Iron-molybdenum-sulphur and iron-tungsten-sulphur complexes of diimines

The complexes FeLMS4 (L = bipy or phen; M = Mo or W) were prepared and characterized. The linearity of the χ-1`M vs T plot and Mössbauer spectral parameters (δ: 0.28 mm s-1; EQ: 0.37 mm -1) of [Fe(bipy)2MoS4] suggested that iron(II) assumes a distorted octahedral geometry with an intermediate spin state. The thiometallate acts as a bidentate chelating ligand towards iron(III), as evidenced by IR spectral results. An irreversible anodic wave observed at +1.04 V vs S.C.E. in the cyclic voltammogram of [Fe(bipy)2MoS4] in DMSO suggested the oxidation of iron(II) to iron(III) and the reduction of the bipyridyl ligand occurs at -1.40 V. © 1993.