Preparation of tungsten(V) aqua ion, W2O2S2(aq)2+, and X-ray structure of di-μ-sulfido-bis[(cysteinato)oxotungstate(V)] ion, [W2O2S2(cys)2]2−

Di-μ-sulfido tungsten(V) dimers, [W2O2S2(cys)2]2− (1) and W2O2S2(aq)2+ (2) have been prepared and characterized. The structure of the former has been determined by the X-ray crystal structure analysis. The W–W bond distance is 2.843(1) A. Peak positions of electronic spectra are : 428 nm (e=259 M−1 cm−1 per dimer; 1 M = 1 mol dm−3), 330sh (3920), and 276 (10760) for 1; 435 (144), 320 (2640), and 263 (7180) for 2.