Thermal decomposition of some acyl(dialkyl)-, dialkyl(allyl)-, dialkyl(benzyl)-, and trialkyl-halogenobis(dimethylphenylphosphine)platinum(IV) complexes

Abstract

The complexes [PtR₂(R′)X(PMe₂Ph)₂](X = halogen : R = Me, R′= benzyl or allyl; R = CD₃, R′= acetyl; R = Et, R′= Me) have been prepared. On pyrolysis, the benzyl and acetyl complexes undergo reductive elimination with C–C bond formation, the former giving ethane and ethylbenzene and the latter giving CD₃COMe as the organic products. Acetone elimination from the complex [PtMe₂(COMe)Cl(PMe₂Ph)₂] has been studied by differential-scanning calorimetry and a mean value of the Pt–C σ-bond energy has been estimated. The complex [PtBr(Me)₂(CH₂CHCH₂)(PMe₂Ph)₂] apparently decomposes by a free-radical mechanism, and [PtI(Me)Et₂(PMe₂Ph)₂] decomposes by a mechanism involving β-elimination of ethylene as the first step. The relative ease of elimination of a series of alkyl, acyl, and allyl groups from Pt^IV complexes has been deduced.