Structurally characterized one oxo–desoxo bridged Mo2–bis(dithiolene) complex and its interconversion to a discrete oxo or desoxo DMSOR model

Abstract

A new molybdenum complex, [Et₄N]₂[Mo(PPh₃)(mnt)₂–OMo(mnt)₂]·CH₂Cl₂·½H₂O (1, mnt = maleonitrile dithiolene = S₂C₂(CN)₂), with unique structural features was synthesized, in which the fragment {Mo(PPh₃)(mnt)₂–} was attached to another important {–OMo(mnt)₂} moiety. The structure of 1 was formed by the association of both the oxo and desoxo motifs of the dimethylsulfoxide reductase (DMSOR) class of enzymes. This dissymmetrical binuclear complex 1 is rare, and it utilized the basic inorganic aspects to accommodate both moieties; under basic conditions, it was converted to (Et₄N)₂[MoO(mnt)₂] (2). Similarly, when treated with PhSH and PPh₃, it was completely converted to [Et₄N]₂[Mo(PPh₃)(mnt)₂(SPh)] (3) (J. Am. Chem. Soc., 2006, 128, 4196–4197). The chemistry of 1 was analyzed with regard to its synthesis, reactivity, crystal structure, and spectroscopic and photophysical properties. In addition, the results were complemented with DFT calculations.