Oxidation of compounds containing the π-cyclopentadienylnitrosylmanganese group

Abstract

The syntheses and characterisation of the thioxanthate complexes, [(π-C₅H₅)Mn(NO){S₂CSR}](R = Bu^t, Bu^s, Buⁿ, Prⁱ, or Prⁿ), and of the binuclear mercaptide complexes. [(π-C₅H₅)Mn(NO)SR]₂^z(z= 0 or + 1; R = Bu^t, Bu^s, or Prⁱ), are described. The former group are shown, by voltammetry, to undergo a reversible one-electron oxidation, and the latter group can be oxidised in two one-electron steps. The Lewis base complexes, [(π-C₅H₅)Mn(NO)LL′]⁺[L = L′= CO, P(OPh)₃, PPh₃, PMe₂Ph, 4-methylpyridine, bipyridyl, etc.], also undergo a one-electron voltammetric oxidation process. These new voltammetric data are compared with those previously obtained from related 1,2-dithiolene, 1,1-dithiolene, and dithiocarbamate complexes, and it is shown that the E_1/2 values can be correlated with the charge on the complex, and with the N–O stretching frequency. The data indicate that the {(π-C₅H₅)Mn(NO)} group is significantly responsible for the redox behaviour of the complexes.