Reduction of Methanol by Tetracarbonylcobalt Anion Assisted by Carbon Dioxide and Cobalt Cation

Fundamental electron-transfer reactions involving CH3OH and Co2(CO)8 are investigated. In a fully disproportionated CH3OH solution of Co2(CO)8, in the presence of CO2, a CH3OH reduction by Co(CO)4- occurs, under the intervention of the highly polarizing Co2+ cations. In tetrahydrofuran as solvent under carbon monoxide atmosphere, the CH3O- nucleophile formed gives rise to the Co(I) species tetracarbonyl(methoxycarbonyl)cobalt. Under low carbon monoxide pressure, this Co(I) species disproportionates to Co(OCH3)2 and Co2(CO)8. Catalytic amounts of Co2(CO)8 activate the carbonylation reaction of Co(OCH3)2 to dimethyl carbonate and tetracarbonyl(methoxycarbonyl)cobalt.