Synthesis of a new salt containing polyoxometallate anion and MCuS cluster cation [MS4Cu4(γ-MePy)8][M6O19] (M = Mo, W). Crystal structure of [WS4Cu4(γ-MePy)8] [W6O19]

Reactions of (NH4)2MS4, AgBr and CuBr in γ-methylpyridine produced one new compound, [MS4Cu4(γ-MePy)8][M6O19] (1, M = W;2, M = Mo), of which 1 was characterized by single crystal X-ray analysis. The crystal data: orthorhombic, Pbcn, a = 15.434(4), b = 16.732(2), c = 28.657(7) A, V = 7400.8(8) A3, Z =4, R = 0.072 for 3121 independent data. The compound is the first example which contains both polyoxotungstate anion and heteropolynuclear cluster cation. In the structure of the cation four edges of the tetrahedral WS2−4 core are coordinated by four copper atoms, giving a WS4Cu4 aggregate of approximate D2h symmetry. The differences between the reaction of Cu+ with MS2−4 and that of Ag+ with MS2−4 in pyridine and its derivatives are discussed.