Preparation, characterization, and some reactions of hydridobis(tri-tert- butyl)phosphineplatinum(II) cation containing three-coordinate platinum

Abstract

Removal of the chloride ligand from trans-PtHCl[P(t-Bu)3]2 by a noncoordinating anion affords the complexes trans-[PtH{P(t-Bu)3}2]X (X = PF6, BF4, ClO4, SO3CF3), 1a, 1b, 1c, and 1d respectively, which contain the cationic hydride in which platinum is formally three-coordinate. Complexes 1 react with several σ-donor neutral ligands, L, to give the square-planar complexes trans-[PtHL{P(t-Bu)3}2]X. No reaction occurs with H2C=CH2 or F2C=CF2 but (NC)2C=C(CN)2 reacts with 1c to give an air-stable complex trans-[PtH{(NC)2C=C(CN)2}{P(t-Bu)3}2]ClO4 which is indicated to contain π-bonded (NC)2C=C(CN)2. Neither PhC≡CPh nor MeO2CC≡CCO2 reacts with 1 but HC≡CH seems to react reversibly to form the four-coordinate species trans-[PtH(HC≡CH){P(t-Bu)3}2]+, which could not be isolated. In marked contrast to the behaviour of previously reported cationic platinum(II) hydrides, addition of an equivalent of PCy3 of P(t-Bu)3 to an acetone solution of 1 results in its deprotonation and gives the platinum(0) complex Pt[P(t-Bu)3]2 quantitatively. Deprotonation of 1 also occurs upon treatment with NH3, Me2S, and NaOMe in acetone.