The cis influence of the corrin in vitamin B12 models

P. P. Govender (1) , Isabelle Navizet (2) , C. B. Perry (2) , H. M. Marques (2)

1 Department of Applied Chemistry [University of Johannesburg]
2 Molecular Science Institute, School of Chemistry

Density Functional Theory (DFT) and Quantum Theory of Atoms in Molecules (QTAIM) calculations on [NH3[Co(III)(C10-X-corrin)]-CH3]+, where the C10-H of corrin is replaced by electron-donating or -withdrawing groups, X, explore the cis influence in these vitamin B12 models. As the electron donating ability of X increases, a normal trans influence is observed: the Co-NH3 bond weakens while the Co-CH3 bond strengthens. Surprisingly, though, the Co-CH3 bond dissociation energy decreases monotonically as the Co-C bond strengthens. This is found to be a consequence of the extent of shortening of the Co-NH3 during the homolysis reaction.

Domaines: Chimie théorique et/ou physique

P. P. Govender, Isabelle Navizet, C. B. Perry, H. M. Marques. The cis influence of the corrin in vitamin B12 models. Chemical Physics Letters, 2012, 550 (1), pp.150-155. ⟨10.1016/j.cplett.2012.08.061⟩. ⟨hal-00749810⟩