Ir— P(l)—C(21) 127.4(3) N—Ir—P(3) 79.7(1) Ir—P(2)—C(2) 109.5(2) P(l)—Ir—P(2) 110.9(1) Ir—P(3)—C(3) 106.8(2) P(l)—Ir—P(3) 144.5(1) Ir—P(3)—C(51) 117.3(2) P(2)—Ir—P(3) 104.5(1) Ir—P(3)—C(61) 120.4(2) N—Si(l)—C(2) 106.5(3) , N—Si(2)—C(3) 105.2(3) N—Si(l)—C(5) 117.6(4) N—Si(2)—C(6) 118.0(4) C(2)—Si(l)—C(5) 103.3(4) N—Si(2)—C(7) 116.5(4) C(4)—Si(l)—C(5) 103.8(4) Ir—N—Si(l) 113.4(3) Ir—N—Si(2) 114.1(1) Si(l)—N—Si(2) 131.0(4) Ir—C(l)—P(l) 67.8(2) 207 Table A 1.2.3 Final Atomic Coordinates (Fractional) and B(eq) Ir 0. 143521 3) 0.35691( 1) 0.22349( D 2 8 . 9(1) P(1) 0 . 3110 < 2) 0.3170( 1) 0.1567( 1) 35(1 ) P(2) -o .0732 2) 0.3099( 1) 0.2080( 1) 30(1) P(3) 0 .1048 2) 0 .4247( 1) 0.3081{ D 33(1) S i ( 1 ) -0 .09521 2) 0.4210( 1) 0.1192( 1) 41(1) Si (2) 0 .1291 2) 0.5051( 1) 0.1861( 1) 42(1 ) N 0 .0554< 6) 0.4377( 3) 0.1645( 3) 38(3) c d ) 0 .3751 8) 0.3754( 4) 0.2094( 4) 45(4) C(2) -0 .1987 8) 0 .362K 3) 0.1686( 4) 40(4) C(3) 0 . 1720< 8) 0.4983( 3) 0.2800( 4) 43(4) C(4) -0 .0553 11) 0.3941( 4) 0.0329( 4) 62(6) C(5) -0 .2317 10) 0.4837( 4) 0.1059( 5) 69(6) C(6) 0 .0169 11) 0.5758( 3) 0.1735( 4) 60(6) C(7) 0 .2993 11) 0.5268( 4) 0.1432( 5) 70(6) C (1 1 ) 0 . 3961 7) 0.2429( 3) 0.1704( 4) 37(4) C d 2 ) 0 .5100 8) 0.2238( 4) 0.1299( 4) 48(5) C d 3 ) 0 . 5794 9) 0.1691( 4) 0.1427( 5) 59(6) C d 4 ) 0 .5363 10) 0.1329( 4) 0.1936( 5) 65(6) C(15) 0 .4219 11) 0.1504( 4) 0.2322( 5) 67(6) C d 6 ) 0 .3551 9) 0.2049( 4) 0.2211( 4) 53(5) C(21 ) 0 .3356 8) 0.3322( 4) 0.0686( 4) 45(4) C(22) 0 .4171 12) 0.3794{ 5) 0.0462( 5) 74(7) C(23) 0 .4307 16) 0.3911( 6) -0.0201( 6) 107(10) C(24) 0 .3584 17) 0.3555( 7) -0.0652( 6) 107(10) C(25) 0 .2767 13) 0.3069( 7) -0.0449( 5) 95(9) 208 C(26) 0. 2642I 10) 0. 2944( 5) 0. 0241 ( 4) 65(6) C(31 ) - 0 . 16131 7) 0. 2766( 3) 0. 2806( 3) 36(4) C(32) - 0 . 0786< 9) 0. 2515( •4) 0. 331 3 ( 4) 48(5) C(33) -o - 14151 10) 0. 2245( 4) 0. 3860( 4) 57(5) 0(34) - 0 . 2880 11) 0. 2237( 4 > 0. 3908( 4) 67(6) C(35) - 0 . 3727 10) 0. 2492( 5) 0. 3406( 5) . 67(6) C(36) - 0 . 3094 9) 0. 2745( 4) 0. 2858( 4) 54(5) C(41) - 0 . 0659 7) 0. 2445( 3) 0. 1 51 5 ( 3) 34(4) C(42) - 0 . 0002 9) 0. 1907( 3) 0. 1732( 4) 50(4) C(43) 0. 0174 10) 0. 1 41 4 ( 4) 0. 1305( 5) 60(5) C(44) -o.- 0294 11) 0. 1446( 4) 0. 0657( 4) 62(6) C(45) - 0 . 0971 11 ) 0. 1967( 4) 0. 0443( 4) 66(6) C(46) - 0 . 1155 9) 0. 2458( 4) 0. 0858( 4) 52(5) C(51) - 0 . 0841 ( 8) 0. 4372( 3) 0. 3334 ( 3) 34(4) C(52) - 0 . 1419 8) 0. 3993( 4) 0. 381 8 ( 4) 44(4) C(53) - 0 . 2867 9) 0. 4039( 4) 0. 3972 ( 4) 56(5) C(54) - 0 . 3734 9) 0. 4444( 5) 0. 3645( 5) 67(6) C(55) - 0 . 3167 9) 0. 4812( 4) 0. 3173( 5) 64(6) C(56) - 0 . 1722 9) 0. 4776( 4) 0. 3023( 4) 54(5) C(61 ) 0. 1953 8) 0. 4150( 3) 0. 3882( 3) 40(5) C(62) 0. 2777 8) 0. 3647( 4) 0. 4036( 4) 46(4) C(63) 0. 3495 10) 0. 3599( 4) 0. 4654 ( 4)" '63(6) C(64). 0. 3385 11) 0. 4055( •5) 0. 51 07 ( 4) 74(7) C(65) 0. 2568 12) 0. 4554 ( 5) 0. 4971 ( 4) 79(7) C(66) 0. 1B67 10) 0. 4600( 4) 0. 4 3 58 ( 4) 58(5) 209 H 0.1884 0.2949 0 .2489 100 H(1A) 0 .4412 0.3652 0.2442 60 H(1B) 0 .4026 0.4131 0.1901 60 H(2A) - 0 . 2 6 1 6 0.3401 0.1395 60 H(2B) - 0 . 2 5 3 8 0 .3819 0.2018 60 H(3A) 0 .1252 0 .5302 0 .3034 60 H(3B) 0 .2734 0 .5009 0 .2875 60 H(4A) 0 .0135 0 .3620 0 .0349 70 H(4B) ~ - 0 . 0 1 7 5 0 .4269 0 .0076 70 H(4C) - 0 . 1 4 1 9 0 .3797 0 .0123 70 H(5A) - 0 . 2 5 8 4 0 .5002 0 .1477 80 H(5B) - 0 . 3 1 4 9 0 .4676 0 .0839 80 H(5C) - 0 . 1 9 0 6 0 .5148 0 .0792 80 H(6A) - 0 . 0 7 4 6 0.57Q3 0 .1936 70 H ( 6B) 0 .0037 0 .5830 0 .1272 70 H(6C) 0 .0647 0 .6096 0..1934 70 H(7A) 0 .3664 0.4941 0 .1462 80 H(7B) 0 .3396 0 .5619 0 .1639 80 K(7C) 0 .2786 0.5354 0 .0977 80 H(12) 0 .5397 0.2486 0 .0938 60 H(13) 0 .6575 0.1568 0 .1156 70 H(14) 0 .5847 0.0955 0 .2022 70 H (1 5 ) 0 .3900 0.1247 0.2671 80 H(16) 0 .2779 0.2168 0 .2490 60 H(22) 0 .4657 0.4048 0 .0776 80 210 H(23) 0 .4900 0 .4235 - 0 . 0 3 4 9 110 H(24) 0 .3642 0 .3645 - 0 . 1 1 1 4 110 H(25) 0 .22B9 0 .2818 - 0 . 0 7 6 8 100 H(26) 0 .2083 0 .2610 0 .0393 70 H(32) 0 .0238 0 .2522 0.3281 60 H(33) - 0 . 0 8 2 9 0 .2074 0 .4204 70 H(34) - 0 . 3 3 1 9 0 .2054 0 .4283 70 H(35) - 0 . 4 7 4 9 0 .2489 0 .3445 70 H(36) - 0 . 3 6 8 6 0 .2907 0 .2510 70 H(42) 0 .0340 0 .1877 0 .2179 60 H(43) 0 .0608 0 .1049 0 .1466 70 H(44 ) - 0 . 0 1 5 2 0 .1117 0 .0360 70 H ( 4 5 ) - 0 . 1 3 1 4 0 .1992 - 0 . 0 0 0 4 70 H(46) - 0 . 1 6 3 1 . 0 .2812 0 .0692 60 H(52) - 0 . 0 8 1 8 0 .3706 0 .4042 60 H(53) - 0 . 3 2 5 9 0.3791 0 .4313 70 H(54) - 0 . 4 7 3 8 0.4461 0 .3736 70 H(55) - 0 . 3 7 6 2 0 .5106 0 .2956 70 H(56) - 0 . 1 3 3 8 0 .5040 0 .2693 60 H(62) 0 .2864 0 .3328 0 .3719 60 H(63) 0 .4057 ' 0 .3247 0 .4753 80 H(64) 0 .3886 0 .4023 0 .5522 80 H(65) 0.2471 0 .4869 0 .5292 90 H(66) 0 .1313 0 .4955 0 .4262 70 211 A1.3 X-ray Crystallographic Analysis of I r (CH3)PPh2{C2(C02Meh}[N(SiMe 2 CH2PPh2)2] , 12 Experimental Details E m p i r i c a l F o r m u l a F o r m u l a W e i g h t C r y s t a l C o l o r , H a b i t C r y s t a l D i m e n s i o n s (mm) C r y s t a l S y s t e m N o . R e f l e c t i o n s Used f o r U n i t C e l l D e t e r m i n a t i o n (26 r a n g e ) Omega S c a n Peak W i d t h a t H a l f - h e i g h t L a t t i c e P a r a m e t e r s : Space G r o u p Z v a l u e D c a l c F o o o "(MoKex) D i f f T a c t o m e t e r R a d i a t i o n T e m p e r a t u r e T a k e - o f f A n g l e D e t e c t o r A p e r t u r e C 4 9 H 5 5 I r N 0 4 P 3 S i 2 1 0 6 3 . 2 9 g r e e n , p r i s m 0 .200 X 0 .200 X 0 .250 m o n o c l i n i c 2 5 ( 3 0 . 1 - 3 4 . 9 ° ) 0 .34 a - 20 .04 (2 ) A b - 23 .764 ( 4 ) A . c - 20 . 496 (4 )A 6 - 100 .40 ( 4 ) ° V - 9599 ( 9 ) A 3 P 2 x / n (#14) 8 1.471 g / c m 3 4304 2 9 . 6 0 c m - 1 B . I n t e n s i t y M e a s u r e m e n t s R i g a k u AFC6S MoKex (X - 0 .71069 A ) 2 1 e C 6 . 0 e 6 .0 mm h o r i z o n t a l 6 .0 mm v e r t i c a l 2 1 2 C r y s t a l t o D e t e c t o r D i s t a n c e S c a n Type Scan R a t e S c a n W i d t h 26 max N o . o f R e f l e c t i o n s M e a s u r e d C o r r e c t i o n s C . S t r u c t u r e S o l u t i o n S t r u c t u r e S o l u t i o n R e f i n e m e n t F u n c t i o n M i n i m i z e d L e a s t - s q u a r e s W e i g h t s p - f a c t o r A n o m a l o u s D i s p e r s i o n No . O b s e r v a t i o n s ( I > 3 . 0 0 c ( I ) ) N o . V a r i a b l e s R e f l e c t i o n / P a r a m e t e r R a t i o R e s i d u a l s : R; R w Goodness o f F i t I n d i c a t o r Max S h i f t / E r r o r i n F i n a l C y c l e Maximum Peak i n F i n a l D i f f . Map Minimum Peak i n F i n a l D i f f . Map 265 mm u> 16.0 ° / m i n ( i n omega) (6 r e s c a n s ) (0.79 + 0.35 tan6)° 55.0° T o t a l : 22625 U n i q u e : 21995 ( R i n t - .057) L o r e n t z - p o l a r i z a t i o n A b s o r p t i o n ( t r a n s , f a c t o r s : 0.75 - 1.00) S e c o n d a r y E x t i n c t i o n ( c o e f f i c i e n t : 0.10956E-07) and R e f i n e m e n t P a t t e r s o n Method F u l l - m a t r i x l e a s t - s q u a r e s I w ( | F o | - | F c | ) 2 2 2 2 4 F o V ° (Fo'') 0.03 A l l n o n - h y d r o g e n atoms 11022 1082 10.19 0.036; 0.036 1.16 0.05 0.67 e~/k\ -0.57 e"/A 3 213 Table A l . 3 . 1 Bond Lengths (A) with estimated standard deviations in parentheses atom atom d i s t a n c e atom atom d i s t a n c e l r ( l ) 'P(l) 2.352(2) P(5) C(87) 1.843(6) l r ( l ) P(2) 2.288(2) P(6) C(74) 1.852(7) l r ( l ) P(3) 2.335(2) P(6) C(80) 1.841(6) l r ( l ) N ( l ) 2.281(5) P(6) C(88) 1.851(7) l r ( l ) C(43) 2.145(7) S i d ) N ( l ) 1.694(6) l r ( l ) C(49) 2.119(7) S i d ) C ( l ) 1.878(7) l r ( 2 ) P(4) 2.343(2) S i d ) C(3) 1.891(8) l r ( 2 ) P(5) 2.284(2) S i d ) C(4) 1.885(8) l r ( 2 ) P(6) 2.335(2) S i ( 2 ) N ( l ) 1.707(6) l r ( 2 ) N(2) 2.281(5) S i ( 2 ) C(2) 1.898(8) l r ( 2 ) C(92) 2.123(7) S i ( 2 ) C(5) 1.868(8) l r ( 2 ) C(98) 2.140(7 ) S i ( 2 ) C(6) 1.882(8) P ( l ) C ( l ) 1.833(7) S i (-3 ) N(2) 1.689(6) P ( l ) C(7) 1.832(7) S i (3 ) C(50) 1.896(7) P ( l ) C(13) 1.841(7) S i ( 3 ) C( 52 ) 1.882(8) P(2) C(2) 1.789(7) S i ( 3 ) C(53) 1.882(8) P(2) C(19) 1.827(7) S i ( 4 ) N(2) 1.709(6) P(2) C(38) 1.851(7) S i ( 4 ) C(51) 1.909(8) P(3) C(25) 1.831(7) S i ( 4 ) C(54) 1.876(8) P(3) C(31) 1.837(7) S i ( 4 ) C(55) 1.868(8) P(3) C(39) 1.825(7) 0(1) C(37) 1.332(9) P(4) C(50) 1.806(7) 0(1) C(41) 1.44(1) P(4) C(56) 1.822(7) 0(2) C(37) 1.202(9) P(4) C(62) 1.833(7) 0(3) C(40) 1.335(8) P(5) C(51) 1.795(7) 0(3) C(42) 1.44(1) P(5) C(68) 1.822(7) 0(4) C(40) 1.192(8) 214 T a b l e . ( c o n t i n u e d ) atom atom d i s t a n c e 0( 5) C(86) 1 .311(9) 0(5) C(90) 1 .447(9) 0(6) C(86) 1 .196(9) 0(7) C(89) 1 .323(8) 0(7) C(91) 1 .45(1) 0(8) C(89) 1 .191(8) C(37) C(38) 1 .50(1) C( 38) C(39) 1 .34(1) C(39) C(40) 1 .52(1) C( 86 ) C(87) 1 .51(1) C(87) C(88 ) 1 .316(9) C( 88 ) C(89) 1 .517(9) 215 Table Al.3.2 Bond Angles (deg) with estimated standard deviations in parentheses atom atom atom angle P ( l ) l r ( l ) P(2) 169 .98(6) P ( l ) l r ( l ) P(3) 96 .16(7) P ( l ) l r ( l ) N( l ) 84 .9(1) P ( l ) l r ( l ) C(43) 98 .8(2) P ( l ) l r ( l ) C(49) 90 .9(2) P(2) l r ( l ) P(3) 84 .88(7) P(2) l r ( l ) N(l) 85 .1(1) P(2) l r ( l ) C(43) 81 .1(2) P(2) l r ( l ) C(49) 99 .1(2) P(3) I r (1) N(l ) 96 .1(1) P(3) i r ( l ' ) C(43) 164 .5(2) P(3) l r ( l ) C(49) 89 .2(2) N( 1) l r ( l ) C(43) 89 .2(2) N( 1 ) l r ( l ) C(49) 173 .6(2) C(43) l r ( l ) C(49) 66 .7(3) P(4) l r (2 ) P(5) 170 .57(6) P( 4 ) l r (2 ) P(6) 95 .97(6) P( 4 ) Ir(2) N(2) 85 .3(1) P(4) l r ( 2 ) C(92) 98 .5(2) P(4) l r (2 ) C(98) 90 .7(2) P(5) l r (2 ) P(6) 85 .25(7) P(5) l r (2 ) N(2) 85 .3(1) P(5) l r (2 ) C(92) 81 .1(2) P(5) l r ( 2 ) C(98) 98 .7(2) P(6) l r (2 ) N(2) 94 .7(1) P(6) l r (2 ) C(92) 165 .1(2) atom atom atom angle P(6) l r ( 2 ) C(98) 90 .2(2) N(2) l r ( 2 ) C(92) 90 .0(2) N(2) l r ( 2 ) C(98) 174 .0(2) C(92) l r ( 2 ) C(98) 86 .2(3) l r ( l ) P d ) C( l ) 106 .7(2) l r ( l ) P ( D C(7) 120 .4(3) l r ( l ) P d ) C(13) 119 .5(2) C( l ) P d ) C(7) 105 .9(3) C( l ) P d ) C(13) 104 .1(3) C(7) P d ) C(13) 98 .5(3) l r ( l ) P(2) C(2) 109 .0(3) l r ( l ) P(2) C(19) 125 .8(2) I r d l P(2) C(38) 108 .6(2) C(2) P(2) C(19) 107 .3(3) C(2) P(2) C(38) 104 .4(3) C(19) P(2) C(38) 99 .6(3) l r ( l ) P(3) C(25) 126 .3(2) l r ( l ) P(3) C(31) 116 .3(2) l r ( l ) P(3) C(39) 106 .7(2) C(25) P(3) C(31) 104 .3(3) C(25) P(3) C(39) 97 .9(3) C(31) P(3) C(39) 101 .0(3) l r (2 ) P(4) C(50) 106 .7(2) l r (2 ) P(4) C(56) 118 .8(2) l r (2 ) P(4) C(62) 121 .3(2) C(50) P(4) C(56) 104 .8(3) 216 Table (continued) atom atom atom angle C(50) P(4) C(62) 105 .4(3) C(56) P(4) C<62) 98 • 2(3) l r (2 ) P(5) C(51) 108 .9(2) l r ( 2 ) P(5) C(68) 124 .2(2) l r ( 2 ) P(5) C(87) 108 .2(2) C(51) P(5) C(68) 107 .4(3) C(51) P(5) C(87) 105 .0(3) C(68) P(5) C(87) 101 .5(3) l r (2 ) P(6) C(74) 127 .3(2) Ir(2) P(6) C(80) 115 .9(2) l r (2 ) P(6) C(88) 106 .0(2) C(74) P(6) C(80) 104 .4(3) C(74 ) P(6) C(88) 97 .1(3) C(80) P(6) C(88) 101 .5(3) N(l) S i ( l ) C( l ) 105 .0(3) N ( l ) S i ( l ) C(3) 119 .0(3) N(l) S i ( l ) C(4) 114 .2(3) C( l ) S i ( l ) C(3) 107 .2(3) C( l ) S i d ) C(4) 107 .7(3) C(3) S i d ) C(4) 103 .2(4) N(l) Si(2) C(2) 106 .6(3) N(l) Si(2) C(5) 113 .9(3) N(l) Si(2) C(6) 113 .9(3) C(2) Si(2) C(5) 106 .7(3) C(2) Si(2) C(6) 108 .7(3) C(5) Si(2) C(6) 106 .7(3) atom atom atom angle N(2) Si(3) C(50) 105 • 2(3) N(2) Si (3) C(52) 118 .8(3) N(2) S i d ) C(53) 114 .0(3) C(50) Si(3) C(52) 105 .3(3) C(50) S i d ) C(53) 109 .2(3) C(52) S i d ) C(53) 103 .9(4) N(2) Si(4) C(51) 106 .3(3) N(2) Si(4) C(54) 113 .9(3) N(2) Si(4) C(55) 114 .8(3) C(51) S i d ) C(54) 107 .0(4) C(51) S i d ) C(55) 108 .1(3) C(54) Si(4) C(55) 106 .4(4) C(37) 0(1) C(41) 116 • 5(7) C(40) 0(3) C<42) 116 .9(6) C(86) 0(5) C(90) 116 .9(7) C(89) 0(7) C(91) 114 .9(6) l r ( i ) N(l) S i ( l ) 118 .6(3) l r ( l ) N(l) Si(2) 117 .5(3) S i ( l ) N( l ) Si(2) 123 .2(3) l r ( 2 ) N(2) Si(3) 117 .8(3) l r (2 ) N(2) Si(4) 117 .8(3) S i d ) N(2) Si(4) 123 .4(3) P d ) C( l ) S i ( l ) 108 .2(4) P(2) C(2) Si(2) 108 .1(4) 0(1) C(37) 0(2) 125 .6(8) 0(1) C(37) C(38) 112 .0(7) 217 T a b l e ( c o n t i n u e d ) a t o m a t o m a t o m 0 ( 2 ) C ( 3 7 ) C ( 3 8 ) P ( 2 ) C ( 3 8 ) C ( 3 7 ) P ( 2 ) C ( 3 8 ) C ( 3 9 ) C ( 3 7 ) C ( 3 8 ) C ( 3 9 ) P ( 3 ) C ( 3 9 ) C ( 3 8 ) P ( 3 ) C ( 3 9 ) C ( 4 0 ) C ( 3 8 ) C ( 3 9 ) C ( 4 0 ) 0 ( 3 ) C ( 4 0 ) 0 ( 4 ) 0 ( 3 ) C ( 4 0 ) C ( 3 9 ) 0 ( 4 ) C ( 4 0 ) C ( 3 9 ) P ( 4 ) C ( 5 0 ) S i ( 3 ) P ( 5 ) C ( 5 1 ) S i ( 4 ) 0 ( 5 ) C ( 8 6 ) 0 ( 6 ) 0 ( 5 ) C ( 8 6 ) C ( 8 7 ) 0 ( 6 ) C ( 8 6 ) C ( 8 7 ) P ( 5 ) C ( 8 7 ) C ( 8 6 ) P ( 5 ) C ( 8 7 ) C ( 8 8 ) C ( 8 6 ) C ( 8 7 ) C ( 8 8 ) P ( 6 ) C ( 8 8 ) C ( 8 7 ) P ( 6 ) C ( 8 8 ) C ( 8 9 ) C ( 8 7 ) C ( 8 8 ) C ( 8 9 ) 0 ( 7 ) C ( 8 9 ) 0 ( 8 ) 0 ( 7 ) C ( 8 9 ) C ( 8 8 ) 0 ( 8 ) C ( 8 9 ) C ( 8 8 ) a n g l e 1 2 2 . 4 ( 7 ) 1 2 0 . 7 ( 5 ) 1 1 7 . 4 ( 5 ) 1 2 1 . 7 ( 6 ) 1 2 0 . 3 ( 5 ) 1 2 0 . 8 ( 5 ) 1 1 8 . 9 ( 6 ) 1 2 4 . 7 ( 7 ) 1 1 0 . 2 ( 6 ) 1 2 5 . 0 ( 7 ) 1 0 8 . 1 ( 4 ) 1 0 8 . 4 ( 3 ) 1 2 4 . 5 ( 8 ) 1 1 2 . 3 ( 7 ) 1 2 3 . 2 ( 7 ) 1 2 0 . 9 ( 5 ) 1 1 9 . 0 ( 5 ) 1 2 0 . 0 ( 6 ) 1 1 9 . 5 ( 5 ) 1 1 8 . 1 ( 5 ) 1 2 2 . 3 ( 6 ) 1 2 5 . 4 ( 7 ) 1 0 8 . 9 ( 6 ) 1 2 5 . 6 ( 6 ) 218 Table A 1.3.3 Final Atomic Coordinates (Fractional) and B(eq) atom X y z B ( e q ) l r ( l ) 0 . 1 9 3 1 5 ( 1 ) 0 . 1 7 2 2 8 ( 1 ) 0 . 2 0 6 6 0 ( 1 ) 2 . 0 3 ( 1 ) •> l r ( 2 ) 0 . 7 1 6 3 3 (1 ) 0 . 0 4 9 3 5 ( 1 ) 0 .2125641) 1 . 8 5 ( 1 ) P d ) 0 . 1 6 7 9 6 ( 9 ) 0 . 2 6 8 8 7 ( 8 ) 0 . 2 0 8 9 1 ( 9 ) 2 . 4 0 ( 8 ) P ( 2 ) 0 . 2 3 2 5 6 ( 9 ) 0 . 0 8 3 1 5 ( 8 ) 0 . 1 9 5 0 1 ( 9 ) 2 . 4 3 ( 8 ) P ( 3 ) 0 . 2 5 9 9 4 ( 8 ) 0 . 1 6 8 5 6 ( 8 ) 0 . 3 1 2 4 0 ( 8 ) 2 . 3 0 ( 7 ) P ( 4 ) 0 . 6 8 6 2 9 ( 9 ) 0 . 1 4 4 7 6 ( 8 ) 0 . 2 0 7 6 1 ( 9 ) 2 . 2 0 ( 7 ) P (5 ) . 0 . 7 5 9 4 0 ( 9 ) - 0 . 0 3 9 3 0 ( 8 ) 0 . 2 0 8 2 4 ( 9 ) 2 . 3 4 ( 8 ) P (6 ) 0 . 7 8 0 8 4 ( 8 ) 0 . 0 5 2 5 1 ( 8 ) 0 . 3 1 9 4 3 ( 8 ) 2 . 0 7 ( 7 ) S i ( l ) 0 . 2862(1 ) 0 . 2 6 9 2 ( 1 ) 0 . 1 3 7 1 ( 1 ) 2 . 8 8 ( 9 ) S i ( 2 ) 0 . 3 2 1 7 ( 1 ) 0 . 1 4 8 4 ( 1 ) 0 . 1 2 0 5 ( 1 ) 2 . 9 0 ( 9 ) S i ( 3 ) 0 . 8 0 9 0 ( 1 ) ' 0 . 1 4 5 3 ( 1 ) 0 . 1 4 2 7 ( 1 ) 2 . 8 3 ( 9 ) S i ( 4 ) 0 . 8493(1 ) 0 . 0 2 4 9 ( 1 ) 0 . 1 3 1 9 ( 1 ) 3 . 0 2 ( 9 ) 0(1 ) 0 . 3770(3 ) 0 . 0 0 9 1 ( 2 ) 0 . 2 2 1 1 ( 3 ) 4 . 8 ( 3 ) 0 ( 2 ) 0 . 3380(3 ) - 0 . 0 2 0 1 ( 3 ) 0 . 3 1 1 9 ( 3 ) 5 . 8 ( 3 ) 0 ( 3 ) 0 . 4 2 8 7 ( 2 ) 0 . 0 8 1 7 ( 2 ) 0 . 3 4 8 7 ( 2 ) 4 . 2 ( 3 ) 0 ( 4 ) 0 . 3 7 0 1 ( 3 ) 0 . 1 0 4 3 ( 2 ) 0 . 4 2 8 2 ( 2 ) 4 . 3 ( 3 ) 0 ( 5 ) 0 . 8 9 3 2 ( 3 ) - 0 . 1 1 7 5 ( 2 ) 0 . 2 4 0 0 ( 3 ) 4 . 7 ( 3 ) 0 ( 6 ) 0 . 8 7 1 8 ( 4 ) - 0 . 1 3 1 0 ( 3 ) 0 . 3 4 1 4 ( 3 ) 7 . 2 ( 4 ) 0 ( 7 ) 0 . 9 5 3 9 ( 3 ) - 0 . 0 1 9 8 ( 3 ) 0 . 3 6 2 2 ( 3 ) 6 . 2 ( 3 ) 0 ( 8 ) 0 . 8 9 2 2 ( 2 ) - 0 . 0 0 5 6 ( 2 ) 0 . 4 4 1 3 ( 2 ) 4 . 0 ( 3 ) N ( l ) 0 . 2 7 8 1 ( 3 ) 0 . 1 9 9 8 ( 2 ) 0 . 1 5 3 0 ( 3 ) 2 . 4 ( 2 ) N(2 ) 0 . 8 0 3 3 ( 2 ) 0 . 0 7 6 4 ( 2 ) 0 . 1 6 1 5 ( 2 ) 2 . 3 ( 2 ) C ( l ) 0 . 2 4 5 7 ( 3 ) 0 . 3 0 6 7 ( 3 ) 0 . 2 0 0 6 ( 3 ) 2 . 7 ( 3 ) C ( 2 ) 0 . 2 7 1 7 ( 3 ) 0 . 0 8 0 8 ( 3 ) . 0 . 1 2 3 3 ( 3 ) 3 . 0 ( 3 ) 219 T a b l e ( con t inued) atom X y z B ( e q ) C ( 3 ) 0 . 2461(4) 0. 2977(4) 0. 0530(4) 4 . 4 ( 4 ) C ( 4 ) 0. 3768(4) 0. 2941(4) 0 . 1471(4) 4 . 6 ( 4 ) C ( 5 ) 0 . 3286(4) 0 . 1601(3) 0 . 0319(4) 4 . 0 ( 4 ) C ( 6 ) 0. 4105(4) 0 . 1372(3) 0. 1674(4 ) 4 . 0 ( 4 ) C ( 7 ) 0. 1005(3 ) 0 . 2994(3) 0 . 1468(3) 2 . 8 ( 3 ) C ( 8 ) 0 . 1002(4) 0. 3556(4) 0 . 1311(4 ) 4 . 3 ( 4 ) C ( 9 ) 0 . 0470(5) 0. 3804(4) ° -0897(5) 5 . 4 ( 5 ) C ( 1 0 ) - 0 . 0087(5) 0 . 3478(5) 0 . 0620(5) 5 . 5 ( 5 ) C ( l l ) - 0 . 0096(4) 0. 2914(4) 0 . 0762(5) 5 . 4 ( 5 ) C ( 1 2 ) o'. 0449(4) 0. 2675(3) 0 . 1179(4) 3 . 9 ( 4 ) C ( 1 3 ) 0. 1434(3) 0. 2994(3) 0. 2837(3) 2 . 9 ( 3 ) C(14 ) o. 1 8 9 K 4 ) 0. 3299(3) 0. 3268(4) 3 . 6 ( 3 ) C ( 1 5 ) 0 . 1701(5) 0 . 3511(4 ) 0 . 3861(4) 4 . 5 ( 4 ) C ( 1 6 ) 0. 1060(5) 0. 3425(4) 0 . 3977(4) 4 . 7 ( 4 ) C ( 1 7 ) 0. 0591(4) 0. 3134(4) 0. 3528(4) 4 . 7 ( 4 ) C ( 1 8 ) 0. 0779(4) 0. 2913(3) 0. 2961(4) 3 . 4 ( 4 ) C ( 1 9 ) 0 . 1838(4) 0 . 0183(3) 0. 1960(4 ) 3 . 1 ( 3 ) C ( 2 0 ) 0. 1597(4) 0. 0035(4) 0. 2524(4) 4 . 8 ( 4 ) C ( 2 1 ) 0 . 1247(5) - 0 . 0463(4) 0. 2550(5) 6 . 3 ( 5 ) C ( 2 2 ) 0 . 1135(5) - 0 . 0817(4) 0 . 2010(6) 6 . 6 ( 6 ) C ( 2 3 ) 0. 1347(6) - 0 . 0664(4) 0 . 1437(5) 6 . 8 ( 6 ) C ( 2 4 ) 0 . 1708(5) - 0 . 0173(4) 0 . 1422(4) 5 . 2 ( 5 ) C ( 2 5 ) 0 . 3251(3) 0 . 2194(3) 0. 3479(3) 2 . 6 ( 3 ) C ( 2 6 ) 0 . 3733(3) 0. 2314(3) 0. 3082(4) 3 . 2 ( 3 ) C ( 2 7 ) 0. 4268(4 ) 0. 2662(4) 0. 3321(5) 4 . 6 ( 4 ) 220 T a b l e ( c o n t i n u e d ) atom X y z B ( e q ) C(28) 0 .4329(4) 0 .2902(4) 0. 3936(5) 5 .2(5) C(29) 0 .3856(5) 0 .2803(4) 0 . 4317(4) 4 .7(4) C(30) 0 .3322(4) 0 .2444(4) 0. 4099(4) 3 .9(4) C(31) 0 .2156(3) 0 .1519(3) 0. 3810(3) 2 .9(3) C(32) 0 .1831(4) 0 .1952(3) 0. 4079(4) 3 .7(4) C(33) 0 .1465(4) 0 .1836(4) P- 4578(4) 5 .3(5) C(34) 0 .1405(4) 0 .1296(5) 0. 4796(5) 5 .6(5) C(35) 0 .1717(4) 0 .0872(4) 0. 4512(4) 4 .4(4) C(36) 0 .2093(4) 0 .0980(3) 0. 4025(4) 3 .4(4) C(37) 0 .3406(4) 0 •0140(3) 0. 2691(4) 3 .5(4) C(38) 0 .3026(3) 0 .0687(3) 0. 2651(3) 2 .7(3) C(39) 0 .3149(3) 0 .1072(3) 0. 3137(3) . 2 .3(3) C(40) 0 .3729(4) 0 .0973(3) 0. 3712(4) 3 .0(3) C(41) 0 .4219(5) -0 .0388(4) 0. 2251(5) 6 .6(6) C(42) 0 .4861(4) 0 .0641(4) 0. 3974(5) 5 .6(5) C(43) 0 .1323(3) 0 .1515(3) 0. 1125(3) 2 .6(3) C(44) 0 .1462(3) 0 .1709(3) 0. 0522(3) 3 .4(3) C(45) 0 .1128(4) 0 .1506(4 ) - 0 . >0082( 4 ) 4 .2(4) C(46) 0 .0633(4) 0 .1100(4) - 0 . 0118(4) 4 .5(4) C(47) 0 .0469(4) , 0 .0898(4) 0. 0463(4) 3 .9(4) C<48) 0 .0810(4) 0 .1101(3) 0. 1072(4) 3 .6(4) C(49) 0 .1070(3) 0 .1524(3) 0. 2488(3) 3 .0(3) C( 50) 0 .7623(3) 0 .1839(3) 0. 2019(3) 2 .9(3) C(51) 0 .8017(3) -0 .0439(3) 0. 1363(3) 2 .9(3) C(52) 0 .7689(4) 0 .1702(4) 0. 0575(4) 4 .2(4) 221 Table (continued) atom X y z B(eq) C ( 5 3 ) 0. 6986 4) 0 . 1 7 2 3 ( 4 ) 0 . 1 5 3 6 ( 4 ) 4 . 6 ( 4 ) C(5.4) 0. 8564 4) 0 . 0 3 3 9 ( 4 ) 0 . 0 4 2 5 ( 4 ) 4 . 6 ( 4 ) C(5S) 0. 9377 4) 0 . 0 1 6 2 (4 ) 0 . 1 7 8 8 ( 4 ) 4 . 3 ( 4 ) C(56) 0. 6550 3) 0 . 1 7 5 9 ( 3 ) 0 . 2 7 7 5 ( 3 ) 2 . 4 ( 3 ) C ( 5 7 ) 0. 6946 3) 0 . 2 1 2 5 ( 3 ) 0 . 3 2 2 2 ( 3 ) 3 . 2 ( 3 ) C ( 5 8 ) 0. 6696 4) 0 . 2 3 3 4 ( 3 ) 0 . 3 7 6 5 ( 4 ) 4 . 0 ( 4 ) C ( 5 9 ) 0. 6068 5) 0 . 2 1 8 8 ( 4 ) 0 .3872( 4 ) 4 . 4 ( 4 ) C ( 6 0 ) 0 . 5664 4) 0 . 1 8 3 9 ( 4 ) 0 . 3 4 2 5 ( 5 ) 4 . 5 ( 4 ) C ( 6 1 ) 0 . 5897 3) 0 . 1 6 2 9 ( 3 ) 0 .2886( 4 ) 3 . 1 ( 3 ) C ( 6 2 ) 0 . 6210 3) 0 . 1 7 2 1 ( 3 ) 0 . 1 4 0 8 ( 3 ) 2 . 4 ( 3 ) C ( 6 3 ) 0 . 6153 4) 0 . 2 2 9 9 ( 3 ) 0 . 1 2 8 3 ( 4 ) 3 . 1 ( 3 ) C(64 ) 0. 5641 4) 0 . 2 5 1 3 ( 3 ) 0 . 0 8 2 2 ( 4 ) 3 . 5 ( 4 ) C{65) 0 . 5177 4) 0 • 2168(4 ) 0 .0458(4 ) 3 . 5 ( 4 ) C(66) 0 . 5215 3) 0 . 1 5 9 6 ( 3 ) 0 . 0 5 6 3 ( 4 ) 3 . 1 ( 3 ) C(67) 0. 5722 3) 0 . 1 3 7 4 ( 3 ) 0 . 1 0 3 8 ( 3 ) 2 . 8 ( 3 ) C(68) 0. 7101 3) - 0 . 1 0 3 6 ( 3 ) 0 . 2 0 9 9 ( 4 ) 3 . 0 ( 3 ) C ( 6 9 ) 0. 6850 4) - 0 . 1 1 7 9 ( 4 ) 0 . 2 6 6 7 ( 4 ) 4 . 6 ( 4 ) C ( 7 0 ) 0. 6460 5) - 0 . 1 6 5 9 ( 4 ) . 0 . 2 6 8 6 ( 5 ) 5 . 7 ( 5 ) C ( 7 1 ) 0 . 6313 5) - 0 . 2 0 0 3 ( 4 ) 0 . 2 1 4 3 ( 6 ) 5 . 6 ( 5 ) C ( 7 2 ) 0 . 6548 5) - 0 . 1 8 7 1 ( 4 ) 0 . 1 5 7 9 ( 5 ) 5 . 4 ( 5 ) C ( 7 3 ) 0. 6939 4) - 0 . 1 3 9 1 ( 4 ) 0 . 1 5 6 0 ( 4 ) 4 . 4 ( 4 ) C ( 7 4 ) 0 . 8457 3) 0 . 1 0 5 5 ( 3 ) 0 . 3 5 3 3 ( 3 ) 2 . 4 ( 3 ) C ( 7 5 ) 0. 8964 4) 0 . 1 1 5 5 ( 3 ) 0 . 3 1 7 1 ( 4 ) 3 . 7 ( 4 ) C ( 7 6 ) - 0 . 9510 4) 0 • 1487(4 ) 0 . 3 4 0 8 ( 4 ) 4 . 4 ( 4 ) C ( 7 7 ) 0. 9537 4) 0 . 1 7 5 3 ( 4 ) 0 . 4 0 0 9 ( 4 ) 4 . 6 ( 4 ) 222 Table ( c o n t i n u e d ) atom X y z B ( e q ) C ( 7 8 ) 0 . 9 0 3 4 ( 4 ) 0. 1672(4) 0 . 4363(4) 4 . 7 ( 4 C ( 7 9 ) 0 . 8 4 9 7 ( 4 ) 0. 1319(4) 0 . 4136(4) . 3 . 8 ( 4 C ( 8 0 ) 0 . 7 3 4 5 ( 3 ) 0. 0391(3) 0 . 3877(3) 2 . 4 ( 3 C ( 8 1 ) 0 . 6 9 9 5 ( 3 ) 0. 0818(3) 0 . 4121(3) 3 . 0 ( 3 C ( 8 2 ) 0 . 6 6 2 3 ( 4 ) 0. 0721(4) 0. 4617(4) 3 . 5 ( 4 C ( 8 3 ) 0 . 6 5 7 2 ( 4 ) 0. 0188(4) 0. 4847(4) 4 . 5 ( 4 C ( 8 4 ) 0 .6887( 4) - 0 . 0251(4) 0 . 4595(4) 4 . 2 ( 4 C ( 8 5 ) 0 .7290( 3) - 0 . 0151(3) 0. 4122(4 ) 3 . 0 ( 3 C<86) 0 .8666( 4) - 0 . 1036(3) 0. 2917(4 ) 3 . 3 ( 4 C ( 8 7 ) 0 .8269( 3) - 0 . 0491(3) 0. 2813(3 ) 2 . 4 ( 3 C ( 8 8 ) 0 .6384( 3) - 0 . 0090(3) 0. 3261(3) 2 . 2 ( 3 C ( 8 9 ) 0 .8968( 3) - 0 . 0115(3) 0. 3846 ( 4 ) 2 . 7 ( 3 C O O ) 0 .9338( 4) - 0 . 1682(4) 0. 2455(5) 6 . 0 ( 5 C ( 9 1 ) 1 .0144( 5) - 0 . 0212(7) 0. 4127(5) 1 1 . 9 ( 9 C(92) 0 .6596( 3) 0. 0236(3) 0. 1197(3) 2 . 4 ( 3 C(93) 0 •6069( 4) - 0 . 0160(3) 0. 1133(4) 3 . 0 ( 3 C ( 9 4 ) 0 .5734( 4) - 0 . 0358(3) 0. 0532 ( 4 ) 4 . 1 ( 4 C ( 9 5 ) 0 .5901( 4) - 0 . 0166(4) - 0 . 0053(4 ) 4 . 5 ( 4 C ( 9 6 ) 0 .6410( 4) 0 . 0216(4) - 0 . 0020(4 ) 4 . 0 ( 4 C ( 9 7 ) 0 . 6 7 5 3 ( 4 ) 0. 0417(3) 0 . 0583(3) 3 . 2 ( 3 C ( 9 8 ) 0 .62791 3) 0 . 0290(3) 0 . 2528(3) 2 . 9 ( 3 223 Calculated hydrogen atom coordinates and B(iso) atom H(l) H (2) H (3) H(4) H(5) H(6) H (7) H(8) H (9) H (10) H(ll) H ( 1 2 ) H (13) H ( 1 4 ) H ( 1 5 ) H ( 1 6 ) H (17 ) H (18) H (19) H (20 ) H (21) H (22) H (23 ) H (24) 0 .2347 0 .2769 0 .3024 0 .2369 0 .2494 0 .2699 0 .1983 0 .3998 0 .4002 0 .3774 0 .3538 0 .3526 0 .2831 0 .4089 0 .4321 0 .4367 0 .1394 0 .0481 - 0 . 0 4 7 1 - 0 . 0 4 8 7 0 .0443 0 .2350 0 .2029 0 .0932 0 .3454 0 .3071 0 .0484 0 .0777 0 .3389 0 .2826 0 .2866 0 .2878 0 .2732 0 .3344 0 .1949 0 .1284 0 .1631 0 .1273 0 .1067 0 .1720 0 .3788 0 .4206 0 .3651 0 .2682 0 .2271 0 .3367 0 .3722 0 .3571 0 .1862 0 .2433 0 .1261 0 .0832 0 .0534 0 .0191 0 .0429 0 .1929 0 .1167 0 .1368 0 .0281 0 .0161 0 .0050 0 .2135 0 .1467 0 .1665 0 .1501 0 .0796 0 .0324 0 .0569 0 .1272 0 .3205 0 .4182 0 .4385 B(iso) 3 . 3 3 . 3 3 .6 3 . 6 5 .2 5 .2 5 .2 5 .5 5 . 5 5 .5 4 .9 4 .9 4 .9 4 .8 4 .8 4 .8 5 .2 6 .5 6 .6 6 .5 4 .7 4 . 3 5 .4 5 .7 224 C a l c u l a t e d hydrogen atom coordinates and B(iso) (cont.) atom H(25) H(26) H(27) H(28) H(29) H(30) H(31) H(32) H(33) H(34) H(35) H(36) H(37) H(38) H(39) H( 40 ) H(41) H(42) H(43) H(44) H(45) H(46) H(47) H(48) 0.0127 0.0449 0.1674 0.1078 0.0904 0.1242 0.1877 0.3689 0.4612 0.4717 0.3894 0.2989 0.1859 0.1246 0.1145 0.1671 0.2316 0.3952 0.4474 0.4536 0.4730 0.5232 0.5011 0.1809 0.3084 0.2699 0.0286 -0.0564 -0.1178 -0.0902 -0.0074 0.2151 0.2740 0.3146 0.2987 0.2365 0.2338 0.2145 0.1215 0.0484 0.0670 -0.0736 -0.0373 -0.0381 0.0323 0.0528 0.0954 0.2000 0.3608 0.2646 0.2910 0.2954 0.2036 6.1041 0.1017 0.2637 0.3047 0.4102 0.4750 0.4384 0.3918 0.4777 0.5146 0.4658 0.3833 0.2218 0.1886 0.2675 0.4227 0.3751 0.4277 0.0526 B(iso) 5.6 4.1 5.8 7.6 7.9 8.1 6.2 3.9 5.5 6.2. 5.7 4.7 4.4 6.4 6.8 5.3 4.1 7.9 7.9 7.9 7.0 7.0 7.0 4.1 225 C a l c u l a t e d h y d r o g e n atom c o o r d i n a t e s and B ( i s o ) ( c o n t . ) atom B ( i s o ) H(49) H(50) H(51) H(52) H(53) H(54) H(55) H(56) H(57) H(58) H(59) H(60) H(61 ) H(62) H(63) H(64) H(65) H(66) H(67) H(68) H(69) H(70) H(71) H(72) 0 .1246 0 .0401 0 .0114 0 .0668 0 .1178 0 .0692 0 .0940 0 .7502 0 .7912 0 .8338 0 .7682 0 .7711 0 .7933 0 .7214 0 .9209 0 .9236 0 .8981 0 .6811 0 .6109 0 .6809 0 .9364 0 .9603 0 .9628 0 .7399 0 .1655 0 .0957 0 .0612 0 .0950 0 .1577 0 .1771 0 .1131 0 .2218 0 .1865 -0 .0754 -0 .0498 0 .2114 . 0 .1542 0 .1581 0 .1676 0 .1511 0 .2123 0 .0019 0 .0357 0 .0688 0 .0069 -0 .0142 0 .0514 0 .2234 -0 .0493 -0 .0549 0 .0449 0 .1480 0 .2969 0 .2300 0 .2389 0 .1850 0 .2458 0 .1444 0 .0977 0 .0558 0 .0246 0 .0478 0 .2000 0 .1248 0 .1418 0 .0283 0 .0154 0 .0372 0 .2251 0 .1588 0 .1770 0 .3152 5 .1 5.4 4 . 7 4 . 3 3 .6 3 .6 3 .6 3 . 5 3 . 5 3 .4 3 .4 5 .0 5 .0 5 .0 5 .6 5 .6 5 .6 5 .5 5 .5 5 . 5 5 .2 5 .2 5 .2 3 . 9 226 C a l c u l a t e d h y d r o g e n atom c o o r d i n a t e s and B ( i s o ) ( c o n t . ) atom H(73) H(74) H(75) H(76) H(77) H(78) H(79) H(80) H(81 ) H(82) H(83) H(84 ) H(85) H( 86 ) H(87 ) H( 88 ) H(89) H(90) H(91) H(92) H(93) H(94) H(95) H(96) 0 .6979 0 .5902 0 .5207 0 .5604 0 .6488 0 .5606 0 .4816 0 .4882 0 .5740 0 .6951 0 .6289 0 .6039 0 .6441 0 .7105 0 .8930 0 .9876 0 .9920 0 .9053 0 .8144 0 .7010 0 .6398 0 .6308 0 .6829 0 .7536 0 .2590 0 .2329 0 .1742 0 .1384 0 .2556 0 .2921 0 .2326 0 .1346 0 .0967 -0 .0937 -0 .1753 -0 .2343 -0 .2114 -0 .1300 0 .0983 0 .1535 0 .2000 0 .1867 0 .1257 0 .1199 0 .1034 0 .0118 -0 .0636 -0 .0462 0 .4075 0 .4263 0 .3494 0 .2574 0 .1532 0 .0752 0 .0121 0 .0300 0 .1117 0 .3059 0 .3092 0 .2160 0 .1187 0 .1151 0 .2732 0 .3154 0 .4182 0 .4786 0 .4402 0 .3940 0 .4802 0 .5197 0 .4747 0 .3960 B ( i so) 4 . 8 5 .2 5 .4 3 . 7 3 . 7 4 .2 4 .2 3 .7 3 .3 5 .5 6 .9 6 . 7 6 . 5 5 .3 4 .4 5 .3 5 .5 5 .7 4 .6 3 .6 4 .2 • 5 . 4 5 .0 3 .6 227 C a l c u l a t e d hydrogen atom coordinates and B(iso) (cont.) atom H ( 9 7 ) H(98) H ( 9 9 ) H ( 1 0 0 ) H ( 1 0 1 ) H ( 1 0 2 ) H ( 1 0 3 ) H ( 1 0 4 ) H(105) H(106) H(107) H(108) H(109) H(110) 0 . 9 0 5 9 0 . 9 5 1 2 0 . 9 7 2 0 1 . 0 1 1 2 1 . 0 5 4 2 1 . 0 1 8 9 0 . 5 9 3 3 0 . 5 3 7 4 0 . 5 6 5 8 0 . 6 5 3 7 0 . 7 1 1 7 0 . 6 3 6 6 0 . 5 8 9 6 0 . 6 1 7 0 - 0 . 2 0 0 4 - 0 . 1 7 4 0 - 0 . 1 6 4 4 - 0 . 0 5 2 1 - 0 . 0 2 6 7 0 . 0 1 4 6 - 0 . 0 3 0 3 - 0 . 0 6 3 9 - 0 . 0 3 0 2 0 . 0 3 5 4 0 . 0 6 9 2 0 . 0 3 6 6 0 . 0 5 2 0 - 0 . 0 1 0 9 0 . 2 5 3 3 0 . 2 0 4 2 0 . 2 8 2 6 0 . 4 4 3 5 0 . 3 9 1 7 0 . 4 3 7 0 0 . 1 5 3 8 0 . 0 5 1 9 - 0 . 0 4 8 2 - 0 . 0 4 3 1 0 . 0 5 8 5 0 . 3 0 0 6 0 . 2 3 1 1 0 . 2 4 5 1 B(iso) 7 . 2 7 . 2 7 . 2 1 4 . 3 1 4 . 3 1 4 . 3 3 . 6 4 . 9 5 . 4 4 . 8 3 . 9 3 . 5 3 . 5 3 . 5 228 A1.4 X-ray Crystallographic Analysis of I r ( C H 3 ) I { C 2 ( C 0 2 M e ) 2 } [ N ( S i M e 2 C H 2 P P h 2 ) 2 ] , 14 Experimental Details E m p i r i c a l F o r m u l a F o r m u l a W e i g h t C r y s t a l S y s t e m L a t t i c e P a r a m e t e r s : S p a c e G r o u p Z v a l u e D c a l c F 0 0 0 mu(Cu K - a l p h a ) D i f f r a c t o m e t e r R a d i a t i o n Tempe r a t u r e 2 - t h e t a ( m a x ) No. O b s e r v a t i o n s ( I > 3 . 0 0 ( s i g ( I ) ) ) No. V a r i a b l e s R e s i d u a l s : R; Rw G o o d n e s s o f F i t I n d i c a t o r Maximum S h i f t i n F i n a l C y c l e L a r g e s t P e a k i n F i n a l D i f f . Map C ( 3 7 ) H ( 4 5 ) 1 ( 1 ) I r ( l ) N ( l ) 0 ( V ) P ( 2 ) S i ( 2 ) 923.94 M o n o c l i n i c a » 1 1 . 9 1 1 ( 2 ) a n g s t r o m s b - 1 9 . 9 9 8 ( 2 ) a n g s t r o m s c • 16.502 ( 2 ) a n g s t r o m s b e t a « 9 4 . 0 5 ( 1 ) d e g r e e s V - 3 9 2 0 . 9 ( 8 ) a n g s t r o m s * * 3 P 2 1 / n (#14) 4 1 .57 g/cm**3 1812 1 4 6 . 6 9 c m * * - l R i g a k u A F C 6 Cu K - a l p h a ( l a m b d a = 1 . 5 4 1 7 8 ) G r a p h i t e - m o n o c h r o m a t e d 21 d e g r e e s C e n t . 1 5 5 . 3 d e g r e e s 4945 434 0 . 0 4 7 ; 0.057 1.66' 0.02 1 .75 e / a n g s t r o m * * 3 229 Table Al.4.1 Bond Lengths (A) with estimated standard deviations in parentheses atom atom distance atom atom distance Ir N 2.044(9) S i d ) C(l) 1.87(1) Ir C(37) 2.146(9) Si(2) C(8) 1.86(1) Ir P d ) 2.278(3) Si(2) C(7) 1.86(1) Ir C(3) 2.32(1) Si(2) C(4) 1.87(1) Ir P(2) 2.433(2) Si(2) C(3) 1.87(1) Ir I 2.6929(9) 0(1) C(9) 1.33(1) P ( D C d ) 1.81(1) 0(1) C( 35) 1.44(2) P d ) C d l ) 1.82(1) 0(2) C(9) 1.18(1) P d ) C(17) 1.82(1) 0(3) C(10) 1.35(1) P(2) C(4) 1.83(1) 0(3) C(36) 1.44(1) P(2) C(23) 1.83(1) 0(4) C(10) 1.21(1) P(2) C(29) 1.84(1) N C(2) 1.28(1) S i ( l ) N 1.796(9) C(2) C(3) 1.51(1) S i d ) C(5) 1.85(1) C(2) C(9) 1.52(1) S i d ) C(6) 1.85(1) C(3) C(10) 1.46(1) 230 Table Al.4.2 Bond Angles (deg) with estimated standard deviations in parentheses a t o m a t o m a t o m a n g l e N I r C ( 3 7 ) 8 5 . 1 ( 4 ) N I r P d ) 9 1 . 1 ( 2 ) N I r C ( 3 ) 6 4 . 3 ( 3 ) N I r P d ) 9 3 . 7 ( 2 ) N I r I 1 6 5 . 6 ( 2 ) C ( 3 7 ) I r P d ) 9 1 . 5 ( 3 ) C ( 3 7 ) I r C ( 3 ) 8 3 . 6 ( 4 ) C ( 3 7 ) I r P d ) 1 7 2 . 1 ( 3 ) C ( 3 7 ) I r I 8 4 . 7 ( 3 ) P d ) I r C d ) 1 5 5 . 2 ( 3 ) P d ) I r P d ) 9 6 . 3 7 ( 9 ) P d ) I r I 9 9 . 2 4 ( 7 ) C ( 3 ) I r P d ) 8 8 . 8 ( 2 ) C( 3) I r I 1 0 4 . 5 ( 2 ) P ( 2 ) I r I 9 5 . 1 3 ( 7 ) C d ) P ( D C ( l l ) 1 0 5 . 3 ( 5 ) C ( l ) P d ) C ( 1 7 ) 1 0 6 . 6 ( 5 ) C ( l ) P d ) I r 1 0 2 . 8 ( 3 ) C U D P d ) C ( 1 7 ) 9 9 . 6 ( 5 ) C ( l l ) P d ) I r 1 2 1 . 8 ( 3 ) C ( 1 7 ) P d ) I r 1 1 9 . 3 ( 4 ) C ( 4 ) P d ) C ( 2 3 ) 1 0 5 . 3 ( 5 ) C ( 4 ) P d ) C ( 2 9 ) 1 0 0 . 1 ( 5 ) C ( 4 ) P d ) I r 1 0 4 . 9 ( 4 ) C ( 2 3 ) P d ) C ( 2 9 ) 1 0 0 . 8 ( 5 ) C ( 2 3 ) P d ) I r 1 2 0 . 1 ( 4 ) a t o m a t o m a t o m a n g l e C ( 2 9 ) P ( 2 ) I r 1 2 2 . 8 ( 3 ) N S i CI ) C ( 5 ) 1 1 1 . 0 ( 5 ) N S i d ) C ( 6 ) 1 1 2 . 9 ( 5 ) N S i d ) C ( l ) 9 8 . 8 ( 4 ) C ( 5 ) S i d ) C ( 6 ) 1 1 2 . 0 ( 7 ) C ( 5 ) S i d ) C ( l ) 1 1 0 . 7 ( 6 ) C ( 6 ) S i d ) C ( l ) 1 1 0 . 8 ( 5 ) C ( 8 ) S i d ) C ( 7 ) 1 0 8 . 7 ( 6 ) C ( 8 ) S i ( 2 ) C ( 4 ) 1 1 0 . 9 ( 5 ) C ( 8 ) S i d ) C ( 3 ) 1 1 2 . 0 ( 5 ) C ( 7 ) S i ( 2 ) C ( 4 ) 1 0 8 . 9 ( 6 ) C ( 7 ) S i ( 2 ) C ( 3 ) 1 1 2 . 9 ( 5 ) C ( 4 ) ' S i ( 2 ) C ( 3 ) 1 0 3 . 4 ( 5 ) C ( 9 ) 0 ( 1 ) C ( 3 5 ) 1 1 6 ( 1 ) C ( 1 0 ) 0 ( 3 ) C ( 3 6 ) 1 1 5 . 9 ( 9 ) C ( 2 ) N S i ( l ) 1 3 7 . 8 ( 8 ) C ( 2 ) N I r 9 9 . 7 ( 7 ) S i ( l ) N I r 1 2 0 . 2 ( 4 ) P d ) C ( l ) S i d ) 1 1 4 . 0 ( 6 ) N C ( 2 ) C ( 3 ) 1 1 3 ( 1 ) N C ( 2 ) C(9.) 1 2 4 ( 1 ) C ( 3 ) C ( 2 ) C ( 9 ) 1 2 2 . 2 ( 9 ) C ( 1 0 ) C d ) C ( 2 ) 1 1 4 . 2 ( 9 ) C ( 1 0 ) C ( 3 ) S i ( 2 ) 1 1 0 . 2 ( 7 ) C ( 1 0 ) C d ) , I r 1 2 1 . 0 ( 7 ) C ( 2 ) C ( 3 ) S i ( 2 ) 1 2 0 . 0 ( 7 ) 231 T a b l e ( c o n t i n u e d ) a t o m a t o m C ( 2 ) C ( 3 ) S i ( 2 ) C ( 3 ) P ( 2 ) C ( 4 ) 0 ( 2 ) C ( 9 ) 0 ( 2 ) C ( 9 ) 0 ( 1 ) C ( 9 ) 0 ( 4 ) C ( 1 0 ) 0 ( 4 ) C ( 1 0 ) 0 ( 3 ) C ( 1 0 ) a t o m a n g l e l r 8 2 . 2 ( 6 ) I r 1 0 7 . 3 ( 4 ) S i ( 2 ) 1 0 8 . 4 ( 5 ) 0 ( 1 ) 1 2 5 ( 1 ) C ( 2 ) 1 2 5 ( 1 ) C ( 2 ) 1 1 0 ( 1 ) 0 ( 3 ) 1 2 1 ( 1 ) C ( 3 ) 1 2 6 ( 1 ) C ( 3 ) 1 1 3 . 1 ( 9 ) 232 Table Al.4.3 Final Atomic Coordinates (Fractional') and B(eq) a t o m X y z B ( e q ) I r 0. 54293(4) 0 .28052(2) 0 .2760K 3) 2 .21(1) I 0. 65116(7) 0 .37548(4) 0 .36706(5) 3 .92(4) P ( l ) 0. 4653(2) 0 .3460(1) 0 .1739(2) 2 .5(1) P(2) 0. 3783(2) 0 .2776(1) 0 .3552(2) 2 .5(1) S i ( l ) 0. 4378(3) 0 .2016(2) 0 .1099(2) 3 .1(1) S i(2) 0. 5284(3) 0 .1719(1) 0 .4322(2) 3 .0(1) 0(1) 0. 5583(9) 0 .0708(4) 0 .1570(6) 5 .1(5) 0(2) 0. 5636(8) 0 .0344(4) 0 .2854(6) 4 .8(4) 0 ( 3) 0. 7634(6) 0 .1291(4 ) 0 .2915(5) 3 .6(4 ) 0 ( 4 ) 0. 7808(7) 0 .1813(5) 0 .4113(5) 5 .2(5) N 0. 4981(7) 0 .1958(4) 0 .2125(5) 2 .6(3) C ( l ) 0. 3778(8) 0 .2880(5) 0 .1142(6) 2 .8(4) C(2) 0. 5494(9 ) 0 .1520(5) 0 .2582(6) 2 .6(4) C(3) 0. 6018(8 ) 0 .1805(5) 0 .3364(6) 2 .4(4) C(4) 0. 3797(9) 0 .1943(5) 0 .4005(6) 2 .8(4 ) C(5) 0. 548(1) 0 .1978(8) 0 .0368(8) 5 .3(7) C(6) 0. 325(1) 0 .1394(6) 0 .0866(7) 4 .0(5) C(7) 0. 532(1) 0 .0851(7) 0 .4727(8) 4 .8(7) C(8) 0. 587(1) 0 .2292(7) 0 .5130(7) 4, .1(6) C(9) 0. 5577(9) 0 .0783(5) 0 .2373(7) 3, .0(5) C(10) 0. 7214(9) 0 .1653(5) 0 .3517(6) 2, .8(4) C ( l l ) 0. 374(1) 0 .4161(5) 0 .1936(6) 2. .9(4) C(12) 0. 259(1 ) 0 .4159(6) 0 .1713(8) 4 , .4(6) C(13) 0. 191(1) 0 .4699(7) 0 .1878(8) 4 . 7(6) C(14) 0. 236(1) 0 .5249(6) 0 .2277(7) 4 . 3(6) 233 atom X y z B (e q) C ( 1 5 ) 0 . 3 5 1 ( 1 ) 0. 5258(6) 0 . 2 4 9 8 ( 9 ) 4 . 9 ( 7 ) C ( 1 6 ) 0 . 4 1 8 ( 1 ) 0 . 4723(6) 0 . 2 3 3 9 ( 8 ) 3 . 9 ( 5 ) C ( 1 7 ) 0 . 5 5 7 ( 1 ) 0 . 3859(6) 0 . 1 0 4 4 ( 7 ) 3 . 3 ( 5 ) C ( 1 8 ) 0 . 5 3 6 ( 1 ) 0 . 3839(8) 0 . 0 2 0 5 ( 8 ) 5 . 3 ( 7 ) C ( 1 9 ) ' 0 . 6 0 8 ( 1 ) 0 . 416(1) - 0 . 0 2 7 2 ( 8 ) 6 . 8 ( 9 ) C{20) 0 . 6 9 9 ( 1 ) 0. 4529(8) 0 . 0 0 4 ( 1 ) 5 . 7 ( 8 ) C ( 2 1 ) 0 . 7 2 2 ( 1 ) 0 . 4544(7) 0 . 0 8 6 8 ( 9 ) 4 . 9 ( 7 ) C ( 2 2 ) 0 . 6 5 0 ( 1 ) 0. 4218(6) 0 . 1 3 6 3 ( 7 ) 3 . 7 ( 5 ) C ( 2 3 ) 0 . 3 6 7 ( 1 ) 0. 3355(5) 0 . 4 3 9 9 ( 7 ) 3 . 0 ( 5 ) C ( 2 4 ) 0 . 3 7 7 ( 1 ) 0. 4032(6 ) 0 . 4 2 3 7 ( 8 ) 4 . 8 ( 7 ) C ( 2 5 ) 0 . 3 6 5 ( 1 ) 0. 4503(6) 0 . 4 8 6 ( 1 ) 5 . 8 ( 8 ) C(26) 0 . 3 5 0 ( 1 ) 0. 4295(7) 0 . 5 6 2 ( 1 ) 5 . 6 ( 8 ) C ( 2 7 ) 0 . 3 3 9 ( 1 ) 0. 3630(7) 0 . 5 7 8 6 ( 7 ) 4 . 7 ( 7 ) C ( 2 8 ) 0 . 3 4 7 ( 1 ) 0. 3161(6) 0 . 5 1 6 8 ( 7 ) 3 . 5 ( 5 ) C(29) 0 . 2 3 3 3 ( 8 ) 0. 2798(6) 0 . 3 0 8 5 ( 6 ) 3 . 0 ( 4 ) C O O ) 0 . 2 0 0 ( 1 ) 0. 2285(6) 0 . 2553(8 ) 4 . 0 ( 5 ) C ( 3 1 ) 0 . 0 9 1 ( 1 ) 0. 2252(7) 0 . 2 2 0 2 ( 8 ) 4 . 7 ( 6 ) C ( 3 2 ) 0 . 0 1 2 ( 1 ) 0. 273(1) 0 . 2 3 5 4 ( 8 ) 5 . 8 ( 7 ) C ( 3 3 ) 0 . 0 4 4 ( 1 ) 0 . 322(1) 0 . 2 8 8 ( 1 ) 6 . 6 ( 9 ) C ( 3 4 ) 0 . 1 5 5 ( 1 ) 0. 3267(8) 0 . 3 2 4 6 ( 8 ) 5 . 1 ( 7 ) C ( 3 5 ) 0 . 5 6 3 ( 2 ) 0. 0029(8) 0 . 1 2 9 ( 1 ) 9 (1) C ( 3 6 ) 0 . 8 7 9 ( 1 ) 0. 1073(7) 0 . 3 0 6 0 ( 8 ) 5 . 0 ( 7 ) C ( 3 7 ) 0 . 6 9 7 9 ( 8 ) 0 . 2730(6) 0 . 2 1 7 7 ( 7 ) 3 . 3 ( 5 ) 234 H y d r o g e n a t o m c o o r d i n a t e s a n d B ( i s o ) . atom X y H ( l ) 0 . 3 0 4 8 0 . 2 8 5 2 H ( 2 ) 0 . 3 6 7 2 0 . 3 0 5 3 H ( 3 ) 0 . 3 3 4 7 0 . 1 9 4 3 H ( 4 ) 0 . 3 4 8 4 0 . 1 6 1 8 H ( 5 ) 0 . 5 6 8 2 0 . 1 5 5 2 H ( 6 ) 0 . 5 1 3 1 0 . 2 0 1 5 H ( 7 ) 0 . 6 0 1 0 0 . 2 3 4 8 H ( 8 ) 0 . 2 6 4 3 0 . 1 4 6 4 H ( 9 ) 0 . 2 9 5 5 0 . 1 4 4 7 H ( 1 0 ) 0 . 3 5 5 8 0 . 0 9 4 3 H ( l l ) 0 . 4 8 6 6 0 . 0 8 2 5 H ( 1 2 ) 0 . 5 0 2 0 0 . 0 5 4 3 H ( 1 3 ) 0 . 6 1 0 1 0 . 0 7 2 8 H ( 1 4 ) 0 . 6 6 5 4 0 . 2 1 6 6 H ( 1 5 ) 0 . 5 8 5 0 0 . 2 7 5 2 H ( 1 6 ) 0 . 5 4 2 5 0 . 2 2 5 9 H ( 1 7 ) 0 . 2 2 5 9 0 . 3 7 6 8 H ( 1 8 ) 0 . 1 1 0 4 0 . 4 6 8 7 H ( 1 9 ) 0 . 1 8 8 8 0 . 5 6 2 9 H ( 2 0 ) 0 . 3 8 4 4 0 . 5 6 5 2 H ( 2 1 ) 0 . 4 9 6 6 0 . 4 7 3 8 H ( 2 2 ) 0 . 4 7 0 7 0 . 3 5 9 7 H ( 2 3 ) 0 . 5 9 4 5 0 . 4 1 3 4 H ( 2 4 ) 0 . 7 4 6 1 0 . 4 7 7 4 H ( 2 5 ) 0 . 7 8 7 6 0 . 4 7 8 3 z B ( i s o ) 0 . 1 3 7 9 3 . 4 0 . 0 5 8 7 3 . 4 0 . 4 4 8 0 3 . 4 0 . 3 6 0 6 3 . 4 0 . 0 4 3 0 6 . 3 0 . 0 1 8 6 6 . 3 0 . 0 4 7 2 6 . 3 0 . 1 2 2 7 4 . 8 0 . 0 3 0 0 ' 4 . 8 0 . 0 9 4 6 4 . 8 0 . 5 1 9 7 5 . 8 0 . 4 3 0 4 5 . 8 0 . 4 8 9 2 5 . 8 0 . 5 2 8 5 4 . 9 0 . 4 9 2 6 4 . 9 0 . 5 6 0 4 4 . 9 0 . 1 4 3 3 5 . 3 0 . 1 7 1 0 5 . 7 0 . 2 4 0 4 5 . 1 0 . 2 7 7 2 5 . 9 0 . 2 5 1 2 4 . 7 0 . 0 0 4 3 6 . 4 0 . 0 8 6 3 8 . 2 0 . 0 3 2 5 6 . 8 0 . 1 1 0 6 5 . 9 235 Hydrogen atom coordinates and B(iso) (continued). atom x y z B(iso) H(26) H(27) H(28) H(29) H(30) H(31) H(32) H(33) H( 34 ) H(35) H(36) H(37) H(38) H(39) H( 40 ) H(41) H(42) H(43) H(44) H(45) 0.6661 0.3932 0.3664 0.3468 0.3260 0.3377 0.2547 0.0693 -0.0640 -0.0113 0.1746 0.4965 0.5643 0.6311 0.8856 0.9010 0.9278 0.7344 0.6822 0.7 478 0.4239 0.4181 0.4982 0.4624 0.3484 0.2684 0.1942 0.1880 0.2714 0.3552 0.3638 -0.0215 0.0027 -0.0187 0.0789 0.0818 0.1464 0.2303 0.2754 0.3099 0.1954 0.3692 0.4732 0.6055 0.6339 0.5287 0.2424 0.1837 0.2091 0.3013 0.3616 0.1443 0.0693 0.1528 0.3544 0.2590 0.3143 0.2321 0.1586 0.2357 4.4 5.8 7.0 6.7 5.6 4.2 4.8 5.6 6.9 7.9 6.1 10.3 10.3 10.3 6.0 6 .0 6.0 4.0 4.0 4.0 236 A1.5 X-ray Crystallographic Analysis of /flc-Ir{ri4.C(CH2)3}[N(SiMe2CH 2PPh2)2], 24 Experimental Details E m p i r i c a l F o r m u l a F o r m u l a W e i g h t C r y s t a l C o l o r , H a b i t C r y s t a l D i m e n s i o n s (mm) C r y s t a l S y s t e m N o . R e f l e c t i o n s U s e d f o r U n i t C e l l D e t e r m i n a t i o n (29 r a n g e ) Omega S c a n Peak W i d t h a t H a l f - h e i g h t L a t t i c e P a r a m e t e r s : Space G r o u p Z v a l u e D c a l c Fooo ' ' ( M o K a ) D i f f T a c t o m e t e r R a d i a t i o n T e m p e r a t u r e T a k e - o f f A n g l e C 3 4 H 4 2 I r N P 2 S i 2 775.05 c o l o r l e s s , p r i s m 0.120 X 0.250 X 0.350 t r i c l i n i c 25 ( 25.3 - 30 .0 e ) 0.36 a - 11 .202 (2)A b - 1 3 . 6 2 9 (2)A c - 10 .972 (2)A a - 9 0 . 4 3 ( 2 ) e P - 9 0 . 8 0 ( 2 ) ° Y - 9 6 . 6 7 ( 2 ) ° V - 1 6 8 7 . 9 ( 6)A 3 P i (#2) 2 1 .525 g / c m 3 776 4 1 . 2 7 c m - 1 I n t e n s i t y M e a s u r e m e n t s R i g a k u AFC6S MoKo (X - 0 .71069 A) 2 1 ° C 6 . 0 ° 237 D e t e c t o r A p e r t u r e C r y s t a l t o D e t e c t o r D i s t a n c e S c a n Type S c a n R a t e S c a n W i d t h 26 max N o . o f R e f l e c t i o n s M e a s u r e d C o r r e c t i o n s C . S t r u c t u r e S o l u t i o n S t r u c t u r e S o l u t i o n R e f i n e m e n t F u n c t i o n M i n i m i z e d L e a s t - s q u a r e s W e i g h t s p - f a c t o r A n o m a l o u s D i s p e r s i o n N o . O b s e r v a t i o n s ( I > 3 . 0 0 c ( U ) N o . V a r i a b l e s R e f l e c t i o n / P a r a m e t e r R a t i o R e s i d u a l s : R; R w G o o d n e s s o f F i t I n d i c a t o r Max S h i f t / E r r o r i n F i n a l C y c l e Maximum Peak i n F i n a l D i f f . Map Minimum Peak i n F i n a l D i f f . Map 6 . 0 mm h o r i z o n t a l 6 . 0 mm v e r t i c a l - 265 mm u>-2 6 3 2 . 0 ° / m i n ( i n omega) (6 r e s c a n s ) ( 1 . 1 0 + 0 . 3 5 t a n 6 ) e 5 9 . 9 " T o t a l : 10289 U n i q u e : 9822 ( * i n t - .030) L o r e n t z - p o l a r i z a t i o n A b s o r p t i o n ( t r a n s , f a c t o r s : 0 .54 - 1. and R e f i n e m e n t P a t t e r s o n Method F u l l - m a t r i x l e a s t - s q u a r e s z w ( | ro I - I F c I ) 2 2 2 2 4 F o V o ( F o z ) 0.03 A l l n o n - h y d r o g e n atoms 6397 385 1 6 . 6 2 0 . 0 3 4 ; 0 .036 1 .27 0 .08 1 .29 e~/A* - 1 . 3 5 e"/A 3 238 Tahle Al.S.l Rnnd Lengths (k) with estimated standard deviations in parentheses atom atom distance l r ( l ) P ( l ) 2.296(1) l r ( l ) P(2) 2 .295(1) l r ( l ) N ( l ) 2 .198(4) l r ( l ) C(31) 2 .055(5) l r ( l ) C(32) 2 .189(5) l r ( l ) C(33) 2 .222(5) l r ( l ) C(34) 2 .202(5) P ( l ) C ( l ) 1 .827(5) P ( l ) C(7) 1 .840(5) P ( l ) C(13) 1 .826(5) P(2) C(2) 1 .821(5) P(2) C(19) 1 .834(5) P(2) C(25) 1 .823(5) S i ( l ) N ( l ) 1 .688(4 ) S i ( l ) C ( l ) 1 .898(5) S i ( l ) C(3) 1 .861(7) S i ( l ) C(4) 1 .868(6 ) S i ( 2 ) N ( l ) 1 .694(4 ) S i ( 2 ) C(2) 1 .897(5) S i ( 2 ) C(5) • 1 .873(6) S i ( 2 ) C(6) 1 .887(6) C(7) C(8) 1 .387(7) C(7) C(12) 1. .374(7) C(8) C(9) 1. 379(8) atom atom distance C(9) C(10) 1 .35(1) C(10) C ( l l ) 1 .39(1) C ( l l ) C(12) 1 .376(8) C(13) C(14) 1 .390(7) C(13) C(18) 1 .386(8) C(14) C(15) 1 .393(8) C(15) C(16) 1 .36(1) C(16) C(17) 1 .38(1) C(17) C(18) 1 .395(9) C(19) C(20) 1 .399(8) C(19) C(24) 1 .396(7) C(20) C(21) 1 .366(8) C(21) C(22) 1 .39(1) C(22) C(23) 1 .36(1) C(23) C(24) 1 .400(9) C(25) C(26) 1 .400(6) C(25) C(30) 1 .390(7) C(26) C(27) 1 386(7 ) C(27) C{28) 1. 362(8) C(28) C(29) 1. 388(8) C(29) C(30) 1. 395(8) C(31) C(32) 1. 426(7) C(31) C(33) 1. 437(7) C(31) C(34) 1. 441(7) 239 Table Al.5.2 Bond Angles fdegl with estimated standard deviations in parentheses atom a t o m a t o m a n g l e a tom a tom a t o m a n g l e P ( l ) l r ( l ) P(2) 106.49(5) C(7) P d ) C(13) 100 .5(2) P (1) I r ( l ) N d ) 87.0(1) l r ( l ) P (2) C(2) 104 .7(2) P ( l ) I r ( l ) C(31) 123.1(1) i r ( l - ) P(2) C(19) 121 .8(2) P d ) I r ( l ) C(32) 101.9(2) i r d ) P(2) C(25) 118 .1(2) P d ) I r ( l ) C(33) 97.1(2) C(2) P(2) C(19) 103 .0(2) P d ) I r ( l ) C(34) 161.9(1) C(2) P(2) C(25) 105 .8(2) P(2) l r ( l ) N d ) 83.0(1) C(19) P(2) C(25) 101 .5(2) P(2) I r ( l ) C(31) 120.7(1) N(l ' ) S i d ) C ( l ) 104 .7(2) P(2) I r (1) C(32) 105.3(2) N ( l ) S i d ) C(3) 115 .5(3.) P(2) i r (1) C(33) 156.3(2) N ( l ) S i d ) C(4) 114 .9(3) P(2) I r (1) C(34) 90.4(2) C d ) S i d ) C(3) 111 .0(3) N ( l ) I r (1) C(31) 126.2(2) C ( l ) S i d ) C(4) 105 .2(3) N ( l ) , I r ( l ) C(32) 165.3(2) C(3) S i ( l ) C(4) 105 .1(3) N ( l ) I r (1) C(33) 101.1(2) N ( l ) ' S i (2) C(2) 106 .3(2) N ( l ) l r ( l ) C(34) 101.6(2) N ( l ) S i d ) C(5) 115 .1(2) C(31) I r ( l ) C(32) 39.1(2) N ( l ) S i ( 2 ) C(6) 114 .7(3) C(31) I r ( l ) C(33) 39.0(2) C(2) S i d ) C(5) 107 • 5(2) C(31) I r ( l ) C(34) 39.4(2) C(2) S i ( 2 ) C(6) 107 • 4(3) C(32) I r ( l ) C(33) 66.4(2) C(5) S i d ) C(6) 105 .4(3) C(32) I r ( l ) C(34) 66.7(2) I r d ) N ( l ) S i d ) 112 • 4(2) C(33) I r (1) C(34) 65.8(2) l r ( l ) N ( l ) S i ( 2 ) 114 .6(2) l r ( l ) P d ) C d ) 109.0(2) S i ( l ) N ( l ) S i ( 2 ) 132 .9(2) l r ( l ) P d ) C(7) 122.5(2) P d ) C d ) S i d ) 109 .2(2) l r ( l ) P d ) C d 3 ) 113.5(2) P(2) C(2) S i ( 2 ) 109 .1(2) C ( l ) P d ) C(7) 104.5(2) P d ) C(7) C(8) 120 .0(4) C ( l ) P d ) C(13) 105.2(2) P d ) C(7) C(12) 121 .9(4) 240 I n t r a m o l e c u l a r B o n d A n g l e s I n v o l v i n g t h e N o n h y d r o g e n Atoms ( c o n t ) atom atom atom a n g l e atom atom atom angl e C(8) C(7) C(12) 118 .1(5) C(26) C(27) C(28) 120 .6(5) C(7) C(8) C(9) 120 .0(6) C(27) C(28) C(29) 120 .1(5) C(8) C(9) C(10) 121 .2(6) C(28) C(29) COO) 119 .6(5) C(9) C(10) C ( l l ) 119 .8(6) C(25) COO) C(29) .121 .0(5) C(10) C ( l l ) C(12) 119 .0(6) l r ( l ) C O D C(32) 75. 5(3) C(7) C(12) C ( l l ) 121 .7(6) l r ( l ) C(31) C(33) 76. 8(3) P d ) C(13) C(14) 120 .7(4) l r ( l ) C O D C(34) 75. 8(3) P ( l ) C(13) C(18) 121 .7(4) C(32) C O D C(33) 115 .2(5) C(14) C(13) C(18) 117 .6(5) C(32) C O D C(34) 114 .7(5) C(13) C(14) C(15) 121 .1(6) C(33) C O D C(34) 113 .3(5) C(14) C(15) C(16) 120 .5(6) l r ( l ) C(32) C O D 65. 4(3) C(15) C(16) C(17) 119 .7(6) l r ( l ) C(33) C O D 64. 2(3) C(16) C(17) C(18) 120 .1(7) l r ( l ) C(34) C O D 64. 8(3) C(13) C(18) C(17) 121 .1(6) -P(2) C(19) C(20) 117 .7(4) P(2) _ C(19) C(24) 123 .0(5) C(20) C(19) C(24) 119 .3(5) C(19) C(20) C(21) 121 .0(6) C(20) C(21) C(22) . 119 .6(8) C(21) C(22) C(23) 120 .2(6) C(22) C(23) C(24) 121 .4(7) C(19) C(24) C(23) 118 .5(7) P(2) C(25) C(26) 120 .1(4) P(2) C(25) COO) 121 .9(4) C(26) C(25) COO) 117 .8(5) C(25) C(26) C(27) 120 .9(5) 241 Table A 1.5.3 Final Atomic Coordinates (Fractional) and Bfeq) atom X y z B ( e q ) l r ( l ) 0 . 12381(2) 0 .21981(1) 0 . 18561(2 ) 3 . 0 4 9 ( 7 ) P d ) 0 . 2688(1 ) 0 . 13678(9) 0 . 2724 (1 ) 3 . 6 1 ( 5 ) P (2 ) 0 . 0644(1 ) 0 . 32045(8) 0 . 3347(1 ) 3 . 3 3 ( 5 ) S i d ) 0 . 4000(1 ) 0 . 3022(1 ) 0 . 1287 (1 ) 4 . 5 0 ( 6 ) S i ( 2 ) 0 . 2192 (1 ) 0 . 4530(1) 0 . 1665 (1 ) 3 . 8 7 ( 6 ) N d ) 0 . 2661(3 ) 0 . 3410(3 ) 0 . 1595(4 ) 3 . 8 ( 2 ) C d ) 0 . 4165(4 ) 0 . 2028(4 ) 0 . 2438 (5 ) 4 . 3 ( 2 ) C(2 ) 0 . 0826(5 ) 0 .4413(3) 0 . 2679(4 ) 3 . 9 ( 2 ) C(3 ) 0 . 4167(6) 0 .2570(6) - 0 . 0296(6 ) 6 . 9 ( 3 ) C(4 ) 0 . 5332(5) 0 .3946(5) 0 . 1559(7 ) 7 . 1 ( 3 ) C(5 ) 0 . 1729(5) 0 . 5023(4 ) 0 . 0168(5 ) 5 . 3 ( 3 ) C(6) 0 . 3323(6 ) 0 . 5509(4 ) 0 .2350(6) 6 . 3 ( 3 ) C(7) 0 . 2720(5) 0 .1086(3) 0 .4360(5) 3 . 9 ( 2 ) C(8) 0 . 1665(5) 0 .1009(4) 0 .5018(5) 5 . 1 ( 3 ) C(9) 0 . 1689(7 ) 0 .0801(5) 0 . 6245(6 ) 6 . 5 ( 3 ) C d O ) 0 .2727(8) 0 .0691(4) 0 . 6834(5 ) 6 . 5 ( 3 ) C d l ) 0 . 3795(7) 0 .0765(5) 0 .6195(6) 6 . 2 ( 3 ) C d 2 ) 0 .3770(5) 0 .0954(4) 0 .4966(5) . 4 . 9 ( 2 ) C d 3 ) 0 .2739(5) 0 . 0156(4 ) 0 .2067(5) 4 . 4 ( 2 ) C d 4 ) 0 . 2082(5) - 0 .0654(4) 0 . 2571(5 ) 5 . 1 ( 3 ) C d 5 ) 0 . 2076(6 ) - 0 .1575(4) 0 . 2046(7 ) 6 . 7 ( 3 ) C d 6 ) 0 . 2721(7 ) - 0 . 1 7 0 K 5) 0 .1024(8) 7 . 1 ( 4 ) C d 7 ) 0 .3381(7) - 0 .0910(6) 0 .0506(7) 7 . 6 ( 4 ) C d 8 ) 0 .3364(6) 0 .0014(4) 0 .1024(6) 6 . 3 ( 3 ) 242 T a b l e ( c o n t i n u e d ) atom X y z B ( e q ) C(19) 0 . 1461(5 ) 0. 3392(3) 0. 4806(4) 4 . 1 ( 2 ) C(20) 0 . 2716(6 ) 0. 3566(4) 0. 4775(5) 5 . 4 ( 3 ) C(21) 0 . 3384(7 ) 0. 3727(5) 0. 5824(7) 7 . 4 ( 4 ) C ( 2 2 ) 0 . 2 8 1 ( 1 ) 0. 3724(5) 0. 6938(7) 8 . 5 ( 5 ) C(23) 0 . 1 5 9 ( 1 ) 0. 3539(5) 0. 6988(5) 7 . 9 ( 4 ) C(24) 0 . 0887(6 ) 0. 3381(4) 0. 5928(5) 5 . 7 ( 3 ) C(25) -0 . 0909(4) 0. 3004(3) 0. 3848(4) 3 . 7 ( 2 ) C(26) -0 . 1414(5 ) 0. 2070(4) 0. 4176(5) 4 . 4 ( 2 ) C(27) - 0 . 2564(5 ) 0. 1916(4) 0. 4641(5) 5 . 0 ( 3 ) C(28) - 0 .3227(5) 0. 2673(5) 0. 4790(6) 5 . 4 ( 3 ) C(29) - 0 . 2753(5 ) 0. 3609(4) 0. 4475(6) 5 . 6 ( 3 ) C(30) - 0 .1604(5) . 0. 3766(4) 0. 3988(5) 4 . 8 ( 2 ) C(31) 0 .0037(4) 0. 1598(4) 0. 0550(5) 4 . 1 ( 2 ) C(32) - 0 .0262(5) 0. 1046(4 ) 0. 1618(5) 4 . 5 ( 2 ) C(33) 0 .1183(5) 0. 1473 ( 4 ) 0. 0039(5) 4 . 8 ( 2 ) C(34) - 0 . 0187(5 ) 0. 2602(4 ) 0. 0624(5) 4 . 4 ( 2 ) 243 A1.6 X-ray Crystallographic Analysis of I r (Ti4 .C4H 6 ) [N(SiMe2CH 2 PPh2)2] , 28 Experimental Details compound f o r m u l a fw crystal system space group « ( A ) 4 (A) C ( A ) Q (deg) 0 (deg) 1 ( d e g) v (A3) z A (g/cm 3) c(Mo'/f.) (cm- 1 ) crystal dimensions (mm) scan type scan range (deg in u>) scan speed (deg/min) data collected 2 f m „ (deg) crystal decay unique, reflections reflections with J > 3cr(7) number of variables R S mean A/cr (final cycle) max A / a (final cycle) residual density ( e /A 3 ) I(Ph J PCH a SiMej),N]lr (T ? 4 .C 4 H6) C M H « l r N P , S i 2 775.05 tri c l i n i c P i * 10.9061(5) 11.1193(9) 14.0083(5) 95.040(6) 91.127(4) 90.520(6) 1691.8(2) ' 2 1.521 776 41.2 0.27x0.35x0.45 u>-26 0.80 -i- 0.35 tan 6 1.7-20.0 -±A,±*,-rJ 60 negligible 9810 7666 362 0.025 0.033 1.143 0.002 0.017 -0.76 to 41.55 (near lr) 244 Table Al.6.1 Bond Lengths (Al with estimated standard deviations in parentheses Bond- Length(A) Bond Length(A) I r - P ( l ) 2.292(1) C(9)--C(10) 1.35(1) I r -P(2) 2.2879(9) C (10 )-C(11) 1.38(1) I r -N 2.214(3) c o 1 )-C(12) 1 .384(8) I r -C(31) 2.139(4) C(13 )-C(14) 1.386(7) I r -C(32> 2.167(4) C(13 )~C(18) 1.386(7) I r -C(33) 2.183 (4 ) C( 14 )-C(15) 1.390(7) I r -C(34) 2.162(4) C(15 )-C(16) 1.36(1) I r -Bu 1.770(2) C( 16 )-C(17) 1.37 ( 1 ) P ( 1 ) - C ( 1 ) 1.829(4) CC17 )~C ( 1 8 ) 1.399(8) P ( 1 )-C(7) 1.837(4) C( 19 )-C(20) . 1.388(7) P ( 1 ) - C ( l 3 ) 1.837(4) C( 19 )-C(24) 1.389(6) P(2 ) - C ( 2 ) 1.826(4) C(20 )~C(21) 1.384(7) P(2)-C(19) 1.832(4) C ( 2 1 )-C(22) 1.41 ( 1 ) P(2)-C(25) 1.828(4) C(22 )-C(23) 1 .36(1) S i ( 1)-N 1.683(4) C(23 )-C(24) 1 .389(8) S i ( 1)-C( 1 ) 1.891(4) C(25 )-C(26) 1.389(6) S i ( 1)-C(3) 1.863(7) C(25 )-C(30) 1.396(6) S i ( 1)-C(4) 1.864(6) C(26 )-C(27) 1.390(7) S i ( 2 ) - N 1.696(4) C(27 )-C(28) 1.369(7) S i ( 2 ) - C ( 2 ) 1.905(4) . C(28 )-C(29) 1.392(7) S i ( 2 ) - C ( 5 ) 1.888(5) C(29 )-C(30) 1.362(7) S i(2)-C(6) 1.883(5) C ( 3 1 )-C(32) 1.430(7) C(7)-C(8) 1 .376(7) C(32 )-C(33) 1.409(7) C(7)-C(12) 1 .397(6) C(33 >-C(34) 1 .421(7) C(8)-C(9) 1 .404 (7) Bu r e f e r s to the c e n t r o i d o f the butadiene l i g a n d . 245 Table Al.6.2 Bond Angles (deg) with estimated standard deviations in parentheses B o n d s A n g l e ( d e g ) P(1) - I r -P(2) 107 .01(4) p(1) - I r -N 87.49(9) P(1) - I r -Bu 122 .23(8) P(2) - I r -N 63 .43(9) P(2) - I r -Bu 123 .22(8) N - I r -Bu 122 .3(1 ) I r - P O ) -CO) 108 .5(1 ) I r -PO ) -C(7) 121 .8(1 ) I r ' -PO ) -C(13) 1 14 .3(1 ) CO ) -PO) -C(7) 106 .1(2) C O ) -PO ) -C(13) 105 .1 (2) C(7) -PO) -C(13) 99 .6(2) I r -P(2) -C(2) 106 .1(1) I r -P(2) -C(19) 1,22 .4(1) I r -P(2) -C(25) 116 .5(1) C(2) -P(2) -CO 9) 101 .8(2) C(2) -P(2) -C(25) 106 .4(2) C(19)-P(2 )-C(25) 101 .8(2) N - S i O )-CO ) 105 .5(2) N - S i O )-C(3) 113 .4(2) N - S i O )-C(4) 115 .7(2) c o ) - S i O )-C(3) 110 .2(3) CO ) - S i O )-C(4) 105 .9(2) C(3) - S i (1 )-C(4) 105 .9(4) N - S i (2 )-C(2) 106 .3(2) N - S i (2 )-C(5) 115 .2(2) N - S i (2 )-C(6) 115 .2(2) C(2) - S i (2 )-C(5) 107 .2(2) C(2) - S i (2 )-C(6) 108 .7(2) C(5) - S i (2 )-C(6) 104 .0(2) I r -N - S i O ) 109 .8(2) I r -N - S i ( 2 ) 116 .5(2) S i ( 1 ) - N - S i ( 2 ) 133 .7(2) P O ) -CO ) - S i O ) 108 .5(2) P(2) -C(2) - S i ( 2 ) 109 .2(2) B o n d s A n g l e ( d e g ) p ( 1 ) - C ( 7 ) - C ( 8 ) 119. 6(3) P (1)-C(7)-C(12) 121 . 2(4) c (8)-C(7)-C(12) 119. 2(4) c I 7 ) - C ( 8 ) - C ( 9 ) 120. 4(5) c ( 8 ) - C ( 9 ) - C O 0 ) 120. 2(6) c ( 9 ) - C O 0 ) - C ( l 1) 119. 8(5) c (10)-C(11)-C(12) 121 . 2(6) C ( 7 ) - C 0 2 ) - C ( 1 1 ) 119. 2(5) p (1 ) - C ( 1 3 ) - C 0 4 ) 121 . 1(4) p [1)-C(13)-C(18) 120. 2(4) C (14)-C(13)-C(18) 118. 5(4) C (13)-C(14)-C(15) 120. 7(6) C (14)-C(15)-C(16) 120. 8(6) C [ 15)-C(16)-C(17) 1 1 9 . 1(5) C ' 16)-C(17)-C(18) 121 . 4(6) C [ 13)-C(1B)-C(17) 119. 5(6) p [2)-C(19)-C(20) 118. 3(3) P 2 ) - C 0 9 ) - C ( 2 4 ) 123. 3(4) C 20) - C O 9 ) - C ( 2 4 ) 118. 3(4) c ' 1 9 ) - C ( 2 0 ) - C ( 2 l ) 121 . 5(5) c 2 0 ) - C ( 2 l ) - C ( 2 2 ) 118. 8(6) CI 21 )-C(22)-C(23) 120. 0(5) c 22)-C(23)-C(24) 120. 6(6) c 19)-C(24)-C(23) 120. 7(6) P 2)-C(25)-C(26) 119. 5(3) p 2)-C(25)-C(30) 122. 0(3) c 26)-C(25)-C(30) 118. 4(4) c 25)-C(26)-C(27) 120. 7(4) ci 26)-C(27)-C(28) 120. 3(5) CI 27)-C(28)-C(29) 119. 0(5) CI 2B)-C(29)-C(30) 121 . 3(5) C( 25)-C(30)-C(29) - 120. 3(4) C( 31)-C(32)-C(33) 1 16. 6(4) C( 32)-C(33)-C(34) 117. 4(4) 246 Table Al.6.3 Final Atomic Coordinates (Fractional) and B(eq) Atom y 2 U eq I r 313715 ( 1 2 ) 375874(13) 282414( 9) 40 P(1 ) 22792( 9) 22874( 9) 36538( 7) - 45 P(2) 16511( 9) 43637( 9) 18003( 6) 43 Si(1 ) 38224 C 1 1 ) 10392(11) 21053( 9) 57 S i (2) 32880(10) 27538( 1 1 ) 51 52 ( 8) 49 N 3451 ( 3) 2340( 3) 1 647 { 2) 49 c d ) 2636( 4) 8 1 5 ( 4) 3042( 3) 53 C(2) 22B3( 4) 4 1 49 ( 4 )' 600( 3) 50 c (3) 5392( 5) 1 060 { 7) 2655( 6) • 96 C ( 4 ) 3725 ( 7) -342( 5) 1 249 ( 5) 93 C (5) 4760( •5) 3 1 76 ( 5) -66( 4) 66 C(6) 2562( 5) 1 579( 5) -375( 4) 77 C(7) 630( 4 ) 2248 ( 4) 3895( 3) 50. C',6) -25( 4) 3302 ( 5) 3940( 3) 64 C O ) -1 284 ( 5) 3291 ( 7) 4 1 30 ( 4) 64 C( 10) -1 862( 5) 2243( 8) 4277 ( 4) S3 C( 1 1 ) - 1 2 1 2 ( 6) 1 181 ( 7) 4227 ( 4) 8E C( 12) 30( 4) 1 1 68 { 5) 4045( 3) 65 Cd3) 2695( 4 ) 2240( 4) 4880( 3) 56 C < 1 4 ) 23 1 7 ( 5) 2B33( 5) 5655( 3) 73 C d 5) 2830( 7 ) 2856( 7 ) 6573 ( 4) . 95 C( 1 6) 391 1 ( 7 ) 2304 ( 7) 6730( 4) 95 C d 7 ) 4507 (. 6) 1 740 ( 7 ) 5967 ( 5) 94 ' Cd8) 40 1 0 ( 5) 1 695 ( 6) 5037( 4) 80 C( 1 9) 1 63 ( 4 ) 3588( 4) 1 628 ( 3) 53 C O O ) 1 47 ( 5) 2337( 5) 1 484 ( 3) 6 7 C ( 2 1 ) -935 ( 6) 1 695( 6) 1 283 ( 4) 89 C(22) -2044( 6) 233 1 ( 9) 1 256( 5) 101 C(23) -2038( 5) 3555( 8) 1 406( 4) 92 C(24) -945( 4) 4191 ( 5) 1 593 ( 3) 69 C(25) 1 1 94 { 4 ) 5944 ( 4 ) 1 976( 3) 50 C(26) 977 ( 5) 6460( 4) 2895( 3) 59 C(27) 539( 5) 7630( 5) 3042( 4) 68 C(28) 333 ( 5) 6297 ( 4) 2280( 4) 67 C(2B) 579( 5) 7791 ( 5) 1 361 ( 4) 73 C O O ) 1 008 ( 5) 6645( 4) 1 207 ( 3) 62 C(31 ) 3360( 5) 5065( 4) 4031 ( 3) 62 C(32) 4474 ( 4) 4404 ( 4) 39 1 9 ( 3) 61 C(33) 5033( 4 ) 4393 ( 4) 3020( 3) 62: C 0 4 ) 4446( 4 ) 503B( 5) 231 1 ( 4) 63 247 A2 Raw Data for the Kinetic Studies of the Thermolysis and Carbonylation Processes A2.1a Thermolysis of Ir(CH 3)PPh2[N(SiMe2CH 2PPh2)2], 2a, in toluen Temperature =  73°C Temperature = 83°C Temperature =. 97 °C [2a] = 3.26 x IO"3 mol L / 1 [2a] = 3.26 x 10"3 mol L / 1 [2a] = 3.26 x 10"3 mol L / 1 Time (s) A t (538 nm) Time (s) A t (538 nm) Time (s) A t (538 nm) 0 0.893 0 0.881 0 0.879 500 0.788 200 0.824 200 0.700 1000 0.686 400 0.765 350 0.610 1500 0.609 700 0.658 500 0.535 2000 0.534 1000 0.573 650 0.480 2550 0.479 1300 ' 0.509 800 0.422 3300 0.385 1800 0.388 1000 0.344 4800 0.253 2300 0.298 1500 0.222 6800 0.155 4000 0.127 2000 0.165 0.060 Aoo 0.060 Aoo 0.060 k o b s = 0.54 x 10-3 s-1 k o b s = 0.84 x 10-3 s- 1 k o b s = 1.04 x 10-3 s- 1 Temperature =  97°C Temperature = 108°C [2a] = 3.26 x IO'3 mol L"1 [2a] = 3.26 x 10-3 mol L"1 . Time (s) A t (538 nm) Time (s) A t (538 nm) 0 0.879 0 0.914 200 0.688 100 0.849 350 0.598 250 0.653 500 0.522 400 0.520 650 0.472 550 0.410 800 0.414 700 0.327 1000 0.337 900 0.223 . 1200 0.277 1100 0.151 1500 0.215 Aoo 0.058 2000 0.097 Aoo 0.060 k o b s = 1.07 x 10-3 s-1 k o b s = 1.07 x IO'3 s- 1 . 248 A2.1b Thermolysis of Ir(CH 3)PPh2[N(SiMe 2CH2PPh2)2], 2a, in hexanes Temperature • = 60°C Temperature = 67°C Temperature = 78°C [2a] = 4.34 x IO"4 mol L" 1 [2a] = 4.34 x 10 - 4 mol L / 1 [2a] = 4.88 x IO"4 mol L / 1 Time (s) A t (538 nm) Time (s) A t (538 nm) Time (s) A t (538 nm) 0 1.010 0 0.912 0 1.490 1500 0.859 1000 0.803 200 1.400 3000 0.738 2000 0.701 600 1.215 4500 0.654 3000 0.613 1000 1.050 6000 0.592 4000 0.547 1400 0.920 8000 0.536 5000 0.483 1800 0.800 12000 0.440 7500 0.361 2200 0.693 15000 0.379 8500 0.322 2700 0.580 19000 0.320 9500 0.289 3500 0.420 24000 0.260 15000 0.106 4500 0.275 30000 0.136 Aoo 0.045 5500 0.190 35000 0.091 Aoo 0.050 •A. CO 0.060 k0bs = 6.06.x 10-5 s-1 k o b s = 1-37 x IO"4 s-1 k o b s = 4.20 x IO"4 s"1 Temperature • = 87 °C Temperature = 67°C [2a] =4.88 x 10-4 mol L" 1 [2a-CD3] = 6.44 x IO"4 mol L _ 1 Time (s) A t (538 nm) Time (s) A t (538 nm) 0 1.503 0 1.353 200 1.178 500 1.307 400 0.926 1250 1.216 550 0.803 3405 1.081 700 0.705 4405 0.986 900 0.577 5405 0.895 1100 0.465 7405 0.745 1300 0.383 9405 0.609 1500 0.320 11405 0.505 1700 0.270 20000 0.241 2350 0.138 25000 0.146 Aoo 0.040 Aoo 0.053 k0bs= l.lOxlO* 3 s-1 k0bs = 8.77 x 10-5 s-l 249 A2.2 Thermolysis o f / a c - I r ( T i 2 - C H 2 P P h 2 ) H [ N ( S i M e 2 C H 2 P P h 2 ) 2 ] , 3a, in toluene Temperature = 91°C Temperature = 91°C Temperature • = 94°C [3a] = 2.04 x IO"4 mol L" 1 [3a] = 2.04x IO"4 mol L" 1 [3a] =-2.04 x 10-4 mol L ' 1 Time (s) A t (360 nm) Time (s) A t (360 nm) Time (s) A t (360 nm) 0 1.054 0 1.014 0 0.945 6000 1.000 4100 0.973 5000 0.906 12000 0.940 8100 0.930 9200 0.868 18650 0.908 12500 0.916 16500 0.828 27650 0.852 23450 0.835 61300 0.680 86870 0.660 32450 0.800 65300 0.673 96370 0.622 81800 0.663 72850 0.640 106370 0.610 99800 0.610 89050 0.603 183870 0.520 161800 0.532 94450 0.607 216770 0.503 Aoo 0.400 100000 0.582 0.400 200000 0.466 Aoo 0.400 k o b s = 0.87 x 10-5 s- 1 kobs = 0.94 x 10-5 s-l k0bs = 1-03 x 10-5 s-l Temperature • = 102°C Temperature : = 112°C Temperature = 112'C [3a] = 2.04 x IO"4 mol L"1 [3a] = 2.04 x IO-4 mol L"1 [3a -CD 2 ]=2.32xl0- 4 mol V Time (s) A t (360 nm) Time (s) A t (360 nm) Time (s) A t (360 nm) 0 1.108 0 1.066 0 1.258 4000 1.053 4000 0.928 4000 1.081 8100 0.994 8000 0.810 8000 0.950 12000 0.940 12550 0.697 12000 0.844 17700 0.876 16550 0.621 16000 0.783 25350 0.798 20550 0.584 20570 0.746 63950 0.563 38270 0.454 33070 0.588 0.400 Aoo 0.400 Aoo 0.366 k0bs = 2.31 x 10-5 s-1 kobs = 6.59 x 10-5 s"1 kobs = 4.19 x 10-5 s-l 250 A2.3 Thermolysis of /ac-Ir(Ti2-CH2PPh2)H[N(SiMe2CH2PPh2)2l, 6a, in toluene Temperature =  36°C Temperature =  46'C [6a] = 2.08 x 10"4 mol L" 1 [6a] = 2.08 x 10"4 mol L" 1 Time (s) A t (360 nm) Time (s) A t (360 nm) 0 0.458 0 0.458 1000 0.479 600 0.528 2000 0.500 1200 0.581 6150 0.596 1800 0.633 8150 0.641 2400 0.678 10150 0.720 3200 0.732 26550 0.904 4200 0.792 32000 0.965 5200 0.840 45000 1.032 6200 0.883 Aoo 1.100 8200 0.963 9700 0.992 Aoo 1.100 kobs = 0.50 x 10"4 s-1 kobs = 1.84 x 10-4 s-1 Temperature = 59°C [6a] = 2.08 x 10"4 mol L"1 Time (s) A t (360 nm) 0 0.460 150 0.516 f 300 0.557 450 „ 0.585 650 0.659 850 0.719 1050 0.779 1300 0.827 2000 0.926 3000 1.026 1.100 k o b s = 7.15 x lO^s" 1 Temperature • = 56°C [6a] = 2.08 x 10"4 mol Time (s) A t (360 0 0.455 200 0.511 400 0.545 • 600 0.571 900 0.629 1900 0.784 2300 0.860 2700 0.903 3300 0.964 3800 0.995 4400 1.024 Aoo 1.100 kobs = 4.87 x lO"4 s"1 251 A2.4a Thermolysis of Ir(CH 3 )PHPh[N(SiMe2CH2PPh 2 )2L 2d, in toluene Temperature = 69°C [2d] = 2.84 x lO"4 mol L / 1 Time (s) A t (460 nm) 0 0.688 320 0.650 650 0.595 1020 0.550 1620 0.496 2620 0.434 0.310 kobs = 0.430 x 10-3 s"1 Temperature = 93°C [2d] = 2.84x 10-4 mol L-l Time (s) A t (460 nm) 0 0.690 150 0.647 305 0.539 510 0.449 700 0.386 1000 0.336 Aoo 0.310 kobs = 2.800 x 10-3 s-1 Temperature = 82°C Temperature = 86°G [2d] = 2.84 x 10^ mol L ' 1 [2d] = 2.84 x 10"4 mol Time (s) A t (460 nm) Time (s) A t (460 0 0.628 0 0.690 110 0.581 100 0.660 260 0.535 300 0.577 500 0.460 550 0.472 800 0.378 800 0.405 1200 0.304 1100 0.356 1700 0.249 1400 0.331 0.310 Aoo 0.310 k o b s = 1-600 x 10-3 s- 1 kobs =2.102 x 10'3 s' 1 252 A2.4b Thermolysis of I r (CH3)PHPh[N(S iMe 2 CH 2PPh2)2], 2d, in hexanes Temperature = 54°C Temperature = 54°C Temperature = 65°C [2d] = 1.15 x lO ' 3 mol L / 1 [2d] = 1.15 x lO' 3 molL" 1 [2d] = 1.15 x lO"3 molL" 1 Time (s) A t (515 nm) Time (s) A t (515 nm) Time (s) A t (515 nm) 0 1.630 0 1.628 0 1.632 500 1.617 1000 1.490 400 1.520 1000 1.510 2000 1.299 800 1.238 2020 1.305 2800 1.169 1000 1.160 2800 1.178 4000 0.989 1300 1.040 4000 0.999 6000 0.759 1600 0.936 6000 0.763 8000 0.585 1900 0.845 8000 0.587 Aoo 0.230 2300 0.738 12000 0.410 2900 0.585 Aco 0.236 4000 0.463 5000 0.373 Aoo 0.238 k o b s = 0.176 x 10-3 s-1 kobs = 0.178 x lO"3 s-1 kobs = 0.476 x 10-3 s-1 Temperature = 74°C Temperature = 79°C Temperature = 74°C [2d] =1.15 x 10-3 mol L - l [2d]=1.15 x lO"3 mol L - 1 [2d-CD3]=1.12xlO-3mol L" : Time (s) A t (515 nm) Time (s) A t (515 nm) Time (s) A t (515 nm) 0 1.650 0 1.634 0 1.611 400 1.185 150 1.540 150 1.225 600 1.020 350 1.156 400 1.185 800 0.902 450 1.079 600 1.020 1000 0.787 600 0.940 800 0.879 1200 0.686 750 0.806 1000 0.771 1400 0.607 900 0.703 1200 0.678 1600 0.542 1050 0.620 1400 0.604 1850 0.460 1250 0.508 1700 0.485 Aoo 0.253 1525 0.380 2000 0.397 Aoo 0.240 2500 0.283 Aoo 0.214 k o b s = 1.008 x 10-3 s-1 k o b s = 1-008 x 10-3 s-1 k o b s = 0.994 x 10-3 s-1 253 A2.5 Carbonylation of /ac-Ir(rt2-CH 2PPh2)H[N(SiMe2CH2PPh2)2], 6a, in toluene Temperature = 46°C [6a] = 4.22 x 10-4 mol L - 1 Time (s) A t (360 nm) 0 0.929 600 0.842 1000 0.795 1400 0.752 1900 0.706 2400 0.657 3200 0.581 4000 0.510 5010 0.425 6010 0.365 7010 0.305 8110 0.247 9210 0.201 10210 0.158 11010 0.140 Aoo 0.020 k o b s-= 1.82 x 10-4S"1 254 

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