Redox Properties of Thiolate Compounds of Oxomolybdenum(V) and Their Tungsten and Selenium Analogues

Julie R. Bradbury, Anthony F. Masters, Angus C. McDonell, Andrew A. Brunette, Alan M. Bond, Anthony G. Wedd

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The rich electrochemistry of the mononuclear [MvO(XR)4]- and triply bridged binuclear [Mv202(XR)6Z]n- anions (M = Mo, W; X = S, Se; R = Ph, p-tolyl, CH2Ph; Z = uninegative (n = 1) or neutral (n = 0) ligand) is explored in MeCN and DMF at platinum and mercury electrodes over the temperature range +25 to -60 °C. Interconversion of the mononuclear and binuclear forms occurs via reduction and oxidation processes involving the metal and ligand centers. Stepwise reduction of the binuclear Mv2 to MIV,V2 and MIV *2 species is observed, and the reduced forms undergo chemical reactions which lead to the appearance of 1 molecule of [MrvO(XR)1 4]2-/molecule of [Mv2O2(XR)6Z]- reduced. In this way, the alkyl-substituted [MoO(SCH2Ph)4]2-/- ions can be generated at 25 °C. Chemically reversible, one-electron reduction of [MvO(XR)4]’ is observed, while oxidation leads to the formation of [Mv2O2(XR)6Z] (Z = solvent) and RXXR via a process involving oxidative dissociation of ligand XR-. For [WvO(XR)4]-, the following one-electron couples are observed: [WVIO(XR)4] + e- = [WvO(XR)4]- + e- = [WrvO(XR)4]2-. In view of the direct observation of [WvlO(XR)4], an intramolecular redox step is apparently involved in the overall oxidation process described above. Wider implications of the ligand redox processes are discussed.

Original languageEnglish
Pages (from-to)1959-1964
Number of pages6
JournalJournal of the American Chemical Society
Issue number8
Publication statusPublished - Apr 1981
Externally publishedYes

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