Synthesis and Conjoint Experimental-DFT Characterization of Some Pyrazolone Functionalized Dioxovanadium (V) Schiff Base Complexes

Abstract

This paper is concerned with the synthesis and hyphenated DFT-experimental characterization of dioxovanadium(V) complexes of semicarbazone ONO-donor ligands, LH [where, LH = N-(4’-benzoylidene-3’- methyl-1’-phenyl-2’-pyrazolin-5’-one)-semicarbazone (bmphp-semH), N-(4’-butylidene-3’-methyl-1’-phenyl-2’- pyrazolin-5’-one)-semicarbazone (bumphp-semH), N-(4’-iso-butylidene-3’-methyl-1’-phenyl-2’-pyrazolin-5’-one)- semicarbazone (iso-bumphp-semH) or N-(3’-methyl-1’-phenyl-4’-propionylidene-2’-pyrazolin-5’-one)-semicarbazone (mphpp-semH)] and were prepared from ethanol-methanol mixed solvent (1/10) solutions of bis(acetylacetonato) oxovanadium(IV) complexes of the above ligands by oxidizing with atmospheric oxygen (bubbling air) for 2-3 days. The composition and formulae of complexes were confirmed by various physiochemical analysis, viz., percentage of different elements, magnetic susceptibility, conductance, FT-IR, UV-Visible and mass spectrometry. One of the representative complexes, cis-[VO2(bmphp-sem)(H2O)] was investigated at the convergence of DFT and experimental formulation interface. The standard B3LYP/LANL2DZ combinations were used to arrive at the approx of geometry optimization, charge distribution and molecular orbital descriptions. The global reactivity parameters like absolute electronegativity (χabs) and absolute hardness () have also been involved. From the overall studies it has been found that the compounds possess cis-octahedral structure.