The carbonyl insertion reaction of ethylCo(CO) n(PH 3) 4− n and vinylCo(CO) n(PH 3) 4− n: A detailed DFT study

Abstract

A DFT study on CO insertion into Co-ethyl and Co-vinyl is carried out comprehensively. All structures are optimized completely and the mechanism of the CO insertion is discussed in detail. These CO insertion processes of ethylCo(CO) n (PH 3) 4− n and vinylCo(CO) n (PH 3) 4− n ( n=1–4) are actually alkyl migration onto carbonyl. The entropy does not play a critical role in the ethyl and vinyl migration. The computational results indicate that CO insertion into sp 2-C is easier than the CO insertion into sp 3-C from the view of kinetics except for the three-PH 3-ligand-substituted system. It attributes to the interaction between the 3d orbital of Co and π orbital of vinyl, possibly. Transition sates of all processes occur late on potential energy surface and the transition states of vinyl migration occur later than ethyl migration.