Polymer complexes. LXXV. Characterization of quinoline polymer complexes as potential bio-active and anti-corrosion agents.

The Cu2+, Co2+, Ni2+ and UO22+ polymer complexes of 5-(2,3-dimethyl-1-phenylpyrazol-5-one azo)-8-hydroxyquinoline (HL) ligand were prepared and characterized. Elemental analyses, IR spectra, X-ray diffraction analysis and thermal analysis studies have been used to confirm the structure of the prepared polymer complexes. The chemical structure of metal chelates commensurate that the ligand acts as a neutral bis(bidentate) by through four sites of coordination (azo dye nitrogen, carbonyl oxygen, phenolic oxygen and hetero nitrogen from pyridine ring). The molecular and electronic structures of the hydrogen bond conformers of HL ligand were optimized theoretically and the quantum chemical parameters were calculated. Elemental analysis data suggested that the polymer complexes have composition of octahedral geometry for all the polymer complexes. Molecular docking of the binding between HL and the receptors of prostate cancer (PDB code 2Q7L Hormone) and the breast cancer (PDB code 1JNX Gene regulation) was studied. The interaction between HL and its polymer complexes with the calf thymus DNA (CT-DNA) was determined by absorption spectra. The antimicrobial activity of HL and its Cu2+, Co2+, Ni2+ and UO22+ polymer complexes were investigated; only Cu(II) polymer complex (1) was specifically active against Aspergillus niger. It inhibited the fungal sporulation and distorted the fungal mycelia, which became squashed at a concentration of 150 µg/ml; transmission electron microscope (TEM) also showed a deactivation of autophagy in the treated A. niger cells via accumulation of autophagic bodies in vacuoles. The inhibition process of the prepared ligand (HL) against the corrosion of carbon steel in 2 M HCl solution was determined by various methods (weight loss, potentiodynamic polarization, electrochemical impedance spectroscopy (EIS) and electrochemical frequency modulation (EFM) techniques) are found to be in reasonable agreement. The mechanism of inhibition in presence of HL in carbon steel corrosion obeys Friendlish adsorption isotherm.