A Recent Study on the Synthesis and DFT Collaborated Experimental 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 (c_abs) and absolute hardness (h) have also been involved. From the overall studies it has been found that the compounds possess cis-octahedral structure.