Date of Award


Degree Type


Degree Name

Doctor of Philosophy


This is a study into the steric and electronic factors governing the synthesis and reactivity of some platinum diphosphine complexes. We report the preparation of a number of new diphosphine ligands: The ethyl and methyl derivatives of (RO){dollar}\sb2{dollar}PCH{dollar}\sb2{dollar}P(OR){dollar}\sb2{dollar} and (Me{dollar}\sb{lcub}\rm n{rcub}{dollar}C{dollar}\sb5{dollar}H{dollar}\sb{lcub}\rm 5-n{rcub})\sb2{dollar}PCH{dollar}\sb2{dollar}P(C{dollar}\sb6{dollar}H{dollar}\sb{lcub}\rm 5-n{rcub}{dollar}Me{dollar}\sb{lcub}\rm n{rcub})\sb2{dollar}, where n = 1 ({dollar}p, m{dollar} and {dollar}o{dollar}-tolyl), 2 ({dollar}m{dollar}-xylyl) and 3 (mesityl).;The preparation and characterization of some platinum(II) complexes, (PtX{dollar}\sb2{dollar}(R{dollar}\sb2{dollar}PCH{dollar}\sb2{dollar}PR{dollar}\sb2)\rbrack\sb{lcub}\rm n{rcub}{dollar}, where X = halide or methyl, have shown how the bulk of the ligand, R{dollar}\sb2{dollar}PCH{dollar}\sb2{dollar}PR{dollar}\sb2{dollar}, can have dramatic effects upon the nuclearity, n, and upon the conformations adopted by the Pt{dollar}\sb2{dollar}P{dollar}\sb4{dollar}C{dollar}\sb2{dollar} rings in binuclear platinum complexes (n = 2). The reactivity of these complexes towards oxidative addition was also influenced by the bulk of the diphosphine ligands, but in the platinum complexes with the ligands, (RO){dollar}\sb2{dollar}PCH{dollar}\sb2{dollar}P(OR){dollar}\sb2{dollar}, electronic effects were important also. The low steric bulk of the (RO){dollar}\sb2{dollar}PCH{dollar}\sb2{dollar}P(OR){dollar}\sb2{dollar} ligand has allowed the formation of some binuclear platinum(II) species with three bridging diphosphine ligands. The bulk of the diphosphine ligands was also influential in determining the level of ligand coordination, n, in the diplatinum(0) complexes, (Pt{dollar}\sb2(\mu{dollar}-R{dollar}\sb2{dollar}PCH{dollar}\sb2{dollar}PR{dollar}\sb2)\sb3{dollar}(PPh{dollar}\sb3)\sb{lcub}\rm n{rcub}\rbrack,{dollar} where n = 0.2.;The extent of reduction that the complexes, (Pt(O{dollar}\sb2{dollar}CCF{dollar}\sb3)\sb2{dollar}(R{dollar}\sb2{dollar}PCH{dollar}\sb2{dollar}PR{dollar}\sb2)\rbrack,{dollar} where R = Me{dollar}\sb{lcub}\rm n{rcub}{dollar}C{dollar}\sb6{dollar}H{dollar}\sb{lcub}\rm 5-n{rcub}{dollar} and n = 0-3, experience under Water-Gas Shift Reaction conditions was dependent upon the bulk of the aryl substituents R. When R = Ph, {dollar}p{dollar}-, {dollar}m{dollar}-tolyl or {dollar}m{dollar}-xylyl reduction of (Pt(O{dollar}\sb2{dollar}CCF{dollar}\sb3)\sb2{dollar}-(P{dollar}\sp\frown{dollar}P)) to the trinuclear cluster, (Pt{dollar}\sb3{dollar}(O{dollar}\sb2{dollar}CCF{dollar}\sb3)(\mu\sb3{dollar}-CO)-({dollar}\mu{dollar}-P{dollar}\sp\frown{dollar}P){dollar}\sb3\rbrack\sp+{dollar} occurred after 2.5 days of reaction. When R = {dollar}m{dollar}-xylyl or {dollar}o{dollar}-tolyl, the binuclear species, (Pt{dollar}\sb2{dollar}H{dollar}\sb2(\mu{dollar}-H)-({dollar}\mu{dollar}-P{dollar}\sp\frown{dollar}P){dollar}\sb2\rbrack\sp+{dollar} and (Pt{dollar}\sb2{dollar}H(CO)({dollar}\mu{dollar}-P{dollar}\sp\frown{dollar}P){dollar}\sb2\rbrack\sp+{dollar}, were detected. The reactivities of these complexes were dependent upon the bulk of the {dollar}\mu{dollar}-P{dollar}\sp\frown{dollar}P ligands.;This work has been able to demonstrate that both steric and electronic factors must be considered when interpreting the reactivity and structures of binuclear and trinuclear platinum diphosphine complexes.



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