Oxidation Product of Oxidovanadium Porphyrin: Combination of Experimental and Computational Study

Abstract

Oxidovanadium 5,10,15,20-tetrakis(3,4,5-trimethoxyphenyl)porphyrin, VO[(3,4,5-(OCH₃)₃TPP)] (complex 1) has been synthesized. The oxidation products of complex 1 were identified and analyzed using Cyclic Voltammetry, UV-Vis, Electron Paramagnetic Resonance, and Nuclear Magnetic Resonance techniques. Cyclic voltammetric data show that complex 1 exhibits a one-electron oxidation process, resulting in the creation of a π-cation radical. This observation is further confirmed by the analysis of the complex using FT-IR. The addition of CF₃COOH (TFA) with complex 1 has resulted in the development of mono-cation with geometrical changes from square pyramidal to octahedral, which has been confirmed by UV-Vis and EPR spectra.The interaction between Complex 1 and TFA, is investigated by Non-covalent Interaction (NCI) analysis, Visual Molecular Dynamics (VMD) visualization, Electron Localization Function (ELF) analysis, and Molecular Electrostatic Potential (MEP) mapping. The vanadium atom in Complex 1 interacts with the oxygen atom in CF₃COOH at a distance of 2.18 Å. NCI and RDG analyses highlight the predominant van der Waals interactions. VMD visualization confirmes these interactions with green patches. ELF analysis shows strong electronic localization around certain atoms and delocalized electron clouds. MEP mapping reveals nucleophilic and electrophilic sites, with prominent acidic strength around the complex and TFA.