Vanadium complexes with salicylaldehyde-based Schiff base ligands—structure, properties and biological activity SzklarzewiczJanusz JurowskaAnna HodorowiczMaciej GrybośRyszard KruczałaKrzysztof Głuch-LutwinMonika KazekGrzegorz 2020 <p>Schiff base ligands based on 5-bromosalicylaldehyde and 4-tertbutylbenzhydrazide or benzhydrazide were used in syntheses of eight vanadium complexes with VOSO<sub>4</sub>(aq), [VO(acac)<sub>2</sub>] and [V(acac)<sub>3</sub>] in ethanolic solution. In selected syntheses 1,10-phenanthroline (phen), 2,2’-bipyridine (bpy) or 2,5-pyridinedicarboxylic acid (dpy) were used as co-ligands to fill the coordination sphere and to increase complex stability. The complexes were characterized by elemental analyses, IR, UV-Vis, EPR spectroscopy, cyclic voltammetry, magnetic susceptibility and for one complex two single crystal X-ray structures were determined for complexes with two different solvent molecules (H<sub>2</sub>O and MeCN). Three complexes were found to be active in inhibition of human recombinant PTP1B, one of them is twice more active than suramin.</p>