Electrochemical, spectroscopic, structural and magnetic characterization of the reduced and protonated α=Dawson anions in two iron and molybdenum complexes (see abstract)

Abstract

Reaction of excess Fe(cp*)2 (cp* = η5-C5Me5) dissolved in Et2O with [NHex4]4[S2Mo18O62] in acetonitrile, followed by recrystallization of the precipitated solid from N,N′-dimethylformamide (DMF), leads to isolation of the complex [Fe(cp*)2]5[HS2Mo18O 62]·3DMF·2Et2O. The solid has been characterized by microanalysis, by voltammetric analysis, by 1H NMR, diffuse reflectance infrared, EPR, and Mössbauer spectroscopies, and by temperature-dependent magnetic susceptibility measurements. The data are consistent with the presence of a paramagnetic [Fe(cp*)2]+ cation and a diamagnetic two-electron-reduced [HS2Mo18O62]5- anion. The related salt [NBu4]5[HS2Mo18O62] ·2H2O crystallizes in space group C2..