Reactions of cis-[PtCl2(PEt3)2] with silver salts in aqueous solution, in the presence or absence of PEt3

Abstract

Reaction of AgX(X = NO₃ or ½SO₄) with cis-[PtCl₂(PEt₃)₂] in neutral water affords [Pt₂(OH)₂(PEt₃)₄]²⁺ or [Pt(SO₄)(PEt₃)₂] the latter of which can be isolated from dilute sulphuric acid solutions. In water in the presence of PEt₃(2 mol equivalents), [Pt(PEt₃)₄][PtCl₄] gives a mixture of [PtCl(PEt₃)₃]⁺ and [Pt(PEt₃)₄]²⁺ although the latter gives [PtCl(PEt₃)₃]⁺ and [PHEt₃]⁺ on acidification. Addition of 2AgX (X = NO₃, O₂CMe, ClO₄, or ½SO₄) to these acidified solutions gives [PtX(PEt₃)₃]⁺, although, in aqueous solution, complex equilibria apparently exist between the co-ordinated anion and water. The ions [PtX(PEt₃)₃]⁺(X = NO₃, ClO₄, or O₂CMe) can be isolated as their [PF₆]^– or [ClO₄]^–(X = ClO₄) salts. For X =½SO₄, attempts to isolate a product by addition of KPF₆ generally led to [PtCl(PEt₃)₃]⁺ although on one occasion [Pt(H₂O)(PEt₃)₃]²⁺ was recovered. Reaction of H₂ with [PtY(PEt₃)₃]ⁿ⁺(Y = HSO₄, n= 1; Y = H₂O, n= 2) gives [PtH(PEt₃)₃]²⁺ which with K₂S₂O₈ gives [PtY(PEt₃)₃]ⁿ⁺. The isolated complexes have been fully characterised by spectroscopic means and their relevance to systems employed in the photochemical decomposition of water is discussed.