Electrochemical behavior of thiolate-bridged manganese dimers

Article abstract of DOI:10.1021/om00092a018

The oxidative behavior of thiolate-bridged manganese dimers having the general formulae Et₄N-[Mn₂(μ-SR)₃(CO)₆], Mn₂(μ-SR)₂L₂(CO)₆, and Mn₂(μ-SR)₂(μ-CO)L₂(CO)₄ where R = Me, t-Bu, or Ph and L = PMe₃, PPh₃, or CH₂[PPh₂]₂ (dppm) was studied. The ease of oxidation is dependent on the electron-donating ability of the R group in the thiolate bridge of the dimers. Oxidation of a recently characterized compound, Mn₂(μ-SMe)₂(μ-CO)(PMe₃) ₂(CO)₄, occurs by an ECE (E = electrochemical step, C = chemical step) process. The character of the chemical step has been probed by cyclic voltammetry in solvents of varying donor ability and through ESR spectroscopy of the intermediate. The ECE mechanism has been confirmed quantitatively by digital simulation. An X-ray structure determination was carried out on Mn₂(μ-SMe)₂(μ-CO)(PMe₃) ₂(CO)₄. Crystal data: monoclinic, space group P2₁/c; a = 9.753 (4), b = 14.872 (6), c = 16.052 (6) A?; β = 115.38 (2)°; Z = 4. The Mn-Mn distance is 2.581 A?, and the bridging carbonyl is symmetrically disposed with respect to the two manganese atoms.