Crystal Structure, spectroscopic investigations (FT-IR, UV/Vis), and DFT/QTAIM/NCI Computations of a novel (η2-hydrogencarbonato) Six-coordinate high-spin Iron(II) picket fence porphyrin complex

Abstract

In this work we have prepared the novel (η²-hydrogencarbonato) high-spin (S = 2) iron(II) picket fence porphyrin ([Fe^II(TpivPP)(η²-HCO₃)]⁻ ion complex (complex I) which was characterized by UV/Vis and IR spectroscopy and single crystal X-ray diffraction molecular structure. These techniques show that the HCO₃⁻ axial ligand is coordinated to the Fe²⁺ metal ion in a bidentate mode and that complex I is high-spin (S = 2). Density functional theory (DFT) calculations were performed on complex I using the DFT/B3LYP/LanL2DZ level of theory to study the HOMO-LUMO shapes and energy, Molecular Electrostatic Potential (MEP) as well as several other global chemical reactivity descriptors in order to evaluate the reactivity of our ferrous η²-hydrogencarbonato porphyrin coordination complex. Furthermore, Quantum Theory of Atoms in Molecules (QTAIM) and Non-Covalent Interaction (NCI) analyses have been performed to study the non-covalent interactions in the crystal lattice of complex I.