DFT computational study on Fe(III)-N,N′-ethylene-bis(salicylideneiminato) derivatives

DFT calculations, at unrestricted B3LYP level, have been performed on the structures of three iron(III) complexes, Fe(Salen)Cl, [Fe(Salen)]+ and [Fe(Salen)OH2]+, where Salen is the anion of Schiff base ligand N,N′-ethylene-bis (salicylideneimine), considering the spin multiplicity (S) values 2, 4 and 6. The results obtained have been compared with the available structural an magnetic experimental data, allowing us to conclude that a stable form of the FeIII(Salen) complex in aqueous solution should be characterized by an energy stabilization of the S=4 compared to the S=6 state.