Synthesis, spectral characterization, SC-XRD, HSA, DFT and catalytic activity of novel dioxovanadium(V) complex with aminobenzohydrazone Schiff base ligand: An experimental and theoretical approach

A new dioxovanadium(V) complex was prepared by the reaction of VO(acac)2 with a tridentate ONO donor Schiff base, derived by condensing 3-ethoxysalicylaldehyde and 4-aminobenzohydrazide. The structures of synthesized products were characterized spectroscopically through FT-IR, 1H & 13C NMR and by elemental composition through combustion analysis. The structure of the complex was determined with the help of single crystal X-ray crystallography. It was inferred from the diffraction data that the geometry around the central metal ion in the complex is distorted square pyramidal. The tridentate Schiff base ligand is bonded to the central metal through the oxygen of the carbonyl group, the deprotonated phenolic oxygen atom and the azomethine nitrogen. The pyramid base is completed by other oxo ligands that are in cis positions. The theoretical calculations, performed by DFT using B3LYP/Def2-TZVP level of theory, determined that the intended outcomes are in compliance with the actual consequences. Furthermore, the catalytic potential of the vanadium complex was explored for the selective oxidation of the aryl and alkyl sulfides to the corresponding sulfones in the presence of 30% aqueous H2O2 in ethanol. In this work, rPBE and B3LYP methods are used to locate transition structures and to compare free energies of reactants, transition structures and the products involved in the reaction. Analyzing nudge elastic band data shows that the barrier free energy for the oxidation of sulfide to sulfoxide and sulfone are 13 and 83 kcal.mol-1, respectively. The main advantages of the present catalytic study are high yields of the products, less time required for the completion of the reaction and simple work-out procedure.

Automated summary

The article discusses the synthesis and characterization of a new dioxovanadium(V) complex, as well as its catalytic potential for the oxidation of aryl and alkyl sulfides. Experimental and theoretical studies show that the complex exhibits good catalytic activity for the selective oxidation of sulfides to sulfones.