Redox reactions of binuclear tetranitrosyl iron complexes with bridging N-C-S ligands

Abstract

Reduction of neutral binuclear tetranitrosyl iron complexes of “μ-N-C-S” structural type of [Fe2(SR)2(NO)4] composition with R being functional azaheterocyclic thiolyls has been studied by cyclic voltammetry in aprotic solvents in a wide range of potential scan rates. Redox potentials of these reactions have been determined. The consecutive transfer of two electrons was shown to be typical for all the complexes. For some complexes the products of the first electron addition are unstable, while for the others the products of reduction by both the first and the second electrons are stable. The calculations of geometric and electronic structures of monoanions, dianions and intermediates forming upon the reduction of the complexes were performed by DFT methods. Using quantum-chemical modeling, electrochemical reduction of the complexes has been studied; their energy and theoretical redox potentials have been calculated.