Computational Investigations of Heme Carbenes and Heme Carbene Transfer Reactions

Engineered heme proteins and biomimetic iron porphyrins have been found to possess excellent catalytic properties for numerous carbene transfer reactions. Computational studies, including the use of DFT calculations and molecular dynamics simulations, have been employed to help understand some important mechanistic aspects of heme carbene transfer reactions. This review summarizes advances in the computational results published in the following two areas: 1) the electronic and geometric structures of heme carbenes; spectroscopic properties; and effects of carbene substituent, porphyrin substituent, axial ligand, and spin state on heme carbene formation; and 2) mechanisms of heme carbenoid X-H (X=C, Si, B, N, S) insertions and cyclopropanation, including effects of heme carbene structural components and protein environment, as well as oxidation state and spin state. A brief outlook of future development is also addressed.