Unraveling the catalytically preferential pathway between the direct and indirect hydrogenation of CO2 to CH3OH using N-heterocyclic carbene-based Mn(i) catalysts: a theoretical approach

Abstract

CO₂ hydrogenation to CH₃OH is a pivotal transformation for various reasons. A series of N-heterocyclic carbene (NHC)-based Mn-catalysts have been investigated using the density functional theoretical studies for the CO₂ hydrogenation to CH₃OH. The catalytic hydrogenation of CO₂ to CH₃OH can be achieved through direct and/or indirect mechanisms. In the present work, we have carried out both direct and indirect pathways for CO₂ hydrogenation to CH₃OH in the presence of NHC-based Mn(I) catalysts. Various mechanistic pathways have been explored for the reaction. In this study, we show that NHC-based Mn(I) catalysts can be very promising for CO₂ hydrogenation due to the presence of the non-innocent NHC ligand, and these catalysts also favor the direct pathway over the indirect pathway for the CO₂ hydrogenation reaction.