Metal- and ligand-substitution-induced changes in the kinetics and thermodynamics of hydrogen activation and hydricity in a dinuclear metal complex

Abstract

Catalytic function in organometallic complexes is achieved by carefully selecting their central metals and ligands. In this study, the effects of a metal and a ligand on the kinetics and thermodynamics of hydrogen activation, hydricity degree of the hydride complex, and susceptibility to electronic oxidation in bioinspired NiFe complexes, [Ni^IIX Fe^II(Cl)(CO)Y]⁺ ([NiFe(Cl)(CO)]⁺; X = N,N′-diethyl-3,7-diazanonane-1,9-dithiolato and Y = 1,2-bis(diphenylphosphino)ethane), were investigated. The density functional theory calculations revealed that the following order thermodynamically favored hydrogen activation: [NiFe(CO)]²⁺ > [NiRu(CO)]²⁺ > [NiFe(CNMe)]²⁺ ∼ [PdRu(CO)]²⁺ ∼ [PdFe(CO)]²⁺ ≫ [NiFe(NCS)]⁺. Moreover, the reverse order thermodynamically favored the hydricity degree.