Electro- und photoreduction of carbon dioxide with heterodinuclear complexes

• Applicant: Professor Dr. Wolfgang Kaim
• Subject Area: Inorganic Molecular Chemistry - Synthesis and Characterisation
• Term: from 2002 to 2008
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 5383668

The project is directed at the synthesis and the investigation of physicochemical, photo- and electrochemical properties of heterodinuclear complexes which will to be used as novel catalysts for the electro- and photocatalysis of CO2 reduction. The multielectron reduction of CO2, preferentially leading to the production of hydrocarbons or alcohols, remains a fundamental challenge in the chemical activation of CO2. New kinds of supramolecular multifunctional heterobimetallic complexes which combine in the same molecular matrix a hydride transfer catalyst such as [MCp*(L)Cl+ (M = Ir(III) or Rh(III); L = bidentate ligand) and an electrocatalyst or photocatalyst like the metal carbonyl complexes Ru(L)(CO)2Cl2 or Re(L)(CO)3Cl, capable of reducing CO2 to CO, are proposed as effective materials for this type of catalytic activity. The presence of two different complex functions, coupled electronically by p-bridging ligands, and the proximity of the two metal centres in a closed molecular structure during the photo- and electrocatalysis of CO2 reduction is believed to induce a cooperative effect with the result of direct hydrogenation of CO (the primary two-electron reduction product), allowing for the production of hydrogenated compounds, e.g. methanol. The synthesis and the detailed physicochemical study (electrochemistry spectroscopy) of such new kinds of heterobimetallic complex catalysts of CO2 reduction are the principal objective of this project. To conduct this research, the scientifically complementary skills of both groups will be brought together in a synergistic function to design, synthesize and study in detail the new bifunctional molecular systems. Mechanistic studies of multielectron reactivity, including quantum-chemical calculations of precursors and essential intermediates will accompany the actual tests of the catalytic properties of the new systems in order to improve their performance.

• DFG Programme: Research Grants
• International Connection: France
• Participating Person: Alain Deronzier