Synthesis, spectroscopic characterization, biological application and molecular docking studies of some transition metal complexes of isophthalamide ligand

Various spectrum techniques were used to analyze the newly synthesized isophthalamide ligand, N1,N3-bis(1-hydrazinyl-1-oxopropan-2-yl)isophthalamide (L). The reaction of isophthalamide ligand with Fe(III), Co(II), Ni(II) and Zn(II) ions produced complexes of 1:1 (M:L) stoichiometry. The spectral data, FTIR and NMR disclosed that the isophthalamide ligand chelated the central metal ions in neutral tetradentate manner via the two carbonyl oxygens and two amide nitrogen atoms. The octahedral configuration of the complexes has been elucidated by electronic and magnetic moment measurements. The molar conductivity described the electrolytic nature of the synthesized complexes. The structural features of the title compounds were investigated based on mass spectral analysis which showed good agreement between the calculated and experimental data and in concise with the elemental analyses data. The thermal decomposition characteristics of the ligand and its complexes are measured using thermogravimetric analysis. The DFT quantum chemical simulation validated the suggested structures and was used to calculate HOMO-LUMO energies. To optimize the structural formula for the examined ligand, the Gaussian09 program was used. The existence of Fe(III) and Ni(II) complexes in the nanostructure was confirmed using a scanning electron microscope (SEM). The isophthalamide ligand and its transition metal complexes were studied for their antibacterial characteristics against two Gram-positive bacteria (Bacillissubtilis and Staphylococcus aureus) and two Gram-negative (Escherichia coli and Pseudomonas aeruginosa) microorganisms. Title complexes were shown to be more physiologically active than the parent ligand. The title compounds have a positive interaction with the crystal structures of 3t88-E. coli, 3ty7-Staphylococcus aureus, 5h67-Bacillus subtilis, and 5i39-Pseudomonas aeruginosa, according to molecular docking study.