Date of Award


Degree Type


Degree Name

Doctor of Philosophy


This thesis examines the reactivity of the coordinatively unsaturated triplatinum cluster (Pt{dollar}\sb3(\mu\sb3{dollar}-CO){dollar}(\mu{dollar}-dppm){dollar}\sb3\rbrack{dollar} (PF{dollar}\sb6\rbrack \sb2{dollar}, 1. The complex can act as a model for a triangle of platinum atoms on a Pt(111) surface and this thesis describes studies of its reactivity towards various main group reagents.;The halide ions, Cl{dollar}\sp-{dollar}, Br{dollar}\sp-{dollar} and I{dollar}\sp-{dollar}, yielded the clusters (Pt{dollar}\rm\sb3(\mu\sb3{dollar}-CO){dollar}(\mu\sb3{dollar}-X)({dollar}\mu{dollar}-dppm){dollar}\sb3\rbrack \sp{lcub}1+{rcub}{dollar} which were characterized spectroscopically. Attempts were made to investigate the bonding in these systems with respect to the degree of ionic, or covalent, character in the Pt{dollar}\rm\sb3(\mu\sb3{dollar}-X) bonds through ligand exchange studies.;Monodentate tertiary phosphines and phosphites yielded the clusters (Pt{dollar}\rm\sb3(\mu{dollar}-CO)L{dollar}(\mu{dollar}-dppm){dollar}\sb3\rbrack\sp{lcub}2+{rcub}{dollar}, L = phosphine or phosphite. The cluster complex (Pt{dollar}\rm\sb3(\mu\sb3{dollar}-CO){dollar}\rm\{lcub}P(OPh)\sb3\{rcub}(\mu{dollar}-dppm){dollar}\sb3\rbrack \sp{lcub}2+{rcub}{dollar} was characterized by X-ray crystallography. The possibility of a Pt{dollar}\rm\sb3(\mu\sb3{dollar}-PF{dollar}\sb3){dollar} group, unique fluxionality of the phosphine and posphite ligands and asymmetrically capping CO ligands are interesting features of these clusters.;The novel cluster (Pt{dollar}\rm\sb3(\mu{dollar}-CO)({dollar}\mu{dollar}-dppm){dollar}\sb4\rbrack\sp{lcub}2+{rcub}{dollar} was synthesized and was particularly interesting because the {dollar}\mu{dollar}-dppm ligand beneath the plane of the platinum triangle displays a new form of fluxionality not previously observed from dppm.;The triplatinum cluster, complex 1, was reacted with various isocyanides to form the clusters (Pt{dollar}\rm\sb3(\mu\sb3{dollar}-CO)CNR{dollar}(\mu{dollar}-dppm){dollar}\sb3\rbrack\sp{lcub}2+{rcub}{dollar}. The mechanism of the reaction was followed by variable temperature NMR spectroscopy and a novel mechanism of ligand addition for metal-isocyanide complexes was observed.;The cluster (Pt{dollar}\sb3(2,6{dollar}-{dollar}\rm Me\sb2C\sb6H\sb3NC)\sb2)(\mu{dollar}-dppm){dollar}\sb3\rbrack\sp{lcub}2+{rcub}{dollar} was synthesized by adding two molar equivalents of 2,6-Me{dollar}\sb2{dollar}C{dollar}\sb6{dollar}H{dollar}\sb3{dollar}NC to (Pt{dollar}\rm\sb3(\mu\sb3{dollar}-CO){dollar}(\mu{dollar}-dppm){dollar}\sb3\rbrack \sp{lcub}2+{rcub}{dollar}. This complex was characterized by X-ray crystallography and is the first Pt{dollar}\sb3(\mu{dollar}-dppm){dollar}\sb3{dollar} cluster with no capping ligand. The structure also appears to violate the theoretical results obtained for similar systems suggesting that a new theoretical treatment may be warranted.;Mechanistic studies using variable temperature NMR were done on the reaction of various isothiocyanates with complex 1. The strong C=S bond of the isothiocyanate is cleaved under mild conditions by this Pt{dollar}\sb3{dollar} cluster.;Finally a tetraplatinum cluster was also examined. The fluxionality of this cluster, which differs from that of the usual tetraplatinum butterfly fluxionality, was proposed on the basis of variable temperature NMR data.



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