Excess-electron-induced C–C bond formation in transformation of carbon dioxide
Abstract
This study presents a new fixation method of CO2 through excess-electron-induced C–C bond formation using quantum chemical method. Because of active CO2−˙ with a distinct radical character at the carbon center, two divalent anion complexes [O2C–C6H6–CO2]2− (cis-II and trans-II) are obtained via C–C bond formation between the carbon atom of C6H6 and the carbon atom of CO2 in the process of CO2−˙ radical attacking on benzene molecule. Furthermore, the transformations of cis-II and trans-II are predicted. We found that the more favorable transformation is for cis-II. It can produce terephthalic and one H2 molecule via two H-atom elimination with the energy barrier of 35.70 kcal mol−1. Furthermore, we found that the formed hydrogen bond complex CO2–HCN did not reduce the energy barrier; however, it could reduce the energy of the transition state with respect to that of the reactant, due to it dispersing the charge of benzene ring.