High yield synthesis of trinuclear [M3S4X3(diphos)(3)](+) (M = Mo, W; X = Cl, Br and diphos = dmpe, dppe) molecular clusters from solid state materials. Synthesis and structure of [W3S4H3(dppe)(3)](BPh4)

The excision of polymeric {M3S7X4}(x) (M = Mo. W; X = Cl, Br) cluster phase s with diphosphines (dmpe, dppe) in acetonitrile affords a one step general synthetic route for the preparation of trinuclear molecular clusters with formula [M3S4X3(diphos)(3)](+) (M=Mo, W: X=Cl, Br and diphos = dmpe. dppe) in high yields, Following this strategy, the cluster cations [Mo3S4Br3(dmpe )(3)](+) and [W3S4Br3(dppe)(3)](+) have been prepared for the first time. T his last tungsten cluster has proved to be a useful synthon for the synthes is of the hydride derivative [W3S4H3(dppe)(3)](+) in moderate yields. The c rystal structure of [W3S4H3(dppe)(3)](BPh4) consists of a equilateral tungs ten triangle with one capping and three bridging sulfur atoms defining a in complete W3S4 cuboidal unit in which the tungsten and the sulfur atoms occu py adjacent vertex of a cube with a metal atom missing. The hydride ligand occupies the outer position of the metal in a pseudo-octahedral environment . The other two outer positions on each metal are occupied by the diphosphi ne phosphor us atoms. located one above and one bellow the M-3 plane result ing in two different P-31(H-1} NMR signals. Electrochemical studies for all trinuclear clusters reported show one quasi reversible and one irreversibl e reduction process. (C) 2001 Elsevier Science B.V. All rights reserved.