Multifrequency Electron Spin Resonance of Molybdenum(V) and Tungsten(V) Compounds

Abstract

The ESR spectra of a selection of molybdenum(V) and tungsten(V) compounds have been examined as a function of microwave frequency. In particular, reduced line widths at lower (S band: 2-4 GHz) microwave frequencies allow detection of 14N, 1H, 17O,77Se, and 35,37C1 superhyperfine interactions in certain of the following complexes: [Mo(abt)3]- (abtH2 #x003D; o-aminobenzenethiol), [MO(XPh)4] (M = Mo, W; X = S, Se), and m-[MoO(qtl)2X] (X = Cl, Br; qtlH = quinoline-8-thiol). The redistribution of spectral information as a function of frequency, together with computer simulation, has allowed the determination of the hyperfine matrix and its relative orientation to the g matrix, in most cases. A dz..