Influence of the ligands on the molecular hydrogen binding with a half-model of the [NiFe]-hydrogenase active site

The density functional for the characterization of the half-model [NiFe]-hydrogenase active site is defined. The binding energy of the molecular hydrogen with ferrous iron in [FeCO(SCH 3) 2(CN) 2H 2] 2- complex is determined by the coupled cluster with the full treatment singles and doubles and estimate to the connected triples contribution using many-body perturbation theory. The results show that ligands in [Fe(SCH 3) 2(CO) 3P 2], [Fe(SCH 3) 2(CN) 3H 2] 3-, [FeCN(SCH 3) 2(CO) 2H 2] 1, [FeCO(SCH 3) 2(CN) 2H 2] 2- complexes form a distorted octahedral coordination with ferrous iron. The substitution of the CO by CN ligand in complex [FeCO(SCH 3) 2(CN) 2H 2] 2- leads to the stabilization of molecular hydrogen in the vertex of octahedron and elongation H-H bond. It is determined that all modeled structures are Cubas complexes.