An investigation by DFT of the electronic structure and magnetic properties of a novel μ-oxo-iron(III) complex with the 1,10-phenathroline ligand

Abstract

The crystal structure of (H-phen)2[Fe2(μ-O)(H2O)6(phen)2](NO3)6has been determined using single-crystal X-ray crystallography at low and room temperature. Complex 1 crystallizes in the monoclinic C2/c space group. This compound contained two iron(III) centers which are bridged by one oxygen atom to form dinuclear units. This binuclear complex exhibits strong antiferromagnetic coupling between the two iron(III) centers with g = 2, S = 5/2 and J = −223 cm−1. An investigation of the magnetic order was performed using spin projected broken symmetry via density functional theory. This approach of broken symmetry (BS) has provided a good numerical estimation of the J value (J = −198 cm−1), which is in agreement with the experimental magnetic susceptibility measurements. By means of DFT and TD-DFT methods, the electronic absorption and infrared spectra of the title compound were predicted with good agreement with the experimental data. Natural bond orbital (NBO) analysis has been used to explain the formation of a hydrogen bond and the most possible interaction. In addition, the chemical reactivity of the complex has been obtained by mapping electron density with molecular electrostatic potential (MEP) and the electrical, optical and chemical properties have been investigated through the energies of the frontier molecular orbitals (FMO).