Oxovanadium(IV) complexes of medicinal relevance: Synthesis, characterization, and 3D-molecular modeling and analysis of some oxovanadium(IV) complexes in O,N-donor coordination matrix of sulfa drug Schiff bases derived from a 2-pyrazolin-5-one derivative

The present paper reports the synthesis and characterization of some new oxovanadium(IV) complexes of composition[VO(L)2(H2O)]·H2O, where LH = N-(4′-butyrylidene-3′-methyl-1′-phenyl-2′-pyrazolin-5′-one)sulfadiazine (bumphp-sdzH), N-(4′-butyrylidene-3′-methyl-1′-phenyl-2′-pyrazolin-5′-one)sulfaguanidine (bumphp-sgnH), N-(4′-butyrylidene-3′-methyl-1′-phenyl-2′-pyrazolin-5′-one)sulfani-lamide (bumphp-snmH), and N-(4′-butyrylidene-3′-methyl-1′-phenyl-2′-pyrazolin-5′-one)sulfamerazine (bumphp-smrH). These complexes were prepared by the reaction of vanadyl sulfate pentahydrate with the ligands in 1:2 metal–ligand ratios, in ethanol. The compounds so obtained were characterized by different physicochemical studies, such as, elemental analyses, molar conductance, and magnetic measurements, thermogravimetry, cyclic voltammetry, infrared, electron spin resonance, and electronic spectral studies. The overall IR studies conclude that the ligands in the present investigation behave as monobasic bidentate O,N-donors. The 3D molecular modeling and analysis for bond lengths and bond angles have also been carried out for one of the representative compounds,[VO(bumphp-sdz)2(H2O)]·H2O (1) to substantiate the proposed structure. Based on these studies suitable octahedral structures have been proposed for these complexes.