Mechanism of reduction of cymantrene (tricarbonyl eta(5)-cyclopentadienylmanganese) and its methyl carboximidate derivative

The mechanisms of electrochemical reduction of cymantrene, [Mn(CO)(3)(eta ( 5)-Cp)], and its ring-substituted methyl carboximidate derivative, [Mn(CO)( 3)(eta (5)-C5H4C(NH)OMe)], were studied by voltammetry, in situ IR spectroe lectrochemistry and preparative electrolysis. The product of one-electron r eduction undergoes further chemical reactions. Comparison of the data obtai ned under atmosphere of argon and that of carbon monoxide leads to the conc lusion that a ligand substitution reaction and dimerization participate in the overall reaction sequence. FTIR spectra recorded in situ suggest produc t dimerization, the formation of [Mn(CO)(5)](-) and, to a lesser extent, ot her unstable species. The dimer formation was not observed in the course of the reduction of the carboximidate.