An Fe(III)-carbonato six-coordinate picket fence porphyrin complex with the formula [K(2,2,2-crypt)][Fe^III(TpivPP)(CO₃)]·C₆H₅Cl·3H₂O (I) has been synthesized and characterized by UV-Vis and FT-IR spectra. The structure of (carbonato)(α,α,α,α-tetrakis(o-pivalamidophenyl)porphinato)ferrate(III) was also established by XRD. The iron atom is hexa-coordinated by the four nitrogen atoms of the pyrrol rings and the two oxygen atoms of the CO₃²⁻ group. Complex I, characterized as a ferric high-spin complex (S = 5/2), presented higher Fe-Np (2.105(6) Å) and Fe-P_C (0.654(2) Å) distances. Both X-ray molecular structure and Hirshfeld surface analysis results show that the crystal packing of I is made by C-H⋯O and C-H⋯Cg weak intermolecular hydrogen interactions involving neighboring [Fe^III(TpivPP)(CO₃)]⁻ ion complexes. Computational studies were carried out at DFT/B3LYP-D3/LanL2DZ to investigate the HOMO and LUMO molecular frontier orbitals and the reactivity within the studied compound. The stability of compound I was investigated by analyzing both intra- and inter-molecular interactions using the 2D and 3DHirshfeld surface (HS) analyses. Additionally, the frontier molecular orbital (FMO) calculations and the molecular electronic potential (MEP) analyses were conducted to determine the electron localizations, electrophilic, and nucleophilic regions, as well as charge transfer (ECT) within the studied system.

In this work, we report the synthesis, spectroscopic properties, electronic behavior, and DFT modeling of a hexa-coordinated chromium(iii) porphyrin complex, denoted as [Na(2,2,2crypt)][Cr^III(TPP)(NCO)₂]·0.406CHCl₃ (I).

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.