Synthesis and Characterization of Two Ligand Polydentals and Their Complexes with Cobalt(ІІ) and Copper(ІI) Derived from Pyridine-2,6-Dicarbohydrazide and Studying the Biological Activity of Complexes.

Two tridentate-type Schiff-bases’ ligands: 2,6-bis[(salicylidene) hydrazinocarbonyl] pyridine (L) and 2,6-bis[(3-methoxysalicylidene) hydrazinocarbonyl] pyridine (L') are synthesized from the reaction of pyridine2,6-dicarbohydrazide with salicylaldehyde and 3-methoxy salicylaldehyde. The co-ordination behaviour of the (L) and (L') towards Cu(II) and Co(II) ions is investigated. The reaction of the Schiff-base ligands (L) and (L') with cobalt(II) and copper(II) ions in 1:3 molar ratio affords polynuclear metal complexes. The shifts of the some IR-bands’ spectra of synthesized complex in the selected vibrational bands in FT-IR indicate that Schiff bases behave as trilydentate ligands and co-ordinate to metal ions from phenolic oxygen atoms, amide and azomethine nitrogen atoms. The structure of the metal complexes exhibits octahedral arrangements. The antibacterial activity of the ligand (L) and its metal complexes against two bacterial species is studied. The Co(II) complex indicates a good inhibition activity. The structures of the ligands are elucidated by FT-IR, 1H-NMR, and UV–Vis electronic spectra. The characterization and structure elucidation of the complexes are achieved by FT-IR, UV–Vis electronic spectra. [ABSTRACT FROM AUTHOR]