Collect. Czech. Chem. Commun. 2001, 66, 155-169

Mechanism of Reduction of Cymantrene (Tricarbonyl η5-Cyclopentadienylmanganese) and Its Methyl Carboximidate Derivative

Michèle Salmaina, Gérard Jaouena, Jan Fiedlerb, Romana Sokolováb and Lubomír Pospíšilb,*

a Ecole Nationale Supérieure de Chimie de Paris, Laboratoire de Chimie Organométallique (UMR CNRS 7576), 11 rue Pierre et Marie Curie, 75231 Paris Cédex 05, France
b J. Heyrovský Institute of Physical Chemistry, Academy of Sciences of the Czech Republic, Dolejškova 3, 182 23 Prague 8, Czech Republic


The mechanisms of electrochemical reduction of cymantrene, [Mn(CO)35-Cp)], and its ring-substituted methyl carboximidate derivative, [Mn(CO)35-C5H4C(NH)OMe)], were studied by voltammetry, in situ IR spectroelectrochemistry and preparative electrolysis. The product of one-electron reduction undergoes further chemical reactions. Comparison of the data obtained under atmosphere of argon and that of carbon monoxide leads to the conclusion that a ligand substitution reaction and dimerization participate in the overall reaction sequence. FTIR spectra recorded in situ suggest product dimerization, the formation of [Mn(CO)5]- and, to a lesser extent, other unstable species. The dimer formation was not observed in the course of the reduction of the carboximidate.

Keywords: Cymantrene; Manganese tricarbonyl complexes; Electroreductions; Imidates; Cyclopentadienyl ligands; Spectroelectrochemistry; Voltammetry.

References: 26 live references.