Electronic, resonance-Raman, and infrared spectroscopic studies of the thiometalate complexes [NEt4]2[(PhS)2FeS2MS2], M = Mo or W

Abstract

Infrared and resonance-Raman spectra of the thiometalate complexes [NEt₄]₂[(PhS)₂FeS₂MS₂], M - Mo or W, have been studied and bands assigned to the ν(Fe–S), ν(M–S_t), and ν(M–S_br) fundamentals. Electronic absorption spectra and Raman-band excitation profiles indicate that the absorption bands in the visible region of the spectra arise from S→M charge-transfer transitions, red shifted from those of the parent [MS₄]^2– ions, and that the valence electrons on the iron(II) part of the complexes are extensively delocalized. This is in contrast to the situation for mixed-metal complexes in which the second metal ion has a closed (d¹⁰) valence shell.