A theoretical study on single-electron reduction of a thiolate-bridged diiron diazene complex

Abstract

The single-electron reduction of the thiolate-bridged diiron diazene complex [Cp*Fe(μ-SEt)2(μ-η1:η1-HNNH)FeCp*]+ (Cp*=η5-C5Me4H, 1+) to [Cp*Fe(μ-SEt)2(μ-η1:η1-HNNH)FeCp*] (2) has been computationally found to be a metal-based reduction process. Such a reduction event decreased the acidity of NH bond and increased the basicity of N atoms of the diazene moiety. The results derived from broken-symmetry calculations suggest that the electronic ground state of 1+ is better described as antiferromagnetic BS (2,1) and both BS (1,1) and RKS states could coexist in the case of 2. Both the charge decomposition and atom-in-molecule analysis indicate a donor–acceptor interaction between the Fe centers and the diazene ligand.