Synthesis, spectroscopic characterization, structural analysis and DFT study of a five-coordinate iron(III) octaethylporphyrin complex

A five-coordinate chlorido-iron(III) octaethylporphyrin complex [Fe III (OEP)Cl] has been synthesized and investigated experimentally by UV–visible and IR spectroscopy and theoretically using density functional theory (DFT). The crystal geometry of the chloride Fe(III) octaethylporphyrin indicates that the mean equatorial distance between the iron ion and the four nitrogen atoms of the porphyrin (Fe-Np) is equal to 2.063 Å, indicating that the title compound is a ferric high-spin complex (S = 5/2). According to the Hirshfeld surface analysis (HS), the H—H (64.5%) interaction makes a major contribution to the molecular surface. Density functional theory (DFT) calculations were performed at the B3LYP-D3/LANL2DZ level to investigate the ground-state molecular structure, frontier molecular orbitals, global reactivity parameters, molecular electrostatic potential, and electronic absorption properties of the complex. Furthermore, to evaluate the internal interactions, the natural bond orbital (NBO) approach was employed. These results provide a comprehensive understanding of the optoelectronic and spectroscopic characteristics of this complex, making it a significant contribution to the field of molecular chemistry and materials science.