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

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 [Co-n(valp)(m)(L)(z)], (n = 1, 2 ...; m = 1, 2, ...; Z = 1, 2 ...). The complexes [Co-2(valp)(4)] (1), [Co(valp)(2)(2-ampy)(2)] (2) and [Co-2(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 x 10(2) L mol(-1) s(-1) for (3) and 2.60 x 10(-1) L mot(-1) s(-1) for (2). (C) 2017 Elsevier B.V. All rights reserved.