Direct Hydrogenation of Carbon Dioxide by an Artificial Reductase Obtained by Substituting Rhodium for Zinc in the Carbonic Anhydrase Catalytic Center. A Mechanistic Study
Recently, a new artificial carbonic anhydrase enzyme in which the native zinc cation has been replaced with a Rh(I) has been proposed as a new reductase that is able to efficiently catalyze the hydrogenation of olefins. In this paper, we propose the possible use of this modified enzyme in the direct hydrogenation of carbon dioxide. In our theoretical investigation, we have considered different reaction mechanisms such as reductive elimination and σ-bond metathesis. In addition, the release of the formic acid and the restoring of the catalytic cycle have also been studied. Results show that the σ-bond metathesis potential energy surface lies below the reactant species. The rate-determining step is the release of the product with an energy barrier of 12.8 kcal mol–1. On the basis of our results, we conclude that this artificial enzyme can efficiently catalyze the conversion of CO2 to HCOOH by a direct hydrogenation reaction.