Investigation of the interaction of the cationic nitrosyl iron complex [Fe(SC(NH2)2)2(NO)2]+ with molecular oxygen

Abstract

The interaction of a nitrosyl iron complex with molecular oxygen was studied with Density Functional Theory. On the basis our analysis of the geometric and electronic structure of the complex, three variants of coordination of the oxygen molecule on it were investigated: the attachment of molecular oxygen to the iron center, an insertion of oxygen in between the Fe and NO and the bridging of two nitrosyl ligands. All of the coordination complexes require approximately the same amount of energy input to form. In all of the oxygen-enriched nitrosyl complexes we calculated, the doublet state was energetically below the quartet state. Next, we considered decomposition pathways since the products of all of these oxygen-attaching pathways may then decompose further. The result of this decomposition is either the release of nitrogen monoxide or the release of nitrogen dioxide. For all the three processes, transition and intermediate states were found, as well as the final products. The potential energy surfaces of the most important reactions were plotted. Finally, UV spectra of all the possible products of the oxidation of complex by molecular oxygen were calculated.