Studies on the electronic structure of thiolate-bridged diiron complexes and their single-electron reduction reactions

Abstract

The bdt-bridged diiron-amide complex [Cp∗Fe(μ-η2:η2-bdt)(μ-NH2)FeCp∗][BF4]2 (1[BF4]2, Cp∗=η5-C5Me5; bdt=benzene-1,2-dithiolate) and its reduction products [Cp∗Fe(μ-η2:η2-bdt)(μ-NH2)FeCp∗][BF4] (2[BF4]) and [Cp∗Fe(μ-η2:η1-bdt)(μ-NH2)FeCp∗] (3) have been synthesized. DFT calculations suggest that the sequential reduction of 1[BF4]2 to 2[BF4] and further to 3 is a bimetal and single-metal based process, respectively. The ground state of 1[BF4]2 is predicted to be quartet. 2[BF4] has an antiferromagnetic coupling BS(1,1) ground state, and the ground state of 3 is proposed to be BS(1,0). The bdt ligand in these three complexes is better viewed as a dianion ligand rather than a monoanionic radical.