Alkali metals and ammonium as cations in dioxidovanadium(V) complexes with Schiff base ligands – structure, solubility and stability in biological media

Alkali metals (Li, Na, K, Rb and Cs) and ammonium salts were used in synthesis of [VO2L]− complexes (where L = ONO-donating Schiff base ligands derived from 2-hydroxybenzhydrazide and 5‑bromo- or 5-chlorosalicylaldehyde). All 12 compounds were characterized by elemental analysis, IR and UV–Vis spectra. For six complexes, the X-ray single crystal structures were determined and confirmed the general formula of the compounds as M[VO2L] (M = alkali metal or ammonium). The geometry as well as cation to vanadium distance were determined and discussed. The complexes have very good solubility in water and their stability in this solvent as well as at pH = 2 and in DMEM-high glucose cell culture media was tested by UV–Vis spectroscopy.