Some binuclear hydrides of platinum

Abstract

Reaction of [PtCI₂(dppm)](dppm =Ph₂PCH₂PPh₂) with Na[BH₄] gives the binuclear cation [Pt₂H₂(µ-H)-(µ-dppm)₂]⁺ isolated both as its chloride and hexafluorophosphate salts. Reaction of this complex cation with CCl₄ or hydrogen chloride affords the related [Pt₂(µ-CI)H₂(µ-dppm)₂]⁺ and [Pt₂CI₂(µ-H)(µ-dppm)₂]⁺. The latter cation is also formed by protonation of the Pt-Pt bond in the platinum(I) complex [Pt₂CI₂(µ-dppm)₂]. The ¹H and ³¹P n.m.r. spectra of these complexes are reported. Study of the hydride resonances is shown to be an excellent method of distinguishing between terminal and bridging hydride. The Pt-Cl and Pt-H vibrational bands are in agreement with the proposed structures of these complexes, but vibrational bands due to bridging hydride groups could not be observed.