Adducts of co-ordination compounds. Part XI. Isomerism and solvation of dichlorobis(triphenylphosphine)platinum(II)

Abstract

The complex cis-[Pt(PPh₃)₂Cl₂] forms distinct adducts with chloroform and NN-dimethylformamide. The existence of these adducts, for which X-ray powder results are given, accounts for several discrepancies in the literature. In particular, the product (recrystallised from chloroform–hexane) of reaction of carbon tetrachloride with tetrakis(triphenylphosphine)platinum(0), previously incorrectly formulated as [Pt(PPh₃)₂(CCl₃)Cl], is in fact a partly desolvated sample of the chloroform adduct of the cis-dichloro-complex. In solution, cis–trans-isomerisation is easily set up providing access to the trans-isomer. Two further methods, which give much better yields of the trans-isomer, are described.