Collect. Czech. Chem. Commun. 1996, 61, 1342-1352

Infrared Spectroelectrochemical Investigation of Carbon Dioxide Reduction Mediated by the Anion [Ru(SnPh3)(Co)2(iPr-DAB)]- (iPr-DAB = N,N'-Diisopropyl-1,4-diaza-1,3-butadiene)

František Hartl, Maxim P. Aarnts and Karin Peelen

Anorganisch Chemisch Laboratorium, J. H. van't Hoff Research Instituut,Universiteit van Amsterdam, Nieuwe Achtergracht 166, NL-1018 WV Amsterdam, The Netherlands


Carbon dioxide was found to react slowly with the coordinatively unsaturated anion [Ru(SnPh3)(CO)2(iPr-DAB)]- electrogenerated in an IR OTTLE cell via bielectronic reduction of [Ru(Cl)(SnPh3)(CO)2(iPr-DAB)]. This reaction produced free CO, CO32-, O2CH- and other two unidentified carboxylato species. The overall process is not catalytic in nature since the anion cannot be recovered after the attack of CO2 due to its conversion into a stable complex tentatively assigned as {Ru0(CO)2(iPr-DAB)}2. Although limited, the inherent reactivity of [Ru(SnPh3)(CO)2(iPr-DAB)]- towards CO2 demonstrated that the strong π-bonding within the (Sn)Ru(iPr-DAB) metallacycle, stabilizing the five-coordinate structure, is slightly less delocalized in comparison with the closely related, but totally inert anions [Mn(CO)3(α-diimine)]- (α-diimine = bpy, iPr-DAB).

Keywords: Infrared spectroelectrochemistry; CO2 reduction; Ru carbonyls; α-Diimine complexes.