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Reaction of thiols with bimetallic Pd-Pd and Pd-pt complexes containing a P₂N₄ ligand Foo, Serena Jo Ling 2002

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REACTION OF THIOLS WITH BIMETALLIC Pd-Pd and Pd-Pt COMPLEXES CONTAINING A P N LIGAND 2  4  by SERENA JO LING FOO B.Sc, The University of British Columbia, 2000  A THESIS SUBMITTED IN PARTIAL FULFILMENT OF THE REQUIREMENTS OF THE DEGREE OF  MASTER OF SCIENCE  in THE FACULTY OF GRADUATE STUDIES (Department of Chemistry)  We accept this thesis as conforming to the required standard  THE UNIVERISTY OF BRITISH COLUMBIA November, 2002 © 2002 Serena Jo Ling Foo  In presenting this thesis in partial fulfilment of the requirements for an advanced degree at the University of British Columbia, I agree that the Library shall make it freely available for reference and study. I further agree that permission for extensive copying of this thesis for scholarly purposes may be granted by the head of my department  or  by his  or  her  representatives.  It  is  understood  that  copying or  publication of this thesis for financial gain shall not be allowed without my written permission.  Department of  (hmUVk  The University of British Columbia Vancouver, Canada  Date  DE-6 (2788)  Abstract This thesis describes the synthesis, structure, solution behaviour, and reactivity of bimetallic Pd and PdPt complexes containing a P2N4 ligand. Though homobimetallic 2  complexes of the type Pd2X2(u>PP) are widely known (X = CI, Br, or I; PP is a chelating 2  diphosphine such as dppm (Ph2PCH2PPh2)), few containing a single diphosphine bridge are found in the literature. One such new compound is Pd Cl (u-dmapm) 1, which had 2  2  been structurally characterized by a former group member, and may be the first example of a bimetallic Pd' complex supported by a tetradentate ligand. The fluxional behaviour 2  of 1 was studied by variable temperature N M R , while reaction with a chiral reagent supports its stereoselective formation with respect to the coordinated P-atoms. 1 reacts with thiols to yield the thiolate-bridged complexes 2. The proposed mechanism involves the oxidative addition of the thiol across the Pd'-Pd bond (see Scheme), and a hydrido1  thiolate intermediate was detected at low temperature.  Further reaction with triflic acid  yields the thiolate-bridged salts, [Pd Cl2(^-SR)(u-dmapm)] [OTfr (R = Me, Pr, Bu, Ph, +  n  n  2  and Bz), and H . The p.-thiolate products were characterized by N M R , microanalysis, 2  UV-vis, and conductivity, while the corresponding chloride salts (R = Et, "Pr) have been  O ^O rm  0- % 4T> n  n  Me N 2  Pd | CI  Pd—NMe  K  2  |  \/ N  CI  P  d  P  I CI  0-  |—  d  I "^ CI  N M e  M  e  2  N  p  2  N M e  ^ N^D 2  d  P  I CI  1  d  —  N  M  e  2  I CI  2  further characterized by X-ray crystallography. The mixed-metal complex, PdPtCl (u2  dmapm), was also synthesized and found to react with thiols; in the presence of triflic acid (HOTf), the thiolate-bridged salts, [PdPtCl (^-SR)(u-dmapm)] [OTf]~ (R = Et, Pr) +  n  2  3, and H2 were generated.  The proposed mechanism is thought to proceed via the  oxidative addition of R S H across the Pd'-Pt bond, in a fashion similar to that for the Pd2 1  analogues. The u-thiolate products were characterized by N M R , microanalysis, UV-vis, and conductivity, and mass spectrometry;  [PdPtCi2(u-SEt)(u -dmapm)] [OTf]~ was  further characterized by X-ray crystallography.  ii  +  J  Variable temperature N M R was  performed to probe the fluxional processes in 1, 2 (R = Pr), and 3 (R = Pr) in solution; n  n  these were identified as involving the N C H groups coordinated to Pd or Pt and non3  coordinated at the Pd or Pt ends.  CI  CI  PdaCbCdmapm) also reacts with SO2; however, the final products are not wellcharacterized.  Preliminary studies on the reaction Pd2Cl2(u-dppm) with R S H in the 2  presence of acid were also performed; a reaction does indeed occur, but the identities of the products remain uncertain.  In an attempt to synthesize a bimetallic Pd complex  without coordinated halides, Pd(hfac) (hfac = [CF C(0)CHC(0)CF ]") was reacted with 2  3  3  dmapm; again the product remains poorly characterized. The reactivity of MoRu(CO)6(u-dppm) (4) with H S and thiols was also re2  2  studied, following an earlier, unpublished study by a former group member. Although generation of 4 in high in situ or isolated yield was not accomplished, its reaction with H2S yields the bridged-sulfide complex 5 and H , while reaction with EtSH generates the 2  bridged-thiolate complex 6. Attempts to establish intermediates were non-conclusive.  4  5  111  6  Table of Contents Abstract  ii  Table of Contents  iv  List of Figures  viii  List of Tables  xii  List of Symbols and Abbreviations  xiii  Acknowledgements  xv  Dedication  xvi  CHAPTER 1  Introduction  1.1  Previous Work in the James Group  1  1.2  Natural and Industrial Occurrences of Sulfur Compounds  3  1.3  1.2.1  The Natural Sulfur Cycle  3  1.2.2  HDS and the Claus Process  4  Ligand Properties  6  1.3.1  Ligands Containing Both Phosphorus and Nitrogen  1.3.2  Tetradentate Ligands  10  1.3.3  Single Bisphosphine Bridged Complexes  11  1.4  Transition Metal Mercapto and Thiolato Complexes  13  1.5  The Overview of Thesis  16  1.6  References  17  CHAPTER 2  7  General Experimental Procedures  2.1  General Procedures  ."....21  2.2  Physical Techniques and Instrumentation  21  2.2.1  Nuclear magnetic resonance (NMR) spectroscopy  21  2.2.2  X-ray crystallography  22  2.2.3  Elemental analysis  22  2.2.4  Ultraviolet-visible (UV-vis) spectroscopy  22  2.2.5  Infrared (IR) spectroscopy  22  iv  2.3  2.4  2.2.6  Conductivity  22  2.2.7  Mass spectrometry (MS)  22  2.2.8  Gas chromatography (GC)  23  2.2.9  Gas chromatography-Mass spectrometry (GC-MS)  23  Materials 2.3.1  Gases  23  2.3.2  Solvents  23  2.3.3  Reagents  23  2.3.4  Metal complexes  2.3.5  Organic compounds  2.6  2.7  •  23 24  Ligand synthesis 2.4.1  2.5  21  24  l,l-Bis(di-(o-A ,//-dimethylanilinyl)phosphine)methane, dmapm /  Palladium Complex Precursors  24 24  2.5.1  Pd (dba) -CHC1  2.5.2  rra«5-PdCl (PhCN)  2.5.3  PdCl (cod)  25  2.5.4  PdCl(Me)(cod)  25  2  3  2  25  3  25  2  2  Synthesis of Bimetallic Pd Complexes 2  26  2.6.1  Pd Cl (dppm)  2.6.2  Pd Cl (dmapm)  26  2.6.3  Pd Cl (dmapm)  26  2  2  2  26  2  4  2  2  Synthesis of Bimetallic Pd Thiolato Complexes 2  27  2.7.1  [Pd Cl (dmapm)(p-SEt)] Cr  27  2.7.2  [Pd Cl (dmapm)(p-S Pr)] Cr  27  2.7.3  [Pd Cl (dmapm)(p-SPh)] Cr  28  2.7.4  [Pd Cl (dmapm)(p-SMe)] [OTf]"  28  2.7.5  [Pd Cl (dmapm)(u-SEt)] [OTf]~  29  2.7.6  [Pd Cl (dmapm)(p.-S Pr)] [OTf]-  29  2.7.7  [Pd Cl (dmapm)(u-S Bu)] [OTfT  30  2.7.8  [Pd Cl (dmapm)(p-SPh)] [OTf]-  30  2.7.9  [Pd Cl (dmapm)(p-SBz)] [OTf]"  31  +  2  2  n  2  +  2  +  2  2  +  2  2  +  2  2  n  2  +  2  n  2  +  2  +  2  2  +  2  2  v  2.8  2.9  In Situ Reactions of Pd2Cl2(dmapm) Species With Other Reagents  31  2.8.1  Reaction of Pd Cl (dmapm) and S 0  2  31  2.8.2  Reaction of Pd Cl (dmapm) and H S  31  2.8.3  Reaction of Pd2Cl2(dmapm) with a chiral shift reagent  31  2  2  2  2  2  Synthesis of Mixed Metal PdPt Bimetallic Complexes  32  2.9.1  Synthesis of PdPtCl (dmapm)  32  2.9.2  Synthesis of PdPtCl (dmapm)  32  4  2  2.10 Synthesis of Mixed Metal PdPt Bimetallic Thiolato Complexes 2.10.1  Synthesis of [PdPtCl (dmapm)(|i-SEt)] [OTf]"  33  +  2  2.10.2 Synthesis of [PdPtCl2(dmapm)(p.-S Pr)] [OTf] n  +  33  34  _  2.11 Reaction of dmapm With Other Pd Precursors  34  2.11.1 Reaction of Pd(hfac)2 with dmapm  34  2.11.2 Reaction of PdClMe(cod) with dmapm to afford PdCl(Me)(P,iVdmapm)  35  2.11.3 Attempted Synthesis of [Pd (hfac)(dmapm)] [PF r  35  2.11.4 Reaction of Pd Cl2(dppm) with R S H in the presence of acid  36  +  2  6  2  2.12 References  37  C H A P T E R 3 Reactivity and Mechanistic Studies of Pd-Pd and Pd-Pt Complexes 3.1  Fluxionality of Pd2Cl2(dmapm)  38  3.2  Structures of [Pd Cl (u-SR)(dmapm)] X- (R = Me, Et, "Pr, B u , Ph, Bz; X = +  2  n  2  CI and/or OTf)  42  3.3  Mechanistic Studies of the Reaction of Pd Cl (dmapm) with R S H  3.4  Fluxionality of [Pd Cl C«-S Pr)(dmapm)] [OTf]"  3.5  Synthesis of PdPtCl (dmapm)  60  3.6  Reaction of PdPtCl (dmapm) with R S H  60  3.7  Fluxionality of [PdPtCl Cu-S Pr)(dmapm)] [OTfr  66  3.8  Reaction of Pd(hfac) with dmapm  69  3.9  Reaction of Pd Cl (dppm) with thiol R S H  71  2  n  2  2  +  2  2  2  n  +  2  2  2  2  2  3.10 Reaction of Pd Cl (dmapm) and S 0 2  2  3.11 References  2  51 ....56  73 74  vi  CHAPTER 4 Synthesis and Reactivity of a Heterobimetallic Complex of Mo and Ru 4.1 Introduction  4.2  4.3  4.4  74  4.1.1  Relevance of Mo-Ru/H S/RSH Chemistry  76  4.1.2  Properties of Ru and Mo  78  4.1.3  Ru heterobimetallics  4.1.4  Complexes of Ru and Mo  2  :  79 82  Synthesis  ,..88  4.2.1  Cis- and ^rarcs-Ru(H) (dppm) (c- and f-Ru(H) (dppm) )  4.2.2  MoRu(CO) (dppm)  4.2.3  In situ preparation of MoRu(CO) (dppm)  4.2.4  In situ preparation of MoRu(H) (CO) (dppm)  4.2.5  In situ reaction of MoRu(CO) (dppm) with H S  90  4.2.6  In situ reaction of MoRu(CO) (dppm) with EtSH  90  2  6  2  2  2  ;  88 89  2  5  89  2  2  5  6  2  6  89  2  2  2  Discussion  91  4.3.1  Cis- and ?ra«s-Ru(H) (dppm)  4.3.2  MoRu(CO) (dppm) ( = 6, 5)  4.3.3  Reaction of MoRu(CO) (dppm) with H S  95  4.3.4  Reaction of MoRu(CO) (dppm) with EtSH  97  2  n  2  91  2  91  n  6  2  6  2  2  References  CHAPTER 5  100  Conclusions, Recommendations for Future Work  103  Crystal Structure Data  APPENDIX A l Experimental Details for [Pd Cl (u-SEt)(dmapm)] Cr  105  APPENDIX A2 Experimental Details for [Pd Cl (u-S Pr)(dmapm)] Cr  Ill  APPENDIX A3 Experimental Details for [PdPtCl (u-SEt)(dmapm)] [OTfT  115  +  2  2  n  2  +  2  +  2  vii  List of Figures  Figure 1.1  Structural formulations of MoRu(CO) (dppm) (1) and Pd Ci2(dmapm) (2)  1  Figure 1.2  Reaction of Pd2Cl2(dppm)2 (3) with H S to yield the bridged-sulfide product (4) and H  2  Reaction of Pd2Cl2(dmpm) (5) with H2S to give an H2S adduct (II), a hydrido-thiolate species (III), and subsequent formation of 6 and H2  2  Regeneration of 3 from 4 via (a) a p - S 0 intermediate, and (b) production of dppm(S)  3  Figure 1.5  The sulfur cycle in nature  4  Figure 1.6  Reactions of the Claus process: oxidation of H2S to sulfur and water  5  Figure 1.7  Modelling of the heterogeneous Claus process  5  Figure 1.8  Proposed mechanism for the Claus chemistry catalyzed by 7  6  Figure 1.9  P N ligands in the literature  9  Figure 1.10  Mono- and bimetallic compounds containing tetradentate ligands  10  Figure 1.11  Reaction of a Pd-Pd hydroxo-bridged complex with PhSH to yield the bridged-thiolate complex  11  Geometries of bimetallic complexes: ligands oriented in a trans or a cis fashion  11  6  2  2  2  2  Figure 1.3  Figure 1.4  Figure 1.12  Figure 1.13  2  2  Complexes containing a single diphosphine bridge, exemplifying the bimetallic cz's-types  12  Figure 1.14  Bimetallic complexes containing a single bisphosphine bridge  13  Figure 1.15  Bimetallic Pd complex containing dpfanf  13  Figure 1.16  Oxidative addition of H2S and thiols, a) Reaction of RhRe(CO)4(dppm) with H S and thiols, b) Reaction of [Pt (u -CO)(dppm) ] with H S and thiols  14  Proposed n - R S H intermediates en route to the oxidative addition products for reaction of R S H with (a) (MeS)Fe(CO) (PEt ), (b) (RS)Ni(triphos), R = Et, Ph, and (c) Os (CO)n(NCMe)  15  2  3  2  Figure 1.17  3  2+  3  2  2  3  3  viii  3  Figure 3.1  (a) X-ray and (b) structural formulation of 1  Figure 3.2  Variable temperature *H N M R spectrum of Pd Cl (dmapm) in CD C1  Figure 3.3  Reaction of Pd Cl (dmapm) with thiol R S H  Figure 3.4  ' H N M R spectrum of the in situ reaction between Pd Cl (dmapm) and EtSH  42  ORTEP representation (50% ellipsoids) of the molecular structure of the cation in Pd Cl (u-SEt)(dmapm)] Cr. H-atoms have been omitted for clarity  45  ORTEP representation (50% ellipsoids) of the molecular structure of the cation in Pd Cl ((u-S Pr)(dmapm)]Cl. H-atoms have been omitted for clarity  47  (a) ' H and (b) 'H{ P} N M R spectra of the C H moiety at -50 °C (recorded in CD C1 )  51  Reaction of Pd Cl (dppm) with H S to yield the bridged-sulfide product (l)and H  52  Variable temperature *H, 'H{ P}, and P { ' H } N M R spectra at -50 and 80 °C for the reaction of Pd Cl (dmapm) with PhSH in CD C1  54  Figure 3.10  Possible structures of intermediates seen at -80 °C  55  Figure 3.11  Proposed mechanism for the formation of the bridged-thiolate product from the reaction of Pd Cl (dmapm) with an R S H thiol (R = Ph)  ...56  Variable temperature ' H N M R data in C D O D exploring the fluxionality of[Pd Cl 0/-S Pr)(dmapm)] [OTfl"  59  Synthesis of PdPtCl (dmapm), via the reduction of PdPtCLXdmapm) to PdPtCl (dmapm), and subsequent reaction with R S H and triflic acid to yield [PdPtCl ((a-SR)(dmapm)] [OTfJ"  60  ORTEP representation (50% ellipsoids) of the molecular structure of PdPtCl (w-SEt)(dmapm)] [OTf]". H-atoms have been omitted for clarity  62  Structural formulations of (a) PdPtCl (dmapm) (b) PdPtCl (dmapm) (c) [Pd Cl (n-SEt)(dmapm)] (d) [PdPtCl (u-SEt)(dmapm)]  64  Figure 3.5  38 2  2  2  2  2  41 42  2  2  2  +  2  Figure 3.6  2  n  2  Figure 3.7  2  31  2  2  Figure 3.8  2  2  2  2  2  2  Figure 3.9  31  2  2  Figure 3.12  2  2  2  2  3  n  2  Figure 3.13  31  +  2  2  2  +  2  Figure 3.14  +  2  Figure 3.15  2  +  2  4  +  2  2  ix  Figure 3.16  Variable temperature *H NMR [PdPtCl (^S Pr)(dmapm)] [OTfr from -90 to 20 °C n  +  2  Figure 3.17  spectra !  of 64  Pt metal hfac complexes. In a, the PdPd and PdPt complexes have similar structures, with non-coordinating hfac . In b, one hfac ligand is bound and bridges the two Pt centers  69  Figure 3.18  Probable reaction of Pd(hfac) with dmapm  70  Figure 3.19  Synthesis of [Pd(triphos)(hfac)] [hfac]~, in which Pd adopts a distorted square pyramidal geometry  71  Figure 3.20  Reaction mechanism for the formation of the species with the A B pattern  72  Figure 4.1  Structural formula of MoRu(CO)e(dppm)  76  Figure 4.2  (2) Structure of the Fe-Mo cofactor of the Mo-Fe protein of nitrogenase as first solved by X-ray crystallography. (3) Probable structure of the M o cofactor functioning in oxo transfer reactions  77  Figure 4.3  Reaction catalyzed by xanthine oxidase  78  Figure 4.4  Ru catalysts used in asymmetric hydrogenation (4, 5) and as a precursor  2  +  2  for olefin metathesis reactions (6)  79  Figure 4.5  PtRu heterometallic complexes  80  Figure 4.6  A heterobimetallic complex of Ru and Pt bridged by dpb  80  Figure 4.7  Heterobimetallic Ru catalysts used in the R O M P of 1,5-COD  81  Figure 4.8  Rulr heterobimetallic complexes with bridging diphosphine (13) or hydride (14) ligands (15) A ring-coupled RuMo heterobimetallic. (16) CO-bridged, metalmetal bonded RuMo complex  82  Thermolysis of a cycloheptatrienyl-bridged complex of Ru and Mo yields 17  83  Figure 4.11  Unbridged, metal-metal bonded heterobimetallic RuMo complexes  83  Figure 4.12  Reaction of (C Me )Ru(«-H)3MoH3(C5Me5) (20) with phosphines to yield the phosphine derivatives (21a, 21b, 21c) and H  84  Figure 4.9  Figure 4.10  5  81  5  2  x  Figure 4.13  Building blocks of a MoRu heterobimetallic porphyrin dimer: (24a) Mo(OEP), (24b) Ru(TPP)  84  Figure 4.14  Cubane-like cluster compound of Ru and M o  85  Figure 4.15  A heterometallic complex of Ru and Mo  86  Figure 4.16  Synthesis of c- and ?-Ru(H) (dppm)  91  Figure 4.17  Synthesis of MoRu(CO)e(dppm) and its interconvertible forms  92  Figure 4.18  ' H and P { ' H } N M R spectra MoRu(CO) (dppm)  92  2  2  2  31  6  Figure 4.19  of in situ solutions containing  2  Reactions of Ru(H) (dppm) with Vi [IrCl(cod)] , A [RhCl(cod)] and V [RhCl(CO) ] •  94  Proposed mechanism CO)(dppm)  95  l  2  2  Figure 4.20  2  2  2)  2  2  for  the  formation  of  MoRu(CO)3(u-S)(//-  2  Figure 4.21  ' H N M R in the hydride and sulfhydryl region of the reaction between MoRu(CO) (dppm) with H S , at r.t. in C H  96  Proposed mechanism for the formation of MoRu(H)(CO)3(w-SEt)(wCO)(dppm)  97  H N M R in the hydride region for MoRu(CO) (dppm) and EtSH, at r.t. in C D  98  6  Figure 4.22  2  2  6  6  2  Figure 4.23  !  6  Figure 4.24  2  6  the  reaction  between  6  Proposed mechanism for the formation of RhRe(CO)4(«-S)(dppm) and RhRe(CO) C«-H)(^-SRXdppm) 2  3  2  XI  99  List of Tables  Table 2.1  Spectrometer frequencies for H , P , and F for the N M R instruments ]  31  1 9  used in the course of this work Table 3.1  21  ' H chemical shifts (§) of free thiols, with multiplicities given in brackets (recorded in CD C1 ) 2  Table 3.2  Selected bond distances (A) and bond angles (°) for [Pd Cl («2  SEt)(dmapm)] Table 3.3  44  2  2  46  +  Selected bond distances (A) and bonds angles (°) for [Pd Cl (dmapm)(u2  S Pr)] n  2  48  +  Table 3.4  Selected Bond distances (A) and bonds angles (°) for Pd Cl (dmapm)  Table 3.5  Summary of N M R data for [Pd Cl (u-SR)(dmapm)] X" (R = Me, Et, "Pr,  2  2  +  2  2  Bu, Ph, Bz; X = CI, OTf) Table 3.6  49  50  Selected Bond distances (A) and bonds angles (°) for [PdPtCl (dmapm) 2  (u-SEt)] [OTfT  61  Table 4.1  Comparison of Ru-Mo bond distances  87  Table 4.2  Conditions used to generate MoRu(CO)6(dppm)  Table 4.4  *H and P { H } N M R data for the formation of 30a, 30b, and 31  96  Table 4.5  ' H and P { ' H } N M R data for the formation of 32a, 32b, and 33  98  Table A l . l  Atomic Coordinates and Bj /B q  106  Table A l .2  Bond Lengths (A)  108  Table A l .3  Bond angles (°)  109  Table A2.1  Atomic Coordinates and B / B q  112  Table A2.2  Bond Lengths (A)  113  Table A2.3  Bond angles (°)  113  Table A3.1  Atomic Coordinates and B j / B  Table A3.2  Bond Lengths (A)  118  Table A3.3  Bond angles (°)  119  +  3I  2  1  31  S0  iso  e  e  S0  xii  eq  93  116  List of Symbols and Abbreviations  'A  A Anal. aq. atm bp bpy br Bu Bz °C Calcd. CCSD cod cone. Cp  cCy* P  d dba dd dmapm dppa dppe dppen dppm equiv. Et GC J  h HDS hfac IR L M m m  Me min mol MS 3-NBA  absorbance angstroms, (10" m) analysis aqueous atmosphere boiling point 2, 2'-bipyridine broad butyl benzyl degrees Celsius calculated Cambridge Crystallographic Structural Database 1,5-cyclooctadiene concentrated cyclopentadienyl pentamethylcyclopentadienyl cyclohexyl day, or doublet (NMR) dibenzylideneacetone doublet of doublets 1,1 -bis(di-(o-N,N-dimethylanilinyl)phosphino)methane bis(diphenylphosphino)amine bis(diphenylphosphino)ethane bis(diphenylphosphino)ethene bis(diphenylphosphino)methane equivalent(s) ethyl gas chromatography coupling constant (Hz) hours hydrodesulfurization hexafluoroacetylacetonato infrared litre molar (mol L" ) multiplet meta methyl minute mole mass spectrometry 3-nitrobenzyl alcohol 10  1  Xlll  NMR o OAc OTf P ppm Pr py ps pts q qn R r.t. s S sh t TFA THF UV-vis 8 s Tl ^-rnax  AM V  {}  nuclear magnetic resonance ortho acetate trifluoromethanesulfonate, triflate para parts per million propyl pyridine pseudo j9-toluenesulfonate quartet quintet Latin, rectus (right) room temperature singlet (NMR) Latin, sinister (left) shoulder time trifluroacetic acid tetrahydrofuran ultraviolet-visible chemical shift extinction coefficient (L mol" cm") hapticity wavelength of maximum absorption (nm) molar conductivity (Q" cm mor') bridging coordination mode wavenumber (cm") broadband decoupled (NMR) 1  1  1  XIV  2  1  Acknowledgements M y sincere thanks to my supervisor and mentor, Dr. Brian James, whose extensive knowledge of inorganic chemistry and unending enthusiasm for research have inspired my academic pursuits. Among the past and present members of the James group I have had the great pleasure of working with, I am grateful to Nathan for a productive collaboration, and to Paul, Paolo, Craig, Julio, David, Lynsey, and Maria, for their help, patience, and insightful discussions. I express my gratitude to the U B C departmental services staff, particularly Mr. Peter Borda (Elemental Analysis), Dr. Brian Patrick (X-ray crystallography), and Ms. Marietta Austria and Ms. Liane Darge (NMR) for their expertise. I would also like to thank Mr. Mike Yang of the SFU departmental services staff for elemental analyses. Lastly, I am greatly indebted to my family and friends for their unwavering support and encouragement. Without you, I am naught.  xv  This is dedicated to my family.  xvi  Chapter 1  Chapter 1 INTRODUCTION 1.1 Previous W o r k In the James Group Initially, my thesis work was to focus on the reactivity of RuMo(CO)6(u-dppm)2^ (dppm = bis(diphenylphosphino)methane)  (1) and its reaction with H2S, thiols, and other small  2  molecules;  however, a few problems arose with the generation of the starting material.  Concurrent with the start of my thesis project, work by Dr. N . D. Jones, formerly of the James group,  with  the  complex  Pd Ci2(|J.-dmapm) 2  :f  (dmapm  = \,\-bis(d.i-(o-N,N-  dimethylanilinyl)phosphino)methane) (2) (Fig. 1.1) established its reactivity towards thiols; however, these initial findings were not explored in detail and mechanisms were not 3  considered. work.  Reactions and studies with this Pd2 complex make up the bulk of this thesis  In this chapter, a brief introduction to past work in the  James group,  hydrodesulfurization (HDS), P - N donor ligands, and other mercapto and thiolate transition metal complexes, is given.  2 Figure 1.1. Structural formulations of MoRu(CO) (dppm)2 (1) and Pd Cl (dmapm) (2). 6  2  2  Previous work in the James group has focused on mechanistic aspects of the reaction of Pd2Cl2(dppm)2^ (3) with H2S that quantitatively generates H2 and the bridged-sulfide, A 4-8  frame species (4), as illustrated in Figure 1.2.  Kinetic and spectroscopic data are consistent  RuMo(CO) (u-dppm) and P d C l ( u - P P ) (PP = dppm, dmpm) have two bridging bisphosphine ligands; u - has often been omitted throughout the rest of this thesis for convenience. * Pd Cl (u-dmapm) has a single bridging bisphosphine ligand; u - has often been omitted throughout the rest of this thesis for convenience. f  6  2  2  2  2  2  2  1  References on page 17  Chapter 1 with the reaction proceeding via the initial oxidative addition of H S across the Pd-Pd bond to 2  generate the hydrido-mercapto intermediate (I), which was detected at low temperature; '  4  6 8  and H are envisioned to form via subsequent deprotonation of the coordinated SFT and 2  protonation of the coordinated hydride.  Ph P^  ^-pph  2  CI—Pd  8  5  3, however, did not react with thiols.  Ph P  2  Ph P-~  2  ^PPh  2  Pd—CI + H S  Pd  2  ^Pd  CI | P  2  h  \  p  ^PPn  P  2  h  2  p  2  + H,  | "CI  ^-PPh  \  2  Figure 1.2. Reaction of Pd Cl (dppm) (3) with H S to yield the bridged-sulfide product (4) and H . 2  2  2  2  2  Further work in our group has looked at the reaction of Pd Cl (dmpm) (5) with H S, 2  2  2  2  where several intermediates were detected at low temperature; the mechanism for the formation of the u,-S product (6) and H is proposed to proceed via an H S adduct (II), with 2  2  subsequent formation of a hydrido-thiolate intermediate (III) (Fig. 1.3).  The discovery of 6  these Pd /H S reactions has fuelled interest in generating dihydrogen from H S . 2  2  2  H  i  z  CI—Pd Me P 2  i H-,t>  PdPMe  t \ \  M  . 2/ —/-Pri  Me P"^  M e=2 , p  e  1H  P « ^ P d ^  2  2  I  \  P  '  C  '  ^ P M e  2  2  Pd  CI/ 1 | .-PMe  CI | M e P ^  ^  Me P-""^  2  2  "-PMe  |  2  ^Pd CI M e  2  2  a  P ^  2  +H  1 "~  |  ^,PMe  2  CI  II  III  Figure 1.3. Reaction of Pd Cl (dmpm) (5) with H S to give an H S adduct (II), a hydridothiolate species (III), and subsequent formation of 6 and H . 2  2  2  2  2  2  For any catalytic process based on the aforementioned reaction (Fig. 1.2), the regeneration of 3 from 4 must occur.  4 can be oxidized in solution by H 0 2  2  or m-  chloroperbenzoic acid (but not 0 ) to give successively the p,-SO and p - S 0 derivatives, the 5  2  2  10  latter spontaneously losing S 0 to regenerate 3 (Fig. 1.4a). 2  Thus a two-stage process  effecting catalysis of H S to H can be achieved. Alternatively, 3 can be regenerated by 2  2  2  References on page 17  Chapter 1 reaction of 4 with dppm (Fig. 1.4b); this reaction, which is the first reported homogeneous catalytic process utilizing H S, n is the reverse of an HDS process (see Section 1.2.2). 2  Ph p-  -PPh,  2  *Pd CI  -ci  -PPh,  Ph P-^ 2  CI  /Pd |  Ph P^ 2  P  h  2  C,  ?,  p  -Pd |  PPh -Pd_  Ph P^  P  CI  -PPh,  2  CI  2  p  I-  -Pd I  PPh,  °\ 2 - S ^ !4 d^„, I CI p  p  p  h  I  Pd—CI + S O ,  0  Ph P.  Ph P  -PPh,  2  2  PPh,  ^PPh, Pd^ + dppm | ^Cl ^PPh, H S + dppm  H + dppm(S)  2  Figure 1.4. dppm(S).  h  2  2  Regeneration of 3 from 4 via (a) a u-S0 intermediate, and (b) production of 2  1.2 Natural and Industrial Occurrences of Sulfur Compounds 1.2.1. The Natural Sulfur Cycle' ° 2  Sulfur plays an important role in the functioning of many microorganisms and plants, and 12  geochemistry of the earth. The natural sulfur cycle is illustrated in Figure 1.5.  Sulfur is  converted to sulfate by biological oxidation with 0 or N03~ or by anaerobic oxidation using 2  phototrophic bacteria. Sulfate can be reduced by plants and micro-organisms to synthesize organic sulfur compounds (including amino acids) or via the liberation of the toxic H S , a 2  product of heterotrophic bacterial catabolism. While some micro-organisms liberate H S as a 2  waste product, others use the gas for biosynthesis by oxidation to sulfur or sulfate.  Sulfate  13  reserves in seawater are released into the atmosphere as volatile H S 2  which oxidizes back to  sulfate and so is returned by rain to the soil. H S is oxidized to S 0 and ultimately to sulfuric 2  2  acid H S04, which produces acid rain, leading to acidification of streams. Organic sulfur 2  compounds are converted to sulfite via mineralization processes; this reduced form of sulfur exists as sulfidic minerals, such as pyrite. 3  References on page 17  Chapter 1  1.2.2. HDS and the Claus Process Hydrodesulfurization (HDS) is the removal of sulfur from organosulfur compounds present in petroleum-based  feedstocks, and typically involves the treatment of sulfur-containing 14  compounds with H at high temperatures over a Co- or Ni-promoted M o or W catalyst. 2  Sulfur is removed from fuel feedstocks to minimize the production of environmentally hazardous sulfur oxides and to reduce poisoning in automobile catalytic converters and other catalytic petrochemical processes. HDS catalysts are heterogeneous and their mechanisms of desulfurization are not well understood, while catalyst surface reactions have been studied to better understand the mechanism.  5  The products of the HDS of sulfur compounds are hydrocarbons and H S , which is 2  subsequently converted to sulfur via the Claus process.  Here S 0 , obtained by partial 2  oxidation of H S over alumina at 300 °C (Fig. 1.6a), is then converted to sulfur and water 2  with very high efficiencies, although the specifics of the mechanisms of the Claus process are also not well understood.  14,16  However, sulfur-sulfur bond formation and oxygen transfer to 4  References on page 17  Chapter 1 sulfur must be involved - processes that are not well known in homogeneous transition metal sulfur chemistry. The heterogeneous reaction (b, Fig. 1.6) at the catalyst surface has been modelled in three ways (Fig. 1.7). In model A, SO2 is adsorbed on the catalyst surface, which then undergoes reaction with H2S; in model B , S 0 reacts with adsorbed H S, and in model C, 2  both gases are adsorbed and react.  a 2 HS + 3 0 2  b 2H S + S0 2  7  Earlier surface studies on alumina with the sequential  *• 2 H 0 + 2 S0  2  2  »•  2  2  2  3/8S + 2H 0 8  2  Figure 1.6. Reactions of the Claus process: oxidation of H S to sulfur and water. 2  S0  SH  H 2 S 2  I  I A  S 2  °  I  •  B  SH  2  S0  2  I  2  *  C  Figure 1.7. Modelling of the heterogeneous Claus process. 18  adsorption of S 0 and H 2 S provided no conclusive evidence for any particular model. 2  FTER.  spectroscopy was later used to study the adsorption of SO2 and H S on silica or silicon 2  carbide supported sodium catalysts; the intermediate resulting from model A was considered to be a thiosulfate species, intermediates of model B were thiosulfate and tentatively a polythionate species, and intermediates derived from model C (H2S:S02 in a 2:1 mixture) 17  were identified as thiosulfate and polythionate species, en route to water and sulfur.  Though  studies with silica are possible, most of the metal oxides employed as HDS catalysts are not transparent to an IR beam below 1000 cm" , thus limiting the utility of IR spectroscopy as a 1  tool to observe surface intermediates. Therefore, there has been much interest in development of soluble transition metal complexes that mimic catalysts employed in the Claus process; 19,20  homogeneous systems readily allow for the observation of intermediates.  For example,  Shaver and co-workers have prepared cw-[(PPh3)2Pt(SH)2] (7), which was found to bind SO2 at r.t. in C H 2 C I 2 , forming a four-membered PtS3 ring system (IV) with the elimination of 5  References on page 17  Chapter 1 water (Fig. 1.8); sulfur-sulfur bond formation and oxygen transfer are envisioned to be key steps in this reaction and in the Claus process. Reaction of the (PPh ) PtS intermediate (IV) 3  with H S regenerated the starting complex.  2  3  21  2  3/8 S„ + H 0 2  S0  I  2  -SH -SH  Ph P^ 3  ,OH  ^SH-  O  Figure 1.8. Proposed mechanism for the Claus chemistry catalyzed by 7.  1.3 Ligand Properties A complex in which two metal centers are tethered in close proximity to each other may exhibit a cooperative effect in its reactivity.  Many such complexes containing two  bisphosphine ligands such as dppm have been greatly explored for use in catalysis, but few 19,20  have been found to be effective.  Thus, new bimetallic complexes with different properties  are being investigated for catalytic activity (see  Sections 1.3.1,  1.3.2, and 1.3.3).  Pd Cl (dmapm) contains the P N ligand, dmapm, that bridges and chelates two metals; the 2  2  ligand is tetradentate and forms a complex with a single diphosphine bridge (see 2, Section 1.1). A brief summary is given below of some complexes with ligands containing both P- and N-atoms (Section 1.3.1), and tetradentate ligands that both bridge and chelate (Section 1.3.2); some singly-bridged bisphosphine complexes (Section 1.3.3) are also described. Complexes  6  References on page 17  Chapter 1 containing bridging mercapto and thiolate ligands are discussed in the following section (Section 1.4). 1.3.1  Ligands Containing Both Phosphorus and Nitrogen  Many ligands containing both P- and N-atoms have been synthesized over the years. A brief overview of the different types of PN ligands in the literature will now be described, with structures illustrated in Figure 1.9. Pyridylphosphine  ligands  are well-known  and have been reviewed.  22,23  2-  24  Pyridylphosphine ligands coordinate to a variety of transition metals; 8a  has been widely  used to bridge two metal centers in a head-to-head or head-to-tail fashion and such bimetallic 25  platinum group metal complexes have been synthesized.  8b and 8c have been used  extensively in the James group: mono-metallic Ru(II) complexes containing P,N,N'26  coordinated PPh -„(Py)„ (n = 2,3) ligand have been made, 3  while Pd complexes containing  pyridylphosphines have been studied for homogeneous catalysis in aqueous media.  27  Other  related PN pyridylphosphine ligands have been made with a pendant pyridyl arm, such as 22,28  P(CH CH Py)„Ph .„ (Py = 2-pyndyl; n = 1,2,3) (e.g. 9). 2  2  3  For example, in the PN case, the 2  monomer [Pd(C Cl F )Cl{P(C H Py) Ph}] reacts with T1BF to yield the cationic dimeric 6  2  3  2  4  2  4  complex [Pd (C6Cl F ) {P(C H Py) Ph} ][BF ] by halide abstraction, in which the ligand 2  2  3  2  2  4  2  2  4  2  23  coordinates P,N to one metal and bridges the other metal via the other N-atom. The water-soluble nature of pyridylphosphines (e.g. 10) has garnered much interest of 22,29-31  late.  10 has been coordinated to Ag to form [Ag(10) ]NO , in which the pyridyl 2  3  nitrogen atoms remain non-coordinated to Ag; this complex exhibit antitumour activity. ' 3  Some work in the James group with mono- and bidentate 2-pyridylphosphines have found complexes of Ni and Ni° complexes containing 2-pyridylphosphine, e.g. Ni(CO) (PPh py) , 11  2  2  2  Ni(CO) [d(py)pe], Ni(PPh py) , Ni(PPhpy ) , and Ni[d(py)pe] , to be potentially useful water2  2  4  2  4  2  30  soluble catalysts; Another  29  complexes of 3- and 4-pyridylphosphines are also known. ligand  set  containing  the  pyridyl  functionality  are  2-(2-  pyridyl)phosphaalkenes such as [Mes*P=C(R)Py] (R = SiMe , Py = 2-pyridyl (11), which 3  forms monomeric, chelated P-N complexes with Pd that are targeted for use in homogeneous catalysis.  32  7  References on page 17  Chapter 1 Anilinylphosphine  ligands  have  also  been  synthesized.  /V,/V'-Dimethyl-2-  33  (diphenylphosphino)anihne (PNMe2)  (12) has been used as a catalyst ligand in the SHOP  process (Shell Higher Olefins Process) on a commercial scale to manufacture ct-olefins and 34  internal C n through C M alkenes,  and in the James group, 12 has been coordinated to Ru to 35,36  study reactions with H2S, thiols and N 0 .  Another example of a P N ligand is  2  (diisopropylphosphino-dimethylamino)ethane (13), which has been employed in aryl-alkyne 37 38  cleavage, a difficult task to perform. '  The C-C bond in Pt°-diphenylacetylene complexes  bearing chelating P,N- and P,P-ligands is cleaved, when U V irradiation of [(13)Pt(PhC=CPh)] affords [(13)PtPh(C=CPh)], in which the metal center inserts into the C-C bond of 38  diphenylacetylene.  2,6-Bis(diphenylphosphino)-A^-methylamline (LH) (14) and its anion L  are able to form N-bridged bis(chelate) complexes; for example, reaction of L H with excess Mo(CO) yields the bimetallic complex {[p-P,N:P'N-L][Mo(CO) ] }~ in which each P-atom 6  4  39  2  is coordinated to one M o center and the N-atom is bridging. PN-ligands with nitrogen in the backbone have also been used.  For example,  40  Ph PN(Me)N(Me)PPh 2  „  (15) has been employed in the synthesis of a variety of Pd  2  complexes, and has been coordinated to Ru to yield cw-Ru(15) (H) , a complex with potential 2  2  41  in C - H activation.  42  The ligands dppa (bis(diphenylphosphino)amine),  such as PPh (Me)NHP(0)Ph 2  synthesized.  43 2  and its derivatives,  and [PPh (CH Ph)NP(OH)Ph ]" (16), 2  2  44  2  have also been  The ligand dppa coordinates to metals in the same way as dppm, while the  derivatives can coordinate in both a monodentate P-bound mode (Ru", R u , Rh , Ir" ) and or 1 11 ^4 in a chelating bidentate P,0-bound mode (Rh, Ru ) fashion, forming six-membered rings. Chiral P N ligands, such as d(py)pcp (17) and (S,S)-N,N -bis[oIV  111  1  45  ,  46  diphenylphosphine)benzyhdene]-(lS,2,S)-diiminocyclohexane  (18),  have  also  been  synthesized with the aim of forming complexes able to catalyze asymmetric reactions. 17 and 18 and other related chiral ligands have been used to catalyze asymmetric reactions such as Gngnard cross-coupling reactions, hydrogenation of imines,  45  47  48,49  the homogeneous hydrogenation of prochiral olefins, 46,50  or the enantioselective epoxidation of olefins.  8  References on page 17  Chapter 1  a  n = 1; 2 - ( P h P ) P y  b  n = 2; 2 - ( P h P ) P y  c  n = 3;2-PPy  2  2  Ph—P  3  Py = pyridyl  (2-pyridyl)phosphine  P(CH CH Py)Ph 2  8  2  2  9 Mes*  SiMe, Mes* =  PPh, feu  NMe, 1,2-bis(di-2-pyridylphosphino)ethane  Mes*P=C(SiMe )Py  PNMe  3  11  d(py)pe  10  2  12  Me  Pr.  CH,  Ph P  N.  y  X' C, H  Pr  Me  I  PPh,  2  /  I  N  N \  PPh,  3  (diisopropylphosphino-dimethylamino)ethane  2,6-bis(diphenylphosphino)-N-methylaniline  13  14  bis(phosphanyl hydrazine)  15  * Br" PhoP^ " 7  ^PPh,  I  I  PhH C  OH  2  '2 dppa derivative  \  pyridyldiphosphine  16  d(py)pcp  ' 2 ( S . S ) - P N N P ligand  18  17 Figure 1.9. PN ligands in the literature.  9  References on page 17  Chapter 1 1.3.2  Tetradentate Ligands  Dmapm (cf. 2, Section 1.1) is a tetradentate ligand that both simultaneously bridges and chelates transition metals; a brief survey of the literature has found a few others. A Pd complex  containing  the  tetradentate  diphenylphosphino)phenyl]formamidoyl)biphenyl  diimine (19)  ligand  has  been  2  2,2'-bis-(N-[(2-  synthesized  via the  51  PdClMe(cod) precursor.  Stanley and co-workers have synthesized the tetraphosphine  ligands, meso- and rac-(Et PCH2CH2)(Ph)PCH2P(Ph)(CH2CH PEt2), designed to chelate and 2  2  52  bridge two transition metal centers,  while a monomeric Rh(ffl) complex (20) containing the  rac form of the n -ligand is illustrated in Figure 1.10. 4  Figure 1.10. Mono- and bimetallic compounds containing tetradentate ligands.  Recently, the first Pd-Pd bonded, hydroxo-bridged organopalladium bimetallic complex, [Pd (n-OH)(THF)(p-ri :n -l,3-C4H )(PPh )2][PF ] (21a) was synthesized," and its 2  2  2  6  3  6  treatment with one equiv. of benzenethiol afforded the bridged-thiolate product (21b), as illustrated in Figure 1.11.  A Pd2 complex containing a metal-metal bond with a bridging 54  thiolate has been synthesized previously.  10  References on page 17  Chapter 1  PF  R  PhSH, THF Ph P  Ph P  PPh,  3  3  21b Figure 1.11. Reaction of a Pd-Pd hydroxo-bridged complex with PhSH to yield the bridgedthiolate complex.  1.3.3  Single Bisphosphine Bridged Complexes  Dipalladium and diplatinum complexes can adopt a trans orientation when containing two bisphosphines, or a cis orientation when a single bisphosphine bridges the two metal centers 4-7,9,19,55-57  (Fig. 1.12). There are many examples of Pd ,  58-60  Pt ,  2  2  61,62  and PdPt  complexes in a  trans orientation, with so called A-frame, side-by-side, or face-to-face geometries (Fig. 1.12).  trans  cis  (M = metal, L = P or N, X = other ligands)  Figure 1.12. Geometries of bimetallic complexes: ligands oriented in a trans or a cis fashion. Complexes containing a single bisphosphine in a cis orientation are less common than in the trans orientation (Fig. 1.13). Heterobimetallic complexes involving Ru/Pt and Mo/Pt have been made containing a single dppm ligand.  63  The complex RuCp(PPh )(u-Cl)(u3  dppm)PtCl (22) has been used in the catalytic electrooxidation of methanol to C H ( O C H ) 2  2  11  3  2  References on page 17  Chapter 1 and C H O O C H  64 3>  while Fe/Rh complexes with bridging dppm or dppen ligands have been  65  made (23);  interest lies toward new catalytic applications and metal-assisted organic  chemistry.  X — CH , C—CH2 2  22  23  Figure 1.13. Complexes containing a single diphosphine bridge, exemplifying the bimetallic cis-types (Fig. 1.12). As already mentioned, dmapm (see Fig. 1.1) is a binucleating tetradentate ligand. A few other examples of complexes containing such ligands are known,  and these show a  natural  A n example is  preference  for the  cis arrangement  of X (Fig. 1.12).  Rh Cl (CO) (eLTTP) (24) (Fig. 1.14) in which the coordination geometry around the Rh(I) 2  2  2  66  centers is square planar, with the ligand being chiral at the 2 central P-atoms.  The ligand  DPyPM has also been used to chelate two Rh(I) centers (25) as seen in Figure 1.14; the R h Rh distance is not indicative of a metal-metal interaction.  67  the linked pyridylphosphine units have a cis coordination.  The P-atoms are cis to CO and These complexes were both  reported prior to my thesis work.  12  References on page 17  Chapter 1  Figure 1.14. Bimetallic complexes containing a single bisphosphine bridge.  However, during the writing of this thesis, a somewhat related bimetallic complex of Pd  was  reported,  containing  the  binucleating  ligand  derived  from  7V,7Y-bis[2-  68  diphenylphosphino)phenyl]formamidine (Hdpfam).  The reaction of Hdpfam with 2 equiv.  of PdCi2(cod) yields the A-frame complex Pd Cl2(|J.-Cl)(dpfam), as shown in Figure 1.15; no 2  Pd-Pd bond was formulated.  Figure 1.15. Bimetallic Pd complex containing dpfam .  1.4 Transition Metal Mercapto and Thiolato Complexes As well as the work done in this group (Section 1.1), Cowie and co-workers have also studied the reactions of homo- and heterobimetallic compounds containing C O and bridging dppm 69,70  ligands with H2S and thiols.  For example, RhRe(C0)4(dppm)2 reacts to yield the bridged-  sulfide product (with the production of H2) or the bridged-hydride, bridged-thiolate product (with the elimination of CO), as shown in Fig. 1.16a. ' For R S H (R = H , Et, Ph), the R S H 7  adducts, presumably formed by coordination at the unsaturated Rh center, undergo oxidative 13  References on page 17  Chapter 1 addition to yield a bridging hydride species; for R = H , oxidative addition of the second S - H linkage can occur with subsequent elimination of H , and the formation of the bridged-sulfido 2  product, ' i i N M R signal for the proposed thiol adducts were not found. Trimetallic complexes such as the Pt cluster shown in Figure 1.16b also react with 3  H S and thiols: oxidative addition of H S yields a complex with a terminal hydride and a p. 2  2  3  sulfide, with the elimination of a H and CO (the proton does not react with the terminal +  72  hydride to generate H2).  Reaction of the cluster with thiols yields a complex with a terminal  hydride and a (j. -bridging thiolate (Fig. 1.16b). 3  Ph P—  ^PPh  2  oc„  +H S  /(  2  Ph P—  ^PPh  2  ''Rh  ^•co Ph P  -PPh,  Ph P  -PPh,  2  --—Re—CO O C ^  I  2  Ph P,  -PPh,  9  ^ C O  'J-Re'  -H, 2  oc,,, OC—Rh-  2  oc,,,, I  + RSH = Et, Ph -CO  OC  Rh"  Re. •CO  P  h  2  p  \  R  -PPh, +  Ph P-  -PPh  2  2  +  + H S 2  H , - CO  PPh,  +  P  h  2  p  o ^PPh  "  pph  2  ft  2  ^PPh PPh  2  \  J  /  2  Ph P-  -PPh  ^2  2  /  -PPh  p  2  ,  \  R  + R S H , - CO PPh  2  12  +  / ^ P P h ,  pt  (R = Me, Et, CH Ph, 2  ^pt  C H C 0 E t , Ph, p-tolyl) 2  2  Figure 1.16 Oxidative addition of H S and thiols, a) Reaction of RhE.e(CO) (dppm) with H S and thiols, b) Reaction of [Pt (p. -CO)(dppm) ] with H S and thiols. 2  4  3  2  2  2+  3  3  14  2  References on page 17  Chapter 1 Studies have been done to probe the mechanism of thiol reaction at metal centers. There is evidence of an r| -(MeSH)Fe intermediate en route to an oxidative addition product 2  73  as illustrated in Figure 1.18a;  at higher temperatures, decomposition yields H and thiolate2  bridged dimers. In another study, [Ni(SR)(triphos)] (R = Ph or Et) was titrated with the +  lutidinium salt [lutH] to give [Ni(SHR)(triphos)] ; an r| -RSH intermediate was invoked, but +  2+  2  not detected as the S - H protons are sufficiently acidic to undergo exchange with protons in 74  solution (Fig. 1.17b).  ,  Another instance where an r| -RSH intermediate has been proposed  involves the oxidative addition of R S H to IrCl(CO)(PPh ) . 3  2  This reaction is thought to  proceed via a three-center transition state Ir-S(H)R, in which the lengthening of the S-H bond was considered synchronous with the binding of these two atoms/  A n agostic Os-H-S  5  interaction has been proposed for the reaction of thiols with Os3(CO)n(NCMe) (c in Fig. 76  1.17),  2  7  and proton transfer between sulfur and the n - H has been observed in [Os(n 2  H )(CO)(quS)(PPh ) ] (quS = quinoline-8-thiolate). +  2  3  77  2  a  b  c  Figure 1.17. Proposed ri -RSH intermediates en route to the oxidative addition products for reaction of R S H with (a) (MeS)Fe(CO) (PEt ), (b) (RS)Ni(triphos), R = Et, Ph, and (c) Os (CO) (NCMe). 2  3  3  3  u  Claver and co-workers have synthesized heterobimetallic d -d 8  8  complexes with  bridging dithiolates. PtRh, PdRh, hPt, and IrPd complexes were made with no metal-metal bonds using bridging ligands such as RSSR, R = Bu, Pr, Et.  78,79  Bimetallic complexes of the types [(dppe)M(p-SR) Pd(r| -allyl)][C10 ] ( M = Pd or 3  2  Pt),  and  [(dppe)Pt(|a-SC H4Me- p) Pd(ri -C H )][C104] 3  6  j  2  3  5  4  (dppe  =  1,2-  bis(diphenylphosphino)ethane; allyl = Q H 5 , C4H7) have been synthesized with potential for ,  •  8  0  use in homogeneous catalysis.  15  References on page 17  Chapter 1 [Ru(H2edta)(u-SPh)]2, a R u  2  complex containing a Ru-Ru single bond has been  synthesized, with interest in developing metal-based drugs; the precursor, Ru(Hedta)(OH ) 2  remains intact in dilute aqueous solution and is not scavenged by the presence of RSH groups 81  (e.g. within glutathione, cysteine, etc.). Rhenium sulfido species and their interactions with H2 have been found to catalyze S82  atom transfer.  At r.t., ReH(SH)2(PMe3)4 catalyzes the reaction of H S with P M e to give 2  3  S P M e 3 and H ; S-atom transfer from an M - S H species to P M e is rare, but is known to occur via sulfido complexes. 2  3  1.5 The Overview of Thesis As mentioned in Section 1.1, my thesis work was initially aimed at studying the reactivity and mechanisms of reaction of RuMo(CO)6(dppm) with thiols, H 2 S , and other small molecules. 2  The initial findings that were made and the problems that were encountered are discussed in Chapter 4.  The bulk of this thesis work (Chapter 3) focusses on the reactivity of  Pd Ci2(dmapm) and PdPtCl2(dmapm) with thiols and H 2 S and on elucidating mechanistic 2  aspects of the reactions.  The study was aimed at characterizing the reaction products  (bridged-thiolate  and detecting possible reaction intermediates  species)  via variable  temperature N M R . A preliminary study of the reaction of SO2 with Pd2Ci2(dmapm) was also made. The reactivity of dmapm was also explored with Pd(hfac)2. This general introductory Chapter 1 summarizes relevant transition metal-H S and 2  -thiol chemistry, and describes also some associated P-P and P - N ligand systems. Chapter 2 provides experimental procedures for syntheses and characterization of the dmapm ligand and complexes, as well as the associated instrumental methods, especially N M R .  16  References on page 17  Chapter 1 1.6 References (1)  Laarab, H . B . ; Chaudret, B . ; Dahan, F.; Devillers, J.; Poilblanc, R.; Sabo-Etienne, S. NewJ. Chem. 1990, 14, 312.  (2)  Khorasani-Motlagh, M . ; James, B. R. , unpublished results.  (3)  Jones, N . D. Ph. D. Dissertation, University of British Columbia, 2001.  (4)  Lee, C.-L.; Besenyei, G.; James, B . R.; Nelson, D. A . ; Lilga, M . A . Chem. Commun. 1985,1175.  (5)  Besenyei, G.; Lee, C.-L.; Gulinski, J.; Rettig, S. J.; James, B . R.; Nelson, D. A.; Lilga, M . A . Inorg. Chem. 1987, 26, 3622.  (6)  James, B. R. Pure Appl. 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(80)  Ruiz, J.; Giner, J.; Rodriguez, V.; Lopez, G.; Casabo, J.; Molins, E.; Miravitlles, C. Polyhedron 2000,13.  (81)  Cameron, B. R.; Bridger, G. J.; Maresca, K. P.; Subieta, J. Inorg. Chem. 2000, 39, 3928.  (82)  Schwarz, D. E.; Dopke, J. A.; Rauchfuss, T. B.; Wilson, S. R. Angew. Chem. Int. Ed. 2001,40, 2351.  20  References on page 17  Chapter 2  Chapter 2 GENERAL EXPERIMENTAL PROCEDURES  2.1 General Procedures A l l procedures were conducted using standard Schlenk techniques under an A r or N  2  atmosphere unless otherwise noted. In some cases, an Ar-filled glovebox was used to handle particularly 0 - or H 0-sensitive materials. A l l reactions were performed at r.t. 2  2  unless otherwise specified.  2.2 Physical Techniques and Instrumentation  2.2.1. Nuclear magnetic resonance (NMR) spectroscopy Solution N M R spectra were obtained using two spectrometers. Spectrometer frequencies for *H, P , and F for each instrument are given in Table 2.1. Proton chemical shifts are 31  19  given with reference to the residual solvent peak, relative to SiMe (8 0.00), P{'H} 31  4  shifts are reported relative to external P(OMe) ( ^ P ^ H } 8 141.00 vs. external 85 % 3  H3PO4), and F{'H} N M R chemical shifts are reported relative to external C F 3 C O O H . 19  Table 2.1.  Spectrometer frequencies for H , P , and F for the N M R instruments used in the course of this work. Spectrometer Frequency (MHz) ]  31  31  Spectrometer  19  p  19  F  Bruker AC-200E  200.13  81.01  188.30  Bruker AV-300  300.13  121.49  282.39  Variable temperature H , ' H l / ' P } and P{'H} N M R were performed using the Bruker ]  AV-300 spectrometer. frequency).  31  Chemical shifts are reported in 8 units (positive shifts to high  A l l J-values are given in Hz; s = single, d = doublet, t = triplet, m =  multiplet, br = broad, p = pseudo.  21  References on page 37  Chapter 2 2.2.2. X-ray crystallography X-ray crystallographic analyses were performed by Dr. Brian Patrick of the U B C Chemistry Department, using a Rigaku/ADSC C C D area detector with graphite monochromated M o - K a radiation.  2.2.3. Elemental analysis Elemental analyses were conducted either by Mr. Peter Borda of the U B C Chemistry Department, using a Carl Erba 1108 C H N - 0 analyzer, or by Mr. M . K . Yang, of the SFU Chemistry Department, using a Carlo Erba Model 1106 C H N analyzer.  2.2.4  Ultraviolet-visible (UV-vis) spectroscopy  UV-vis  spectra  were  Spectrophotometer.  obtained using a Hewlett-Packard 8452A  Array  Wavelength maxima, Xmax, are reported in nm, and extinction  coefficients are shown in units of M  2.2.5  Diode  - 1  c m after the reported wavelengths. -1  Infrared (IR) spectroscopy  IR spectra were recorded on an ATI Matheson Genesis Series FTIR instrument. Samples were prepared as K B r discs. IR data are reported in cm' . 1  2.2.6  Conductivity  Conductivity measurements were obtained using a Thomas Serfass conductance bridged model RCM151B1 (Arthur H . Thomas Co. Ltd.) connected to a 3404 cell (Yellow Springs Instrument Co.). A l l measurements were made at 25 °C, in a thermostatted water-bath, at 10 mol L -3  2.2.7  _ 1  solutions and are reported as A in QT moF cm . 1  1  2  M  Mass spectrometry (MS)  MS was performed at the U B C Chemistry Department facility, using the LSIMS technique.  22  References on page 3 7  Chapter 2 2.2.8  Gas chromatography (GC)  A Hewlett Packard 5890A gas chromatograph equipped with a 25 m-0.32 mm HP17 column and an H2/air flame ionization detector (FED) was used, with He as the carrier gas.  2.2.9  Gas chromatography-Mass spectrometry (GC-MS)  An Agilent 6890 Series gas chromatograph system with a 5973 Network MS Detector equipped with a 0.25 mm-0.25 um HP-5 MS column and an H2/air flame ionization detector (FID) was used. He was used as the carrier gas.  2.3  Materials  2.3.1  Gases  Gases were purchased from commercial sources and used without purification.  2.3.2  Solvents  Reagent grade solvents (Fisher Scientific) were either distilled from CaH2 (CH2CI2), Na (Et20, hexanes,  C^i^), Mg/I (EtOH), Na^enzophenone (C H ), or anhydrous K2CO3 2  7  g  (acetone) under N . All deuterated solvents (CDCI3, CD C1 , C D , C H , and CD OD) 2  2  2  6  6  7  8  3  were purchased from Cambridge Isotope Laboratories and used as supplied.  2.3.3. Reagents Unless otherwise noted, reagents were purchased from commercial sources and used without further purification.  2.3.4. Metal complexes PdCl and K PtCl were obtained from Colonial Metals Inc. 2  2  4  Ni(CO) (PPh ) and 2  3  2  Pd(hfac) were kindly donated by Dr. Craig Pamplin, formerly of the James Group. 2  NMR spectroscopic data for these complexes are in agreement with those given in the 1,2  literature.  23  References on page 37  Chapter 2 2.3.5  Organic compounds  2-Bromoaniline was purchased from Aldrich and was further purified by sublimation as a white crystalline solid at r.t.  7Y,7V-Dimethyl-2-bromoaniline was synthesized via  methylation of the pure compound with dimethylsulfate according to a literature procedure.  2.4  Ligand Synthesis  2.4.1. 1,1 -BisCdi-Co-TVjA^-dimethylanilinyOphosphine)methane, dmapm To a solution of "BuLi in hexanes (1.6. mol L , 16.5 mL, 26.4 mmol), cooled to -40 °C _ 1  in a dry ice/CH CN bath, was added o-bromo-Af Af-dimethylaniline (5.05 g, 25.2 mmol). 3  The yellow solution was stirred for 15 min when a white precipitate formed. The slurry was allowed to warm to r.t. and stirring was continued for 1 h. After the solution was cooled again to -40 °C, l,l-bis(dichlorophosphino)methane (1.33 g, 6.09 mmol) in Et20 (15 mL) was added over 5 min. The resulting orange-red slurry was stirred for 15 min and then allowed to warm to r.t. Stirring was continued for 1 h and then HC1 (ca. 1 mol L ) was added dropwise to the aqueous layer until it was neutral. The aqueous fraction -1  was extracted with CH2CI2 (3 x 20 mL) and the combined extracts were dried over MgSC>4. The solvent was removed in vacuo and EtOH was added. The slurry was refluxed for 0.5 h, cooled to r.t. and filtered to give a white powder that was washed with cold EtOH (3x5 mL) and dried in vacuo. Yield: 1.84 g (54 %). 'H NMR (300 MHz, CDCI3,  300 K): 8 2.23 (t, 2H, CH , 2  Jhp  2  = 4.2), 2.68(s, 24H, NCH ), 3  7.02 (pt, 2H, Ar),  7.11 (pt, 4H, Ar), 7.25 (pt, 4H, Ar), 7.40 (pt, 4H, Ar). P{ H} NMR (121 MHz, C D C I 3 , 31  300 K): 8 -36.0 (s).  !  The synthesis of this ligand has been published, along with full  characterization, including the X-ray structure.  2.5  Palladium Complex Precursors  All were prepared according to published procedures, and in each case their *H NMR data agreed with reported values.  24  References on page 3 7  Chapter 2 2.5.1  Pd (dba) CHCl3 2  5  3  To a solution of dba (4.60 g, 19.61 mmol) and NaOAc (3.90 g, 47.54 mmol) in MeOH (150 mL) was added PdCl (1.05 g, 5.93 mmol). The suspension was stirred at 45 °C for 2  30 min, resulting in a dark red solution, which upon cooling yielded a dark precipitate. The solid was collected by filtration, washed with H 0 (2 x 10 mL) and Et 0 (2x10 2  2  mL) and dried in vacuo. The crude product was then dissolved in warm C H C I 3 (100 mL) and the mixture filtered; addition of Et 0 (400 mL) to the filtrate provided a violet 2  crystalline solid that was isolated by filtration, washed with Et 0 (2 x 30 mL) and dried 2  at r.t. in vacuo. Yield: 2.06 g (67 %). *H NMR (300 MHz, CDC1 , 300 K): 5 4.80 to 7.60 3  (m, 24 H).  2.5.2  fra/is-PdCl (PhCN) 2  6 2  A suspension of PdCl (2.00 g, 11.3 mmol) in PhCN (50 mL) was heated to 100 °C for 8 2  h. The red solution was filtered in to a flask containing hexanes (300 mL) and the yellow precipitate was isolated by filtration, washed with hexanes (3><10 mL) and dried in vacuo. Yield: 3.97 g (91 %).  2.5.3 PdCl (cod)  ?  2  A stirred solution of PdCl (1.22 g, 6.85 mmol) in hot, concentrated HC1 (5 ml) was coled 2  to r.t. and diluted with EtOH (140 mL). The solution was filtered and cod (3.0 mL, 2.65 g, 0.024 mmol) was added to the filtrate. The resulting yellow precipitate was isolated by filtration, washed with Et 0 (2 * 10 mL) and dried in vacuo. Yield: 1.95 g (97 %). 'H 2  NMR (300 MHz, C D C I 3 , 300 K): 5 2.54 (m, 4H, CH ), 2.89 (m, 4H, CH ), 6.30 (m, 4H, 2  2  CH).  2.5.4 PdCl(Me)(cod)  8  To a yellow solution of PdCl (cod) (1.50 g, 5.25 mmol) in CH C1 (50 mL) was added 2  2  2  SnMe (1.04 mL, 1.50 g, 0.0079 mmol). After being stirred at r.t. for 18 h, the colourless 4  solution was filtered through Celite and the filtrate was evaporated. The white residue was recrystallized from CH C1 /Et 0 and dried in vacuo. Yield: 0.97 g (70 %). 'H NMR 2  2  2  25  References on page 3 7  Chapter 2 (300 MHz, C D C I 3 , 300 K): 5 1.15  CH, V  2.6  (s, 3H, CH ), 2.36 to 2.70 3  = 2.6), 5.88 (t, 2H, CH, J 3  H H  H H  (m, 8H, CH ) 2  5.12 (t, 2H,  = 4.0).  Synthesis of Bimetallic Pd Complexes 2  These were again synthesized according to reported procedures, and the *H and P{'H} 31  NMR data agreed with reported values.  2.6.1 Pd CI (dppm) 2  2  9 2  To a solution of Pd (dba) -CHC1 (0.277 g, 0.27 mmol) and dppm (0.411 g, 1.07 mmol) 2  3  3  in CH C1 (20 mL) was added PdCl (PhCN) (0.205 g, 0.535 mmol). The solution was 2  2  2  2  refluxed for 30 min, filtered and then cooled to r.t. The volume of the solution was reduced to ca. 5 mL and hexanes (20 mL) was added to precipitate an orange powder. The product was washed with acetone (2><10 mL) and Et 0 (10 mL) and dried in vacuo. 2  Yield: 0.173 g (61 %). 'H NMR (300 MHz, CDC1 , 300 K): 5 4.12 (m., 4H, CH , J 2  3  2  PH  =  3.9). 7.05 to 7.80 (m, 40 H, Ph). P{'H} NMR (121 MHz, CDC1 , 300 K): 5 -1.7 (s). 31  3  2.6.2 Pd Cl (dmapm) ° 2  4  To a Schlenk tube containing 7rara-PdCl (PhCN) (110 mg, 0.29 mmol) and dmapm (82 2  2  mg, 0.15 mmol) was added CH C1 (10 mL), and the resulting yellow solution was stirred 2  2  for 15 min. The solvent was removed in vacuo to leave ca. 1 mL volume, and Et 0 (20 2  mL) was then added to give the product a yellow powder that was isolated by filtration, washed with Et 0 (3x3 mL) and dried under vacuum. Yield: 105 mg (76 %). H NMR l  2  (300 MHz, CDC1 , 300 K): 5 2.31 (s, 12H, NCH ), 2.78 (s, 6H, NCH ), 3.28 (s, 6H, 3  3  3  NCH ), 4.97 (t, 3H, CH , J p = 17.1), 7.40 (br m, 6H, Ar), 7.65 (br m, 4H, Ar), 7.80 (br 2  3  2  H  m, 2H, Ar), 8.52 (br m, 2H, Ar), 8.74 (br m, 2H, Ar). P{'H} NMR (121 MHz, CDC1 , 3l  3  300 K): 5 34.8 (s).  2.6.3 Pd Cl (dmapm) 2  10  2  To a Schlenk tube containing rra«s-PdCl (PhCN) (32 mg, 0.083 mmol) and dmapm (47 2  2  mg, 0.084 mmol) was added CH C1 (10 mL), and the resulting yellow solution was 2  2  stirred for 15 min. Solid Pd (dba) CHCl (44 mg, 0.043 mmol) was then added and the 2  3  3  26  References on page 37  Chapter 2 resulting purple solution was warmed to reflux for 3 h during which it became orange. The solution volume was reduced to ca. 1 mL, and E t 0 (20 mL) was added to give the 2  product as an orange powder that was isolated by filtration, washed with E t 0 ( 3 x 5 mL) 2  and dried under vacuum. Yield: 54 mg (76 %). ' H N M R (300 M H z , CDC1 , 300 K): 5 3  2.44 (s, 12H, N C H ) , 2.89 (s, 6H, NCH ), 3.07 (s, 6H, N C H ) , 3.70 (t, 3H, C H , J 2  3  3  3  2  H?  =  11.3), 7.18 (pt, 2H, Ar), 7.45 (m, 6H, Ar), 7.58 (m, 4H, Ar). P { H } N M R (121 M H z , 31  !  C D C I 3 , 300 K): 8 -29.2 (s). UV-vis (CH C1 , r.t.): 232 (42,800), 452 (10,265). 2  2.7  2  Synthesis of Bimetallic Pd -Thiolato Complexes 2  2.7.1  [Pd CI (dmapm)(u-SEt)] Cr +  2  2  To a solution containing Pd Cl (dmapm) (50 mg, 0.059 mmol) in CH C1 (5 mL) was 2  2  2  2  added excess EtSH (0.35 mL, 4.7 mmol). The solution was stirred for 24 h at r.t. and filtered through a plug of Celite 545 and MgS04. The volume of the yellow filtrate was reduced in vacuo to ca. 1 m L and E t 0 (20 mL) was added to give a yellow precipitate. 2  This was isolated by filtration, washed with E t 0 (3 2  x  3 mL) and dried in vacuo. Yield:  20.3 mg (33 %). Anal. Calcd. for Pd Cl P N C H47S: C 44.9, H , 5.1, N 6.0. Found: C 2  3  2  4  35  45.2, H 5.1, N 5.9. *H N M R (300 MHz, CDC1 , 300 K): 8 1.14 (s, 3H, C # C H S ) , 2.66 3  3  2  (s, 2H, CH Gr7 S), 2.89 (br s, 24 H , NC7/ ), 4.76 (t, 2H, P C / / P , V = 10.8). 7.65 to 8.04 3  2  3  2  P H  (m, 16H, Ar). P { ' H } N M R (121 M H z , CDC1 , 300 K): 8 49.0 (s). A 31  3  M  ( C H C N , 298 3  K): 136. Yellow platelet-shaped crystals were isolated from a solution of the title complex in CH C1 layered with E t 0 , and their structure determined by X-ray analysis. 2  2.7.2  2  2  [Pd Cl (dmapm)(u-S Pr)] Cr n  2  +  2  This complex was prepared in a fashion similar to that described for [Pd Cl (dmapm)(u2  2  SEt)] Cl~. Thus, excess PrSH (0.35 mL, 3.86 mmol) was injected into a CH C1 solution +  n  2  2  containing Pd Cl (dmapm) (50 mg, 0.059 mmol). The solution was stirred for 24 h at r.t. 2  2  and filtered through a plug of Celite 545 and MgS04. The volume of the yellow filtrate was reduced in vacuo to ca. 1 mL and E t 0 (20 mL) was added to give the product as a 2  yellow precipitate.  This was isolated by filtration, washed with E t 0 ( 3 x 3 L ) and 2  27  m  References on page 37  Chapter 2 dried in vacuo. Yield: 44.4 mg (79 %). Anal. Calcd. for Pd Cl3P2N4C36H 9S: C 45.5, H, 2  4  5.2, N 5.9. Found: C 45.3, H 5.4, N 5.9. 'H NMR (300 MHz, CDC1 , 300 K): 5 0.74 (t, 3  3H, C// CH CH S) 1.60 (sx, 2H, CH3C//2CH2S), 2.70 (t, 2H, CH3CH2C//2S), 3.05 (br s, 3  2  2  24 H, NC// ), 4.71 (t, 2H, PC7/ P, J  = 10.8). 7.40 to 8.10 (m, 16H, Ar).  2  3  2  P H  P{'H} NMR  31  (121 MHz, CDCI3, 300 K): 5 49.3 (s). A (CH CN, 298 K): 98. UV-vis (CH C1 , r.t.): M  3  2  2  368 (953), 234 (4730). Yellow needle-shaped crystals of [Pd Cl (dmapm)((j.-S"Pr)] Cr suitable for X-ray +  2  2  diffraction were isolated from a solution of the title complex in CH C1 layered with 2  2  Et 0. 2  2.7.3  [Pd Cl (dmapin)(n-SPh)] Cr +  2  2  This complex was prepared in a similar fashion to [Pd Cl (dmapm)(|J,-SEt)] Cr. Thus, +  2  2  excess PhSH (0.35 mL, 3.9 mmol) was added to a CH C1 2  Pd Cl2(dmapm) (50 mg, 0.059 mmol). 2  2  solution containing  The solution was stirred for 24 h at r.t. and  filtered through a plug of Celite 545 and M g S 0 . The volume of the yellow filtrate was 4  reduced in vacuo to ca. 1 mL and Et20 (20 mL) was added to give the product as a yellow precipitate. This was isolated by filtration, washed with E t 0 ( 3 x 3 mL) and 2  dried in vacuo. Yield: 39.6 mg (68 %). A satisfactory elemental analysis was not obtained. H NMR (300 MHz, CDC1 , 300 K): 5 3.54 (br s, 24 H, NC77 ), 4.76 (t, 2H, !  3  3  PC# P, J?n= 10.8), 6.76 (t, 2H, m - C ^ S , J p= 7.5), 6.90 (d, 2H, o - C ^ S , J = 7.3), 2  2  2  2  H  W  7.16 (t, 1H, p-C^sS), 7.20 to 7.80 (m, 16H, Ar), 6.70 to 7.70 (m, 16H, Ar). P{'H} 31  NMR (121 MHz, C D C I 3 , 300 K): 5 51.6 (s).  2.7.4  [Pd Cl (dmapm)(n-SMe)] [OTf]+  2  2  To a solution containing Pd Cl (dmapm) (50 mg, 0.059 mmol) in CH2CI2 (5 mL) was 2  2  added excess MeSH (via vacuum transfer) and 1 equiv. of triflic acid (0.003 mL, 0.059 mmol). The solution was stirred for 24 h at r.t. and filtered through a plug of Celite 545 and M g S 0 .  The volume of the yellow filtrate was reduced in vacuo to ca. 1 mL and  4  Et 0 (20 mL) was added to give the product as a yellow precipitate. This was isolated by 2  filtration, washed with E t 0 (3x3 mL) and dried in vacuo. Yield: 24.2 mg (40 %). Anal. 2  Calcd. for Pd Cl2P N C35H S20 F3: C 40.6, H, 4.4, N 5.4. Found: C 40.8, H 4.4, N 5.3. 2  2  4  45  3  28  References on page 3 7  Chapter 2 ]  H NMR (300 MHz, C D 3 O D , 300 K): 5 1.90 (s, 3H, C# S), 2.90 (br s, 24 H, NC// ), 3  4.04 (t, 2H, PC7/ P, Jp = 10.4), 7.56 (t, 4H, Ar, V 2  2  H  NMR (121 MHz, CD OD, 300 K ) : 5 50.3 (s). A  M  = 7.2), 7.85 (q, 12H, Ar).  P{'H}  31  F{'H} NMR (282 MHz, CD OD, 300  19  3  K): 5 -3.4 (s).  H H  3  3  (MeOH, 298 K): 116. UV-vis (MeOH, r.t.): 208 (74,260), 372  (5,800).  2.7.5  [Pd Cl (dmapm)(n-SEt)] [OTfr +  2  2  This complex was prepared exactly as described for [Pd Cl (dmapm)(u-SMe)] [OTf]~but +  2  2  with excess EtSH (0.036, mL, 0.59 mmol). Yield: 42.2 mg (68 %) Anal. Calcd. for Pd Cl P2N4C H47S 0 F : C 41.2, H, 4.5, N 5.3. Found: C 40.9, H 4.5, N 5.2. 2  2  36  2  3  3  'H NMR (300 MHz, CD OD, 300 K ) : 8 1.14 (t, 3H, Cf/ CH S, J H = 7.3), 2.60 (q, 2H, 3  3  3  2  H  CH C# S), 2.92 (br s, 24 H, NC# ), 7.53 (t, 4H, Ar, J H = 9.5), 7.84 (m, 12H, Ar). 3  3  2  3  H  P{'H} NMR (121 MHz, CD OD, 300 K): 8 50.3 (s).  31  19  3  CD OD, 300 K ) : 8 -3.4 (s). 3  A  M  F{ H} NMR (282 MHz, !  (MeOH, 298 K ) : 112. UV-vis (MeOH, r.t.): 208  (74,040), 370 (5520).  2.7.6  [Pd Cl (dmapm)(n-S Pr)] [OTfT n  2  +  2  This complex was prepared in a fashion similar to that given for [Pd Cl (dmapm)(u2  2  SMe)] [OTfp. Thus, excess "PrSH (0.0038 mL, 0.59 mmol) and 1 equiv. of triflic acid +  (0.003 mL, 0.059 mmol) were syringed into a solution containing Pd Cl (dmapm) (50mg, 2  2  0.059 mmol) in CH C1 . The pale green precipitate that formed after 24 h was isolated by 2  2  filtration, washed with Et 0 (3><3 mL) and dried in vacuo. Upon addition of Et 0 to the 2  2  pale green solution, further product precipitate, which was also washed with Et 0 (3x3 2  mL)  and dried in vacuo.  Yield:  42.5  mg (68  %).  Anal.  Calcd. for  Pd Cl P N C H49S 0 F : C 41.7, H, 4.6, N 5.3. Found: C 41.5, H 4.6, N 5.1. 'H NMR 2  2  2  4  37  2  3  3  (300 MHz, CD OD, 300 K ) : 8 0.72 (t, 3H, C/f CH CH S, 7 H = 7.3), 1.57 (ps sx, 2H, 2  3  CH C// CH S, J  3  3  3  2  2  H H  2  H  = 7.0) 2.50 (t, 2H, CH CH C// S), 2.93 (br s, 24 H, NCH ), 4.03 (t, 3  2H, C H J = 10.8), 7.54 (t, 4H, Ar, V 2  2i  2  HP  H H  2  2  3  = 7.3), 7.84 (m, 12H, Ar).  31  P{ H} NMR (121 ]  MHz, CD OD, 300 K): 8 49.2 (s). F{'H} NMR (282 MHz, CD OD, 300 K): 8 -3.5 (s). 19  3  A  M  3  (MeOH, 298 K): 114. UV-vis (MeOH, r.t.): 208 (73,520), 372 (4,870).  29  References on page 37  Chapter 2 2.7.7 [Pd Cl (dmapm)(u-S Bu)] [OTfT n  2  +  2  This complex was prepared as described for [Pd Cl (dmapm)(p-SMe)] [OTf]~, but using +  2  2  excess "BuSH (0.063 mL, 0.59 mmol). The resulting red filtrate was reduced in vacuo to ca. 1 mL and Et 0 (20 mL) was added to give the product as a yellow precipitate, 2  isolated by filtration, washed with Et 0 (3 x 3 mL) and dried in vacuo. Yield: 43.5 mg 2  (68 %). Anal. Calcd. for Pd Cl P N4C38H S 03F : C 42.3, H, 4.8, N 5.2. Found: C 42.0, 2  2  2  51  2  3  H 5.0, N 5.1. H NMR (300 MHz, CD OD, 300 K): 5 0.68 (t, 3H, C// CH CH CH S, !  3  2  J  H H  3  2  2  2  = 7.3), 1.07 (sx, 2H, CH C# CH CH S) 1.47 (qn, 2H, CH CH C// CH S), 2.45 (t, 3  2  2  2  3  2  2  2H, CH CH CH C// S), 2.86 (br s, 24 H, NC/7 ), 7.89 (t, 4H, Ar, J 2  3  2  12H, Ar).  2  2  3  HH  P{'H} NMR (121 MHz, CD OD, 300 K): 8 48.8 (s).  31  19  3  2  = 7.4), 7.77 (m,  F{'H} NMR (282  MHz, CD OD, 300 K): 8 -3.4 (s). A (MeOH, 298 K): 63. UV-vis (MeOH, r.t.): 210 3  M  (73,140), 370(6,010).  2.7.7  [Pd Cl (dmapm)(u-SPh)] [OTfT +  2  2  Method 1. This was identical to that described for [Pd Cl2(dmapm)(u-SEt)] [OTf]~, but +  2  using excess PhSH (0.061, mL, 0.59 mmol). A yellow product was again obtained from a red filtrate. Yield: 32.1 mg (49 %). Anal. Calcd. for Pd Cl P N4C4oH47S 03F : C 43.7, 2  2  2  2  3  H, 4.3, N 5.1. Found: C 43.5, H 4.4, N 5.2. *H NMR (300 MHz, CD OD, 300 K): 8 1.95 3  (br s, 12 H, NC// ), 3.50 (br d, 12 H, NC// ), 4.05 (t, 2H, PC// P, J p = 10.0), 6.77 (t, 2  3  3  2  H  2H, m-CstfsS, J p= 7.6), 6.87 (d, 2H, o - C ^ S , J =7.5), 7.01 (t, 1H, p - Q ^ S , J ? = 2  2  H  2  H?  7.4), 7.30 to 8.40 (m, 16H, Ar).  H  P{'H} NMR (121 MHz, CD OD, 300 K): 8 51.4 (s).  31  3  F{'H} NMR (282 MHz, CD OD, 300 K): 8 -3.4 (s). A (MeOH, 298 K): 116. UV-vis  19  3  M  (MeOH, r.t.): 208 (73,830), 308 (6,700). An in situ reaction was performed in a similar manner by the addition of an excess of PhSH (0.0012 mL, 0.12 mmol) to a septum-sealed NMR tube containing an orange solution of Pd Cl (dmapm) (10 mg, 0.012 mmol) in CDC1 (0.5 mL). 2  Method 2.  2  3  Excess PhSH (0.061, mL, 0.59 mmol) and methyl triflate (0.033 mL, 0.295  mmol) were added to a CH2CI2 (5 mL) solution containing Pd Cl (dmapm) (50 mg, 0.059 2  2  mmol). The solution was stirred for 24 h at r.t. andfilteredthrough a plug of Celite 545 and MgS0 . The volume of the redfiltratewas reduced in vacuo to ca 1 mL and Et20 4  (20 mL) was added to give the product as a yellow precipitate. This was isolated by  30  References on page 3 7  Chapter 2 filtration, washed with Et20 (3 x 3 mL) and dried in vacuo. Yield: 26.9 mg (41 %). The NMR data agree with those found for the complex made by Method 1.  2.7.8 [Pd Cl (dmapm)(u-SBz)] [OTfr +  2  2  Excess BzSH (0.061, mL, 0.59 mmol) was used in a method otherwise identical to that given  in  Section  2.7.7.  Yield:  44.1  mg  (68  %).  Anal.  Calcd.  for  Pd Cl P N C4oH S 03F : C 44.3, H, 4.4, N 5.0. Found: C 44.5, H 4.5, N 5.0. 'H NMR 2  2  2  4  52  2  3  (300 MHz, CDC1 , 300 K): 5 1.90 (br s, 12H, NC// ), 2.90 (s, 2H, -SCrY C H ) 3.44 (br 3  3  2  s, 6H, NC// ), 3.67 (br s, 6H, NGfY ) 4.05 (t, 2H, PGrY P, V 3  3  2  P H  6  5  = 10.0) 6.71 (t, 2H, m-  SCH C6// ,), 6.86 (d, 2H, o-SCHzC^s), 7.01 (t, 1H, p-SCT^C^), 7.40 to 8.30 (m, 16H, 2  Ar).  5  P{'H} NMR (121 MHz, CD3OD, 300 K): 5 51.4 (s). ^{'H} NMR (282 MHz,  31  CD3OD,  2.8  300 K): 5 -3.4 (s). UV-vis (MeOH, r.t): 210 (71,350).  In Situ Reactions of Pd Cl (dmapm) Species With Other Reagents 2  2.8.1  2  Reaction of Pd Cl (dmapm) and S 0 2  2  2  S0 (1 atm) was introduced into a septum-sealed NMR tube containing Pd Cl (dmapm) 2  2  2  (10 mg, 0.012 mmol) in CDCI3 (0.5 mL) at r.t. Upon addition of the gas, the orange solution turned purple instantaneously. solution.  31  After 24 h, a pink solid precipitated from  P{ H} NMR (121 MHz, C D C I 3 , 300 K) for purple filtrate above the 1  precipitate: 8 45.4 (s), 51.4 (s).  2.8.2  Reaction of Pd Cl (dmapm) and H S 2  2  2  H S (1 atm) was introduced into a septum-sealed NMR tube containing Pd Cl (dmapm) 2  2  2  (10 mg, 0.012 mmol) in C D C I 3 (0.5 mL) at r.t; the initially orange solution turned red. 'H NMR (300 MHz, C D C I 3 , 300 K): 8 2.89 (br s, NCrY ), 4.81 (t, PGr7 P), 7.48 to 7.77 3  2  (m, Ar). P{'H} NMR (121 MHz, C D C I 3 , 300 K): 8 48.6 (s). 3,  2.8.3  Reaction of Pd Cl (dmapm) with a chiral shift reagent 2  2  An excess of tris((3-heptafluoropropylhydroxymethylene)-rf-camporato) praseodymium (III) was added to an NMR tube containing a solution of Pd Cl (dmapm) (10 mg, 0.012 2  31  2  References on page 37  Chapter 2 mmol) in CDC1 (0.5 mL).  P{'H} NMR (121 MHz, CDC1 , 300 K): 5 29.308 (s),  31  3  3  29.343 (s).  2.9  Synthesis of Mixed Metal PdPt Bimetallic Complexes  2.9.1  Synthesis of PdPtCl (dmapm)  10  4  To a combination of rra«s-PdCl2(PhCN) (130 mg, 6.33 mmol) and dmapm (190 mg, 2  0.33 mmol) in a Schlenk tube was added CH2CI2 (7 mL). The initially orange solution turned yellow within a few seconds. The solvent was removed under reduced pressure and EtOH (10 mL) was added followed by an aqueous solution (5 mL) containing K PtCl (140 mg, 0.33 mmol). The slurry was heated to 70 °C for 1.5 h,filteredthrough 2  4  a plug of Celite 545/MgS0 , and the filtrate reduced to ca. 1 mL. Addition of Et^O (10 4  mL) gave the product as a beige precipitate that was isolated by filtration, washed with Et 0 ( 3 x 3 mL) and dried in vacuo. Yield: 200 mg (61 %). *H NMR (300 MHz, CDCI3, 2  300 K): 5 2.10 (s, 3 H , NC//3), 2.23 (s, 3 H , NC//3), 2.56 (s, 3 H , NC// ), 2.69 (s, 3 H , 3  NGr7 ), 2.70 (s, 3 H , NGr7 ), 2.85 (s, 3 H , NCr7 ), 3.30 (s, 3 H , NC//3), 3.44 (s, 3 H , NC# ) 3  3  3  3  4.74 (dt, 1H, CH ), 5.27 (dt, 1H, CH ), 7.36 (m, 6 H , Ar), 7.60 (m, 6 H , Ar), 7.85 (t, 1H, 2  2  Ar), 8.35 (ddd, 2H, Ar), 8.82 (dd, 1H, Ar), 9.22 (dd, 1H, Ar). ^P^H} NMR (121 MHz, CDCI3, 300 K): 8 13.0 (s, 'jpp = 3,860, P bound to Pt), 32.0 (s). The NMR data are in t  10  agreement with those reported by Jones. 2.9.2  Synthesis of PdPtCI (dmapm) 2  To a combination of £ra«s -PdCi2(PhCN)2 (130 mg, 0.33 mmol) and dmapm (190 mg, ,  0.33 mmol) in a Schlenk tube was added CH2CI2 (7 mL). The initially orange solution turned yellow within a few seconds. The solvent was removed under reduced pressure and EtOH (10 mL) was added followed by an aqueous solution (5 mL) containing K^PtCU (140 mg, 0.33 mmol). The orange slurry was heated to 70 °C for 1 h when it turned yellow. An ethanolic solution containing KOH (15 mL, 60 mmol P ) was added 1  over 3 min and the resulting brown solution stirred at 70 °C for a further 0.5 h. The solvents were then removed in vacuo and the residue dried thoroughly overnight. The residue was partially dissolved in warm CeH6 (30 mL) and then the mixture was filtered  32  References on page 37  Chapter 2 through a plug of Celite 545/MgS04. The solid trapped on the Celite plug was then washed through with CH2CI2 (10 mL) and the brown-redfiltratewas concentrated to ca. 1 mL at the pump.  Addition of Et20 (25 mL) gave the product as a green-brown  precipitate which was isolated byfiltration,washed with Et20 (3 x 3 mL) and dried in vacuo. Yield: 99.0 mg (32 %).  ]  H NMR (300 MHz, CDC1 , 300 K): 8 2.36 (s, 6H, 3  NC// ), 2.45 (s, 6 H , NC// ), 2.78 (s, 3 H , NC//3), 3.02 (s, 3 H , NC// ), 3.08 (s, 3 H , NC7/ ), 3  3  3  3  3.20 (s, 3 H , NC// ), 3.54 (ddd, 1H, CH , JHH = 15.9, J p = 7.8), 3.93 (ddd, 1H, CH , 2  2  3  2  J  = 15.9, J 2  H H  2  H  = 7.8), 6.94 (ddd, 1H, Ar, J  = 6.4, J  3  H P  3  H H  H P  2  = 8.0, V  H P  = 1.3), 7.01 (pt,  1H, Ar), 7.13 (pt, 1H, Ar), 7.24 (m, 4 H , Ar), 7.41 (m, 4 H , Ar), 7.53 (m, 4 H , Ar), 8.18 (dd, 1H, Ar, V  = 7.5, J p = 14.2). P{'H} NMR (121 MHz, CDCI3, 300 K): 8 -22.0 3  H H  31  H  (d, V p = 20.9, Jp = 260, P bound to Pd), -31.8 (d, V 2  P  Pt  P P  = 21.9, V  = 4,200, P bound to  P P t  10  Pt). The NMR data are in agreement with those reported by Jones.  2.10 Synthesis of Mixed Metal PdPt Bimetallic Thiolato Complexes  2.10.1 Synthesis of [PdPtCl (dmapm)(u-SEt)] [OTfT +  2  Excess EtSH (0.040 mL, 0.54 mmol) and 1 equiv. of triflic acid (0.005 mL, 0.054 mmol) were added to a solution containing PdPtCl2(dmapm) (50 mg, 0.054 mmol) in CH2CI2 (5 mL). The solution was stirred for 24 h at r.t. and filtered through a plug of Celite 545 and MgSCu. The volume of the red filtrate was reduced in vacuo to ca. 1 mL and Et 0 (20 2  mL) was added to give the product as a yellow precipitate.  This was isolated by  filtration, washed with Et20 ( 3 * 3 mL) and dried in vacuo. Yield: 31.6 mg (51 %). Anal. Calcd. for PdPtCl2P2N C36H47S203F : C 38.0, H, 4.1, N 4.8. Found: C 37.8, H 4.1, N 4.8. 4  3  'H NMR (300 MHz, CD OD, 300 K): 8 1.01 (t, 3H, C// CH S, V H = 7.3), 2.15 (q, 2H, 3  3  2  H  CH3C//2S), 2.20 (br s, 12 H, NCrY ), 2.47 (s, 3H, NC//3), 3.43 (m, 1H, CH ) 3.55 (s, 3H, 3  NC//3),  2  3.60 (s, 3 H , NCi/3), 3.66 (s, 3 H , NGrY ), 3.94 (m, 1H, CH ), 7.24 to 8.08 (m,  16H, Ar).  3  2  P{'H} NMR (121 MHz, CD OD, 300 K): 8 23.4 (d, J = 43.2,  31  P bound to Pt), 48.9 (d, V  2  3  = 43.2, y 2  P P  PPt  PP  = 260, P bound to Pd).  !  J  P P t  - 3900,  F{'H} NMR (282  19  MHz, CD3OD, 300 K): 8 -3.5 (s). A (MeOH, 298 K): 84. Mass Spectrum [LSPMS, M  m/z, matrix:3-NBA]: 991 [M ]. +  33  References on page 3 7  Chapter 2 Yellow platelet-shaped crystals were isolated from a solution of the title complex in MeOH layered with Et20, and analyzed by X-ray diffraction.  2.10.2 Synthesis of [PdPtCl (dmapm)(u-S Pr)] [OTfr n  +  2  This complex was synthesized as described for [PdPtCl2(dmapm)((x-SEt)] [OTf]", but +  using excess "PrSH (0.049 mL, 0.54 mmol). The pale green precipitate that formed after 24 h was isolated byfiltration,washed with Et20 (3 x 3 mL) and dried in vacuo. Upon addition of E t 2 0 (20 mL), further product precipitated, which was also washed with Et 2 0 ( 3 x 3 mL) and dried in vacuo. Yield: 40.9 mg (66 %). *H NMR (300 MHz, CD OD, 300 3  K): 8 0.66 (t, 3H, C / / 3 C H 2 C H 2 S , V  H  H  = 7.3), 1.38 (sp, 2H, C H 3 C / / 2 C H 2 S ) , 2.12 (q, 2H,  C H 3 C H 2 C / / 2 S ) , 2.22 (br s, 12 H, NC//3), 2.91 (m, 2H, CH 2 ) 3.46 (s, 3 H , NC// 3 ), 3.54 (s,  3H, NC# ), 3.59 (s, 3 H , NCi/ ), 3.66 (s, 3 H , NC7/ 3 ), 7.27 (pt, 1H, Ar), 7.44 (m, 4 H , Ar), 3  3  7.60 (pt, 2H, Ar), 7.74 (m, 4 H , Ar), 8.03 (m, 4 H , Ar), 8.26 (dd, 1H Ar, V  12.2) P{'H} NMR (121 MHz, C D 3 O D , 300 K): 8 23.1 (d, J 31  2  P?  bound to Pt), 48.6 (d, J = 43.5, / 2  2  ??  H H  = 43.0, 'j  = 9.5, V  PPt  H  P  =  = 3940, P  = 300, P bound to Pd). F{'H} NMR (282 MHz, 19  P P t  C D 3 O D , 300 K): 8 -3.5 (s). Mass Spectrum [LSLMS, m/z, matrix:3-NBA]: 1003 [ M +  H], 969 [ M - CI], 891 [ M - 2C1 - C H ]. +  +  3  7  34  References on page 3 7  Chapter 2 2.11 Reaction of dmapm With Other Pd Precursors  2.11.1 Reaction of Pd(hfac) with dmapm 2  To an NMR tube containing a solution of Pd(hfac) (10 mg, 0.019 mmol) in C D C I 3 was 2  added dmapm (11 mg, 0.019 mmol). The orange solution became yellow within seconds. 'H NMR (300 MHz, CDC1 , 300 K): 8 2.32 (s, 24H, NCH ), 4.80 (t, 2H, CH , V 3  3  2  12.1), 5.3 (s, 1H, CH), 7.3 (q, 8H, Ar), 7.6 (t, 4H, Ar), 7.8 (q, 4H, Ar).  H  =  P  P{'H} NMR  31  (121 MHz, C D C I 3 , 300 K): 8 -60.0 (s). ^Fj'H} NMR (282 MHz, C D C I 3 , 300 K): 8 0.42  (s, 6H, CF3), 1.2 (s, 6H, C F 3 ) . Unsuccessful efforts were made to precipitate a complex out of the solution by the addition of ether, or hexanes, or by conversion to the PF<5 salt.  2.11.2 Reaction of PdClMe(cod) with dmapm to afford PdCl(Me)(P,7Y-dmapm) Reaction of PdCl(Me)(cod) (60 mg, 0.023 mmol) and dmapm (130 mg, 0.23 mmol) in CH C1 (10 mL) yields a yellow solution. The solution was stirred for 5 min, when the 2  2  volume was then reduced under vacuum to ca. 1 mL and Et 0 (20 mL) was added to give 2  a yellow powder. Yield: 86 mg (53 %). 'H NMR (300 MHz, C D C I 3 , 300 K): 8 0.18 (d, 3H, Pd-CH , V 3  H  P  = 3.08), 2.16 (s, 6H, NCf7 ), 2.41 (s, 6H, N G H 3 ) , 2.76 (s, 6H, NC// ), 3  3  2.85 (m, 1H, CH ), ca. 3.1 (m, 1H, CH , obscured), 3.13 (s, 3H, NCH ), 3.30 (s, 3H, 2  2  3  NC// ), 6.6 to 7.6 (m, 14H, Ar), 7.80 (m, 2H, Ar). P{'H} NMR (121 MHz, CDC1 , 300 31  3  3  K): 8 24.0 (d, V  P P  = 128), -39.2 (d, V  P P  = 128).  The NMR data agreed with those  10  reported by Jones. 2.11.3 Attempted Synthesis of [Pd (hfac)(dmapm)] [PF ]" +  2  6  To a combination of Pd(hfac) (100 mg, 0.19 mmol) and dmapm (107 mg, 0.19 mmol) in 2  CH C1 (10 mL) at r.t. was added solid Pd (dba) - CHC1 (104 mg, 0.1 mmol). The 2  2  2  3  3  resulting purple solution was stirred for 3 h, during which it turned red. NH4PF (160 6  mg, 0.96 mmol) was dissolved in acetone (8 mL) and added to the reaction mixture. The solution was evaporated in vacuo to give an orange residue that was taken up in CH C1 2  2  (10 mL). The resulting orange solution was filtered through a plug of Celite and MgSC>4, and reduced in volume to ca. 1 mL. Et 0 (20 mL) was then added to give the product as 2  an orange precipitate. This was isolated by filtration, washed with Et 0 (3 x 3 mL) and 2  35  References on page 3 7  Chapter  dried in  vacuo.  2  Yield: 62 mg (32 %). *H NMR (300 MHz, CDC1 , 300 K): 8 1.23 (s, 6H, 3  NCi/ ), 2.21 (s, 6H, NC// ), 2.70 (s, 6H, NCH ), 2.93 (s, 6H, NCH ), 4.03 (t, 2H, CH , 3  3  3  VHP = 9.5) 7.3 to 7.8 (m, 16H, Ar), 8.42 (s, lh, CH). 300 K): 8 143.1 (sp, 4.3 (d, PF , ' j 6  P F  3  31  2  P{ H} NMR (121 MHz, CDC1 , ]  3  =  714), -24.0 (s). F{'H} NMR (282 MHz, CDC1 , 300 K): 8  = 714).  Mass Spectrum [LSJJVIS, m/z, matrix: thioglycerol]: 769  V  P F  19  3  [Pd (dmapm)(hfac)] - [hfac]. +  2  This poorly characterized species was subsequently treated with excess EtSH (See Section 3.8).  2.11.4 Reaction of Pd CI (dppm) with RSH in the presence of acid 2  2  To a septum-sealed NMR tube containing Pd Cl (dppm) (10 mg, 0.0095 mmol) in CDC1 2  2  3  (1 mL) at r.t. was added EtSH (0.0007 mL, 0.0095 mmol). Recorded 'H and P{ H} 3I  NMR spectra showed that EtSH does not react with Pd Cl (dppm) . 2  2  2  ]  1 equiv. of HC1  (0.35 mg, 0.0095 mmol) was then introduced into the NMR tube, when the colour of the solution lightened to yellow. The in  31  situ  NMR (121 MHz, CDC1 ,300 K): 17.1 (d, V 3  P{ H} NMR was then recorded. P{'H}  P P  36  1  =  27.1), 25.9 (d, V  31  P P  =  27.4).  References  on page 3 7  Chapter 2 2.12 References  (1)  Giannoccaro, P.; Sacco, A.; Vasapollo, G. Inorg. Chim. Acta. 1979, 37, L455.  (2)  Siedle, A. R.; Newmark, R. A.; Pignolet, L. H. Inorg. Chem. 1983, 22, 2281.  (3)  Gilman, H.; Banner, I. J. Am. Chem. Soc. 1940, 62, 344.  (4)  Jones, N. D.; Meessen, P.; Smith, M. B.; Losehand, U.; Rettig, S. J.; Patrick, B. O.; James, B. R. Can. J. Chem. 2002, in press.  (5)  Ukai, T.; Kawazura, H.; Ishii, Y.; Bonnet, J. J.; Ibers, J. A. J. Organometal. Chem. 1974, 65, 253.  (6)  Anderson, G. K.; Lin, M. Inorg. Synth. 1990, 28, 60.  (7)  McDermott, J. X.; White, J. F.; Whitesides, G. M. J. Am. Chem. Soc. 1976, 98, 6521.  (8)  Rulke, R. E.; Ernsting, J. M.; Spek, A. L.; Elsevier, C. J.; Leeuwan, P. W. N. v.; Vrieze, K. Inorg. Chem. 1993, 32, 5769.  (9)  Balch, A. L.; Benner, L. S. Inorg. Synth. 1990, 28, 340.  (10)  Jones, N. D. Ph. D. Dissertation, University of British Columbia, 2001.  37  References on page 3 7  Chapter 3  Chapter 3  REACTIVITY AND MECHANISTIC STUDIES OF Pd-Pd and Pd-Pt COMPLEXES 3.1 Fluxionality of Pd Cl2(dmapm) 2  The dipalladium(I) complex PdiChCu-dmapm) (1), first prepared by Jones, is synthesized by 1  a modification of the general method used in the preparation of bridged Pd compounds such 1  as Pd Cl (p,-dppm) developed by Balch and Benner. ' Thus, the conproportionation reaction 2 3  2  2  of the Pd  2  11  complex formed from the reaction of dmapm with 1.0 equiv. of trans-  PdCl (PhCN) and 0.5 equiv. of Pd (dba) -CHC1 generates 1 in 70-80% isolated yield. 2  2  2  3  3  The solid state structure of Pd2Cl2(dmapm) (Fig. 3.1) is as predicted based on the previously determined solution P { H } and *H N M R spectra taken at r.t. in CDC1 . 31  1  3  In the  Figure 3.1. (a) X-ray and (b) structural formulation of 1.  3I  P { H } spectrum, a singlet at 8 -29.2 is indicative of two chemically equivalent P-atoms. In 1  the *H N M R spectrum, the N C H protons appear as singlets at 8 2.44, 2.89, and 3.07 with 3  relative integrations of 2:1:1, respectively, i.e. 12:6:6 protons; the two sets of six protons  38  References on page 74  Chapter 3 correspond to the two sets of diastereotopic sets of methyl protons attached to the coordinated N-atoms, while the twelve protons correspond to the methyl protons bound to the free N atoms. The methylene bridge protons, which are chemically equivalent, appear as a triplet at 5 3.72 due to coupling to two identical P-atoms. The absolute configuration of the P-atoms is either R,R or S,S; the R,S form is not 3 1 1  present. Since the r.t.  P { H} NMR spectrum of 1 reveals a singlet, there are two possible  explanations: rapid exchange exists between the diastereomers, or the molecule is formed stereoselectively. Experiments were conducted to determine the correct explanation. Firstly, a variable temperature P{'H} NMR experiment was performed, by successively lowering 31  the temperature. No splitting of the singlet was observed, indicating that any diastereomeric exchange occurs very rapidly even at 220 K, or that no such exchange occurs. A second 31  P{ H} NMR experiment was performed using a chiral shift reagent, namely, tris((31  heptafluoropropylhydroxymethylene)-J-camporato)praseodymium(III).  Upon addition of the  chiral shift reagent, the singlet (5 -28.79) split into two closely spaced singlets (8 -29.31 and -29.34) of equal intensity, which are due to the two enantiomeric forms of Pd2Ci2(dmapm). None of the R,S (meso) form is present. These two experiments provide good evidence that the diastereomers are not in rapid exchange and that 1 is formed stereoselectively. In addition to exploring the likelihood of diastereomeric exchange, variable temperature 'H NMR was performed to probe the fluxional nature of 1, and Figure 3.2 shows the fluxional nature of this compound. At r.t., the N C H 3 protons that appear as singlets with relative integrations of 2:1:1 begin to broaden as the temperature is lowered. The singlet at 8 2.44, which initially integrates for twelve protons, begins to broaden at 280 K and eventually disappears into the baseline at 240 K. At 220 K, two singlets at 8 1.59 and 2.89 begin to rise up out of the baseline and sharpen at 200 K. At this temperature, the NCH protons have 3  relative integrations of 1:1:1:1, i.e. 6:6:6:6 protons. In terms of the solution structure of 1, the N C H 3 protons may be "frozen out" and four sets of diastereotopic Me protons are seen with two sets assigned to those attached to the N-atoms bound to the Pd centers, and the other two sets assigned to those attached to the free N-atoms. At 220 K, one of the peaks for the Me protons of the unbound N-atoms is shifted downfield, between the two signals of the bound NCH protons. 3  This indicates that the "unbound" N C H 3 protons are in an environment  similar to those of the "bound" N C H 3 protons. At low temperature, the structure of the  39  References on page 74  Chapter 3 complex may be frozen out such that the two sets of the Me protons on the unbound N-atoms may have more of an interaction with the Pd centers than the other two sets of three, the Pd centers possibly adopting a pseudofive-coordinategeometry. With a P{'H} NMR singlet 31  for the complex being observed at low temperature, a symmetrical complex is indicated. Generally,five-coordinatecomplexes of Pd and Pt have involved the n -coordination of an 2  olefin to the metal center. " 4  6  Smaller formation constants for olefin addition to the 4-  coordinate complex attest to the lower stability of five-coordinate complexes of Pd compared to those of platinum.  7  The peak at 8 1.57 observed at 300 K is due to water and as the temperature is lowered, the peak shifts downfield and eventually disappears into the baseline at ~ 220 K. The r.t. triplet at 8 3.72 due to the methylene protons broadens out as the temperature is lowered.  40  References on page 74  Chapter 3  A JL.  S~  l\  . 300K  A 290K  •  A  280K  A  270K  jJ  •  • 260K  250K  JUL.  -  JUL  240K  -230K  X L .  220K  VA  V  _ 2 1 OK  .200K 4.0  3.5  3.0  2.5  2.0  1.5  ppm  Figure 3.2. Variable temperature ' H N M R spectrum of Pd Cl (dmapm) in CD C1 . A methylene bridge protons; • C H protons of coordinated N-atoms; • C H protons of free N-atoms; • water. 2  3  2  2  2  3  41  References on page 74  Chapter 3 3.2 Structures of [Pd Cl (u-SR)(dmapm)] X (R = Me, Et, "Pr, "Bu, Ph, Bz; X = CI +  2  2  and/or OTf)  The in situ reactions of Pd Cl (dmapm) with excess RSH (R = Et, "Pr, and Ph) to form 2  2  [Pd Cl (u-SR)(dmapm)fCr (Fig 3.3) were performed in CD C1 . Signals for free thiol peaks 2  2  2  2  are given in Table 3.1. Free EtSH has three signals in the r.t. 'H NMR spectrum: a triplet at 8  Figure 3.3. Reaction of Pd Cl (dmapm) with thiol RSH. 2  the methyl protons ( JHH 3  =  2  7.4),  a triplet at 8 1.41 for the. SH proton and a pseudo quintet at 8  2.53 for the methylene protons. At r.t., the formation of the bridged-thiolate product is observed with the appearance of a triplet and a quartet at 8 1.08 and 2.69 for the methyl and the methylene thiolate protons, respectively, and the signal for the SH proton is no longer observed (Fig. 3.4). free EtSH  42  References on page 74  Chapter 3 Figure 3.4. 'H NMR spectrum of the in situ reaction between Pd2Cl (dmapm) and EtSH. 2  However, there is some evidence for an intermediate as pseudo quintets at 8 2.30 and 2.77 are initially observed, indicative of two inequivalent methylene protons of a coordinated thiol O  group (CH3C//2SH), and a corresponding triplet for the methyl of the thiol group is observed at 8 1.50 (Fig. 3.4). A multiplet at 8 0.07 may be due to the coordinated thiol proton (not shown in Fig. 3.4). The obvious explanation for these signals is an intermediate in which the thiol is coordinated. However, the P spectrum shows no evidence for this intermediate; only 31  two singlets are seen, one for Pd2Cl (dmapm) and one for the bridged-thiolate product. 2  Furthermore, in the aryl region of the 'H spectrum, two new peaks are seen: a pseudo triplet at 8 7.76 (VHH = 7.8) and a pseudo quartet at 5 8.01, which are due to the bridged-thiolate product; no evidence of intermediates is observed in this region. Over time, the intensity of these two quintets decreases while those for the triplet and quartet of the thiolate product increase. Low temperature studies of this reaction were not attempted. The in situ reaction was also performed with "PrSH, four free "PrSH signals are observed in the *H NMR spectrum: a triplet at 8 0.97 for CH2, protons, a triplet at 1.35 for SH protons, a multiplet at 1.61 for  CH3CH2,  and a pseudo quartet at 2.49 for C//2SH protons with relative  integration of 3:1:2:2 (Table 3.1). It was difficult to assign signals of the in situ product as they were obscured by signals due to the intermediates. Comparing the *H spectrum of the in situ reaction product to that of isolated product, it is observed that peaks for the free thiol overlap and obscure those of the isolated product. Attempts to observe intermediates at low temperature by NMR were unsuccessful. For PhSH, free benzenethiol peaks are observed in the 'H NMR spectrum as a multiplet from 8 7.16 to 7.31 for the aryl protons and a singlet at 8 3.55 for the SH proton. In the thiolate product, the aryl peaks are seen as three signals at 8 6.76 (t, 2H, m - C ^ S , «/HH= 7.5), 2  6.90 (d, 2H, 0-C6//5S, VHH = 7.3), and 7.01 (t, 1H, p - C ^ S , J H = 9.9). At r.t., it was again 2  H  difficult to observe intermediates and the baseline in the N C H 3 region was scattered with a number of peaks that were unassigned. Low temperature studies were undertaken with this system and intermediates were then observable (see Section 3.3).  43  References on page 74  Chapter 3 Table 3.1. H chemical shifts (8) of free thiols, with multiplicities given in brackets in CD C1 ). ]  2  2  HC c 3  ^ S H CH a  d^ C H  2  b  b^SH  2  c  a  b  a  1.41 (t)  1.35 (t)  3.55 (s)  b  2.52 (qn)  2.49 (p qt)  7.16 to 7.31 (m)  c  1.30 (t)  1.61 (m)  d  0.97 (t) The isolated complexes where X = CI, for R = Et, "Pr, and Ph, were all prepared in a  similar manner using excess thiol and Pd Cl (dmapm) in CH C1 (see Section 2.7). The H ]  2  2  2  2  and P{'H} NMR spectra were recorded in CDCI3, and are summarized in Table 3.5 (see 31  below, p. 47).  In general, the NCH signals were broad and difficult to assign. The 3  resonances for the bridged-thiolate protons and a sharp triplet due to the methylene bridge between the two P-atoms could easily be assigned; however, the signals of the anilinyl aromatic protons were broad. For the u-SPh complex, the number of peaks in the NCH  3  region was indicative of impurity in the isolated complex, and a reasonable elemental analysis was not obtained. For the u-SEt complex, yellow, platelet-shaped crystals suitable for X-ray diffraction were grown from a solution of CH C1 layered with Et 0, and the ORTEP representation of 2  2  2  the molecular structure of [Pd Cl (^-SEt)(dmapm)] is shown in Figure 3.5. Selected bond +  2  2  distances and angles are given in Table 3.2. There is some disorder in the crystal with respect to the position of all the bridged-thiolate atoms, and secondary locations were found for these atoms.  The distorted square-planar geometry around the Pd is clearly seen, with a six-  membered ring formed by Pd P CS atoms. (More detailed discussion of the disorder effects, 2  2  and distortion from square planar geometry is given below, when discussing the u-S Pr n  complex.)  44  References on page 74  Chapter 3  Chapter 3  Table 3.2. Selected bond distances (A) and bond angles (°) for [Pd Cl (^-SEt)(dmapm)]" Pd(l)-S(l) 2.269(3) Pd(2)-S(l) 2.338(3) Pd(l)-P(l) . 2.1961(7) Pd(2)-P(2) 2.1900(9) Pd(l)-Cl(l) 2.3665(9) Pd(2)-Cl(2) 2.3638(10) Pd(l)-N(l) 2.161(3) Pd(2)-N(3) 2.161(3) S(l)-C(34) 1.825(6) C(34)-C(35) 1.511(17) P(l)-C(25) 1.831(3) P(2)-C(25) 1.818(3) Pd(l)-S(l)-Pd(2) 119.72(11) P(l)-C(25)-P(2) 113.56(17) P(l)-Pd(l)-N(l) 85.87(8) P(2)-Pd(2)-N(3) 85.42(9) P(l)-Pd(l)-S(l) 95.70(7) P(2)-Pd(2)-S(l) 85.75(8) P(l)-Pd(l)-Cl(l) 178.06(4) P(2)-Pd(2)-Cl(2) 179.64(4) N(3)-Pd(l)-S(l) 165.70(11) N(l)-Pd(2)-S(l) 175.50(10)  t  2  2  Yellow, platelet-shaped crystals analyzing for [Pd Cl (w-S Pr)(dmapm)] Cr-H 0 and n  2  +  2  2  suitable for X-ray diffraction were grown from a solution of CH C1 /Et 0. 2  2  2  An ORTEP  representation of the cation is shown in Figure 3.6. Selected bond distances and angles are given in Table 3.3. Similar to [Pd Cl (u-SEt)(dmapm)] [Pd Cl («-S Pr)(dmapm)] adopts an +  2  2  >  n  2  +  2  A-frame structure. The u-S Pr ligand is not quite positioned symmetrically relative to the n  metal centers, with Pdl-Sl (2.3030(10) A) and Pd2-Sl (2.3150(10) A). However, it should be noted that the bridged-thiolate fragment was also located at a secondary position with PdlSlb (2.249(4) A) and Pd2-Slb (2.363(4) A); the relative occupancy is 0.84 for the primary location vs. 0.16 for the secondary position. Each Pd center has a square-planar geometry with two a's-chloro ligands. The P-Pd-N angles (85.16(7)°, 85.57(7)°) are slightly acute due to the bidentate PC H N fragment of the ligand and the u-S-Pd-N (178.06(4)°, 179.64(4)°) 6  4  and P-Pd-Cl angles (174.86(3)°, 176.73(3)°) are nearly linear. C17 of the methylene bridge is positioned (1.835(3) A, 1.840(3) A) symmetrically relative to the two P-atoms. The Pd-Pd distance is 3.974 A, indicating the absence of a significant metal-metal interaction.  46  References on page 74  Chapter 3  gure 3.6. O R T E P representation (50% ellipsoids) of the molecular structure of the cation Pd Cl ((w-S Pr)(dmapm)] Cr. H-atoms have been omitted for clarity. n  2  +  2  47  References on page 74  Chapter 3 Table 3.3. Selected bond distances (A) and bonds angles (°) for [Pd Cl2(n-S Pr)(dmapm)] . Pd(l)-S(l) 2.3030(10) Pd(2)-S(l) 2.3150(10) Pd(l)-P(l) 2.1925(8) Pd(2)-P(2) 2.2011(7) Pd(l)-Cl(l) 2.3545(8) Pd(2)-Cl(2) 2.3840(7) Pd(l)-N(l) 2.164(2) Pd(2)-N(3) 2.154(3) S(l)-C(34) 1.830(4) C(34)-C(35) 1.535(5) P(l)-C(17) 1.835(3) P(2)-C(17) 1.840(3) Pd(l)-S(l)-Pd(2) 118.76(5) P(l)-C(17)-P(2) 112.89(14) P(l)-Pd(l)-N(l) 85.16(7) P(2)-Pd(2)-N(3) 85.57(7) P(l)-Pd(l)-S(l) 86.45(3) P(2)-Pd(2)-S(l) 94.57(4) P(l)-Pd(l)-Cl(l) 174.86(3) P(2)-Pd(2)-Cl(2) 176.73(3) N(3)-Pd(l)-S(l) 164.86(8) N(l)-Pd(2)-S(l) 176.67(8) n  +  2  In the u-SEt cation, the thiolate lies closer to one Pd center than the other. The Pd-P and Pd-Cl distances are similar in both complexes, and are not unusual for Pd(II) systems.  9  The P-C-P and Pd-S-Pd angles for the p.-SEt complex are about 1° larger than those for the u.-S"Pr complex, and the P-Pd-Cl angles are more linear. It is of interest to compare the bond distances and bond lengths of Pd2Cl (dmapm) 2  (Table 3.4) with those for the bridged-thiolate species. Of course, the Pd-Pd distances of the !  bridged-thiolate species (3.97 - 3.98 A) are much longer than the metal-metal interaction of Pd Cl2(dmapm) (2.53 A). 2  Other significant differences between the A-frame structures and  the metal-metal bonded species are the Pd-N distances and the P-C-P bond angles. For the bridged-thiolate complexes, the Pd-N bond distances (2.15 - 2.16 A) are significantly shorter than those of Pd Cl (dmapm) (2.23 - 2.26 A), presumably because the N-atoms are trans to 2  2  the thiolate S-atoms rather than the Pd-Pd bond. Thus, these findings reflect on the relative ^raws-influence of RS~ and a metal-metal bond. The P-C-P bond angle of the bridgedthiolate species (~ 113°) is larger than that of Pd2Cl2(dmapm)  (~ 103°), due to the  incorporation of the thiolate bridging the two metal centers. In Pd2Cl2(dmapm), where the N-atoms bonded to Pd are trans to Pd, the N-Pd-Pd angles are non-linear (164.4(4)°, 165.4(4)°), as are the N-Pd-S angles in the bridged-thiolate species (R = Et: 165.70(11)°, 175.50(10)°; R = "Pr: 164.86(8), 176.67(8)). Although it is difficult to make a direct comparison of electron density at the metal, it should be noted that the Pd-S bond lengths in the bridged-thiolate species (2.27 - 2.34 A) are significantly shorter than the Pd-Pd bond length of Pd2Cl2(dmapm) (2.53 A). There are a few considerations that must be made when comparing the bond lengths of Pd - S vs. Pd - Pd: the incorporation of  48  References on page 74  Chapter 3 the thiolate ligand between the two metal centers, the larger size of the Pd center vs. the thiolate S-atom, and the ligand framework. The shorter Pd - S bond cannot be necessarily equated with a stronger bond, but may be a consequence of the geometry of the ligand and molecule. In the hard and soft theory of acids and bases, Pd" is considered a soft acid and the thiolate ligand is considered a soft base, and thus a favourable interaction is predicted for 10  these two moieties. Table 3.4. Selected bond distances (A) and bonds angles (°) for Pd?Cbfdmat>ml Pd-Pd 2.5272(14) Pd(2)-P(2) 2.183(4) Pd(l)-P(l) 2.154(5) Pd(2)-Cl(2) 2.364(4) Pd(l)-Cl(l) 2.386(5) Pd(2)-N(3) 2.259(10) Pd(l)-N(l) 2.235 (11) P(2)-C(17) 1.837(14) P(l)-C(17) 1.841(13) P(l)-C(17)-P(2) 102.9(6) Pd(l)-Pd(2)-N(3) 165.4(4) Pd(2)-Pd(l)-N(l) 164.3(3) P(2)-Pd(2)-N(3) 86.2(3) P(l)-Pd(l)-N(l) 85.7(4) P(2)-Pd(2)-Cl(2) 177.8(2) P(l)-Pd(l)-Cl(l) 176.79(16) For synthesis of the triflate salts (X = OTf; R = Me, Et, "Pr, "Bu, Ph, and Bz), excess thiol (10 equiv.) was added via syringe to the Schlenk tube containing Pd2Cl2(dmapm) dissolved in 5 mL CH2CI2. One equiv. of triflic acid (relative to Pd2Ci2(dmapm)) was then added and the reaction mixture was further stirred for 24 h (Section 2.7). For R = Me, the thiol was added to the Schlenk tube via vacuum transfer. For R = Me, Et, and "Bu, the product reaction mixture was filtered through a plug of Celite 545/MgS04 and the volume of the yellow filtrate was then reduced; for the R = Me, Et, and "Bu systems, a yellow powder was isolated by precipitation with ether. For R = "Pr, a pale green powder precipitated out of solution and was isolated; further product was precipitated with the addition of ether. For R = Ph, Bz, a redfiltratewas evident but the products were isolated as yellow precipitates. The 'H,  31  P{'H}, and F{'H} NMR spectra of these complexes were measured in CD OD 19  3  because the R= "Pr product is insoluble in CH2CI2. A summary of the H and P{ H} NMR J  31  1  data for the chloride and triflate salts is given in Table 3.5. In some cases, the signal for the methylene protons between the two P-atoms was obscured by the broad signal for the NCH  3  protons. The signal for the NCH protons was often one large broad singlet, indicating that at 3  r.t. the complexes are fluxional. Variable temperature NMR studies were undertaken in the  49  References on page 74  Chapter 3 case where R = "Pr, X = OTf to probe this characteristic (vide infra). There does not seem to be any particular trends within the various shifts.  Table 3.5. Summary of NMR data for isolated [Pd Cl (u-SR)(dmapm)] X~ (R = Me, Et, "Pr, "Bu, Ph, Bz; X = CI, OTf). Details (multiplicity and / values) are given in Section 2.7. 'H (PCH P) (8), Complex H (-SR) (8) 'H (NCH ) (8) P{'H} V (HZ) +  2  2  2  ]  31  3  H P  R = Et, X = c r  1.14,2.66  2.89  4.76(10.8)  49.0  0.74, L60.2.70  3.46  4.71 (10.8)  49.3  6.76, 6.91, 7.16  3.54  4.76 (10.8)  51.6  1.90  2.90  4.04 (10.4)  50.3  1.14, 2.60  2.92  0.72, 1.57,2.50  2.93  4.03  0.68, 1.07, 1.47,2.45  2.86  c  R = Ph, X = OTf*  6.75, 6.81, 7.01  1.95,3.50  4.05  51.4  R = Bz, X = OTf*  2.90, 6.71,6.86, 7.01  1.90,3.44,3.67  4.05 (10.0)  51.4  R = "Pr, X = Cl  fl  R = Ph, X = c r R = Me, X = OTf R = Et, X = OTf  5  5  R = "Pr, X = OTf* R = "Bu, X = OTf  6  " N M R performed in CD C1 ; 2  2  c  48.9 49.2 48.8  N M R performed in C D O D ; ° obscured by N C H signal (see text). 3  3  For R = Ph, the three benzenethiolate protons are observed at 8 6.75, 6.81, and 7.01 for the ortho, meta and para protons, respectively, with relative integration of 2:2:1. A similar splitting in the case where R = Bz is seen as well, with the corresponding aryl protons observed at 8 6.71, 6.86, and 7.01. The recently synthesized complex [Pd (p.-SPh)(ii-r) :n 2  2  2  l,3-C H6)(PPh ) ][PF ] similarly exhibits three distinct H NMR signals (in CD C1 ) for the !  4  3  2  6  2  2  magnetically inequivalent aryl protons of the bridging benzenethiolate moiety: these were seen as a doublet at 8 6.39 for o-H, a triplet at 6 6.75 forra-H,and a triplet at 8 6.96 for p-R in the intensity ratio of 2:2:1." The F{'H} NMR data reveal the presence of the anionic 19  triflate.  50  References on page 74  Chapter 3 3.3 Mechanistic Studies of the Reaction of Pd Cl2(dmapm) with RSH 2  To shed some light on the mechanism of formation of the bridged-thiolate products, low temperature NMR experiments on the reaction between Pd Cl (dmapm) and RSH (R = Me, 2  2  Et, Pr, Ph) were carried out in CDCI3 or CD C1 in an attempt to observe reaction n  2  2  intermediates. For R = Me, the excess thiol was introduced into a septum-sealed NMR tube via vacuum transfer. For R = Et, Pr, and Ph, 10 equiv. of thiol were injected into a septumn  sealed NMR tube; the reaction vessel was then frozen at liquid-N temperature and warmed to 2  -50 °C in the NMR spectrometer. For the R = Me, Et and "Pr systems, no intermediates were observed at low temperature; e.g. in the P{'H} NMR spectra just two singlets were observed 31  for Pd Cl (dmapm) and the bridged-thiolate product (see Section 3.2). 2  2  For the R = Ph system, intermediates were observed. The reaction was followed by low temperature 'H, P{'H}, and 'H{ P} NMR spectroscopy as outlined in Chapter 2, in both 31  31  CDCI3 and CD C1 . In CDCI3, once the sample had equilibrated at -50 °C, the P{'H} NMR 31  2  2  spectrum consisted of a singlet at 8 -29.0 characteristic of the starting material. After 20 min at this temperature, the P{ H} NMR spectrum showed a single peak at 8 21.7, and a 31  1  corresponding doublet at 8 -17.0 (VHP = 19.2) appeared in the 'H spectrum; a 'H{ P} 31  measurement confirmed coupling to a P-atom, as the doublet collapsed to a singlet. Two pseudo quartets were observed for the methylene bridge protons at 8 4.79 and 4.26 and a decoupling experiment confirmed coupling to phosphorus as the quartets collapsed to doublets (Fig. 3.7). Further lowering of the temperature to -60 °C saw the singlet in the P 31  spectrum resolved into two distinct, though closely separated doublets at 8 21.9 and 21.6 ( JPP 2  = 15.7), corresponding to two chemically inequivalent P-atoms. These data are consistent with a hydrido-thiolato species (see below, Fig. 3.11)  1  •  1 5.0  •  1 • 1 • r 4.8 4.6 4.4  n -• 1 •—1—•—1—•—1—•—1 5.0 4.8 4.6 4.4 ppm  ppm  b  a  Figure 3.7. (a) H and (b) 'H{ P} NMR spectra of the C H moiety at -50 °C (recorded in CD C1 ). !  31  2  2  2  51  References on page 74  Chapter 3  As mentioned previously (see Section 1.1), the James group has studied the reaction of Pd2Cl (dppm) with H S (Figure 3.8), and, of note, Pd Cl (dppm) shows no reactivity toward 2  2  thiols.  2  2  2  2  It is of interest to make a comparison with respect to the mechanism for the  12  formation of the bridged-sulfide in the case of Pd Cl (u-S)(dppm) and that of the bridged2  2  2  thiolate in the case of [Pd Cl (w-SR)(dmapm)] . Previous work studying the reaction between +  2  2  Pd Cl (dppm) with H S established that the products of the reaction, Pd Cl (u.-S)(dppm) and 2  2  2  2  2  2  2  H , are formed via a hydrido-thiolate intermediate (Fig. 3.7; also, see Section l.l). " 13  2  16  In  low-temperature 'H NMR studies of Pd Br (dppm) with H S, the Pd-H of intermediate I is 2  2  2  2  cis to two equivalent phosphine ligands and is detected as a triplet at 8 -8.45 ( J p - 18); the 2  H  Pd-SH signal typically seen at 8 1.5 to -1.5 is not seen and may be buried under the intense, 8  broad H S signal of free H S at 8 0.9, or the SH proton, which will certainly be acidic, may be 2  2  undergoing rapid exchange with the H S protons. The resonances of the - C H - protons, 2  2  which are all inequivalent in a static structure, appear as two unresolved peaks (8 3.4, 3.6), while the observed four unresolved P{'H} resonances result from the expected AA'BB' 31  pattern. The reaction of Pd I (dppm) shows a similar pattern in the 'H spectrum at low 2  2  2  temperature, though more "fluxional"; only broad resonances are seen for the - C H - protons 2  (8 5.02) and for Pd-H (8 -6.05).  13  The P{ H} for the dppm systems (AA'BB' patterns) will 31  l  be more complicated than for the dmapm system (AB pattern) as there is an additional bisphosphine in the dppm systems. Generation of the bridged-sulfide product and H via I is 2  envisaged to proceed by the deprotonation of the coordinated SH" with subsequent protonation of the coordinated hydride.  16  Cl-^-Pd  Pd—CI + H S 2  I  1  Figure 3.8. Reaction of Pd Cl (dppm) with H S to yield the bridged-sulfide product (1) and 2  TJ  2  2  2  13-17  V  52  J  References on page 74  Chapter  3  To probe if reactivity similar to that of the Pd2Cl2(dppm) /H2S system is possible with 2  Pd Cl (dmapm), reaction with H S was followed at r.t. 2  2  2  in situ  (Sect. 2.8.2). In the 'H NMR  spectrum, peaks at 5 2.89 and 4.81 are assigned, respectively, to the NCH and methylene 3  bridge protons. The P{ H} NMR spectrum shows several peaks: a singlet at 8 48.6 is 31  ,  presumed to be due to the bridged-sulfide complex, based on NMR data for the similar [Pd Cl2()a-SR)(dmapm)] species (5 48 - 52), while broad, ill-defined peaks between 8 25 and +  2  35 remain unassigned. In CD2CI2, additional intermediates were observed in the Pd2Cl2(dmapm)/PhSH system, as illustrated in Figure 3.9. At -50 °C, as in CDC1 , a P{ H} AB pattern is observed with 31  1  3  doublets at 8 23.2 and 20.3, with J 2  a doublet at -17.24 with JHP  =  = 25.2 Hz. The corresponding H NMR spectrum show !  PP  16.8 Hz, a decoupling experiment again showing that the  hydride was coupled to phosphorus. When the probe was cooled to -80 °C, an additional AB pattern appeared in the P{ H) NMR spectrum, with doublets at 8 4.0 and 23.0 and 3I  1  2  J  P P  =  49.6 Hz. In the corresponding H and 'H{ P} spectra another hydride signal was observed at !  -9.56, with V  H  P  31  = 15.9 Hz.  The intermediate observed at -50 °C is consistent with a hydrido-thiolate intermediate (A ) (see Fig. 3.11, p. 56). It is possible that the species appearing at -80 °C (•) may be an RSH adduct; however, the large JHP coupling of 15.9 Hz does not support the assignment of such an adduct. Three-bond J-coupling within a Pd-SH adduct is expected to be much less, and indeed may not be detected.  13  Proposed structures for the intermediate at -80 °C are  depicted in Figure 3.10 (a - d). The formation of the intermediates is reversible as the temperature is cycled between -90 to -30 °C; no change in ratios of the intermediates is evident on recycling. However, once the bridged-thiolate product is formed, the reaction is no longer reversible.  53  References  on page  74  Chapter 3  -50 °C  -80 °C 'H  -10  1  -12  '  ~T  -14  -1.6  \ -10  ppm  p -12  . -14  -16  ppm  1 { P} 3,  H  Figure 3.9. Variable temperature H , 'Hi^P}, and P{'H} NMR spectra at -50 and -80 °C for the reaction of Pd Cl (dmapm) with PhSH in CD C1 . • Intermediates toward the formation of the bridged-thiolate product in CD C1 . !  31  A  2  2  2  2  54  2  2  References on page 74  Chapter 3 As PhSH has no protons a to the S-atom, the SH proton of an M-PhS(H) species cannot exhibit coupling to other thiol protons, although coupling to one P-atom might be observed, resulting in a doublet for the coordinated thiol proton. Such an intermediate (a) is proposed in Fig. 3.10; at low-temperature, however, the signal for the coordinated thiol was not observed. In the corresponding P{'H} NMR spectrum, an AB pattern is expected. For b (Fig. 3.10), 31  similar spectra in the H and P{'H} would also be expected, but with a difference in the ]  31  two-bond coupling constant.  In a, an agostic 3-centred-2 electron interaction between the  metal, the thiol S-atom, and the hydrogen is visualized, but the three-bond coupling value 10  for this type of interaction would be much smaller than the observed 15.9 Hz.  13  Intermediate  b in Figure 3.10 fits the *H and P{'H} NMR data for , however, the positioning of the 31  A  thiolate and the hydride are on opposite sides of the complex is difficult to explain. Intermediate c (Fig. 3.10) is less likely as the NMR data do not support such a structure.  d  c Figure 3.10. Possible structures of intermediates seen at-80 °C.  In the 'H NMR spectrum, a signal closer to 8 0 is expected as the hydride will likely have an agostic interaction with the metal centers and the S-atom of the thiol; in the P{'H} 18  31  spectrum, a singlet is expected. For intermediate d, an AB pattern is expected in the P{'H} 31  55  References on page 74  Chapter 3 NMR spectrum, but the hydride shift in the 'H spectrum would be more downfield, closer to 8 0, than the observed signal (8 9.56) at -80 °C. It is difficult to ascertain which one, if any, of these structures is correct. When the tube was warmed to 25 °C, a singlet at 8 53.9 appeared in the P spectrum, 31  corresponding to the bridged-thiolate product [Pd Cl (^-SPh)(dmapm)] . The mechanism for +  2  2  the formation of the bridged-thiolate product may proceed via the oxidation addition of RSH across the Pd-Pd bond, via an RSH adduct and a hydrido-thiolate species as intermediates, as illustrated in Figure 3.11. The source of the proton required for the formation of hydrogen in the final step is uncertain. When the reactions were performed in CH2CI2, the hydridothiolate intermediate perhaps reacts with trace HC1, this affording the CT counterion; in the presence of HOTf, the intermediate abstracts a proton from the acid, yielding the bridgedthiolate cation with a triflate counterion.  Figure 3.11. Proposed mechanism for the formation of the bridged-thiolate product from the reaction of Pd Cl2(dmapm) with an RSH thiol (R = Ph). 2  3.4 Fluxionality of [Pd Cl (^-S Pr)(dmapm)] [OTfr n  2  +  2  The fluxionality of [Pd Cl (^-S J?r)(dmapm)] [OTf]" was studied in CD OD from -90 to 0 °C +  2  2  3  by *H and P{'H} NMR, the H data being given in Figure 3.12. 31  ]  56  In the P{'H} NMR 31  References on page 74  Chapter 3 spectrum at r.t., a singlet is observed at 5 49.2, indicative of a complex with equivalent Patoms. However, as the temperature is successively lowered, the signal begins to broaden and at -40 °C, a pseudo triplet is observed, possibly an overlapping AB pattern with doublets at 8 49.8 and 50.0 with J 2  P?  of 20.3 Hz, data indicative of two inequivalent P-atoms; further  lowering of the temperature does not further resolve this signal. The corresponding 'H spectra show that the complex is indeed fluxional. At 0 °C, the three bridging thiolate proton signals are observed as a triplet, a pseudo sextet, and a triplet at 8 0.72 (C//3CH2), 1.57 (CH2CR2S),  and 2.50 (CH S), respectively. As the temperature is 2  lowered, the 8 2.50 peak loses its sharpness and, disappears into the baseline at -20 °C. At 40 °C, it reappears but more upfield at 8 1.95, regaining its sharpness as the temperature is successively lowered to -60 °C and, broadening again upon further lowering of the temperature. The CH CR S signal (8 1.57 at 0 °C) is overlapped and partially obscured by a 2  2  broad N C H 3 signal at -30 °C. The peak for the methyl protons of the thiolate bridge (8 0.72 at 0 °C) remains sharp as the temperature is lowered to -70 °C, at which point it begins to broaden out. The triplet for the methylene bridge between the two P-atoms is observed at 8 4.03 at r.t. and, as the temperature is lowered, this peak remains unchanged, but does lose its sharpness at -70 °C. The resonances for the NCH protons show the most change over the different 3  temperatures. At r.t., a broad baseline is observed from 8 2 - 4 ; at -60 °C, four distinct singlets are observed at 8 3.66, 3.50, 2.82, and 1.64 and, as the temperature is successively lowered to -90 °C, all four signals broaden. Two peaks at 8 3.66 and 3.50 amalgamate into one broad singlet at -30 °C, while the two sharp singlets at 8 2.82 and 1.64 observed at -60 °C broaden as well, overlapping and obscuring the C//2S and C//2CH2S signals of the bridgedthiolate protons as the temperature is lowered. At -20 °C, a broad singlet, overlapped by one of the solvent peaks, is observed for the N C H 3 protons. There seems to be two fluxional processes at work, which may be attributed to the NCH protons attached to free and bound 3  N-atoms. The two downfield peaks are assigned to the coordinated N C H protons as they 3  would tend to be less fluxional than the N C H 3 protons attached to free N-atoms. The two more upfield signals are attributed to the latter. The aryl protons of dmapm are observed as two multiplet signals at r.t., averaged signals for the free and coordinated methyl groups. However, as the temperature is lowered, these two signals separate out into five signals that  57  References on page 74  Chapter 3 are sharpest at -60 °C. The structure becomes more static at low temperature; the three higher field signals are due to the Ar protons of the coordinated arms while the two more downfield signals are due to the Ar protons of the free arms. The signals broaden into the baseline when the solution is cooled to -90 °C.  58  References on page 74  Chapter 3  Ar protons  ppm  Figure 3.12. Variable temperature 'H NMR data in CD OD exploring the fluxionality of [Pd Cl (^-S Pr)(dmapm)] [OTf] . • Solvent; A PC// P protons; <>• NCH protons; O o thiolate protons. 3  n  2  +  2  2  59  3  References on page 74  Chapter 3  3.5 Synthesis of PdPtCl (dmapm) 2  Though Pd Cl (dmapm) was synthesized via the conproportionation of a Pd" complex with 2  2  Pd (dba) -CHC1 , the same method is not suitable for the mixed metal case. The title complex 2  3  3  is synthesized via the reduction of PdPtCl (dmapm) with KOH and EtOH, as illustrated in 1  4  Figure 3.13. The NMR data are in agreement with those reported by Jones.  1  PdCI (dmapm) + K,PtCI 2  4  KOH, EtOH  -2 KCI  - KCI, HCI, CH CHO,H 0 3  NMe, 2  \ ^ Me N 2  Me  2  roTfN  Pd  .Pt  CI  NMe  HQ  RSH, HOTf  Pt  2  NMe  2  H,  CI  Figure 3.13. Synthesis of PdPtCl (dmapm), via the reduction of PdPtCl (dmapm) to PdPtCl (dmapm), and subsequent reaction with RSH and triflic acid to yield [PdPtCl ((> SR)(dmapm)] [OTf]-. 2  4  2  2  +  3.6 Reaction of PdPtCl (dmapm) with RSH 2  In an in situ NMR-scale reaction in CD C1 , PdPtCl (dmapm) reacts with excess 2  2  2  EtSH, providing the bridged-thiolate product presumably as a chloride salt as in the corresponding Pd system.  The reaction was undertaken on a preparative scale, in which  2  PdPtCl (dmapm) was reacted with 10 equiv. of EtSH in CH C1 for 0.5 h, after which one 2  2  2  equiv. of triflic acid was added. The mixture was then stirred for 24 h at r.t. and filtered through a plug of Celite 545 and MgS0 . The volume of the resulting red filtrate was then 4  reduced in vacuo, and Et 0 was added to give the product as a yellow precipitate that was 2  filtered off, washed with Et 0 and dried in vacuo (Fig. 3.13) (see Section 2.10). 2  60  References on page 74  Chapter 3 The bridged-thiolate, mixed-metal, triflate salt, [PdPtCl (u-SEt)(dmapm)] [OTf]~ was +  2  characterized by NMR ( H, -"P^H}, F{'H}), mass spectrometry (LSIMS), microanalysis, ]  19  conductivity, and X-ray crystallography. Yellow needles, grown out of a solution of the complex in MeOH layered with Et 0, were found suitable for X-ray determination. The 2  crystal structure is illustrated in Fig. 3.14, and selected bond lengths and bond angles are given in Table 3.6.  Table 3.6. Selected bond distances (A) and bonds angles (°) for [PdPtCl (uSEt)(dmapm)] [OTf| . Pd(l)-S(l) 2.288(1) 2.306(1) PtO)-S(l) Pd(l)-P(2) 2.186(1) 2.189(1) PtO)-P(i) Pd(l)-Cl(2) 2.370(1) Pt(l)-Cl(l) 2.377(1) Pd(l)-N(3) 2.164(2) Pt(l)-N(l) 2.162(4) S(l)-C(34) 1.808(6) C(34)-C(35) 1.49(1) P(2)-C(17) 1.832(5) P(l)-C(17) 1.836(5) Pd(l)-S(l)-Pt(l) 121.61(5) P(l)-C(17)-P(2) 115.6(3) P(2)-Pd(l)-N(3) 85.0(1) P(l)-Pt(l)-N(l) 85.9(1) P(2)-Pd(l)-S(l) 91.01(5) P(l)-Pt(l)-S(l) 96.55(5) P(2)-Pd(l)-Cl(2) 173.76(6) 177.28(5) P(l)-Pt(l)-Cl(l) N(3)-Pd(l)-S(l) 174.5(1) N(l)-Pt-S(l) 176.6(1) 2  +  61  References on page 74  Chapter 3  C34  %)CI1  Figure 3.14. ORTEP representation (50% ellipsoids) of the molecular structure of PdPtCl («SEt)(dmapm)] [OTf] . H-atoms have been omitted for clarity. 2  +  62  References on page 74  Chapter 3 In the structure, the p-SEt moiety is positioned closer to the Pd than the Pt (Pd-S, 2.288(1) A; Pt-S 2.306(1) A), presumably due to the smaller size of the Pd center vs. the Pt center. The metal centers each adopt approximately square planar geometry with the chloro ligands in a syn orientation, a result of the steric bulk of the dmapm ligand on the opposite side of the Pd-Pd plane.  The P-Pd-N and P-Pt-N angles are slightly acute due to the  constraints of the bidentate PC6H4N fragments of the ligand; the S-Pd-N and S-Pt-N angles, and the P-Pd-Cl and P-Pt-Cl angles, are slightly bent, with greater distortion about the Pd center. The carbon of the methylene bridge is positioned symmetrically (1.836(5) A, 1.832(5) A) relative to the two P-atoms. A large Pd - Pt distance reveals no metal-metal interaction. The  crystal  structures  of  [Pd Cl (u-SEt)(dmapm)] Cl* and +  2  2  [PdPtCl (u2  SEt)(dmapm)] [OTf]" show that generally, the complexes share a similar cis A-frame +  structure, with the S-atom at the apex and the coordinated N-atoms of the dmapm ligand making up the A-frame, but there are some small differences worth mentioning. The S-C bond length on the bridging thiolate is longer in the Pd case (1.825(6) A) vs. the PdPt case 2  (1.808(6) A), and the P-C bond lengths of the methylene bridge are longer in the mixed metal case (1.832(5) A, 1.836(5) A) compared to the Pd case (1.831(3) A, 1.818(3) A). The larger 2  P-C-P angle in the PdPt complex (115.6(3)°) compared to that in the Pd species 2  (113.56(17)°) may be attributed to the ligand opening up for the larger Pt center. The N(3)Pd(l)-S(l) bond angle in the Pd complexes is 165°, while in the other cases it is ~ 175°. 2  The 'H NMR spectrum of [PdPtCl (p,-SEf)(dmapm)] differs greatly from those of +  2  PdPtCl (dmapm), PdPtCl (dmapm), and [Pd Cl (u-SEt)(dmapm)] (see +  2  4  2  2  Fig. 3.15 for  structures), especially in the N C H 3 region (see Sections 2.7.5, 2.9.1, 2.9.2, and 2.10.1). For a in Figure 3.14, the NC//3 protons have sharp signals at 8 2.36, 2.45, 2.78, 3.02, 3.07, and 3.19 with relative integration of 2:2:1:1:1:1.' For b in Figure 3.15, the NCH protons have sharp 3  signals at 8 2.10, 2.23, 2.56, 2.69, 2.70, 2.85, 3.30, and 3.44 with relative integrations of one for each methyl group.  19  For the Pd (p,-SEt) complex (Fig. 3.15c), the N C H 3 signal is 2  observed as a broad singlet at 8 2.92. In the PdPt(u-SEt) complex (d, Fig. 3.15), the N C H 3 resonances are observed as a broad singlet at 8 2.20 and sharp singlets at 2.47, 3.55, 3.60, and 3.66, with relative integrations of 4:1:1:1:1; the anilinyl arms are clearly fluxional. Comparing the spectra of the u-SEt cases, it seems that the broad signals in the 'H spectra are  63  References on page 74  Chapter 3  Figure 3.15. Structural formulations of (a) PdPtCl2(dmapm) (b) PdPtCl^dmapm) (c) [Pd Cl (u-SEt)(dmapm)] (d) [PdPtCl (u-SEf)(dmapm)] . +  2  +  2  2  due to the N C H 3 groups on the Pd centers, since both spectra show broad singlets, and the sharp singlets are due to the NCH bound to Pt. The spectra for [PdPtCl (u-SEt)(dmapm)]  +  3  2  should be comparable to that of PdPtCbXdmapm) as the sole difference is the thiolate bridge vs. the two chloro ligands; both complexes contain two Pd" centers, held together by the dmapm ligand. One similarity between the three PdPt complexes is that they all have the 4 sharp downfield peaks representing 4 inequivalent methyl groups. Likely, the sharper peaks in all spectra are due to the N C H 3 "bound" to Pt, whereas the broad peaks are due to N C H 3 "bound" to Pd. For comparison, in the 'H NMR spectrum of Pd Cl (dmapm) the signals for 2  2  NCH are seen at 5 2.44, 2.89, and 3.07 with relative integrations of 2:1:1 (Section 3.1). The 3  signals for NCH  3  protons "bound" to Pd seem to come more upfield ,and, as already  mentioned, are broad at r.t. and are resolved at low temperature. Thus, the more upfield peaks in the NCH region of all three 'H spectra of the PdPt complexes may be due to the methyl 3  groups on the N-atoms bound to Pt. The additional chlorides bound to the Pd and Pt in b seem to confer more stability to the complex in solution, evidenced by eight sharp peaks for inequivalent NCH groups in the 'H NMR spectrum. Upon comparison of the 4 spectra, four 3  64  References on page 74  Chapter 3 different NCH proton environments are able to be distinguished: N C H 3 bound to Pd, NCH 3  3  not bound to Pd, NCH bound to Pt, and NCH not bound to Pt. 3  The  31  3  P{'H} NMR spectra for the complexes shown in Figure 3.15 are also quite  different (see Sections 2.7.5, 2.9.1, 2.9.2, and 2.10.1). For PdPtCl (dmapm), a singlet at 8 4  11.8 with Pt satellites ( J  = 3980) is observed, but J  l  3  PPt  is not seen. For PdPtCl2(dmapm), 1  PPt  an AA'BB' pattern is seen, showing both 'jppt and Jp coupling (8 -23.0 (d, J 3  2  Pt  = 260, P bound to Pd), -31.7 (d, J 2  = 21.9, J  PPt  +  l  P P  = 43.2, ' j  = 3900, P bound to Pt), 48.9 (d, V  P P t  Pd)). It is not clear why V  = 43.2, V  P P  and J 3  PPt  2  t  2  SEt)(dmapm)] , an AA'BB' pattern is also observed, along with both J (8 23.4 (d, J  = 21.9, Vpp  = 200, P bound to Pt)). For [PdPtCl (u-  l  PP  P P  PPt  PPl  coupling  = 260, P bound to  coupling is observed for [PdPtCl (p.-SEt)(dmapm)] but not for +  P P t  2  PdPtCl4(dmapm). In the [Pd Cl2(p-SEt)(dmapm)] case, only a singlet is observed at 8 48.9. +  2  [PdPtCl2(p-S Pr)(dmapm)] [OTf]" was synthesized according to the method used to make n  +  the p,-SEt complex, except with the use of a different thiol. The product was characterized by NMR and mass spectrometry (LSPMS). In LSLVIS mass spectrometry, the parent peak of [PdPtCl (u-S Pr)(dmapm)] should have a mass of 1004; however, the spectrum showed a n  +  2  parent peak at 1003. A molecular ion peak at 969 is attributed to [ M - CI] and one at 891 is +  assigned to [ M - 2C1 - C Hy]. The slight discrepancy may be due to the detection of the +  3  isotope pattern for this complex. In the P{'H} NMR spectrum, an AA'BB' pattern is seen, 31  similar to that of [PdPtCl (u-SEt)(dmapm)] [OTf]", with J +  l  2  2  J  P P  = 43.0, 'Jpp = 3940, P bound to Pt), 48.6 (d, V t  P P  and J 3  PPt  = 43.5, V  P P t  P P t  coupling (8 23.1 (d,  = 300, P bound to Pd)). In  the 'H NMR spectrum, a broad peak in the NCH region is observed at 2.22, while the other 3  NCH signals are seen at 3.46, 3.54, 3.59, and 3.66, with relative integrations of 4:1:1:1:1. 3  The methylene resonances (P-C//2-P) may be obscured by the downfield NCH peaks, and 3  the broad signal NCH for 12 protons obscured the signal for the 3  CH2S  protons; the triplet for  the methyl of the bridged-thiolate is observed at 8 2.12, while a multiplet for the methylene is seen at 8 2.91. To better resolve this system, low-temperature studies were undertaken with [PdPtCl (p-S Pr)(dmapm)] [OTf]-. n  +  2  65  References on page 74  Chapter 3  3.7 Fluxionality of [PdPtCl (^-S Pr)(dmapm)] [OTf]" n  +  2  The fiuxionality of [PdPtCl ((i-S Pr)(dmapm)] [OTfj" was studied from - 9 0 to 20 °C in n  +  2  CD OD, as seen in Figure 3.16. At r.t. the P{'H} spectrum consists of an AB pattern, with 31  3  Pt satellites (see above). As the temperature is lowered, there is slight broadening of the signals, but otherwise the spectrum is unchanged. The 'rl NMR spectrum at r.t. is quite broad in the 8 1 - 3 region. As the temperature is lowered, the fluxionalities of the NCH groups exhibit different behaviour: the NCH peaks 3  3  for protons "bound" to Pd (• 0) sharpen while those for protons "bound" to Pt (A ) broaden. At 20 °C, the NCH signals for protons bound to Pt observed at 8 3.46, 3.54, 3.59, and 3.66 3  are sharp. However, as the temperature is successively lowered, the four signals broaden. At -80 °C, the four signals broaden almost into two, and at - 9 0 °C roughly one broad signal is seen. However, the r.t. signal at 8 2.22 is very broad for the N C H 3 protons "bound" to Pd. At 0 °C, this signal splits into two broad signals, rising up out of the baseline at 8 2.77 and 1.60 as the temperature is successively lowered. The broad singlet at 8 2.77 at - 3 0 °C splits into two broad singlets at 8 2.66 and 2.87, with the signal at 8 2.87 (•) obscuring the signal for the P-CH -P protons, initially present at r.t (20 °C). At -30 °C, the broad peak at 8 1.60 (0) splits 2  into two peaks with signals at 8 1.63 and 8 1.58. Four well-resolved peaks for the N C H 3 protons "bound" to Pd are seen at - 5 0 °C with relative integrations of 1:1:1:1. Thus, the four methyl groups must be inequivalent.  Indeed, at - 5 0 °C, all eight methyl groups of the  complex are inequivalent. As the temperature is successively lowered, the different rates of the four fluxional processes at work involving the N C H 3 protons can be seen: the rate of fluxionality of the Pt-bound N C H 3 groups, that of the free NCH protons on the Pt side, and 3  the rate of fluxionality of the N C H 3 groups "bound" to Pd, and that free ones at the Pd end. The various fluxional processes must result from the difference in size of the metal centers, and their relative rate of ligand substitutions. The bridged-thiolate protons (• ) also broaden as the temperature is lowered. At r.t., in the 'H spectrum, the bridged-thiolate protons can be observed as a triplet at 8 0.66 for the methyl, a multiplet at 8 1.38 for the methylene farthest away from the S-atom, and a pseudo quartet at 8 2.12 for the methylene adjacent to the S-atom. As the temperature is successively  66  References on page 74  Chapter 3 lowered, the broad signal for the N C H 3 protons sharpens, revealing the signal for the S~CH  2  protons. The thiolate signals broaden out into the baseline as the temperature is lowered further.  67  References on page 74  Chapter 3  Ar groups  20  10  -10  -20  »J  -30  -40  -50  -60  -70  -80  -90  ppm  Figure 3.16. Variable temperature 'H NMR spectra of [PdPtCl (uS Pr)(dmapm)] [OTfJ~ from -90 to 20 °C. A NGr7 "bound" to Pt; • bridged-thiolate protons $0 NC# "bound" to Pd; O protons of methylene bridge between the two P-atoms; • solvent (CD OD). n  +  2  3  3  3  68  References on page 74  Chapter 3 3.8 Reaction of Pd(hfac)2 with dmapm A common Pd" metal precursor is Pd(hfac) , and this has been used as a metal organic 2  precursor for the chemical vapor deposition (CVD) of thin Pd films, one desirable characteristic of metal-organic precursors being that they are usually more volatile than corresponding inorganic precursors.  The Pd compound of stoichiometry "Pd(hfac)(PMe3)3"  has been synthesized, and shown to have the bimetallic ionic structure, [Pd (PMe3)6][hfac] , 2  containing  Me P 3  a  PMe | Pd  I  p  PMe  metal-metal  bond,  as  • [  l  +  3  ^ e M-—PMe  h f a c  illustrated  Figure  3.17;  21  CH,  H C—pf F C  P M  +  the  mixed  [hfac]  3  3  ^e  in  2  CF,  3  3  3  3  Me P  M = Pd, Pt  3  a  ^PMe  3  b  Figure 3.17. Pt metal hfac complexes. In a, the PdPd and PdPt complexes have similar structures, with non-coordinating hfac . In b, one hfac ligand is bound and bridges the two Pt centers. metal PdPt analogue has also been synthesized.  Both are made via the conproportionation  of a Pd° or Pf° complex with Pd(hfac) . A similar method was used to prepare the bimetallic 2  Pt analogue, but with a different result: the crystal structure shows a bound hfac that bridges the two Pt centers, with one Pt bound through the two oxygens and one to the olefinic carbons (Fig.3.17).  22  A single dmapm ligand can bridge and stabilize a two-metal center system, unlike other well-known bisphosphine ligands such as dppm, where two ligands bridge the metals, and in an attempt to synthesize a Pd complex without coordinated chloride ligands, it was thought 2  that Pd(hfac) might be a good starting material. 2  [Pd(hfac)(dmapm)] [hfac]~  (Fig. 3.18)  +  would be  First, a Pd" monomer such as synthesized,  then the  subsequent  conproportionation reaction with a Pd° complex might generate a Pd dimer such as 2  [Pd (hfac)(dmapm)] [hfac] . For Pd(hfac) , the 'H spectrum consists of a singlet at 8 6.38 for +  2  2  the methine bridge, and the F{'H} spectrum shows a singlet at 8 3.56 for the C F 3 . The IR 19  69  References on page 74  Chapter 3 data of Pd(hfac)2 is consistent with those previously published. One equiv. of Pd(hfac) was 23  2  reacted with one equiv. of dmapm in CH2CI2, when the initially orange solution became yellow instantaneously. Efforts were made to precipitate the product (by the addition of Et 0, 2  hexanes, MeOH, NH4PF6), but to no avail. The complex was thus characterized in situ by 'H, 31  P{'H}, and '^{'H} NMR. The H NMR spectrum shows a singlet at 8 2.32 due to the ]  NCH protons, a triplet at 8 4.77 due the methylene bridge of dmapm ( J p - 12.1) and a 2  3  H  singlet at 8 5.3 due to the methine proton of hfac; in the aryl region, three signals are observed for the o-, m-, and jc-protons of the anilinyl ring (positions labeled with respect to the phosphorus substituents): a pseudo-quartet at 7.3, a pseudo-triplet at 7.6, and a pseudo-quartet at 7.8 with relative integrations of 2:1:1. In the P{'H} NMR spectrum, a singlet at 8 -60.0 31  is observed and, in the F{'H} spectrum, the two singlets are seen at 8 1.24 and 0.42, 19  assigned to two inequivalent hfac ligands, one coordinated and the other non-coordinated. The NMR data suggest that the 24 NC//3 protons are equivalent, almost certainly with the N atoms not coordinated. The likely structure is illustrated in Figure 3.18, but it is difficult  Figure 3.18. Probable reaction of Pd(hfac) with dmapm. 2  to ascertain the structure; other binding modes are possible for the hfac ligand.  For  23  example, Pd(hfac)2 reacts with triphos to yield the semichelating metal-P-diketonate complex, as illustrated in Figure 3.19; one of the hfac-oxygens has a weakly bonding interaction, such that the coordination geometry around Pd can be described as distorted square pyramidal.  24  70  References on page 74  Chapter 3 F  3  C  \  O  FC  ^  \  \  / >d  /CF  3  O  n hu  P  +•  AJL  3  /  P'  "  PPh2 Ph2 CF  triphos  3  Figure 3.19. Synthesis of [Pd(triphos)(hfac)] [hfac]", in which Pd adopts a distorted square pyramidal geometry. +  The  synthesis of a PdVbridged dimer was attempted via the conproportionation  route. Thus, the in situ Pd" species formed from the reaction of dmapm with 1.0 equiv. of 3  Pd(hfac)2 was reacted with A equiv. of Pd2(dba) -CHCi3 and the mixture was refluxed for 2 h. l  3  Excess NH4PF6 was added to precipitate a complex that was investigated by NMR, spectrometry and IR.  mass  The H spectrum shows a triplet due to the methylene bridge of dmapm !  at 8 4.0 and a singlet for hfac protons at 8 8.4. The multiplets from 8 7.3 to 7.7 are due to the Ar groups of dmapm. The N C H 3 region is complicated. The m/z value does not show a peak for the molecular ion peak, but it does show an m/z corresponding to [Pd2(dmapm)(hfac)] +  [hfac] (see  Section 2.11.3).  It should be noted that in the mass spectrum of  [Pd2(PMe)e][hfac] the highest m/z corresponded to Pd2(hfac)2(PMe) , while the most intense 2  2  peak was due to the species Pd(hfac)(PMe3)2. The P{'H} spectrum show a singlet at 8 21  31  -24.0, indicative of two equivalent P-atoms, and a septet at 8 -143.1 for the PF anion. 6  The poorly characterized product resulting from the attempted conproportionation of the Pd° and Pd -hfac species was reacted with EtSH. A clean in situ P {'H} NMR spectrum n  31  was recorded with a singlet at 8 47.6 and a septet for the PF6 anion. Further studies are required to better characterize these products.  3.9 Reaction of Pd Cl (dppm) with thiol R S H 2  2  2  During the course of my thesis work, the reaction of Pd Cl2(dmapm) with thiols was found to 2  proceed more cleanly with the addition of acid.  As Pd2Ci2(dppm)2 does not react with  thiols, the question arose as to whether Pd Cl (dppm) would react with thiol RSH in the 12  2  2  2  presence of acid.  71  References on page 74  Chapter 3 The in situ reaction of Pd2Cl2(dppm)2 with EtSH was performed in CD2CI2 at r.t. in the presence of HCI and followed by 'H and P{ H} NMR over a period of 48 h. It should 31  1  be noted that Pd2Cl2(dppm) is known to react with 2 equiv. of HCI to yield 2 equiv. of the 2  mononuclear PdCl2(dppm) species and H2, via pathways outlined in Fig. 3.20. ' ' 16  Ph P  Ph P  2  26  PPh, SEt  2  HCI  25  EtSH  First,  + H,  PPh, HCI -H,  Ph P  Ph,  CI  2  2  /  V \  CI  .  P Ph  Figure 3.20. Reaction mechanism for the formation of the species with the AB pattern.  one equiv. of EtSH was added to a solution containing Pd2Cl2(dppm)2 in an NMR tube. No reaction was observed; the quintet at 5 4.12 in the *H spectrum for the methylene bridge and the singlet at 8 -1.7 in the P{'H} spectrum remained unchanged. Two equiv. of HCI were 31  25  then added to the NMR tube; after 1 h, no reaction was observed, but after 24 h, formation of PdCl2(dppm) was observed by the appearance of a triplet at 8 4.28 for the methylene bridge and a singlet in the P{'H} spectrum at 8 —53.3. ' However, a two doublet AB pattern was 31  25 26  also distinguished in the P{'H} spectrum at 8 17.1 (d, J = 27.1), 25.9 (d, J = 27.5). The 31  2  2  PP  ?P  nature of this "AB species" is unknown, but generation of a chloro-thiolate as shown in Fig. 3.20 is plausible. One equiv. of HCI may first oxidatively add to Pd2Cl2(dppm) to yield the 2  known Pd21! hydrido-chloro intermediate, and this is known to react with a second equiv. of HCI  may react to yield the tetrachloro Pd " species, which breaks apart to form 2  25 PdCl2(dppm);  alternatively, one equiv. of EtSH may react with the hydrido-chloro  intermediate to afford the thiolate species and H . Further studies are required to substantiate 2  this proposal. 72  References on page 74  Chapter 3  3.10  Reaction of Po^ChCdmapm) and SO2  The reaction of Pd Ci2(dmapm) with SO2 was monitored by NMR ( H and P). The in situ ]  31  2  reaction was first performed, in which 1 atm of SO2 was injected into a septum-sealed NMR tube containing Pd2Cl2(dmapm) in CDCI3; the initially orange solution turned purple instantaneously, and in the P{ H} NMR spectrum, two singlets were observed at 8 51.4 and 3I  1  45.4. One possible structure to give a singlet is an A-frame complex with the SO2 bridging moiety at the apex (analogous to Pd2Ci2(u.-S02)(dppin) ).  26  2  After 24 h, a pink solid  precipitated from solution, and the reaction was subsequently undertaken on a preparative scale. The IR of the isolated purple solid showed bands at 1181 and 1140 and cm" which are 1  indicative of v(S-O) stretches, linked with. a bridging A-frame structure.  26  The system  requires further study.  73  References on page 74  Chapter 3 3.11  References  (1)  Jones, N. D. Ph. D. Dissertation, University of British Columbia, 2001.  (2)  Benner, L. S.; Balch, A. L. J. Am. Chem. Soc. 1978,100, 6099.  (3)  Balch, A. L.; Benner, L. S. Inorg. Synth. 1982, 21, 47.  (4)  Panunzi, A.; Renzi, A. D.; Paiaro, G.J. Am. Chem. Soc. 1970, 92, 3488.  (5)  Fanizzi, F. P.; Natile, G.; Lanfranchi, M.; Tiripicchio, A.; Pacchioni, G. Inorg. Chim. Acta 1998, 275-276, 500.  (6)  Davies, B. W.; Puddephatt, R. J. Can. J. Chem. 1972, 50, 2276.  (7)  Fanizzi, F. P.; Intini, F. P.; Maresca, L.; Natile, G.; Lanfranchi, M.; Tiripicchio, A. J. Chem. Soc, Dalton Trans. 1991, 1007.  (8)  Ma, E. Ph. D. Dissertation, University of British Columbia, 1999.  (9)  Connelly, N. G.; Freeman, M. J.; Orpen, A. G.; Sheehan, A. R.; Sheridan, J. B.; Sweigart, D. A. J. Chem. Soc, Dalton Trans. 1985, 1019.  (10)  Huheey, J. E.; Keiter, E. A.; Keiter, R. L. Inorganic Chemistry: Principles of Structure and Reactivity, 4th; Harper Collins College: New York, 1993, 310.  (11)  Jalil, M. A.; Nagai, T.; Murahashi, T.; Kurosawa, H. Organometallics 2002, in press.  (12)  Besenyei, G.; Lee, C.-L.; Gulinski, J.; Rettig, S. J.; James, B. R.; Nelson, D. A.; Lilga, M. A. Inorg. Chem. 1987, 26, 3622.  (13)  Barnabas, A. F.; Sallin, D.; James, B. R. Can. J. Chem. 1989, 67, 2009.  (14)  Besenyei, G.; Lee, C.-L.; Gulinksi, J.; Rettig, S. J.; James, B. R.; Nelson, D. A.; Lilga, M. A. Inorg. Chem. 1987, 2f5, 3622.  (15)  Lee, C.-L.; Chisholm, J.; James, B. R.; Nelson, D. A.; Lilga, M. A. Inorg. Chim. Acta 1986,121, L7.  (16)  James, B. R. Pure Appl. Chem. 1997, r5P, 2213.  (17)  Lee, C.-L.; Besenyei, G.; James, B. R.; Nelson, D. A.; Lilga, M. A. J. Chem. Soc, Chem. Commun. 1985, 1175.  (18)  Pamplin, C. B. Ph. D. Dissertation, University of British Columbia, 2001.  (19)  Jones, N. D.; James, B. R. Adv. Syn. and Cat. 2002, in press.  (20)  Rubrezhov, A. Z. Platinum. Met. Rev. 1992, 36, 26.  (21)  Lin, W.; Wilson, S. R.; Girolami, G. S. Inorg. Chem. 1994, 33, 2265.  74  References on page 74  Chapter 3 Lin, W.; Wilson, S. R.; Girolami, G. S. Inorg. Chem. 1997, 36, 2662. Siedle, A. R.; Newmark, R. A.; Pignolet, L. H. Inorg. Chem. 1983, 22, 2281. Siedle, A. R.; Newmark, R. A.; Pignolet, L. H. J. Am. Chem. Soc. 1981,103, 4947. Barnabas, F. A. M. Sc. Dissertation, University of British Columbia, 1989. Lindsay, C. H.; Benner, L. S.; Balch, A. L. Inorg. Chem. 1980,19, 3503.  75  References on page 74  Chapter 4  Chapter 4  SYNTHESIS AND REACTIVITY OF A HETEROBIMETALLIC COMPLEX OF Mo AND Ru  4.1 Introduction Initially, I began my Masters thesis with the intention of studying the synthesis of a known heterobimetallic complex of Ru and Mo namely MoRu(CO)6(dppm) ' and its reactivity 2j  towards H S and RSH thiols  (1, Fig. 4.1).  2  A former group member, Dr. M. Khorasani-  Motlagh, initiated the work, and her findings will be discussed in Section 4.3. Although 2  work in this area revealed some complications, eventually leading me to work with other bimetallic platinum metal complexes (Chapter 3), some results are worth mentioning. A brief introduction on aspects of work in this area is given in several sections: the relevance of MoRu/H S/RSH chemistry not mentioned previously in Chapter 1 (Sect. 4.1.1), an overview of 2  Ru and Mo properties (Sect. 4.1.1), a brief review of Ru heterobimetallics (Sect. 4.1.2), and comparison with other heterometallic complexes of Mo and Ru (Sect. 4.1.3). Experimental details (Sect. 4.2) and discussion of results (Sect. 4.3) are included in this chapter.  Figure 4.1. Structural formula of MoRu(CO) (dppm) . 6  4.1.1  2  Relevance of Mo-Ru/H S/RSH Chemistry 2  Mo-containing enzymes have important biological functions in nitrogen fixation (e.g. nitrogenase) and oxo transfer chemistry (e.g. xanthine oxidase); Mo is the only essential, second-row transition metal in biology.  3  The nitrogenase enzyme system catalyzes the  reduction of dinitrogen to ammonia, which is an integral part of the nitrogen cycle on earth.  76  References on page 100  Chapter 4 The enzyme is made up of two component metalloproteins, the molybdenum iron (MoFe) protein (Fig. 4.2) and the iron (Fe) protein , whose structures have been determined 4  5  crystallographically. The overall stoichiometry of the biological nitrogen fixation reaction: N + 8H + 8e"+16Mg-ATP  *~  +  2  2NH + H + 16Mg-ADP + 16 P, 3  2  Figure 4.2. (2) Structure of the Fe-Mo cofactor of the Mo-Fe protein of nitrogenase as first solved by X-ray crystallography. (3) Probable structure of the Mo cofactor functioning in oxo transfer reactions. demonstrates also the requirement for reducing equivalents, Mg-ATP and protons. The Feprotein transfers electrons to the Mo-Fe-protein in a process that is coupled to the hydrolysis of Mg-ATP. The MoFe protein consists of two cuboidal fragments, one containing four Fe atoms and the other three Fe-atoms and the Mo-atom. The Mo and the Fe are octahedrally and tetrahedrally coordinated, respectively, although a much discussed structure determined in 1992 had incorrectly revealed a trigonal prismatic arrangement of 6 Fe centres, implying a vacant coordination site at each Fe. ' 4  6  It had been postulated that N binds to the FeMo 2  protein at the vacant site, without direct coordination to Mo, but this aspect is now being 4  reconsidered.  6  The new structure reveals a missing central atom in the core of the 6 Fe6  atoms (see 2 in Fig. 4.2), most likely a N-atom. In oxo transfer chemistry, the Mo-binding moiety is a substituted pterin that coordinates the metal via two S-atoms (3 in Fig. 4.2). One example of such an enzyme is xanthine oxidase, which catalyzes the oxidation of xanthine to uric acid as illustrated in Figure 4.3. Although this enzyme is the most widely studied Mo oxotransferase, the function of the reduced pterin is still not well understood.  77  References on page 100  Chapter 4  xanthine  u r  j acjd c  Figure 4.3. Reaction catalyzed by xanthine oxidase.  4.1.2  Properties of R u and M o  While Mo exhibits a strong affinity for sulfur ligands, as illustrated in Figure 4.2, Ru has a strong affinity for hydrogen ligands and, for example, Ru-based catalysts have been widely used in the field of homogeneous hydrogenation. '  The first detailed report on the  7 8  homogeneous catalytic hydrogenation by a platinum metal complex was given by Halpern and coworkers, who discovered that aqueous solutions of chlororuthenate(II) were active for 9  the hydrogenation of maleic, fumaric and acrylic acids.  In 1965, with the advent of Ru-  phosphine complexes, Wilkinson et al. reported that RuCl (PPh3)„ (n = 3, 4) reacted with 2  hydrogen at r.t. in ethanol/benzene to give RuCl(H)(PPh )3, which was an extremely active 3  catalyst for the reduction of olefins and acetylenes.  10  Furthermore, Ru is the most active  component of heterogeneous catalysts for the Fischer-Tropsch (FT) process," in which synthesis gas (CO + H2) is converted to a variety of hydrocarbons; however, its cost compared to that of Co and Fe limits its commercial viability. Chiral Ru catalysts have also been successfully used in asymmetric transfer hydrogenation of C=0 and C=N bonds (4, 5 in Fig. 12  4.4),  for which a sharing of the Nobel Prize in Chemistry for 2002 was awarded. Ru-  containing complexes with phosphine and hydride/hydrogen ligands (Fig. 4.4) have also been widely applied in: olefin metathesis (6, 7 in Fig. 4.4) with applications including the construction of macrocycles in peptides and other systems, tandem ring opening/ring closing and construction of fused ring systems, and ring-opening metathesis polymerization (ROMP) in aqueous media.  13  By incorporating the known affinities of Mo for sulfur and Ru for hydrogen into a single complex, namely, MoRu(CO)6(dppm) ,  1,14  2  it was hoped that new H S/RSH chemistry 2  could be explored and that intermediates could be characterized en route to new products.  78  References on page 100  Chapter 4  PCy  3  CI  H  Ru(H)(H) CI(PCy ) + H2  3  H —Ru-  2  2  6  Cl  R-i*  2  P C ya y H H 3  P  C  y3,ci  I x^'  Ru=^ CI  PCy  R,  H, R  ^R  2  3  7 Figure 4.4. Ru catalysts used in asymmetric hydrogenation (4, 5) and as a precursor for olefin metathesis reactions (6). 4.1.3  R u heterobimetallics  Mixed-metal heterobimetallic and heterotrimetalllic complexes have received interest for their potential to act as models for mixed-metal heterogeneous catalysts; and much work has been 15  done involving Ru as one of the metals. For example, PtRu-bonded clusters are of interest because supported Pt/Ru/alumina catalysts are useful in petroleum refining and PtRu electrodes are used to catalyzed methanol oxidation in fuel cells.  16  A simple route for making  PtRu clusters is reported by Puddephatt and coworkers, the reaction of [Pt(dppm)2] with 17  2+  one or two equiv. of [HRu(CO)4]" yielding 8 or 9, respectively (Fig. 4.5).  79  References on page 100  Chapter 4  CO OC •  8  / \  9  Figure 4.5. PtRu heterometallic complexes.  Another application for mixed-metal RuPt complexes is in the area of DNA-binding. With the discovery and use of cz's-Pt(NH3)2Cl2 (cisplatin) as an anticancer drug, the research in the field of metallodrugs has undergone a resurgence. One approach taken is to bind a cisPt"Cl2 moiety to Ru light absorbers. These complexes are potentially bifunctional, capable of both intercalative and covalent binding to DNA. The complex [(bpy)2Ru"(dbp)PtCl2]Cl210 (bpy = 2,2'bipyridine; dpb = 2,3-bis(2-pyridyl)benzoquinoxaline) (Fig. 4.6) and the OsPt io  analogue interact with DNA.  The studies suggest that the complexes form covalent bonds to  DNA through the Pt, while the presence of the Ru allows for tuning of the Pt site reactivity.  10 Figure 4.6. A heterobimetallic complex of Ru and Pt bridged by dpb.  As monometallic non metal-metal bonded ruthenium catalysts have been found active in olefin metathesis (see Section 4.1.2), bridged RuOs and RuRh species have been explored for their activities in the ROMP of 1,5-COD.  19  80  Compared to the monometallic Ru alkylidene  References on page 100  Chapter 4 complexes (7, Fig. 4.4), species 11 were 40 times as active, while species 12 were approximately 80 times as active. It was proposed that the ancillary metal moiety acts as a hemilabile chelating group, while the tricyclohexylphosphine of the monometallic species does not readily dissociate during olefin metathesis.  19  PCy  3  R = CH=CPh , Ph 2  11 Figure 4.7. Heterobimetallic Ru catalysts used in the ROMP of 1,5-COD.  Heterometallic complexes of Ru and Ir are known. As illustrated in Figure 4.8, some containing a single diphosphine bridged ligand, notably dppm, dppen (PH2PC(=CH2)PPh ), or 2  dppa (PH PN(H)PPh ), have been synthesized (13).  20  2  2  A polyhydride complex with three  hydrides bridging Ru and Ir centers, with a Cp or CsMes ligand bonded to each metal center (14), has also been made (Fig. 4.8).  Comparison of the activity of 14 with that of the  homobimetallic Ru complex shows a remarkable site selectivity in the heterobimetallic case in reactions with alkenes and alkynes.  21  has been synthesized;  Furthermore, a tetrametallic Ru3lr butterfly cluster  the structure consists of metal-metal bonds between the three Ru  centers, with two of these also bonded to Ir, while bridging phosphido and chloro ligands also reinforce the butterfly framework.  E = C H , C=CH , or N(H) 2  R=H, Me  2  13  14  Figure 4.8. Rulr heterobimetallic complexes with bridging diphosphine (13) or hydride (14) ligands.  81  References on page 100  Chapter 4  4.1.4  Complexes of Ru and Mo  As well as 1, made via reaction of cis- and ^ra«,s'-RuH (dppm) with Mo(CO)6 (see Section 2  2  4.3), other heterobimetallic complexes of Ru and Mo are known, as illustrated in Figure 4.9. In the metal-metal bonded complex 15 (Fig. 4.9), the Ru and Mo are bridged by a bis(cyclopentadienyl) ligand in which the two cyclopentadienyl rings are coupled by a carbon linkage.  23  The synthesis involves  reaction of [Cl Ru(CO)3]2 2  with  1 equiv. of  C(CH3)2(C5H4T1) (R = C H 3 ) in refluxing benzene to yield an isolable intermediate that reacts 2  with Mo(CO) or Mo(CO) (CH CN) to afford 15; this can further react with PPh , to form a 6  3  3  3  3  phosphido carbonyl-bridged product. 15 is similar to compounds reported by Vollhardt and Weidman, such as MoR^CO^^-^^-CsFLjCsFL;) that is synthesized by reaction of Mo(CO)6, R U 3 ( C O ) i  and dihydrofulvalene in glyme.  24  2  Salzer and coworkers have reported  the synthesis of (77 -C Me5)Mo(CO)3Ru07 -C H ) (16) as illustrated in Figure 4.9. 5  5  5  5  generated photochemically, was reacted in THF at -40 °C with  [C Me Ru(CH3CN)3] , +  5  25  5  5  [C5Me Mo(CO) ]", prepared in situ by reaction of lithium pentamethylcyclopentadienide with 5  3  Mo(CO)6. 16 was isolated after the mixture was stirred for several hours at r.t.  15  25  16  Figure 4.9. (15) A ring-coupled RuMo heterobimetallic. (16) A CO-bridged, metal-metal bonded RuMo complex.  Another metal-metal bonded RuMo complex has been synthesized by Davies and Whiteley and coworkers.  26  As illustrated in Figure 4.10, thermolysis of the y\rf bridged  complex Mo(CO) (^-?7 :?7-C7H )Ru(CO) (^-C5Me ) affords 17. 6  3  ,  7  2  5  82  References on page 100  Chapter 4  Figure 4.10. Thermolysis of a cycloheptatrienyl-bridged complex of Ru and Mo to yield 17.  Unbridged, metal-metal bonded heterobimetallic complexes of Ru and Mo have also been synthesized, involving only Cp and carbonyl ligands.  27  18 (Fig. 4.11) is synthesized via  the metathesis reaction of NaMo(CO) Cp with Ru(CO) (Cp)X (X=Br, I) in THF or by metal3  2  lic  18 Figure 4.11. Unbridged, metal-metal bonded heterobimetallic RuMo complexes. metal bond metathesis between [Mo(CO)3Cp] and [Ru(CO) Cp] . 19 was synthesized in a 2  2  2  similar manner, using the corresponding sodium metallates with the appropriate Ru bromide complex. The hydride-bridged RuMo species, 20 was synthesized from a suspension of a 1/1 mixture of [(C5Me5)RuCl] and (C5Me )MoCl in diethyl ether, which was treated with excess 4  5  4  LiBH at r.t. for 12 h, the complex being isolated after workup with methanol at -78 °C. 4  83  28  20  References on page 100  Chapter 4 reacted with PMe , PPh or P(OMe) , with removal of two of the three terminal hydrides 3  3  3  bound to Mo as dihydrogen, to give 21a, 21b and 21c. 20 also reacts with acacH and NH 'Pr, 2  both of which coordinate to the Mo center.  28  [(C Me )RuCI] 5  5  4  +  (C Me )MoCI 5  5  1) LiBH  H  »~ 4  it  4  M  2) CH OH  —Mo  3  JRu H H R=Me (21a), Ph (21b), OMe (21c)  20  21  Figure 4.12. Reaction of (C5Me )Ru(//-H) MoH (C Me ) (20) with PR compounds to yield the phosphine derivative (21a, 21b, 21c) and H . 5  3  3  5  5  3  2  RuMo porphyrin dimers have also been synthesized (Fig. 4.13).  29  Two distinct  conformers crystallized in the asymmetric unit of [(OEP)MoRu(TPP)] [PF6]" (OEP = +  octaethylporphyrin, TPP = tetraphenylporphyrin).  The heterobimetallic complex is  synthesized from Mo(OEP) 22a and Ru(TPP) 22b (Fig. 4.13). This is the first report of a  22a  22b  Figure 4.13. Building blocks of a MoRu heterobimetallic porphyrin dimer: (24a) Mo(OEP), (24b) Ru(TPP). simultaneous structural characterization of two unique metal-metal bonds in a single asymmetric unit. One has eclipsed porphyrin macrocycles (twist angle = 4.4°), while the other exhibits two porphyrin ligands staggered at almost exactly 45 °. It is postulated that the  84  References on page 100  Chapter 4 eclipsed conformer is preferred electronically, while the staggered conformer is preferred for steric reasons. In addition to bimetallics, a cubane-like cluster containing Ru and Mo (23) has also been made (Fig. 4.14).  30  For the synthesis, Ru3(CO)i2 was refluxed with excess cod for 6 h,  and the product mixture then extracted with pentane; the extract was then reacted with [(rfCp')3Mo3S4][pts] (Cp' = CsH Me, pts =/?-toluenesulfonate). When kept in a CF^CVpentane 4  solution for several days, 23 partially loses CO and dimerizes, affording a species with a solid-state structure that consists of two M03S4RU cubane units held together by a Ru-Ru bond reinforced by three bridging carbonyl ligands.  30  1) benzene, 6 h reflux  [Ru (CO) ] + cod 3  *•  12  2) extract with pentane 3) [Cp' Mo S ] pts+  3  3  4  Figure 4.14. Cubane-like cluster compound of Ru and Mo. 24 was synthesized by heating Cp2Mo(CO) (u-?/ -Ci4H2o) with Ru3(CO)i2 in re fluxing 2  4  n-heptane for 16 h, and purified by TLC (Fig. 4.15); 21 can also be made by the thermolysis of  the  product  formed  from  the  reaction  Ru (CO),o(NCMe) in CH C1 at r.t. for 20 min. 3  2  2  of  Cp2Mo(CO)4(u-?7 -Ci4H2o) 2  with  31  2  85  References on page 100  Chapter 4  Listed in Table 4.1 are the Ru-Mo distances in A of the aforementioned complexes. It is interesting to note that MoRu(CO)6(dppm)2 has the longest Ru-Mo bond distance of the structures in which the distance is known. This is due most likely to the bite angle of the dppm ligand. 20 and 21 are bridged by hydrides, which does not impose a strict bond distance on the complexes. In the cubane-like cluster 23, Mo and Ru are held together by p.sulfido ligands, and there is no direct bonding between the two metal centers. The geometry of 15 is stabilized by a ligand containing two cyclopentadienyl rings joined by a carbon bridge. 16 is bridged by three ligands but the crystal structure has yet to be solved; however, that for the analogous RuW structure shows a Ru-W bond distance of 2.4101 A, which is indicative of a Ru-W triple bond. The overall structure is similar to that of a triple-decker sandwich, with the middle being formed by the three carbonyl C-atoms. By far the shortest reported Ru-Mo bond distances are reported for the heterobimetallic porphyrin dimers of 22a and 22b (2.21 and 2.18 A).  A metal-metal bond order of 3.5 is proposed for the eclipsed  conformation though it does have a longer Ru-Mo, while a metal-metal bond order of 2.5 is proposed for the staggered conformation with the shorter Ru-Mo bond. The steric strain between the two porphyrins moieties contributes to the Ru-Mo bond length.  86  References on page 100  Chapter 4  Table 4.1. Comparison of Ru-Mo bond distances. Complex 1 MoRu(CO) (dppm) 6  15 16 17 18 19 20 21 22a + 22b 23  2  Ru-Mo Bond distance (A)  Reference  3.059(1) 2.958(1) No structure No structure 3.0101(3) 3.0424(3) 2.5255(7) Not given Conformer 1: 2.21; conformer2: 2.18 2.971(1), 2.957(1), 2.893(1)  1 23 25 26 27 27 28 31 29 30  87  References on page 100  Chapter 4 4.2 Synthesis General procedures, physical techniques, and instrumentation and materials used, are as described in Chapter 2 of this thesis.  RuCl -3H 0 was obtained on loan from Johnson 3  2  Matthey Ltd. and Colonial Metals Inc. The metal complex Mo(CO)6 and the ligand dppm were purchased from Aldrich and used without further purification. All other reagents were purchasedfromcommercial sources and used without further purification. The  Ru precursors [RuCl (cod)] 2  and frYms-[Ru(H)Cl(dppm) ] were prepared  32  33  x  2  following literature procedures. The ' H and P{'H} NMR data of these precursors are in 31  agreement with those previously published. 4.2.1  Cis- and fra«s -Ru(H) (dppm) (c- and f-Ru(H) (dppm) ) ,  2  2  2  2  This mixture of complexes was synthesized according to a modified literature procedure of 34  one reported by Grubbs and co-workers.  35  Thus, a 250 mL Schlenk flask containing a Teflon-  coated magnetic stir bar was charged with degassed 2-butanol (45 mL). [RuCl (cod)] (200 2  x  mg, 0.71 mmol) and dppm (545 mg, 1.42 mmol) were added to the reaction vessel and to this suspension was added NaOH (568 mg, 14.8 mmol). The tube was sealed, heated to 80 °C, and the contents stirred for 3 h, after which the brown suspension became green-yellow in colour. After 3 h, the reaction vessel was left to cool to r.t., and degassed H 0 (~ 80 mL) was 2  added to dissolve excess NaOH. The resulting suspension was then transferred via cannula to a medium porosity frit, further washed with MeOH (3 xio mL), and finally dried in vacuo. The analytically pure product is obtained as a mixture of cis and trans isomers in the typical 4:1 ratio.  34  Yield: 0.370 g (60 %). Anal. Calcd. for C50H46P4RU: C 68.88, H 5.34. Found: C  68.76, H 5.34. cis isomer: ' H NMR (300 MHz, 300 K, C D ): 8 -7.57 (dq, 2H, 7HP=71.7 Hz (trans P), 2  6  6  / p=16.9 H Z (cis P)), 4.10 (m, 2H, CH ), 4.62 (s, 4H, CH ), 6.8-8.3 (m, 20H, Ar).  2  H  2  3 ,  2  P H} { 1  NMR (121 MHz, C D , 300 K): 8 2.59 (t, J =28.4 Hz), 16.1 (t, J =28.4 Hz). 2  6  6  2  PP  PP  trans isomer: *H NMR (300 MHz, 300 K, C D ): 8 -4.81 (qn, 2H, J p=18.2 Hz), 4.79 (m, 2  6  2H, CH ), 6.8-8.3 (m, 20H, Ar). 2  3,  6  H  P H} NMR (121 MHz, C D , 300 K): 8 2.59 (t, J =28.4 {1  2  6  6  PP  Hz), 11.2 (s), 16.1 (t, J =28.4 Hz) (see Fig. 4.16, Sect. 4.3.1). NMR data are agreement with 2  PP  those previously published.  33  88  References on page 100  Chapter 4  4.2.2  MoRu(CO) (dppm) 6  2  According to the synthesis published by Chaudret and co-workers, the title complex can be 1  prepared by the adding the Ru(H) (dppm) mixture (100 mg, 0.11 mmol) and Mo(CO)6 (32 2  2  mg, 0.12 mmol) to toluene (10 mL) and heating the resulting suspension at 80 °C for 2 h. The resulting red solution was left at r.t. when large orange-brown crystals formed within 24 h. Addition of hexanes (20 mL) to the filtrate led to a further crop of microcrystals. Anal. Calcd. for  C 59.32, H 3.91. Found: C 60.97, H 4.76. H NMR (300 MHz, 300 K, ]  C56H44O6P4M0RU:  C D ): 5 3.55 (pqn, 4H, CH , V p=4 Hz). 6  6  2  31  H  P H} NMR (121 MHz, C D , 300 K): 2 sets of {1  6  6  resonances centred at 5 36.1, 44.1. These data are in agreement with literature data. ' '  1 2 14  4.2.3  In situ preparation of MoRu(CO)s(dppm)  2  This complex was prepared in a manner similar to that used for MoRu(CO)e(dppm) . Thus, to 2  a Schlenk tube containing toluene (10 mL) was added c- and ?-Ru(H) )dppm) (100 mg, 0.11 2  2  mmol) and Mo(CO)6 (32 mg, 0.11 mmol). The resulting suspension was heated at 80 °C for 2 h. The red solution was then reduced in volume to ca. 5 mL, this precipitating a red solid. The filtrate was very air-sensitive. 'H NMR spectrum of the filtrate (300 MHz, 300 K, C D ): 6  3.1 (pqn, 4H, CH , J p=4). 2  2  H  31  6  P H} NMR (121 MHz, C D , 300 K): 5 35.9 (br s). The (1  6  6  spectral data are close to those quoted by Chaudret and co-workers.  The red solid was  1  insoluble in all common solvents except CH C1 , in which it slowly decomposes. 2  4.2.4  2  In situ preparation of MoRu(H) (CO)s(dppm) 2  2  According to previously published literature, the title complex can be prepared by 1  suspending MoRu(CO)e(dppm) in toluene, and bubbling H through the solution. 2  The  2  initially red solution rapidly became a pale yellow. 'H NMR (300 MHz, 300 K, C D ): 8 6  6  7.95 (m, 2H, \i-H), 3.95 (br s, 4H, CH ). P H} NMR (121 MHz, C D , 300 K) 5 35.9 (br 31  {1  2  6  6  s). The data agree with suggested literature data.  14  89  References on page 100  Chapter 4  4.2.5  In situ reaction of MoRu(CO)6(dppm)2 with H2S  H S (1 atm) was introduced at r.t. into a septum-sealed NMR tube containing an in situ 2  solution of MoRu(CO)6(dppm) (formed from c- and t- RuH (dppm) (10 mg, 0.011 mmol) 2  2  2  and Mo(CO) (3.2 mg, 0.011 mmol)) in C D (1 mL). The final 'H and P{'H} NMR spectra 31  6  6  6  were taken after 84 h. Among the mixture of compounds formed are believed to be: MoRu(SH)(CO) Cw-H)Cu-CO)(dppm) , MoRu(H)(CO) Cu-SH)Cu-CO)(dppm) , MoRu(CO) (^3  2  3  2  4  SH)(u-H)(dppm) , and MoRu(CO) (u-S)(dppm) (see Section 4.3.3). 2  4.2.6  4  2  In situ reaction of MoRu(CO) (dppm) with E t S H 6  2  An excess of EtSH (0.005 mL, 0.068 mmol) was introduced at r.t. into a septum-sealed NMR tube containing a solution of MoRu(CO)6(dppm) (formed from c- and t- RuH2(dppm) (10 2  2  mg, 0.011 mmol) and Mo(CO) (3.2 mg, 0.011 mmol)) in C D (1 mL). The final U and l  6  6  6  P{'H} NMR spectra were recorded after 72 h. Among the mixture of compounds formed  31  are probably: MoRu(SEt)(CO) (u-H)( u-CO)(dppm) , MoRu(H)(SEt)(CO) Cu-CO)(dppm) , 3  /  2  3  2  and MoRu(H)(CO) (u-SEt)(«-CO)(dppm)2 (see Section 4.3.3). 3  90  References on page 100  Chapter 4 4.3  Discussion  4.3.1  Cis- and *rafls-Ru(H) (dppm)2 2  A previous multistep synthesis of c- and /-Ru(H) (dppm) involving zinc reduction of 2  2  [Ru(COD)(COT)] under H in the presence of phosphine gives relatively low yield (102  40%). Here, a more convenient synthesis by modification of a reported method leads to 33  34  35  higher yield of c- and /-Ru(H) (dppm) , in the typical 4:1 ratio, as illustrated in Figure 4.16, 34  2  2  where 2-BuOH is the source of the hydrogen. excess NaOH  1/x [RuCI (cod)] + 2 dppm 2  •  x  Ru(H) (dppm) + C H + 2 NaCI 2  2  8  1 6  .  2-BuOH  trans Figure 4.16. Synthesis of c- and ^-Ru(H)2(dppm)2. 4.3.2  MoRu(CO) (dppm) ( = 6, 5) n  2  n  Difficulties were encountered in the isolation of pure MoRu(CO) (dppm) which has been 6  previously reported. '  1 14  2)  MoRu(CO) (dppm) can be prepared by reaction of c- and t6  2  Ru(H) (dppm) with Mo(CO) at 80 °C as described (Section 4.2.2). In solution under Ar, 2  2  6  MoRu(CO) (dppm) exists in three interconvertible forms, and formation of one of these 6  2  involves loss of CO to give MoRu(CO) (dppm) as illustrated in Figure 4.17-' It was decided 5  2;  that obtaining the complex in a good in situ yield would satisfy the purposes of carrying on research involving further reactions of H2S or RSH with the heterobimetallic complex. However, even this was unsuccessful. Many other species are present in solution as can be seen  by  typical  !  H  and  P{'H}  31  NMR  91  data,  shown  in  Figure  4.18.  References on page 100  Chapter 4  PPh 80 °C, C H , 2 h O C c-, t- Ru(H) (dppm) + Mo(CO) OC—Mo 6  2  2  OC OC  6  6  2  | OC. ' Mo -Ru—CO c o  P  2  h  p  \  I  ^ C O  ^-PPh,  Figure 4.17. Synthesis of MoRu(CO) (dppm) and its interconvertible forms. 6  2  Ar region  CH,  H NMR  4.5  4.0  3.5  ppm  _i !'"~' "'"1  T'""I™"""'r—"1—r-r-  r  <.k_A_  --t • •* -1 •  i.5 8.0 7.5 7.0 6.5 6.0 5.5 5.0 4.5 4.0 3,5 3.0 2.5 2.0 1.5 1.0 31  P{'H} NMR  AA'BB' pattern of MoRu(CO) (dppm) 6  47  46  ITT  45 1  44  43  42  41  40  39  1  •I • ' ' I 1  n n m  :  38  37  36  ppm  rK J 31T-> 1  Figure 4.18. ' H and P { ' H } NMR spectra of in situ solutions containing MoRu(CO) (dppm) (Experiment 4, Table 4.2). In the P { ' H } NMR spectrum, extraneous peaks are seen at 8 40.7, 29.3, 20.8, 16.0, 11.2,2.5, 1.0. 31  6  2  92  References on page 100  Chapter 4 The conditions used in attempts to generate MoRu(CO) (dppm) in high in situ yield 6  are summarized in Table 4.2.  Using the conditions described in the literature,  MoRu(CO)6(dppm) was not generated exclusively, as revealed by the P{'H} NMR data. 31  2  Present in solution were MoRu(CO) (dppm) , the Ru(H) (dppm) starting material, and 6  2  2  2  possibly MoRu(H) (CO) (dppm) . 2  5  2  Table 4.2. Conditions used to generate MoRu(CO) (dppm) . Experiment h Temperature °C Atmosphere  Ru(H) (d pm) :Mo(CO)  1 2 3 4 5  Mole ratio 1:1 1:1 1:1 1:1.2 1:1.5  6  2 4 2 2 2  a  .  80 100 100 80 80  2  2  Ar CO Ar Ar Ar  " As used in ref. 1.  P  2  6  The formation of MoRu(CO)e(dppm) occurs when Ru(H) (dppm) acts as a Lewis 2  2  2  base in reaction with Mo(CO)5, a Lewis acid, formed by the loss of CO at 80 C . ' ' 0  14  The  reaction of Lewis acid with a Lewis base to synthesize homo- and heterobimetallic complexes is well established. '  37 38  The reaction of Ru(H) (dppm) with Mo(CO)s is similarly envisioned 2  2  as proceeding via an intermediate having a dative Ru—»Mo bond, with one bridging and one chelating dppm ligand, and with H bonded to Ru; this step would be followed by a 2  rearrangement of the complex and elimination of H upon addition of CO. Because of the 2  conversions  outlined  in  Fig.  4.17,  any  of  the  products,  MoRu(CO)6(dppm) , 2  MoRu(CO)5(dppm) , and MoRu(H) (CO)s(dppm) could be present in the reaction mixture, 2  2  2  as well as the unconverted reactants Ru(H) (dppm) and Mo(CO)62  2  Heating the reaction  mixture at a higher temperature, or for a longer period of time, or performing both, or using a CO atmosphere did not increase the yield of the desired MoRu(CO)6(dppm) . 2  A relevant example of the envisioned Lewis Base—»Lewis acid interaction occurs in the preparation of some heterobimetallic complexes of Ru and Rh or Ir.  39  As illustrated in  Figure 4.19, Ru(H) (dppm) , the Lewis base, reacts with one half equivalent of [RhCl(cod)] , 2  2  2  the Lewis acid, to afford 25 as product, in which there is one bridging dppm and one chelating dppm as seen in the X-ray structure.  39  The analogous reaction with one half equivalent of  [Ir(Cl(cod)] yields 28. Further reaction of 25 with CO yields the A-frame complex 26 with a 2  bridging CO and two bridging dppm ligands. Reaction of Ru(H) (dppm) with one half2  93  2  References on page 100  Chapter 4 equivalent of [RhCl(CO) ] yields the A-frame complex 27, with bridging CO and bridging 2  2  H . 27 can also be prepared by reaction of 26 with H . 2  3 9  2  Ph P  -PPh,  2  slr(cod) Ph P | |^PPh  2  2  28  2  A V [IrCI(cod)]. 2  RuH (dppm) ' 2  V [RhCKCOy 2  Ph P  2 1  l [RhCI(cod)]  2  2  -PPh,  2  OC  Ph P-  Ru H' | Ph P.  -PPh,  2  -Cl  -CL  Rh  =Rh(cod)  Ru-  CO"  Ph P 2  PPh,  2  PPh,  25  27s CO Ph,P-  -PPh,  OC.  -CI ;RU  Rh  Ph P.  PPh,  2  26 Figure 4.19. Reactions of Ru(H) (dppm) with >/ [IrCl(cod)] , '/ [RhCl(cod)] , and V [RhCl(CO) ] . 2  2  2  2  2  2  2  2  2  94  References on page 100  Chapter  4.3.3  4  Reaction of MoRu(CO) (dppm) with H S 6  2  2  Though MoRu(CO)6(dppm) was not isolated or synthesized 2  in high yield, reactions  in situ  with various sulfur-containing compounds were undertaken. MoRu(CO)6(dppm) can react 2  with H S to yield as a final product the bridged-sulfide complex 31 and H , and 31 has been 2  2  characterized structurally and spectroscopically (see also Table 4.4). The mechanism for the 2  formation of MoRu(CO)3(u-S)(w-CO)(dppm)  2  is thought to proceed via the oxidative addition  of H S across the Ru-Mo bond as illustrated in Figure 4.20, while the  in situ  2  2  spectra recorded at r.t. in C6D , 84 h after the addition of H S to 6  2  ]  H and P{'H} 31  in  situ  formed  MoRu(CO)6(dppm) , provide evidence for intermediates such as 30a and 30b (Table 4.4). In 2  the 'll NMR, 2 hydride signals are observed in the 5 - 7 to - 1 2 range, while the sulfhydryl proton signals are seen more downfield, from 8 - 2 to 0 (Fig. 4.21): the higher field  PPh,  ,co R u — -CcOo + H,S  \  2 2 CO  PPh,  30a  30b  Ph,P-  -PPh,  OC Mo  f;Ru  OC  CO Ph P^ 2  O ^PPh  31 Figure 4.20. Proposed mechanism for the formation of MoRu(CO) (w-S)(«-CO)(dppm) . 3  2  2  hydride triplet (5 -10.92, JHP = 18.8) is assigned to the terminal hydride of 30b, while the signal observed at 8 -7.44 is assigned to the p.-H species of 30a.  The triplet for 30b is  considered due to 2-bond /-coupling to two equivalent P-atoms ( JHP 2  =  22.5) bonded to the  Ru, while the broadness of the triplet could result from coupling to the P-atoms attached to the Mo. For 30a, the hydride should exhibit 2-bond /-coupling to 2 inequivalent sets of 2 P95  References  on page  100  Chapter 4 atoms, but the observed pattern is best described as a pseudo triplet. Both the sulfhydryl resonances are quintets, with the signal for 30b centred at 8-1.04 and that for 30a at 8 -0.48, the latter being broader. The patterns presumably result from the SH-protons coupling to the P-atoms and to the hydride. The resonances for the inequivalent protons of the C H H A  B  methylene bridges result from coupling to each other and to the P-atoms: for 30a and 30b, multiplets are observed at 8 3.3 and 3.4, respectively. The intermediates 30a and 30b were detected at r.t.; further low temperature studies may better resolve signals and may detect other intermediates. As a function of time, 30a is formed initially, this then slowly converting to 30b; eventually 30b converts to 31 with liberation of H . In the 'H spectrum, 31 exhibits 2  multiplets at 8 2.68 and 5.36 assigned to the methylene bridge protons, while the P{'H} 31  spectrum reveals an AA'BB' centered around 8 16.3 and 25.9. Complementary IR studies to determine v(CO) values are required to determine more definitively the nature of the intermediates.  Table 4.4. 'H and P{'H} NMR data for the formation of 30a, 30b, and 31. 31  Complex 30a 30b 31  'H(S) -10.92 (brt), -1.04 (qn), 3.3 (m) -7.44 (br t), -0.48 (qn), 3.4 (m) 2.68 (m), 5.36(m)  'P{'H} (8) 40.1 35.7 16.3,25.9  J  Hydride region  I  30a 30b  -10  -ii  ppm  Sulfhydryl region  A J V U -0.4  -0.2  -0.6  -0.8  -1.0  -1.2  ppm  Figure 4.21. 'H NMR in the hydride and sulfhydryl region for the reaction between MoRu(CO) (dppm) with H S, at r.t. in C H . 6  2  2  6  6  96  References on page 100  Chapter 4  4.3.4  Reaction of MoRu(CO) (dppm) with EtSH 6  2  A mechanism similar to that shown in Fig. 4.20 is proposed for the reaction of MoRu(CO)6(d ppm) with EtSH, activation of the S-H bond proceeding via oxidative addition across the 2  Mo-Ru bond (Fig. 4.22).  In this system, the final product (33) is the bridged-thiolate,  terminal hydride species that has been characterized structurally and spectroscopically (see 2  also Table 4.5). 33 is the analogue of 30b in Figure 4.20, but there is no acidic hydrogen present in the thiolate to generate H by reaction with the terminal hydride. H and P{'H} ]  31  2  spectra were taken in C^Df, at r.t., 72 h after the addition of EtSH to MoRu(CO)6)(dppm) that 2  had been formed in situ. Intermediates believed to be 32a and 32b are observed en route to the formation of the final product 33.  SEt  32a  32b  co  Figure 4.22. CO)(dppm) .  Proposed mechanism for the formation of MoRu(H)(CO) (w-SEt)(«3  2  The NMR spectral data given in Table 4.5 correspond closely to those recorded by Khorasani-Motlagh. Based on more extensive ' H , P{'H}, and selectively P decoupled H 2  31  3 1  !  studies performed by Khorasani-Motlagh, tentative assignments of the observed signals have 2  been made. Selective decoupling experiments showed evidence that 33 contained a terminal hydride, while the structure of 33 was later confirmed by X-ray crystallography. The ' H 2  NMR spectrum of the hydride region is seen in Figure 4.23. The broad triplet at § -12.92 is  97  References on page 100  Chapter  4  assigned to intermediate 32a, that at 5 -8.85 is assigned to intermediate 32b and the triplet at 5 -11.18 to 33. The quartet and triplet signals within each species are assigned, respectively, to the C H - and C H - moieties of the ethyl group, while the multiplets arise from the CH 2  3  2  protons of the bridged dppm ligands. The P{'H} signals centred at the positions shown, 31  arise from AA'BB' patterns. With the loss of two carbonyls from 1, EtSH is considered to oxidatively add to the Ru to afford species 32a and 32b; "cycling" of the CO, hydride and thiolate ligands about the Ru and Mo centers eventually leads to the formation of 33. The ratios of 32a:32b:33 do change with time and further studies are needed to ascertain these more accurately, although 33 is clearly the last species to be generated. 33 32b  32a  -10  -11  -12  -13  Figure 4.23. H NMR spectrum in the hydride region for the reaction between MoRu(CO) (dppm) and EtSH, at r.t. in C D . !  6  2  6  6  Table 4.5. H and P{'H} NMR data for the formation of 32a, 32b, and 33. !  31  Complex  'H(8)  J1  32a  -12.92 (br t), 3.70 (m), 2.53 (q), 1.44 (t)  22.5, 40.2  32b  -8.85 (br t, V = 20.9 Hz), 3.04 (m), 2.53 (q), 1.44 (t) -11.18 (t, J = 20.9 Hz) 2.66 (m), 3.46(m), 1.85 (q), 0.98 (t)  26.8,38.7  P{'H} (5)  H H  33  2  m  21.8,39.5  In addition to work in the James group studying reactions of dipalladium-dppm complexes with H S and thiols (see Section l.l), " 40  43  2  some related heterobimetallic studies  with H S and RSH have been performed by Cowie and co-workers, notably on the reactivity 2  of RhRe(CO) (dppm) 4  44  2  and RhMn(CO) (dppm) .  In RhRe(CO) (dppm) , a dative bond  45  4  2  4  2  between the coordinatively saturated Re(-l) center and the unsaturated Rh(+1) center is formulated, and the complex reacts with 1 equiv. of H S to yield RhRe(CO) (u-S)(dppm) and 2  98  4  References  2  on page  100  Chapter 4 H quantitatively (Fig. 4.24). The mechanism is proposed to proceed via the coordination of 2  H S at the Rh center, followed by intermediates containing a terminal sulfhydryl and a 2  "terminal to bridging" hydride, with the eventual elimination of H and formation of the 2  bridged sulfide product (Fig. 4.24). The suggestion of an H S intermediate was not supported 2  spectroscopically.  The reaction with thiols RSH (R = Et, Ph) is thought to proceed in a  similar manner with an additional step of CO elimination, to afford RhRe(CO)3(w-H)(uSR)(dppm) (R=Et, Ph) (Fig. 4.24). 2  ~PPh I Rh-  OC  | p  h  2  0 C  o  p  RSH »-  P  h  2  „ _ ,, _  2  0 ^ ~ ~ "  P  P  P  h  P h  2  P ^  i l ( l  2  —  | \  £  H  P  \ h  , ° °  -  l  p 2  0 C  ^ ~ P P h  Ph P-"  U *.L -co  Rh R S h^ |P \ p  2  |  H  2  2  COH  ' / , I .>^/,„ | „oCO R = Et, Ph: ^ R h ^ R e ' R S ^ | | Ph P.  :  Ph P-.  h 2  | --Re—CO  I  OC„, | OC„, | , ^ C O *''Rh '^Re' I ^ C O  Ph  - P P h' 2,  '>,. | ' ,. RS— Rh0 C  J>Ph,  P  I C„„ I CO -H ^Rh ^Re'' HS^I ^ M ^ I N r n i 0  2  pp  2  O C  oc^ I  |  H  ^PPh  \  Ph P-"'^  2  OC,,,| OC„ | RS—Rh-~Re—CO  |  c  ^ - P P h  2  '«, I --—Re—CO  OC,,, R = H:  Ph P  2  2  -PPh  2  R«  1  L  O C ^ ^- P P h^ C O 2  O  ,  OC  2  1 >>  co  Rh'  v  CO Ph P^ 2  R  -PPh  2  Figure 4.24. Proposed mechanism for the formation of RhRe(CO)4(w-S)(dppm) and RhRe(CO) 0/-H)Cu-SR)(dppm) . 2  3  2  In the RhMn(CO)4(dppm) case, similar intermediates with corresponding cycling of 2  the sulfhydryl and hydride ligands from terminal to bridging were invoked en route to the final [i-SR product. Analogies to the MoRu(CO)6(dppm) systems are readily apparent: initial 2  coordination of RSH (R = H, Et, Ph) to Ru or Mo and oxidative addition of RSH across the Ru-Mo bond (with loss of two CO ligands), movement of CO from terminal to bridging, and eventual elimination of H (in the case of H S). Further studies must be performed to more 2  2  exactly ascertain the nature of the intermediates, but isolation and/or generation of in situ MoRu(CO)e(dppm) in good yield must first be accomplished. 2  99  References on page 100  Chapter 4 4.4 References  (1)  Laarab, H. B.; Chaudret, B.; Dahan, F.; Devillers, J.; Poilblanc, R.; Sabo-Etienne, S. New. J. Chem. 1990,14, 312.  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(36)  Jessop, P.; Lee, C ; Rostar, G.; James, B. R.; Lock, C. J. L.; Faggiani, R. Inorg. Chem.  1992, 22, 4001. (37)  Delavaux, B.; Chaudret, B.; Taylor, N. J.; Arabi, S.; Poilblanc, R. J. Chem. Soc, Chem. Commun. 1985, 805.  (38)  Venanzi, L. M. Coord. Chem. Rev. 1982, 43, 251.  (39)  Delavaux, B.; Chaudret, B.; Devillers, J.; Dahan, F.; Commenges, G.; Poilblanc, R. J. Am. Chem. Soc. 1986, 108, 3703.  (40)  Barnabas, A. F.; Sallin, D.; James, B. R. Can. J. Chem. 1989, 67, 2009.  (41)  Besenyei, G.; Lee, C.-L.; Gulinski, J.; Rettig, S. J.; James, B. R.; Nelson, D. A.; Lilga, M. A. Inorg. Chem. 1987, 26, 3622.  (42)  James, B. R. Pure Appl. Chem. 1997, 69, 2213.  (43)  Wong, T. Y.; Barnabas, A. F.; Sallin, D.; James, B. R. Inorg. Chem. 1995, 34, 2278.  101  References on page 100  Chapter 4 McDonald, R.; Cowie, M . Inorg. Chem. 1990, 29, 1564. Wang, L.-S.; M c D o n a l d , R.; Cowie, M . Inorg. Chem. 1994, 33, 3735.  102  References on page 100  Chapter 5  Chapter 5  CONCLUSIONS, AND RECOMMENDATIONS FOR FUTURE WORK  Dipalladium complexes and mixed-metal PdPt complexes of the type [MM'Cl (u2  SR)(dmapm)] X~ (M = Pd, M ' = Pd or Pt; R = Me, Et, Pr, "Bu, Ph, and Bz; X = CI, OTf) +  n  have been synthesized. These cj's-diphosphine type complexes have different structures and show different reactivity towards H S and RSH thiols than their /raws-diphosphine type 2  counterparts (Sect. 1.3.3). The behaviours of Pd Cl (dmapm) (Sect. 3.1), [Pd Cl (u.-S Pr)(dmapm)] [OTf]" (Sect. n  2  2  2  +  2  3.4), and [PdPtCl (u.-S Pr)(dmapm)] [OTf] (Sect. 3.6) were studied by variable temperature n  +  _  2  NMR and revealed that the N-anilinyl arms of dmapm are fluxional in solution; fluxional processes are identified involving NCH groups that are (i) coordinated to Pd, (ii) coordinated 3  to Pt, (iii) non-coordinated at the Pd end, and (iv) non-coordinated at the Pt end. Mechanistic studies at low temperature of the reaction of Pd Cl (dmapm) with PhSH (Sect. 3.3) allowed 2  2  for the observation of a hydrido-thiolate intermediate and another intermediate, possibly an RSH adduct, en route to the bridged-thiolate product.  Though the reaction of  PdPtCl (dmapm) with EtSH at low temperature showed evidence for the formation of H , 2  2  further studies are required to ascertain the intermediates and the fate of the hydride. With the intention of synthesizing a dipalladium complex without coordinated halide ligands, the conproportionation of Pd(hfac) and dmapm with 0.5 equiv. of Pd (dba)3-CHC1 2  was attempted (Sect. 3.8).  2  3  The synthesis of dipalladium-dmapm complexes from other  precursors, such as PdClMe(cod) (Sect. 2.5.4), would be useful; the formation of new organometallic compounds of the type Pd R (dmapm) by reaction of Pd Cl (dmapm) with 2  2  2  2  Grignard reagents or RLi would open doors to new chemistry not previously explored and allow for comparison with trans-typo, side-by-side complexes (e.g. Pd R (dppm) (Sect. 2  2  2  1.3.3)). As concluded in previous studies by the James group, Pd Cl (dppm) does not react 2  2  2  with thiols. However, in this thesis work, preliminary studies showed that, in the presence of acid, a reaction does indeed occur, though the identity of the intermediates and products is still not known. Further studies are required to elucidate the structures of these products.  103  Chapter 5 The reactivity of Pd Cl2(dmapm) with small molecules has not been fully explored. 2  The reaction of SO2 with Pd Cl (dmapm) was initiated (Sect. 3.10), but further work at low 2  2  temperature must be done to characterize fully the intermediates and final product(s) of this reaction. The reaction of RuMo(CO)6(dppm)2 with H2S and RSH thiols leads to the formation of bridged-sulfido and semi-bridging-thiolato (R = Et) species (Sect. 4.3). The mechanisms of these reactions are still unclear, though the formation of H2 (in the H S system) was 2  observed, and the loss of two CO (in the EtSH system) is implied. Further low temperature studies are required to ascertain the structures of intermediates en route to the products.  104  Appendix A1 Appendix A l  E X P E R I M E N T A L D E T A I L S F O R [Pd Cl (u-SEt)(dmapm)] Cr +  2  2  A. Crystal Data Empirical Formula Formula Weight Crystal Colour, Habit Crystal Dimensions Crystal System Lattice Type Lattice Parameters  C H5oN P SCl4Pd 36  4  2  2  987.44  Yellow, platelet 0.50 x 0.30 x 0.08  mm  Monoclinic Primitive a=  13.350(1) A  b=  17.070(1) A  c=  18.091(2)  /?=  101.174(2)°  V =  4044.6(5)  Space Group Z Value  4  Dcalc  1.621 g/cm  A  P2i/n(#14)  Fooo M(MoKa)  3  2000.00 13.16  cm"  1  B. Intensity Measurements Diffractometer Radiation  Rigaku. A D S C C C D MoKoc (X = 0.71069 A) Graphite monochromated 94 mm x 94 mm 460 exposures @ 35.0 seconds 0.0-190.0° -17.0-23.0° 38.12 mm -5.56° 55.7° Total: 36479 Unique: 9368 (R,„, = 0.045) Lorentz-polarization Absorption/ scaling/decay  Detector Aperture Data Images <p oscillation Range (x = -90) co oscillation Range (% = -90) Detector Position Detector Swing Angle 2 0 i a x n  No. of Reflections Measured Corrections  C. Structure Solution and Refinement Structure Solution Refinement Function Minimized Least Squares Weights p-factor Anomolous Dispersion No. Observations (I>0.00o(I)) No. Variables Reflection/Parameter Ratio Residuals (on F , all data): R; R Goodness of Fit Indicator  Direct Methods (SIR97) Full-matrix least squares Eco(Fo - Fc ) 2  2  2  co = \/(cr(Fo-2) 0.0000 A l l non-hydrogen atoms 9055 451 20.49 0.052 ; 0.085 0.95  2  w  105  [Pd Cl (ju-SEt)(dmapm)] Cr +  2  2  Appendix A1 Max Shift/Error in Final Cycle No. Observations (I>3a(I)) Residuals (on F, I>3CT(I)): R; R Maximum peak in Final Diff. Map Minimum peak in Final Diff. Map  0.00 6505 0.034 ; 0.080 1.08 e 7 A -0.72 e7 A  W  3  Table A l . l . Atomic Coordinates and B /Beq isn  atom Pd(l) Pd(2) Cl(l) Cl(2) *S(1A) P(l) P(2) N(l) N(2) N(3) N(4) C(l) C(2) C(3) C(4) C(5) C(6) C(7) C(8) C(9) C(10) C(ll) C(12) C(13) C(14) C(15) C(16) C(17) C(18) C(19) C(20) C(21) C(22) C(23) C(24) C(25) C(26) C(27) C(28) C(29) C(30) C(31) C(32) C(33) *C(34A) *C(35A) *C(35B)  X 0.18746(2) 0.40544(2) 0.18514(9) 0.9009(10) 0.3118(2) 0.18795(6) 0.42069(6) 0.0775(2) -0.0025(2) 0.5196(2) 0.6021(3) 0.1195(3) -0.0160(3) 0.0490(3) -0.0236(3) -0.0493(3) -0.0023(3) 00703(3) 0.0950(2) 0.1569(3) 0.0622(3) 0.0333(3) 0.1016(3) 0.1964(3) 0.2210(3) -0.1010(3) -0.0167(4) 0.5202(3) 0.5570(3) 0.6394(4) 0.6803(4) 0.6425(3) 0.5612(3) 0.4778(3) 0.6050(3) 0.3088(2) 0.4543(3) 0.5404(3) 0.5648(4) 0.5032(4) 0.4167(3) 0.3920(3) 0.7031(4) 0.6099(3) 0.2430(5) 0.3076(12) 0.2885(18)  y 0.05980(1) 0.15989(1) -0.07883(5) 0.13582(6) 0.04912(14) 0.18839(4) 0.18201(5) 0.06629(16) 0.17580(18) 0.25026(16) 0.08364(19) 0.0253(2) 0.0238(2) 0.14775(19) 0.1596(2) 0.2359(2) 0.2994(2) 0.2874(2) 0.21017(19) 0.24768(18) 0.2366(2) 0.2833(2) 0.3390(2) 0.3486(2) 0.30426(19) 0.2059(3) 0.1135(3) 0.25448(19) 0.2820(2) 0.3329(3) 0.3565(3) 0.3323(2) 0.2796(2) 0.3174(2) 0.2137(3) 0.22788(18) 0.10111(19) 0.0581(2) -0.0069(3) -0.0298(18) 0.0140(19) 0.0785(2) 0.1107(3) 0.0222(3) 0.0084(4) -0.0534(9) -0.0717(13)  106  z 0.69830(1) 0.60829(1) 0.69821(7) 0.47791(5) 0.62933(17) 0.70207(5) 0.72920(5) 0.77140(16) 0.59247(17) 0.61168(18) 0.73759(19) 0.8440(2) 0.7320(2) 0.78788(19) 0.8319(2) 0.8472(2) 0.8189(2) 0.7753(2) 0.75962(18) 0.61822(19) 0.57242(19) 0.5086(2) 0.4896(2) 0.5341(2) 0.5986(2) 0.6056(3) 0.5359(3) 0.7487(2) 0.8212(2) 0.8336(3) 0.7738(3) 0.7013(3) 0.6883(2) 0.5619(2) 0.5797(3) 0.75.95(18) 0.79356(19) 0.7891(2) 0.8354(3) 0.8844(3) 0.8902(3) 0.8450(2) 0.7776(3) 0.6820(3) 0.5406(3) 0.5126(8) 0.5377(12)  u (A ) 0.0160(1) 0.0172(1) 0.0445(4) 0.0488(4) 0.0172(6) 0.0125(2) 0.0143(2) 0.0196(8) 0.0262(9) 0.0246(9) 0.0332(11) 0.0335(14) 0.0340(14) 0.0188(10) 0.0274(11) 0.0363(12) 0.0364(16) 0.0267(11) 0.0176(10) 0.0173(9) 0.0218(10) 0.0345(12) 0.0343(14) 0.0300(11) 0.0226(11) 0.0422(16) 0.0443(16) 0.0217(10) 0.0331(12) 0.0477(17) 0.0582(19) 0.0440(14) 0.0257(11) 0.0323(11) 0.0394(14) 0.0165(9) 0.0204(10) 0.0264(11) 0.0480(17) 0.0521(16) 0.0408(16) 0.0267(11) 0.065(2) 0.0609(19) 0.030(2) 0.055(5) 0.059(7) 2  e q  [Pd Cl (p.-SEt)(dmapm)] Cr +  2  2  Appendix A1 *S(1B) *C(34B)  0.2783(3) 0.3548(9)  0.0718(2) -0.0189(5)  0.5990(7) 0.5951(7)  0.0172(9) 0.044(4) U (A ) 0.0500 0.0500 0.0510 0.0500 0.0330 0.0440 0.0440 0.0320 0.0410 0.0510 0.0510 0.0270 0.0640 0.0640 0.0640 0.0670 0.0670 0.0670 0.0390 0.0570 0.0700 0.0530 0.0490 0.0490 0.0490 0.0590 0.0590 0.0590 0.0200 0.0200 0.0580 0.0620 0.0490 0.0320 0.0970 0.0970 0.0970 0.0910 0.0910 0.0910 0.0410 0.0360 0.0890 0.0890 0.0360 0.0360 0.0820 0.0820 0.0820 0.0530 0.0530 0.0890 2  H(1B) H(1A) H(2A) H(1C) H(4) H(5) H(6) H(7) H(22) H(2B) H(2C) H(14) H(15A) H(15B) H(15C) H(16A) H(16B) H(16C) H(18) H(19) H(20) H(21) H(23A) H(23B) H(23C) H(24A) H(24B) H(24C) H(25A) H(25B) H(28) H(29) H(30) H(31) H(32A) H(32B) H(32C) H(33A) H(33B) H(33C) H(12) H(13) H(35D) H(35E) H(34A) H(34B) H(35A) H(35B) H(35C) H(34C) H(34D) H(35F)  0.14430 0.17600 -0.06710 0.06560 -0.05530 -0.09920 -0.02060 0.10280 0.03250 0.00210 -0.04400 0.28900 -0.13840 -0.08880 -0.14130 -0.05620 -0.05350 0.05000 0.52600 0.66710 0.73720 0.67140 0.42890 0.44340 0.53380 0.65980 0.57890 0.63160 0.31110 0.31140 0.62480 0.51960 0.37520 0.33280 0.69430 0.74160 0.74070 0.64600 0.34760 0.54130 0.08210 0.24280 0.32430 0.27470 0.17790 0.22680 0.26970 0.32400 0.37090 0.41980 0.37030 0.22390  -0.2670 0.05600 0.02330 0.01990 0.11640 0.24510 0.35130 0.33040 0.27740 -0.03020 0.05040 0.31200 0.23020 0.24490 0.16250 0.13360 0.06970 0.09530 0.26610 0.35100 0.39100 0.35120 0.34660 0.29730 0.35120 0.25210 0.19730 0.16810 0.28480 0.22080 -0.3600 -0.07550 -0.00080 0.10810 0.15170 0.13190 0.06660 -0.02310 0.04250 0.00640 0.37020 0.38560 -0.12120 -0.04560 -0.01510 0.05060 -0.07590 -0.09480 -0.02960 -0.00650 -0.04450 -0.08220  i s o  0.83330 0.87260 0.76420 0.87350 0.85130 0.87710 0.82990 0.75640 0.47790 0.72160 0.68450 0.63010 0.55930 0.64600 0.62010 0.48840 0.55350 0.52800 0.86180 0.88300 0.78260 0.66060 0.58520 0.51270 0.55520 6.58070 .0.52760 0.61000 0.74400 0.80860 0.83330 0.91430 0.92500 0.84820 0.81371 0.74110 0.80450 0.70760 0.64470 0.65660 0.44570 0.52060 0.53370 0.48850 0.54820 0.50260 0.46550 0.55050 0.50350 0.57910 0.64510 0.55390  fPd Cl (ju-SEt)(dmapm)J Cr +  2  2  Appendix A1  Table A1.2. Bond Lengths (A) Atom Pd(l) Pd(l) Pd(l) Pd(l) Pd(l) Pd(2) Pd(2) Pd(2) Pd(2) Pd(2) S(1A) S(1B) P(l) P(l) P(l) P(2) P(2) P(2) N(l) N(l) N(l) N(2) N(2) N(2) N(3) N(3) N(3) N(4) C(l) C(l) C(l) C(2) C(2) C(2) C(4) C(5) C(6) C(7) C(ll) C(12) C(13) C(14) C(15) C(15) C(15) C(16) C(16) C(16) C(18)  atom Cl(l) S(1A) P(l) N(l) S(1B) Cl(2) S(1A) P(2) N(3) S(1B) C(34A) C(34B) C(8) C(9) C(25) C(17) C(25) C(26) C(2) C(3) C(l) C(15) C(16) C(10) C(23) C(24) C(22) C(32) H(1A) H(1B) H(1C) H(2A) H(2B) H(2C) H(4) H(5) H(6) H(7) H(ll) H(12) H(13) H(14) H(15A) H(15B) H(15C) H(16A) H(16B) H(16C) H(18)  distance 2.3665(9) 2.269(3) 2.1961(7) 2.161(3) 2.363(4) 2.3638(10) 2.338(3) 2.1900(9) 2.161(3) 2.249(4) 1.825(6) 1.864(11) 1.806(3) 1.804(3) 1.831(3) 1.99(4) 1.8183() 1.806(3) 1.499(5) 1.487(4) 1.498(5) 1.473(5) 1.463(6) 1.441(5) 1.497(5) 1.510(5) 1.477(5) 1.476(7) 0.9798 0.9797 0.9798 0.9792 0.9803 0.9797 0.9506 0.9491 0.9503 0.9494 0.9493 0.9498 0.9492 0.9506 0.9802 0.9787 0.9807 0.9791 0.9810 0.9794 0.9499  atom N(4) N(4) C(3) C(3) C(4) C(5) C(6) C(7) C(8) C(9) C(10) C(ll) C(12) C(13) C(17) C(17) C(18) C(19) C(20) C(21) C(26) C(26) C(27) C(28) C(29) C(30) C(34A) C(34B) C(19) C(20) C(21) C(23) C(23) C(23) C(24) C(24) C(24) C(25) C(25) C(28) C(29) C(30) C(31) C(32) C(32) C(32) C(33) C(33) C(33)  108  atom C(33) C(27) C(8) C(4) C(5) C(6) C(7) C(8) C(10) C(14) C(ll) C(12) C(13) C(14) C(22) C(18) C(19) C(20) C(21) C(22) C(31) C(27) C(28) C(29) C(30) C(31) C(35A) C(35B) H(19) H(20) H(21) H(23A) H(23B) H(23C) H(24A) H(24B) H(24C) H(25A) H(25B) H(28) H(29) H(30) H(31) H(32A) H(32B) H(32C) H(33A) H(33B) H(33C)  distance 1.471(6) 1.426(5) 1.377(5) 1.383(5) 1.388(5) 1.398(5) 1.378(6) 1.401(5) 1.384(5) 1.409(5) 1.395(5) 1.405(5) 1.372(6) 1.380(5) 1.382(5) 1.390(5) 1.386(7) 1.364(8) 1.374(7) 1.394(5) 1.417(5) 1.379(5) 1.390(6) 1.377(8) 1.397(7) 1.373(5) 1.511(17) 1.52(2) 0.9502 0.9499 0.9514 0.9793 0.9811 0.996 0.9798 0.9803 0.9783 0.9897 0.9900 0.9495 0.9504 0.9499 0.9492 0.9797 0.9812 0.9802 0.9789 0.9800 0.9796  fPd Cl (ju-SEt)(dmapm)J Cr +  2  2  Appendix A1  Table A1.3. Bond angles (°) atom Cl(l) Cl(l) Cl(l) Cl(l) S(1A) S(1A) P(l) S(1B) S(1B) Cl(2) Cl(2) Cl(2) Cl(2) S(1A) S(1A) P(2) S(1B) S(1B) Pd(l) Pd(l) Pd(2) Pd(l) Pd(2) Pd(l) Pd(l) Pd(l) C(9) Pd(l) C(4) C(3) C(4) C(5) C(6) P(l) P(l) C(3) P(l) C(10) P(l) C(9) N(2) N(2) C(10) C(ll) C(12) C(9) C(18) P(2) P(2) C(17) C(18) C(19) C(20)  atom Pd(l) Pd(l) Pd(l) Pd(l) Pd(l) Pd(l) Pd(l) Pd(l) Pd(l) Pd(2) Pd(2) Pd(2) Pd(2) Pd(2) Pd(2) Pd(2) Pd(2) Pd(2) S(1A) S(1A) S(1A) S(1B) • S(1B) S(1B) P(l) P(l) P(l) P(l) C(3) C(4) C(5) C(6) C(7) C(8) C(8) C(8) C(9) C(9) C(9) C(10) C(10) C(10) C(ll) C(12) C(13) C(14) C(17) C(17) C(17) C(18) C(19) C(20) C(21)  atom S(1A) P(l) N(l) S(1B) P(l) N(l) N(l) P(l) N(l) S(1A) P(2) N(3) S(1B) P(2) N(3) N(3) P(2) N(3) Pd(2) C(34A) C(34A) C(34B) C(34B) Pd(2) C(8) C(9) C(25) C(25) C(8) C(5) C(6) C(7) C(8) C(3) C(7) C(7) C(10) C(14) C(14) C(ll) C(9) Cll) C(12) C(13) C(14) C(13) C(22) C(18) C(22) C(19) C(20) C(21) C(22)  distance 86.00(7) 178.06(4) 92.37(8) 95.44(9) 95.70(7) 175.50(10) 85.87(8) 86.45(9) 166.04(12) 94.37(8) 179.64(4) 94.40(9) 83.74(10) 85.75(8) 165.70(11) 85.42(9) 96.47(9) 175.66(12) 119.72(11) 102.5(2) 111.0(2) 108.8(4) 95.5(4) 119.48(15) 103.03(11) 122.40(11) 105.11(16) 112.39(10) 120.9(3) 118.7(3) 120.6(4) 120.6(3) 118.3(3) 117.4(3) 121.7(3) 120.9(3) 117.5(3) 119.6(3) 122.9(3) 119.5(3) 118.1(3) 122.5(3) 120.0(4) 120.4(3) 119.7(3) 120.7(4) 121.3(3) 122.0(3) 116.7(3) 119.3(4) 119.0(5) 122.6(5) 119.0(4)  atom C(8) C(8) Pd(2) Pd(2) Pd(2) C(25) C(17) C(17) Pd(l) C(l) C(2) Pd(l) C(l) Pd(l) C(10) C(10) C(15) Pd(2) C(22) Pd(2) C(22) Pd(2) C(23) C(32) C(27) C(27) N(l) N(l) P(l) •P(2) P(2) C(27) N(4) N(4) C(26) C(27) C(28) C(29) C(26) S(1A) S(1B) N(l) N(l) N(l) H(1A) H(1A) H(1B) N(l) N(l) N(l) H(2A) H(2A) H(2B)  109  atom P(l) P(l) P(2) P(2) P(2) P(2) P(2) P(2) N(l) N(l) N(l) N(l) N(l) N(l) N(2) N(2) N(2) N(3) N(3) N(3) N(3) N(3) N(3) N(4) N(4) N(4) C(3) C(3) C(25) C(26) C(26) C(26) C(27) C(27) C(27) C(28) C(29) C(30) C(31) C(34A) C(34B) C(l) C(l) C(l) C(l) C(l) C(l) C(2) C(2) C(2) C(2) C(2) C(2)  atom C(9) C(25) C(17) C(25) C(26) C(26) C(26) C(25) C(3) C(2) C(3) C(l) C(3) C(2) C(15) C(16) C(16) C(23) C(24) C(24) C(23) C(22) C(24) C(33) C(33) C(32) C(4) C(8) P(2) C(27) C(31) C(31) C(26) C(28) C(28) C(29) C(30) C(31) C(30) C(35A) C(35B) H(1A) H(1B) H(1C) H(1B) H(1C) H(1C) H(2A) H(2B) H(2C) H(2B) H(2C) H(2C)  distance 107.32 105.33 13.68 113.49 118.39 106.49 108.51 105.44 113.7 109.1 109.0 109.2 109.1 106.6 112.8 110.5 111.6 110.5 109.0 106.0 109.5 113.8 109.9 112.3 110.8 111.3 119.2 120.0 113.56 118.4 121.9 119.7 118.0 122.7 119.3 121.0 120.1 119.4 120.4 109.8 105.5 109.41 109.47 109.39 109.50 109.52 109.54 109.47 109.43 109.50 109.39 109.54 109.50  [Pd Cl (n-SEt)(dmapm)] Cr +  2  2  Appendix Al C(17) N(3) N(3) C(6) C(5) C(7) C(6) C(8) C(10) C(12) C(ll) C(13) C(12) C(14) C(9) C(13) N(2) N(2) N(2) H(15A) H(15A) H(15B) N(2) N(2) N(2) H(16A) H(16A) H(16B) C(17) C(19) C(18) C(26) C(30) N(4) N(4) N(4) H(32A) H(32A)  C(22) C(22) C(22) C(5) C(6) C(6) C(7) C(7) C(ll) C(ll) C(12) C(12) C(13) C(13) C(14) C(14) C(15) C(15) C(15) C(15) C(15) C(15) C(16) C(16) C(16) C(16) C(16) C(16) C(18) C(18) C(19) C(31) C(31) C(32) C(32) C(32) C(32) C(32)  C(21) C(17) C(21) H(5) H(6) H(6) H(7) H(7) H(H) H(H) H(12) H(12) H(13) H(13) H(14) H(14) H(15A) H(15B) H(15C) H(15B) H(15C) H(15C) H(16A) H(16B) H(16C) H(16B) H(16C) H(16C) H(18) H(18) H(19) H(31) H(31) H(32A) H(32B) H(32C) H(32B) H(32C)  118.8(4) 120.2(3) 121.1(4) 119.65 119.62 119.75 120.82 120.83 120.00 119.96 0119.88 119.7. 120.16 120.13 119.70 119.60 109.42 109.45 109.44 109.50 109.46 109.55 109.52 109.40 109.54 109.48 109.47 109.41 120.38 120.35 102.55 119.79 119.82 109.54 109.47 109.54 109.35 109.49  C(3) C(5) C(4) C(20) C(19) C(21) C(20) C(22) N(3) N(3) N(3) H(23A) H(23A) H(23B) N(3) N(3) N(3) H(24A) H(24A) H(24B) P(l) P(l) P(2) P(2) H(25A) C(27) C(29) C(28) C(30) C(29) C(31) H(32B) N(4) N(4) N(4) H(33A) H(33A) H(33B)  110  C(4) C(4) C(5) C(19) C(20) C(20) C(21) C(21) C(23) C(23) C(23) C(23) C(23) C(23) C(24) C(24) C(24) C(24) C(24) C(24) C(25) C(25) C(25) C(25) C(25) C(28) C(28) C(29) C(29) C(30) C(30) C(32) C(33) C(32) C(32) C(32) C(32) C(32)  H(4) H(4) H(5) H(19) H(20) H(20) H(21) H(21) H(23A) H(23B) H(23C) H(23B) H(23C) H(23C) H(24A) H(24B) H(24C) H(24B) H(24C) H(24C) H(25A) H(25B) H(25A) H(25B) H(25B) H(28) H(29) H(30) H(30) H(32C) H(33A) H(33B) H(33C) H(33B) H(33C) H(33B) H(33C) H(33B)  120.72 120.61 119.79 120.49 118.70 118.69 120.51 120.49 109.43 109.42 109.44 109.55 109.51 109.48 109.45 109.41 109.46 109.50 109.47 109.53 108.88 108.90 108.79 108.78 107..77 119.63 119.39 119.91 119.95 120.29 120.29 120.43 109.48 109.43 109.48 109.49 109.53 109.42  fPd Cl (ju-SEt)(dmapm)J Cr +  2  2  Appendix A2 Appendix A2  E X P E R I M E N T A L D E T A I L S F O R [Pd Cl (u-S Pr)(dmapm)] Cr n  2  +  2  A. Crystal Data Empirical Formula Formula Weight Crystal Colour, Habit Crystal Dimensions Crystal System Lattice Type Lattice Parameters  CasHs^PzSCLPdzO 968.99 yellow, needle 0.30 x 0.15 x 0.10 mm monoclinic Primitive a = 9.3678(3) A b = 17.2299(5) A c = 24.7803(9) A P = 91.755(2) A P2,/n(#14) 4 1.610 g/cm 1968.00 12.67 cm"' 3  Space Group Z Value  3  Fooo MMoKa)  B. Intensity Measurements Diffractometer Radiation Detector Aperture Data Images (p oscillation Range {% = -90) co oscillation Range (x = -90) Detector Position Detector Swing Angle  Rigaku/ADSC C C D MoKafA.= 0.71069 A) 94 mm x 94 mm 460 exposures @ 35.0 seconds 0.0-190.0° -17.0-23.0 38.48 mm -5.59° 55.8° Total: 36546 Unique: 9192 (R,„, = 0.048) Lorentz-polarisation Absorption/scaling/decay (corr. factors: 0.8091 - 1.0000)  No. of Reflections Measured Corrections  C. Structure Solution and Refinement Structure Solution Refinement Function Minimized Least Squares Weights p-factor Anomolous Dispersion No. Observations (I>0.00a(I)) No. Variables Reflection/Parameter Ratio Residuals (on F , all data): R; R Goodness of Fit Indicator Max Shift/Error in Final Cycle  Direct Methods (SIR97) Full-matrix least-squares Sco(Fo -Fc ) co= \l(tr(Fo-2) 0.0000 A l l non-hydrogen atoms 8920 477 18.70 0.046 ; 0.070 0.94 0.00 2  2  w  111  2  2  [PdjChhi-S'PrXdmapmtfCr  Appendix A2 No. Observations (I>3c(I)) Residuals (on F, I>3o(I)): R; R Maximum peak in Final Diff. Map Minimum peak in Final Diff. Map  6866 0.030 ; 0.065 3 0.95 e7 A -0.67 e7 A  w  Table A2.1. Atomic Coordinates and B /Beq iso  atom Pd(l) Pd(2) Cl(l) Cl(2) Cl(3) S(l) P(l) P(2) 0(1) N(l) N(2) N(3) N(4) C(l) C(2) C(3) C(4) C(5) C(6) C(7) C(8) C(9) C(10) C(H) C(12) C(13) C(14) C(15) C(16) C(17) C(18) C(19) C(20) C(21) C(22) C(23) C(24) C(25) C(26) C(27) C(28) C(29) C(30) C(31) C(32) C(33) C(34) C(35)  X 0.9098(1) 0.8855(1) 1.1394(1) 0.8892(1) 1.1464(1) 0.9327(2) 0.7008(1) 0.8693(1) 0.6653(3) 0.8378(3) 0.6225(3) 0.8286(3) 1.1509(3) 0.6107(3) 0.6884(3) 0.6228(3) 0.4840(3) 0.4065(3) 0.4702(3) 0.9332(3) 0.8517(4) 0.5932(3) 0.5766(3) 0.5162(4) 0.4803(4) 0.4828(4) 0.5452(3) 0.5030(4) 0.7081(4) 0.7157(3) 0.8247(3) 0.8114(4) 0.7806(4) 0.7632(4) 0.7762(4) 0.8052(3) 0.6890(4) 0.9422(4) 1.0168(3) 1.1462(3) 1.2607(4) 1.2507(4) 1.1250(3) 1.0082(3) 1.2522(4) 1.1823(4) 1.1144(4) 1.1216(4)  y 0.2076(1) 0.0978(1) 0.2047(1) -0.0405(1) 0.5451(1) 0.0948(1) 0.2207(1) 0.2251(1) 0.0209(1) 0.2986(1) 0.1172(1) 0.0999(1) 0.2130(2) 0.2919(2) 0.3232(2) 0.3776(2) 0.3990(2) 0.3683(2) 0.3147(2) 0.3681(2) 0.2664(2) 0.1344(2) 0.0870(2) 0.0138(2) -0.0112(2) 0.0356(2) 0.1088(2) 0.1472(2) 0.0616(2) 0.2629(2) 0.2435(2) 0.1798(2) 0.1896(2) 0.2641(2) 0.3278(2) 0.3178(2) 0.0577(2) 0.0578(2) 0.2883(2) 0.2762(2) 0.3243(2) 0.3830(2) 0.3952(2) 0.3482(2) 0.1532(2) 0.2394(2) 0.0571(2) 0.0110(2)  112  z 0.1009(1) 0.2513(1) 0.0748(1) 0.2488(1) 0.0844(1) 0.1602(1) 0.1473(1) 0.2551(1) 0.4789(1) 0.0566(1) 0.0581(1) 0.3348(1) 0.3076(1) 0.1056(1) 0.0639(1) 0.0292(1) 0.0368(1) 0.0785(1) 0.1133(1) 0.0619(1) 0.0007(1) 0.1540(1) 0.1087(1) 0.1140(2) 0.1637(2) 0.2083(2) 0.2034(1) 0.0250(2) 0.0277(2) 0.2152(1) 0.3241(1) 0.3574(1) 0.4115(1) 0.4315(1) 0.3983(1) 0.3445(1) 0.3399(1) 0.3663(1) 0.2403(1) 0.2692(1) 0.2601(1) 0.2218(1) 0.1926(1) 0.2021(1) 0.2912(2) 0.3628(1) 0.1547(2) 0.1018(2)  u 12(1) 4(1) 34(1) 24(1) 29(1) 13(1) 12(1) 14(1) 34(1) 16(1) 22(1) 21(1) 23(1) 14(1) 15(1) 22(1) 24(1) 24(1) 20(1) 24(1) 26(1) 17(1) 20(1) 32(1) 37(1) 31(1) 26(1) 32(1) 26(1) 15(1) 18(1) 22(1) 31(1) 33(1) 28(1) 24(1) 34(1) 38(1) 16(1) 19(1) 28(1) 28(1) 22(1) 19(1) 41(1) 38(1) 21(1) 32(1)  occ  e q  0.841(5)  0.841(5) 0.841(5)  [Pd Cl (M-S Pr)(dmapm)J Cr n  2  2  +  Appendix A2 C(36) S(1B) C(34B) C(35B)  1.0555(6) 0.9974(11) 0.7640(3) 1.1110(3)  -0.0677(3) 0.1171(10) 0.0291(15) -0.0089(15'  0.1038(2) 0.1730(3) 0.1331(10) 0.1430(13)  68(2) 22(2) 49(7) 82(11)  0.159(5) 0.159(5) 0.159(5)  Table A2.2. Bond Lengths (A) atom Pd(l) Pd(l) Pd(2) Pd(2) S(l) P(l) P(2) P(2) N(l) N(2) N(2) N(3) N(4) N(4) C(l) C(3) C(5) C(9) C(ll) C(13) C(18) C(20) C(22) C(26) C(28) C(30) C(35) C(34B)  atom N(l) S(l) N(3) S(l) C(34) C(9) C(18) C(17) C(7) C(10) C(16) C(19) C(27) C(32) C(6) C(4) C(6) C(10) C(12) C(14) C(23) C(21) C(23) C(27) C(29) C(31) C(36) C(35B)  distance 2.161(2) 2.3030(10) 2.154(3) 2.3150(10) 1.830(4) 1.807(3) 1.800(3) 1.840(3) 1.497(4) 1.435(4) 1.472(4) 1.497(4) 1.447(4) 1.466(4) 1.393(4) 1.370(4) 1.385(4) 1.394(4) 1.384(5) 1.397(4) 1.391(4) 1.387(5) 1.380(4) 1.403(4) 1.387(5) 1.386(4) 1.492(6) 1.535(7)  atom Pd(l) Pd(l) Pd(2) Pd(2) P(l) P(l) P(2) N(l) N(l) N(2) N(3) N(3) N(4) C(l) C(2) C(4) C(9) C(10) C(12) C(18) C(19) C(21) C(26) C(27) C(29) C(34) S(1B)  atom P(l) Cl(l) P(2) Cl(2) C(l) C(17) C(26) C(2) C(8) C(15) C(25) C(24) C(33) C(2) C(3) C(5) C(14) C(ll) C(13) C(19) C(20) C(22) C(31) C(28) C(30) C(35) C(34B)  distance 2.1925(8) 2.3545(8) 2.2011(7) 2.3840(7) 1.797(3) 1.835(3) 1.805(3) 1.478(4) 1.502(4) 1.463(4) 1.489(4) 1.504(4) 1.464(4) 1.392(4) 1.400(4) 1.388(5) 1.388(4) 1.392(4) 1.372(5) 1.381(4) 1.391(4) 1.381(5) 1.401(4) 1.379(4) 1.379(5) 1.535(5) 1.831(6)  Table A2.3. Bond angles (°) atom N(l) P(l) P(l) N(3) P(2) P(2) C(34) Pd(l) C(l) C(l) C(17) C(18) C(18) C(17) C(2)  Atom Pd(l) Pd(l) Pd(l) Pd(2) Pd(2) Pd(2) S(l) S(l) P(l) P(l) P(l) P(2) P(2) P(2) N(l)  atom P(l) S(l) Cl(l) P(2) S(l) Cl(2) Pd(l) Pd(2) C(17) Pd(l) Pd(l) C(17) Pd(2) Pd(2) C(8)  distance 85.16(7) 86.45(3) 174.86(3) 85.57(7) 94.57(4) 176.73(8) 109.34(13) 118.76(5) 106.10(13) 104.08(10) 111.99(10) 104.33(14) 103.53(10) 112.53(14) 109.1(2)  atom N(l) N(l) S(l) N(3) N(3) S(l) C(34) C(l) C(9) C(9) C(18) C(26) C(26) C(2) C(7)  113  atom Pd(l) Pd(l) Pd(l) Pd(2) Pd(2) Pd(2) S(l) P(l) P(l) P(l) P(2) P(2) P(2) N(l) N(l)  atom S(l) Cl(l) Cl(l) S(l) Cl(2) Cl(2) Pd(2) C(9) C(17) Pd(l) C(26) C(17) Pd(2) C(7) C(8)  distance 164.86(8) 92.91(7) 96.45(4) 176.67(8) 92.66(7) 87.05(4) 106.66(13) 111.20(13) 105.53(14) 117.50(10) 106.80(14) 105.57(13) 122.54(10) 109.0(2) 107.9(2)  [Pd Cl (fi-S Pr)(dmapm)] Cr n  2  2  +  Appendix A2 C(2) C(8) C(10) C(25) C(19) C(19) C(27) C(33) C(2) C(l) C(3) C(3) C(5) C(14) C(ll) C(9) C(13) C(9) C(19) C(23) C(18) C(21) C(23) C(31) C(27) C(28) C(27) C(29) C(35) C(35B)  N(l) N(l) N(2) N(3) N(3) N(3) N(4) N(4) C(l) C(2) C(2) C(4) C(6) C(9) C(10) C(10) C(12) C(14) C(18) C(18) C(19) C(20) C(22) C(26) C(26) C(27) C(28) C(30) C(34) C(34B)  Pd(l) Pd(l) C(16) C(19) C(24) Pd(2) C(33) C(32) • P(l) C(3) N(l) C(5) C(l) P(l) C(9) N(2) C(ll) C(13) C(23) P(2) N(3) C(19) C(21) C(27) P(2) N(4) C(29) C(31) S(l) S(1B)  114.24(17) 105.71(17) 113.2(3) 109.6(3) 108.1(2) 114.01(18) 112.5(3) 111.3(3) 116.4(2) 119.0(3) 121.1(3) 121.3(3) 119.6(3) 122.7(2) 119.3(3) 117.6(2) 120.9(3) 120.8(3) 119.9(3) 122.9(2) 119.6(3) 119.1(3) 120.0(3) 119.0(3) 117.5(2) 123.5(3) 120.8(3) 119.2(3) 108.2(3) 97.5(11)  C(7) C(10) C(15) C(25) C(25) C(24) C(27) C(2) C(6) C(l) C(4) C(6) C(14) C(10) C(ll) C(12) C(12) P(l) C(19) C(18) C(20) C(22) C(22) C(31) C(28) C(26) C(30) C(30) C(36)  114  Pd(l) C(15) C(16) C(24) Pd(2) Pd(2) C(32) C(6) P(l) N(l) C(2) C(4) C(10) P(l) N(2) C(10) C(14) P(2) P(2) C(20) N(3) C(20) C(18) P(2) C(26) N(4) C(28) C(26) C(34)  N(l) N(2) N(2) N(3) N(3) N(3) N(4) C(l) C(l) C(2) C(3) C(5) C(9) C(9) C(10) C(ll) C(13) C(17) C(18) C(19) C(19) C(21) C(23) C(26) C(27) C(27) C(29) C(31) C(35)  110.57(17) 111.9(3) 111.3(3) 109.3(3) 107.5(2) 108.24(19) 110.7(3) 120.7(3) 122.9(2) 119.9(2) 119.9(3) 119.5(3) 119.6(3) 117.1(2) 123.1(3) 120.4(3) 119.1(3) 112.89(14) 117.2(2) 120.4(3) 120.0(3) 120.6(3) 119.9(3) 123.6(2) 119.4(3) 117.1(3) 120.6(3) 121.0(3) 114.5(4)  [Pd Cl (n-S Pr)(dmapm)] Cr n  2  2  +  Appendix A3  Appendix A3  E X P E R I M E N T A L D E T A I L S F O R [PdPtCl (n-SEt)(dmapiii)] [OTf]+  2  A. Crystal Data Empirical Formula Formula Weight Crystal Colour, Habit Crystal Dimensions Crystal System Lattice Type Lattice Parameters  C 6H N403P S F Cl PdPt 1139.25 yellow, platelet 0.30 x 0.15 x 0.03 mm monoclinic C-centered a = 39.621(2) A b = 11.7466(5) A c = 17.8781(8) A ^ = 89.228(3)° V = 8320.0(6) A C2/c(#15) 8 1.819 g/cm 4496.00 41.38 cm" 3  47  2  2  3  2  3  Space Group Z Value  3  Fooo //(MoKcc)  1  B. Intensity Measurements Diffractometer Radiation  Rigaku/ADSC C C D MoKct (A. = 0.71069 A) Graphite monochromated 94 mm x 94 rnm 460 exposures @ 51.0 seconds 0.0-190.0° -17.0-23.0° 37.93 mm -5.62° 55.7° Total: 38644 Unique: 9662 (R,„,=0.067) Lorentz-polarization Absorption/scaling/decay (corr. factors: 0.6513 - 1.0000)  Detector Aperture Data Images (p oscillation Range (x = -90) co oscillation Range (x = -90) Detector Position Detector Swing Angle No. of Reflections Measured Corrections  C. Structure Solution and Refinement Structure Solution Refinement Function Minimized Least Squares Weights p-factor Anomolous Dispersion No. Observations (I>0.00o(I)) No. Variables Reflection/Parameter Ratio Residuals (on F , all data): R; R  Patterson Methods (DIRDIF92 P A T T Y ) Full matrix least-squares Eco(Fo -  Fc f  2  2  co = l / ( c r ( F o ) ) 2  2  0.0000 A l l non-hydrogen atoms 9250 489 18.92 0.061 ; 0.076  2  w  115  [PdPtCl (ju-SEt) (dmapm)] [OTf]+  2  Appendix A3 Goodness of Fit Indicator Max Shift/Error in Final Cycle No. Observations (I>3a(I)) Residuals (on F, I>3o(I)): R; R Maximum peak in Final Diff. Map Minimum peak in Final Diff. Map  0.93 0.00 5755 0.030; 0.031 3 1.78 e~/A  w  -1.65 e"7A  3  Table A3.1. Atomic Coordinates and B /B, iso  atom Pt(l) Pd(l) Cl(l) Cl(2) S(l) S(2) P(l) P(2) F(l) F(2) F(3) 0(1) 0(2) 0(3) N(l) N(2) N(3) N(4) C(l) C(2) C(3) C(4) C(5) C(6) C(7) C(8) C(9) C(10) C(ll) C(12) C(13) C(14) C(15) C(16) C(17) C(18) C(19) C(20) C(21) C(22) C(23) C(24) C(25) C(26) C(27) C(28)  X 0.123323(6) 0.083624(7) 0.09221(4) 0.07283(5) 0.08973(3) 0.31668(3) 0.15413(3) 0.08813(3) 0.3512(1) 0.3479(1) 0.3048(1) 0.2999(1) 0.3475(1) 0.2943(1) 0.1522(1) 0.2130(1) 0.0746(1) 0.0143(1) 0.1289(2) 0.1698(1) 0.1780(1) 0.1993(2) 0.2233(2) 0.2255(1) . 0.2050(1) 0.1804(1) 0.2134(2) 0.2449(2) 0.2073(1) 0.2273(1) 0.2213(2) 0.1950(2) 0.1752(1) 0.1810(1) 0.1305(1) 0.0433(2) 0.1045(2) 0.0725(1) 0.0650(2) 0.0645(2) 0.0707(2) 0.0779(1) 0.0786(1) -0.0064(2) -0.0031(1) 0.0254(1)  y 0.09221(2) -0.21675(2) 0.2411(1) -0.2697(1) -0.0292(1) 0.0926(1) -0.0399(1) -0.1753(1) 0.1585(6) -0.0218(5) 0.0738(5) 0.2014(4) 0.0880(4) -0.0026(3) 0.2115(4) 0.0422(4) -0.3892(4) -0.1873(4) 0.2777(5) 0.2916(5) 0.1556(5) 0.2203(5) 0.1682(5) 0.0506(5) -0.0154(5) 0.0378(5) 0.0992(6) 0.0654(6) -0.0796(5) -0.1474(5) -0.2633(5) -0.3115(5) -0.2450(5) -0.1283(4) -0.1369(4) -0.4254(5) -0.4577(5) -0.4005(5) -0.5051(5) -0.5133(6) -0.4207(6) -0.3163(5) -0.3065(5) -0.2551(7) -0.1659(6) -0.0835(5)  116  B 1.072(5) 0.720(6) 2.71(3) 2.83(4) 1.21(3) 1.52(3) 0.89(3) 0.98(3) 7.1(2) 7.0(2) 5.7(1) 3.1(1) 2.48(9) 2.6(1) 1.38(9) 1.6(1) 1.479() 1.9(1) 2.3(1) 2.0(1) 1.3(1) 2.1(1) 2.3(1) 1.9(1) 1.4(1) 1.1(1) 2.8(1) 2.6(1) 1.3(1) 1.8(1) 2.2(1) 2.0(1) 1.5(1) 1.0(1) 1.2(1) 2.6(1) 2.4(1) 1.5(1) 2.4(1) 3.1(2) 2.6(1) 1.9(1) 1.3(1) 3.5(2) 2.5(1) 1.6(1) e q  0.51200(1) 0.47606(1) 0.45506(9) 0.35070(7) 0.44416(6) 0.80977(7) 0.56396(7) 0.59470(6) 0.6920(2) 0.7047(3) 0.6664(2) 0.8095(2) 0.8515(2) 0.8212(2) 0.2774(2) 0.4698(2) 0.5148(2) 0.5866(2) 0.6274(3) 0.5239(3) 0.6256(3) 0.6694(3) 0.7127(3) 0.7152(3) 0.6730(3) 0.6267(3) 0.3965(3) 0.5076(3) 0.4637(3) 0.4178(3) 0.4122(3) 0.4521(3) 0.4999(3) 0.5056(2) 0.6258(3) 0.4811(3) 0.4860(3) 0.5975(3) 0.6300(3) 0.7075(4) 0.7528(3) 0.7200(3) 0.6418(3) 0.6383(3) 0.5157(3) 0.6196(2)  occ  [PdPtCl (n-SEt)(dmapm)] [OTJ]+  2  Appendix A3 C(29) C(30) C(31) C(32) C(33) C(34) C(35) C(36) H(1C) H(1A) H(1B) H(2B) H(2C) H(2A) H(4) H(5) H(6) H(7) H(9A) H(9B) H(9C) H(10C) H(IOA) H(IOB) H(12) H(13) H(14) H(15) H(17B) H(17A) H(18A) H(18B) H(18C) H(19C) H(19A) H(19B) H(21) H(22) H(23) H(24) H(26B) H(26C) H(26A) H(27A) H(27B) H(27C) H(29) H(30) H(31) H(32) H(34A) H(34B) H(35B) H(35C) H(35A)  0.0031(2) 0.0147(2) 0.0488(2) 0.0716(1) 0.0600(1) 0.1054(2) 0.1374(2) 0.3310(2) 0.1401 0.1232 0.1083 0.1531 0.1858 0.1820 0.1974 0.2390 0.2421 0.2051 0.2316 0.2172 0.1917 0.2638 0.2455 0.2467 0.2458 0.2358 0.1902 0.1572 0.1436 0.1283 0.0417 0.0435 0.0235 0.1000 0.1247 0.1079 0.0600 0.0595 0.0697 0.0824 -0.0170 -0.0241 0.0077 -0.0239 -0.0090 0.0116 -0.0212 -0.0014 0.0570 0.0956 0.0880 0.1092 0.1429 0.1341 0.1553  0.0027(6) 0.1058(6) 0.1223(5) 0.0368(5) -0.0667(5) -0.019(6) -0.0769(8) 0.0749(8) 0.3481 0.2321 0.2965 0.3285 0.2486 0.3492 0.3039 0.2141 0.0138 -0.0986 0.0675 0.1809 0.0873 0.0415 0.0232 0.1472 -0.1130 -0.3105 -0.3927 -0.2806 -0.2074 -0.1007 -0.5170 -0.4211 -0.3970 -0.5388 -0.4356 -0.4425 -0.5715 -0.5875 -0.4282 -0.2498 -0.3176 -0.2066 -0.2861 -0.1226 -0.2391 -0.1229 -0.0100 0.1667 0.1941 0.0488 -0.0451 0.0649 -0.0662 -0.1584 -0.0469  117  0.6402(3) 0.6674(33) 0.6782(3) 0.6597(2) 0.6293(3) 0.3491(4) 0.3311(4) 0.7129(4) 0.6432 0.6719 0.6007 0.4625 0.4927 0.5526 0.6695 0.7418 0.7472 0.6750 0.3653 0.4036 0.3722 0.4752 0.5546 0.5175 0.3891 0.3801 0.4467 0.5293 0.6304 0.6749 0.4908 0.4273 0.5041 0.4939 0.5136 0.4328 0.5989 0.7307 0.8072 0.7512 0.6108 0.6606 0.6778 0.5256 0.4924 0.4817 0.6348 0.6798 0.6985 0.6678 0.3157 0.3390 0.2782 0.3415 0.3620  2.5(1) 2.6(1) 2.3(1) 1.6(1) 1.2(1) 3.3(2) 4.4(2) 4.0(2) 2.7805 2.7805 2.7805 2.3671 2.3671 2.3671 2.5500 2.7415 2.1475 1.7338 3.5102 3.5102 3.5102 2.9398 2.9398 2.9398 2.0866 2.6213 2.4804 1.7843 1.4981 1.4981 3.0773 3.0773 3.0773 2.9718 2.9718 2.9718 2.8525 3.7121 2.9468 2.3300 4.0607 4.0607 4.0607 3.0127 3.0127 3.0127 3.0978 3.1982 2.7482 2.0218 3.8760 3.8760 5.3791 5.3791 5.3791  [PdPtCl (n-SEt)(dmapm)]+[OTj]~ 2  Appendix A3 B , = 8/37i ((7n(aa*) + (7 (bb ) + U (cc) + 2t7, aa'bb*cos y + 2t7 aa*cc* cos p 2t/ bb*cc* cos a) 2  3  2  22  a  2  33  2  23  13  Table A3.2. Bond Lengths (A) atom Pt(l) Pt(l) Pd(l) Pd(l) S(l) S(2) S(2) P(l) P(2) P(2) F(2) N(l) N(l) N(2) N(3) N(3) N(4) C(3) C(4) C(6) C(ll) C(12) C(14) C(20) C(21) C(23) C(28) C(29) C(31) C(34)  atom Cl(l) P(l) Cl(2) P(2) C(34) 0(2) C(36) C(16) C(17) C(33) C(36) C(l) C(3) C(10) C(18) C(20) C(27) C(4) C(5) C(7) C(12) C(13) C(15) C(21) C(22) C(24) C(29) C(30) C(32) C(35)  C(l) C(l) C(2) C(4) C(6) C(9) C(9) C(10) C(12) C(14) C(17) C(18) C(18) C(19) C(21) C(23) C(26) C(26) C(27)  H(1C) H(1B) H(2C) H(4) H(6) H(9A) H(9C) H(10A) H(12) H(14) H(17B) H(18A) ' H(18C) H(19A) H(21) H(23) H(26B) H(26A) H(27B)  distance 2.377(1) 2.189(1) 2.370(1) 2.186(1) 1.808(6) 1.439(4) 1.828(7) 1.809(5) 1.832(5) 1.800(5) 1.33(1) 1.495(7) 1.499(6) 1.469(7) 1.490(7) 1.486(6) 1.474(6) 1.386(7) 1.377(8) 1.381(7) 1.385(7) 1.385(8) 1.391(7) 1.389(7) 1.389(8) 1.387(8) 1.390(8) 1.385(9) 1.387(8) 1.49(1) 0.98 0.98 0.98 0.98 0.98 0.98 0.98 0.98 0.98 0.98 0.98 0.98 0.99 0.98 0.98 0.98 .0.98 0.98 0.99  118  atom Pt(l) Pt(l) Pd(l) Pd(l) S(2) S(2) P(l) P(l) P(2) F(l) F(3) N(l) N(2) N(2) N(3) N(4) N(4) C(3) C(5) C(7) C(ll) C(13) G(15) C(20) C(22) C(24) C(28) C(30) C(32)  atom S(l) N(l) S(l) N(3) 0(1) 0(3) C(8) C(17) C(25) C(36) C(36) C(2) C(9) C(ll) C(19) C(26) C(28) C(8) C(6) C(8) C(16) C(14) C(16) C(25) C(23) C(25) C(33) C(31) C(33)  distance 2.306(1) 2.162(4) 2.288(1) 2.169(4) 1.441(4) 1.439(4) 1.791(4) 1.836(5) 1.793(5) 1.316(9) 1.338(7) 1.505(7) 1.472(7) 1.152(7) 1.517(7) 1.464(7) 1.426(7) 1.387(7) 1.386(8) 1.405(7) 1.396(7) 1.378(8) 1.395(7) 1.382(7) 1.380(9) 1.404(7) 1.399(7) 1.382(9) 1.407(7)  C(l) C(2) C(2) C(5) C(7) C(9) C(10) C(10) C(13) C(15) C(17) C(18) C(19) C(19) C(22) C(24) C(26) C(27) C(27)  H(1A) H(2B) H(2A) H(5) H(7) H(9B) H(10C) H(10B) H(13) H(15) H(17A) H(18B) H(19C) H(19B) H(22) H(24) H(26C) H(27A) H(27C)  0.98 0.98 0.98 0.98 0.98 0.98 0.98 0.98 0.98 0.97 0.98 0.98 0.98 0.98 0.98 0.98 0.97 0.98 0.98  [PdPtCl (n-SEt)(dmapm)] [OTj]+  2  Appendix A3 C(29) C(31) C(34) C(35) C(35)  H(29) H(31) H(34A) H(35B) H(35A)  0.98 0.98 0.98 0.98 0.97  C(30) C(32) C(34) C(35)  H(30) H(32) H(34B) H(35C)  0.98 0.98 0.98 0.98  Table A3.3. Bond angles (°) atom Cl(l) Cl(l) S(l) CI(2) Cl(2) S(l) Pt(l) Pd(l) 0(1) 0(2) 0(3) Pt(l) C(8) CO 6) Pd(l) C(17) C(25) Pt(l) C(l) C(2) C(9) Pd(l) Pd(l) CO 8) C(26) C(27) N(l) C(3) C(5) P(l) C(3) N(2) C(H) CO 3) P(l) C(ll) N(3) C(21) C(21) C(23) P(2) N(4) C(29) C(29) C(31) P(2) S(l)  atom Pt(l) Pt(l) Pt(l) Pd(l) Pd(l) Pd(l) S(l) S(l) S(2) S(2) S(2) P(l) P(l) P(l) P(2) P(2) P(2) N(l) . N(l) N(l) N(2) N(3) N(3) N(3) N(4) N(4) C(3) C(4) C(6) C(8) C(8) C(H) C(12) C(14) C O 6) C(16) C(20) C(20) C(22) C(24) C(25) C(28) C(28) C(30) C(32) C(33) C(34)  atom S(l) N(l) N(l) S(l) N(3) N(3) Pd(l) C(34) 0(3) 0(3) C(36) C O 6) CO 6) C O 7) C(25) C(25) C(33) C(2) C(2) C(3) C(ll) C ( l 8) C(20) C(20) C(27) C(28) C(8) C(5) C(7) C(3) C(7) C(16) C(13) C(15) C(H) C(15) C(21) C(25) C(24) C(29) C(24) C(29) C(33) C(31) C(33) C(32) C(35)  distance 85.61(5) 92.0(1) 176.6(1) 92.10(5) 91.5(1) 174.5(1) 121.61(5) 110.6(2) 114.1(3) 114.9(3) 103.3(3) 119.3(2) 108.1(2) 106.4(2) 104.2(2) 104.8(2) 108.9(2) 107.8(3) 109.4(4) 108.9(4) 112.4(4) 110.2(3) 114.1(3) 109.5(4) 111.8(5) 111.1(5) 119.5(4) 120.3(6) 120.2(5) 117.3(4) 119.9(5) 118.6(4) 120.7(5) 120.2(5) 120.2(4) 119.2(5) 120.2(5) 120.4(5) 122.0(6) 119.7(6) 122.7(4) 122.2(5) 118.9(6) 120.0(6) 120.1(5) 122.8(4) 116.3(5)  atom ci(i) S(l) P(l) Cl(2) S(l) P(2) Pt(l) 0(1) 0(1) 0(2) Pt(l) Pt(l) C(8) Pd(l) Pd(l) C(17.) Pt(l) Pt(l) CO) C(9) C(10) Pd(l) C(18) CO 9) C(26) N(l) C(4) C(4) C(6) P(l) N(2) C(12) C(12) C(14) P(l) P(l) N(3) C(20) C(22) P(2) C(20) N(4) C(28) C(30) P(2) C(28) S(2)  119  atom Pt(l) Pt(l) Pt(l) Pd(l) Pd(l) Pd(l) S(l) S(2) S(2) S(2) P(l) P(l) P(l) P(2) P(2) P(2) N(l) N(l) N(l) N(2) N(2) N(3) N(3) N(3) N(4) C(3) C(3) C(5) C(7) C(8) C(H) C(H) C(13) C(15) C(16) C O 7) C(20) C(21) C(23) C(25) C(25) C(28) C(29) C(31) C(33) C(33) C(36)  atom P(l) P(l) N(l) P(2) P(2) N(3) C(34) 0(2) C(36) C(36) C(8) C(17) CO 7) C O 7) C(33) C(33) C(l) C(3) C(3) C(10) C(H) C(19) C O 9) C(20) C(28) C(4) C(8) C(6) C(8) C(7) C(12) C(16) C(14) C(16) C(15) P(2) C(25) C(22) C(24) C(20) C(24) C(33) C(30) C(32) C(28) C(32) F(l)  distance 177.28(5) 96.55(5) 85.9(1) 173.76(6) 91.01(5) 85.0(1) 104.3(2) 115.3(3) 103.6(4) 103.4(3) 103.7(2) 114.4(2) 103.6(2) 115.9(2) 115.7(2) 106.6(2) 109.5(2) 113.4(3) 107.8(4) 109.1(5) 110.7(4) 105.2(3) 108.7(4) 108.9(4) 112.2(5) 120.7(5) 119.8(5) 120.3(5) 119.5(5) 122.7(4) 121.5(5) 119.9(5) 119.7(5) 120.2(5) 120.6()4 115.6(3) 119.3(5) 118.6(6) 119.1(5) 117.1(4) 120.2(5) 118.8(5) 121.1(6) 120.0(6) 117.3(4) 119.7(5) 111.3(6)  [PdPtCl fa-SEt)(dmapm)J [OTJ]' +  2  Appendix A3 S(2) F(l) F(2) N(l) N(l) H(1C) N(l) N(l) H(2B) C(3) C(4) C(5) C(6) N(2) N(2) H(9A) N(2) N(2) H(10C) C(ll) C(12) C(13) C(14) P(l) P(2) H(17B) N(3) H(18A) H(18B) N(3) H(19C) H(19A) C(22) C(23) C(24) C(25) N(4) H(26B) H(26C) N(4) H(27A) H(27B) C(30) C(31) C(32) C(33) S(l) C(35) C(34) C(34) H(35B)  C(36) C(36) C(36) C(l) C(l) C(l) C(2) C(2) C(2) C(4) C(5) C(6) C(7) C(9) C(9) C(9) C(10) C(10) C(10) C(12) C(13) C(14) C(15) C(17) . C(17) C(17) C(18) C(18) C(18) C(19) C(19) C(19) C(21) C(22) C(23) C(24) C(26) C(26) C(26) C(27) C(27) C(27) C(29) C(30) C(31) C(32) C(34) C(34) C(35) C(35) C(35)  F(2) F(2) F(3) H(1C) H(1B) H(1B) H(2B) H(2A) H(2A) H(4) H(5) H(6) H(7) H(9A) H(9C) Ff(9C) H(IOC) H(IOB) H(IOB) H(12) H(13) H(14) H(15) H(17B) H(17B) H(17A) H(18B) H(18B) H(18C) H(19A) H(19A) H(19B) H(21) H(22) H(23) H(24) H(26C) H(26C) H(26A) H(27B) H(27B) H(27C) H(29) H(30) H(31) H(32) H(34B) H(34B) H(35B) H(35A) H(35A)  110.6(6) 107.7(6) 108.5(7)  S(2) F(l)  109.3 109.8 109.6 109.4 109.0 109.7 120.1 120.2 120.1 120.8 109.4 109.4 109.7 109.3 109.3 109.4 119.6 120.0 119.8 119.5 107.9 107.8 109.5 109.8 10.1 109.1 109.1 109.5 109.7 120.8 119.2 120.4 120.1 109.3 109.3 109.6 109.4 108. 109.5 119.8 1199 119. 120.3 108.0 107.3 109.0 109.2 110.6  C(36) C(36)  N(l) H(1C) H(1A) N(l) H(2B) H(2C) C(5) C(6) C(7) C(8) N(2) H(9A) H(9B) N(2) H(10C) H(10A) C(13) C(14) C(15) C(16) P(l) P(2) N(3) N(3) H(18A) N(3) N(3) H(19C) C(20) C(21) C(22) C(23) N(4) N(4) H(26B) N(4) N(4) H(27A) C(28) C(29) C(30) C(31) S(l) C(35) H(34A) C(34) H(35B) H(35C)  120  C(l) C(l) C(l) C(2) C(2) C(2) C(4) C(5) C(6) C(7) C(9) C(9) C(9) C(10) C(10) C(10) C(12) C(13) C(14) C(15) C(17) C(17) C(18) C(18) C(18) C(19) C(19) C(19) C(21) C(22) C(23) C(24) C(26) C(26) C(26) C(27) C(27) C(27) C(29) C(30) C(31) C(32) C(34) C(34) C(34) C(35) C(35) C(35)  F(3) F(3)  H(1A) H(1A) H(1B) H(2C) H(2C) H(2A) H(4) H(5) H(6) H(7) H(9B) H(9B) H(9C) H(10A) H(10A) H(10B) H(12) H(13) H(14) H(15) H(17A) H(17A) H(18A) H(18C) H(18C) H(19C) H(19B) H(19B) H(21) H(22) H(23) H(24) H(26B) H(26A) H(26A) H(27A) H(27C) H(27C) H(29) H(30) H(31) H(32) H(34A) H(34A) H(34B) H(35C) Ff(35C) H(35A)  110.8( 107.7(  109.6 109.0 109.5 109.3 109.9 109.5 119.7 119.5 119.7 119.7 109.2 109.5 109.7 109.4 109.6 109.7 119.7 120.3 120.0 120.3 108.1 107.98 109.7 108.9 109.2 109.1 109.4 110.0 120.7 118.8 120.4 120.2 109.3 109.6 109.6 109.5 110.1 109.6 119.1 120.0 120.2 119.5 107.9 107.6 109.6 108.6 109.6 110.0  [PdPtCl (fi-SEt)(dmapm)] [OTf]" 4  2  

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