Date of Award
1986
Degree Type
Dissertation
Degree Name
Doctor of Philosophy
Abstract
The syntheses of trinuclear clusters, M(,3)((mu)(,3)-CO)((mu)-dppm)(,3) ('2+); M = Pt or Pd; dppm = Ph(,2)PCH(,2)PPh(,2), has been accomplished with the structural features of both the platinum and palladium clusters having been investigated by spectroscopic and x-ray crystallographic structure determinations. The mechanism of formation has been shown to involve the reduction of M(II) monomers through M(I)(,2) dimers to M(2/3)(,3) trimers with parallel oxidation of CO(,(g)) to CO(,2(g)), in aqueous media.;The selective attachment of halide ions to the triply bridging site of Pd(,3)((mu)(,3)-CO)((mu)-dppm)(,3) ('2+) has been established and the equilibrium constants for coordination have been shown to follow the sequence of I('-) >> Br('-) >> Cl('-) >> CF(,3)CO(,2)('-). The unique nature of this coordination chemistry is considered from both spectroscopic studies and an x-ray crystallographic structure determination of Pd(,3)((mu)(,3)-Cl)((mu)(,3)-CO)((mu)-dppm)(,3) ('+).;The oxidative addition of SCN('-) to Pd(,3)((mu)(,3)-CO)((mu)-dppm)(,3) ('2+) to give Pd(,3)((mu)(,3)-S)(CN)((mu)-dppm)(,3) ('+) is established by the x-ray crystallographic determination. This cationic trinuclear cluster product possesses one Pd(II) center and two Pd(I) centers. The reaction in the analogous platinum system proceeds at a much slower rate. As a result, Pt(,3)((mu)(,3)-SCN)((mu)(,3)-CO)((mu)-dppm)(,3) ('+) was isolated and characterized by an x-ray crystallographic structure determination and by spectroscopic studies. The cluster is considered to be an intermediate species in the oxidative addition reaction itself. Syntheses of related complexes by reactions with Na(,2)S(.)9H(,2)O have also been investigated.;Reaction of Pt(,3)((mu)(,3)-CO)((mu)-dppm)(,3) ('2+) with NaBH(,4) was shown to yield first Pt(,3)((mu)(,3)-H)((mu)(,3)-CO)((mu)-dppm)(,3) ('+) and then Pt(,3)((mu)(,3)-H)((mu)-dppm)(,3) ('+). The interconversion of these two clusters via CO(,(g)) loss or coordination is reversible. Evidence is presented that the inversion of the Pt(,3)((mu)(,3)-H) group in Pt(,3)((mu)(,3)-H)((mu)-dppm)(,3) ('+) occurs rapidly through a planar Pt(,3)((mu)(,3)-H) unit. Reaction of Pt(,3)((mu)(,3)-H)((mu)(,3)-CO)((mu)-dppm)(,3) ('+) with CF(,3)CO(,2)H has been shown to generate the original dicationic platinum-carbonyl cluster.;The reaction of Pt(,3)((mu)(,3)-CO)((mu)-dppm)(,3) ('2+) with H(,2(g)) leading to the formation of Pt(,2)((mu)-H)H(,2)((mu)-dppm)(,2) ('+) and an unidentified complex in similar yields is also reported.;Syntheses of a variety of alkyldiphosphine palladium(II) monomeric complexes of the form PdX(,2)(R(,2)PCH(,2)PR(,2)) ; X = Cl('-), CF(,3)CO(,2)('-); R = Me, Et, ('i)Pr, is reported. The complex Pd(,2)Cl(,3)((mu)-('i)PrPCH(,2)P('i)Pr(,2))((mu)-H('i)PrPCH(,2)P('i)Pr(,2)) has been characterized by x-ray crystallography and spectroscopic studies. It contains an unusual bridging phosphido-phosphine ligand.
Recommended Citation
Lloyd, Brian Richard, "Trinuclear Clusters Of Palladium And Platinum" (1986). Digitized Theses. 1508.
https://ir.lib.uwo.ca/digitizedtheses/1508