Fluoro-complexes of platinum metals

Abstract

Metathetical reactions of AgF with chloro-complexes give the fluoro-complexes [PtF(PEt₃)₃][BF₄], trans-[PtF(PEt₃)₂(PPh₃)][ClO₄], trans-[PtF(PEt₃)₂{P(OPh)₃}][ClO₄], [PtF(PPh₃)₃][BF₄], [PtF(PMe₂Ph)₃][BF₄], [PdF(PEt₃)₃][BF₄], trans-[RhF(CO)(PPh₃)₂], and trans-[IrF(CO)(PPh₃)₂]. These products are fully characterised by ¹⁹F and ³¹P n.m.r. spectroscopy, and ³¹P n.m.r. parameters are also reported for the chloro-complexes [PtCl(PEt₃)₃][BF₄], trans-[PtCl(PEt₃)₂(PPh₃)][ClO₄], trans-[PtCl(PEt₃)₂{P(OPh)₃}][ClO₄], and [PtCl(PPh₃)₃][BF₄]. The results suggest that the Pt–F bonding orbital has only small contributions from the Pt 6s and F 2s orbitals. The trans influence of fluorine in these complexes is usually slightly greater than that of chlorine and the Pt–F bond is probably stronger than corresponding Pt–Cl bonds. Hydrolysis of the platinum fluorides yields hydroxo-bridged complexes, [Pt₂(OH)₂(PR₃)₄]²⁺, and reaction of these products with excess of tertiary phosphine gives platinum hydrides, [PtH(PR₃)₃]⁺. Reaction of [Pt(PPh₃)₄] with excess of anhydrous HF yields [PtF-(PPh₃)₃][H_nF_n+1](n ∼ 2–3).