title: Reaction mechanism of epoxide cycloaddition to CO₂ catalyzed by salen-M (M = Co, Al, Zn).
abstract: We propose a catalytic mechanism for the cycloaddition of epoxide to carbon dioxide catalyzed by salen-M (M = Co, Zn, Al) based on density functional theory calculations. The catalytic reaction follows a single-site mechanism rather than a bimetallic-site mechanism, which includes four steps: epoxide adsorption by salen-M, ring opening of epoxide, CO2 insertion, and intramolecular rearrangement. Our calculation results showed that the highest reaction barrier for salen-Co catalyst is only 9.94 kcal/mol, which is lower than that of salen-Al (14.38 kcal/mol) and salen-Zn (13.05 kcal/mol). The results indicate that the reaction catalyzed by salen-Al, salen-Co, or salen-Zn can occur at room temperature and atmospheric pressure, which is in agreement with experimental results. The mechanism can be used for the design of a novel catalyst for this reaction.
authors.affiliation: State Key Laboratory of Molecular Reaction Dynamics, Dalian National Laboratory for Clean Energy, Dalian Institute of Chemical Physics, Chinese Academy of Sciences , Dalian, Liaoning 116023, China.
authors.forename: Ting-Ting
authors.initials: TT
authors.lastname: Wang
authors.forename: Yong
authors.initials: Y
authors.lastname: Xie
authors.forename: Wei-Qiao
authors.initials: WQ
authors.lastname: Deng