SPIN-FORBIDDEN CO BINDING TO IRON-SULFUR CLUSTER-FREE HYDROGENASE: A DENSITY FUNCTIONAL STUDY

Spin-forbidden CO binding to the iron-sulfur cluster-free hydrogenase (Hmd) is studied by the DFT calculation. The result shows that the surface of the triplet causes a PHmd-CO minimum and that (MECP)-M-3,5 is the lowest energy path to PHmd-CO. It is found that this CO binding involves a low barrier of 0.931 kcal/mol because of the need to change from a bound triplet state to the Hmd quintet ground state.