A theoretical study on CO2 inserting into C-H bond

Density functional theory (DFT) and second-order Moller-Plesset theory (MP2) have been employed to investigate CO2 inserting into C-H bond, where CO2 is in the form of an anion CO2-. The reaction begins with CO2 fixing on the pyrrole to produce ion-complex I via C-C bond formation between the carbon atom of pyrrole and the carbon atom of CO2. Subsequent re-aromatization by dehydrogenation or hydrogen migration, furnishes electron-molecule compounds III, which release the excess electron to produce pyrrole-carboxylic acid. The C-H bond activation and the formation of an extended pi-orbital network play important roles in the re-aromatization process. (C) 2016 Elsevier B.V. All rights reserved.