Synthesis, Characterization, and Biological Evaluation of Two Hydrazone Schiff Base Ligands and their Transition Metal Complexes

Schiff bases are widely employed as chelating ligands in coordination chemistry, and their metals complexes have been extensively studied because of their potential applications. N, N-donor Schiff bases ligands are know to form series of transition-metal complexes display interesting structures antioxidant and antibacterial propreties. In this work, two new ligands and their corresponding complexes are prepared. The two ligands are structurally characterized by elemental analysis, infrared, NMR and UV-Vis spectroscopy as well as molar conductance measurements. Ligand H2LA is obtained from the condensation of 5-bromo-2-hydroxyacetophenone with nicotinohydrazide whereas ligand H2LB is synthesized from 4-hydroxy-3-methoxybenzaldehyde and nicotinohydrazide. Two water molecules are associed with H2LB. In this paper the antibacterial activities of the ligands are investigated. Ligand H2LB crystallizes in the monoclinic system, space group P21/c with the unit cell parameters a = 7.9079(2) Å, b = 27.5162(6) Å, c = 6.9736(2) Å, α = 90°, β = 110.495(3) °, γ = 90°.