Exploring the Oxidation of Olefins and Intrinsic Bromoperoxidase-like Catalytic Activities of Highly Nonplanar and Robust Triphenylamine Based Oxidovanadium(IV) Porphyrin

The utilization of metalloporphyrins as green catalysts for environmental and industrial applications is an active area of research. Herein, we have synthesized highly nonplanar oxovanadium 2,3,7,8,12,13,17,18-octatriphenylamino-meso-5,10,15,20-tetraphenylporphyrin, VOTPP(TPA)8 and characterized by various spectroscopic techniques viz. mass spectrometry, cyclic voltammetry, UV-Vis. and DFT calculations. VOTPP(TPA)8 exhibited severe saddled shape conformation and blue-shifted electronic spectral features as compared to freebase. The first oxidation potential of VOTPP(TPA)8 exhibited a cathodic shift of 360 mV as compared to VOTPP. VOTPP(TPA)8 was investigated as an efficient catalyst for selective epoxidation of various alkenes in very good yields and high TOF numbers (11447-13026 h1) with H2O2 as an oxidizing reagent and NaHCO3 as a promotor in CH3CN/H2O as the solvent at the ambient temperature. This catalyst also showed very high TOF values (147213-210305 h1) during catalytic oxidative bromination of phenol and some of their derivatives under acidic conditions (i.e. HClO4) in the presence of KBr as a bromine source using 30% aqueous H2O2. The recyclability of VOTPP(TPA)8 as a catalyst in these catalytic processes is confirmed by the UV–Vis. spectroscopy and MALDI-TOF spectrometry. VOTPP(TPA)8 porphyrin catalyst was recovered carefully at the end of the various catalytic cycles in both catalytic processes indicating it is reusable and of industrial importance.