Elucidation for coordination features of hydrazide ligand under influence of variable anions in bivalent transition metal salts; green synthesis, biological activity confirmed by in-silico approaches

Synthesis of new N′- cyclohexylidene-3‑hydroxy-2-naphthohydrazide (H2L) complexes was carried out by ball milling technique in the lack of solvent (green approach) and then characterized by analytical and spectroscopic techniques. The metal salts used for preparations, were varied in their conjugated anions (Cl−, SO4−2 & OAc−) to investigate the changes in properties of obtained complexes, by changing anions, even with the same ligand. The ligand was coordinated mainly as monobasic with the metal acetate salts, while a neutral with metal chloride or sulfate salts. Such coordination modes were appeared through bidentate or tridentate towards central metals within different molar ratios (1: 1 or 1:2, M:L). Conductometric study was performed for Co(II) complex to estimate the complex stoichiometry and either formation or association constants, in solution state. DMOL3 program was used via DFT/B3LYP method to optimize the studied compounds and to obtain essential quantum parameters. Consequently, we confirmed the coordination of O(11), O(13) and N(16) atoms according to their features appeared in molecular modeling study. In-silico assessment was performed to examine the interaction features of new compounds with pathogenic-DNA, before in-vitro screening. Such assessment was carried out firstly by pharmacophore query within MolPort drug-library to discover the analogues drugs in activity towards DNA proteins. MolPort-007–588–377 and MolPort -000–734–772 were the code numbers of two analogues drugs. Secondly MOE-docking process was executed to explain all interaction features and rank the inhibition activity of complexes. Furthermore, antimicrobial, antioxidant and antitumor activity were investigated for all compounds and Ni(II)-Bis(HL) complex showed excellent antioxidant activity. Whereas, Co(II)-Bis(HL) complex showed excellent cytotoxicity towards liver cancer cells. Finally, the whole characteristics of complexes were changed by changing conjugated anions, even with the same ligand.