Computational Design of New Heterofullerene-Based Biomimetic α-Carbonic Anhydrase Analogues.

Abstract

The biomimetic CO2 hydration activity of Ru/Rh-doped fullerenes was revealed by using density functional theory calculations. The mechanism of CO2 hydration on the proposed heterofullerenes followed the mechanistic action of α-carbonic anhydrases, and consisted of the adsorption and deprotonation of H2 O, CO2 interaction with hydroxyl groups, CO2 bending, and proton transfer to give the HCO-3 product. Free-energy landscapes for the reaction showed the catalysts to be active for the reaction. H2 O adsorption over the catalysts was exergonic whereas CO2 adsorption over the catalyst-OH complex was observed to be an endergonic process. Intramolecular proton transfer resulting in the final product, HCO-3 , was found to be the rate-limiting step for the reaction on C56 N3 M (M=Ru/Rh), whereas H2 O dissociation was found to be the rate-limiting step for the reaction on C59 M (M=Ru/Rh). C56 N3 M catalysts were found to be superior to C59 M catalysts for biomimetic CO2 hydration, as indicated by the free-energy landscapes and energy requirements.