DFT study of the structural and redox properties of [Cp2Fe2S4]q complexes (q=0,+2,+1 and-2)

Geometry optimisation of [Cp2Fe2S4](q) complexes (q = 0, +2, +1 and -2) has been performed using DFT calculations with the B3LYP functional. The theoretical structures of the neutral (two isomers) and the dicationic complexes are in satisfactory agreement with the X-ray data. Structures are proposed for the monocationic and the dianionic species observed in cyclic voltammetry experiments. Free solvation energies have been computed by means of PCM calculations and used to evaluate the redox potentials of the M+/M, M2+/M+ and M/M2- couples in dichloromethane and acetonitrile.