Synthesis, spectral characterization, SC-XRD, HSA, DFT and catalytic activity of a dioxidomolybdenum complex with aminosalicyl-hydrazone Schiff base ligand: An experimental and theoretical approach

Abstract

A new dioxidomolybdenum(VI) complex has been successfully prepared by the reaction of an ONO donor Schiff base, derived by condensing 4-amino-2-hydroxybenzohydrazide and 3-methoxysalicylaldehyde, with MoO2(acac)2. The structures of synthesized products were explored spectroscopically through FT-IR, 1H &13C NMR and by elemental composition (CHN) through combustion analysis. The structural investigations of the dioxidomolybdenum(VI) complex were accomplished by taking its diffraction data through X-ray crystallography. The tridentate Schiff base ligand is bonded to the central metal through its deprotonated enolic and phenolic oxygen atoms and by the nitrogen of the azomethine group. The interpretation of the data obtained through diffraction analysis validates the distorted octahedral geometry of the prepared metal complex. QTAIM, MEP and NCI calculations and Hirshfeld surface analysis were performed to investigate the nature and types of non-covalent linkages present among the sample molecules. The theoretical calculations, performed by DFT using the B3LYP/Def2-TZVP level of theory, direct that the intended outcomes are in compliance with the actual consequences. Furthermore, the catalytic potential of the molybdenum complex was explored for the selective oxidation of benzylic alcohols to the desirable aryl aldehydes at room temperature in the presence of 70% aqueous tert-butyl hydroperoxide (TBHP) under solvent-free conditions. The main advantage of the present catalytic work is the accomplishment of reaction in a short period of time, high percentage yield and easy work-out procedure.