Date of Award

1988

Degree Type

Dissertation

Degree Name

Doctor of Philosophy

Abstract

This thesis describes the chemistry of some homonuclear and mixed-metal complexes of platinum with sulphide and diphosphine ligands.; (PtPh{dollar}\sb2{dollar}({dollar}\eta\sp1{dollar}-dmpm){dollar}\sb2{dollar}); dmpm = bis(dimethylphosphino)methane, is formed by the facile reaction of a diaryl platinum species with excess ligand. Synthesis of symmetric and asymmetric binuclear platinum complexes is achieved through the bonding of the uncoordinated phosphines to a second platinum centre. Oxidative addition reactions of these dimers are studied.; (Pt{dollar}\sb2{dollar}({dollar}\mu{dollar}-dppm){dollar}\sb3{dollar}); dppm = bis(diphenylphosphine)methane, reacts with carbonyl sulphide to yield (Pt{dollar}\sb2{dollar}({dollar}\mu{dollar}-S)({dollar}\mu{dollar}-dppm)({dollar}\eta\sp1{dollar}-dppm){dollar}\sb2{dollar}). This complex is used as a precursor in construction of trinuclear clusters. Coordination to a third centre can be achieved through the mono-coordinated diphosphine ligands as well as the {dollar}\mu{dollar}-S bridge. The reaction of the dimer with d{dollar}\sp8{dollar} and d{dollar}\sp{lcub}10{rcub}{dollar} metal complexes yields (Pt{dollar}\sb2{dollar}M({dollar}\mu\sb3{dollar}-S)({dollar}\mu{dollar}-dppm){dollar}\sb3{dollar}) (X), (M = Pt, Pd, Rh, Ir, Cu, Ag, Au, Hg). The reactivity of these clusters is studied. (Pt{dollar}\sb2{dollar}({dollar}\mu{dollar}-S)({dollar}\mu{dollar}-dppm)({dollar}\eta\sp1{dollar}-dppm){dollar}\sb2{dollar}) reacts with dialkyl and diaryl platinum (II) complexes to give tetranuclear species. These are the first examples of tetraplatinum complexes containing quadruply bridging sulphide groups.;The reactivity of (Pt{dollar}\sb2{dollar}({dollar}\mu{dollar}-dppm){dollar}\sb3{dollar}) towards a variety of thiols is examined. Thiols oxidatively add to the dimer to give platinum (I) and platinum (II) complexes. Since platinum has a great affinity for sulphur, in some cases the dimer abstracts the sulphur atom from the thiol to form sulphur-bridged binuclear species.; (Pt{dollar}\sb2{dollar}({dollar}\mu{dollar}-dmpm){dollar}\sb3{dollar}(PPh{dollar}\sb3{dollar})) reacts with CO(g) under water-gas shift conditions to yield the stable 46-electron triplatinum cluster, (Pt{dollar}\sb3{dollar}({dollar}\mu{dollar}-CO)({dollar}\mu{dollar}-dmpm){dollar}\sb4{dollar}) {dollar}\sp{lcub}2+{rcub}{dollar}. The molecular structure of this cluster shows that the complex possesses strong Pt-Pt bonds. The cluster exhibits very little reactivity. The 46-electron count is not an unfavourable arrangement for low oxidation state platinum complexes since this cluster is clearly reluctant to add or lose a ligand to alter its electron count.

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