Reactivity of Molybdenum and Tungsten Sulfido Complexes with First-Series Transition Metals

Ammonium tetrathiomolybdate (ATTM) is an important compound in bioinorganic chemistry, with medicinal applications. Metal complexes of sulfur-containing ligands have been widely used as building block in biology and inorganic chemistry. This project aims to increase the number of Mo-S and W-S complexes that may contribute to fields such as bioinorganic and medicinal chemistry, by the preparation of heterometallic complexes containing both Mo or S and a metal of the first transition series. The homobimetallic complex anion salts (Et4N)2[Mo2(S)2(μ-S)2(edt)2] (1) and (Et4N)2[W2(S)2(μ-S)2(edt)2] (2) have been prepared from ATTM and ammonium tetrathiotungstate (ATTW) in order to start our work. The overnight treatment of 1 and 2 with MCl2, ( M = Fe, Co, Ni, Cu) under nitrogen at elevated temperatures (84 ˚C) is hypothesized to yield trinuclear cluster anion salts. UV-visible spectra for reaction products 3-6 showed significantly different λmax values compared with starting materials. FTIR spectra were obtained for compounds 1 and 2 for comparison with products 3-6. While the spectra showed clear evidence of transformation from 1 or 2, the structures of the products could not yet be confirmed, as attempts to obtain crystals suitable for single-crystal X-ray diffraction have so far been unsuccessful. Our future goals are to determine the structures of these reaction products, and examine their potential for medicinal and catalytic applications