Ab initio study on the binding of carbon dioxide to cobalt salen complex

Abstract

Metal-organic complexes, such as metal-Schiff bases, can function as catalysts for electrochemical reduction. In this work we present first principles electronic structure calculations for the adduct formation involving carbon dioxide (CO₂) and cobalt salen [Co(salen)] complex. Binding energy calculations show that carbon dioxide forms a stable adduct with [Co(salen)]^- complex. The bonding between carbon dioxide and the cobalt metal center involves back-bonding mainly between the metal d_z² orbital and the π* orbital of CO₂. An accompanying partial charge transfer from Co to CO₂ was observed. This study can be used as a preliminary result to further study the structure and stability of other cobalt-carbon complexes.