Synthesis and chemistry of some binuclear oxomolybdenum(V) xanthate (O-alkyl dithiocarbonate) complexes

Abstract

A simple method for the preparation of pure µ-oxo-bis[bis(O-alkyl dithiocarbonato)oxomolybdenum(V)] complexes, [Mo₂O₃(RO·CS·S)₄](I; R = Me, Et, Prⁱ, Buⁿ, or Buⁱ), and difficulties encountered with previous preparative methods are reported. Assignments of molybdenum–oxygen stretching frequencies in the i.r. spectra have been made and visible spectra have been reinvestigated. Reaction with dialkylamines, alcohols, or hydrogen sulphide results in loss of xanthate ligand and produces, in the last two cases, a series of new di-µ-sulphido-bis[(O-alkyl dithiocarbonato)oxomolybdenum(V)] complexes, [Mo₂O₂S₂(RO·CS·S)₂](II). Spectroscopic studies of these products indicate that those containing unbranched O-alkyl dithiocarbonate groups are polymers in the solid state, which dissociate in solution. Complexes (I) and (II) react with excess of xanthate ligand to produce the ion [Mo₂O₂S₂(O·CS·S)₂]^2–, (III).