Ternary adduct {[W(CN)8]3−,[Pt(en)2]2+,[W(CN)8]3−} in aqueous solution and crystal structure of [Pt(en)2]3[W(CN)8]2·4H2O with infinite linear W⋯Pt chains

Abstract

A new donor–acceptor system based on [W(CN)₈]³⁻ and [Pt(en)₂]²⁺ has been characterised in aqueous solution and in the solid state. Spectroscopic studies indicate formation of the ternary adduct {[W(CN)₈]³⁻,[Pt(en)₂]²⁺,[W(CN)₈]³⁻} in aqueous solution. The aggregate has been described as a mixed-valence species with weak-to-moderate coupling between metal centres. The solid [Pt(en)₂]₃[W(CN)₈]₂·4H₂O exhibits the simultaneous presence of {W^V, Pt^II, W^V} ←→ {W^IV, Pt^IV, W^IV} electronic isomers and can be interpreted in terms of ground state borderline electronic localised-to-delocalised species. The structure of [Pt(en)₂]₃[W(CN)₈]₂·4H₂O consists of one-dimensional infinite chains formed by tungsten and platinum moieties linked through hydrogen bonding from ethane-1,2-diamine nitrogens and water molecules to nitrogens of all cyano ligands.