New mixed ligand cobalt(II/III) complexes based on the drug sodium valproate and bioactive nitrogen-donor ligands. Synthesis, structure and biological properties

Abstract

New cobalt valproate complexes with different nitrogen based ligands were synthesized and characterized using various techniques such as IR, UV–Vis, single crystal X-ray diffraction as well as other physical properties. The general formula of the prepared complexes is [Con(valp)m(L)z], (n = 1, 2 …; m = 1, 2, …; Z = 1, 2 …). The complexes [Co2(valp)4] (1), [Co(valp)2(2-ampy)2] (2) and [Co2(valp)4(quin)2] (3) showed different carboxylate coordination modes. The crystal structures of the complexes 2 and 3 were determined using single crystal X-ray diffraction. Kinetic studies of hydrolysis reactions of BNPP [bis-(p-nitrophenyl)phosphate] with complexes 2 and 3 were performed. The hydrolysis rate of BNPP was studied at different temperatures, pH and concentrations by UV–Vis spectrophotometric method. The results showed that the hydrolysis rate of BNPP was 7.70 × 102 L mol−1 s−1 for (3) and 2.60 × 10−1 L mol−1 s−1 for (2).