Axial ligand influence on geometries, charge distributions and electronic structures of iron tetraazamacrocycle [Fe(II)TIM(X)(Y)]2+ complexes assessed by Density Functional Theory

► Back-donation is not an important issue in these FeTIM compounds. ► The macrocycle total charge is correlated to the axial ligand chemical nature. ► The MLCT transition energy is correlated to the total charge of the macrocycle. ► The low spin state in these systems is stabilized by the field of the axial ligands.