title: Stereochemistry of new nitrogen containing heterocyclic aldehyde. VII. Potentiometric, conductometric and thermodynamic studies of novel quinoline azodyes and their metal complexes with some transition metals.
abstract: A novel series of quinoline azodyes (5-(4'-derivatives phenyldiazo)-8-hydroxy-7-quinolinecarboxaldehyde)) (HL1-HL5) has been prepared and characterized by elemental analyses, 1H-NMR and IR spectra. The IR spectral data indicate that the compounds can exist in two resonance structures. Proton-ligand dissociation constants of quinoline azodyes and their subsituted derivatives, and metal-ligand stability constants of their complexes with bivalent (Mn2+, Co2+, Ni2+, Cu2+) metal ions have been determined potentiometrically in 0.1 m KCl and 40% (v/v) dimethylformamide (DMF)-water mixture. The influence of substituents on the dissociation and stability constants was examined on the basis of the electron repelling property of the substituent. The order of the stability constants of the formed complexes was found to be Mn2+ < Co2+ < Ni2+ < Cu2+. The effect of temperature was studied and the corresponding thermodynamic parameters (deltaG, deltaH, deltaS) were derived and discussed. The stoichiometries of these complexes were determined conductometrically and indicated the formation of 1:1 and 1:2 (metal:ligand) complexes was indicated.
authors.affiliation: Chemistry Department, Faculty of Science, Mansoura University, Demiatta, Egypt. abdelkhedr@yahoo.com
authors.forename: A Z
authors.initials: AZ
authors.lastname: El-Sonbati
authors.forename: A A
authors.initials: AA
authors.lastname: El-Bindary
authors.lastname: Shoair AGF
authors.forename: R M
authors.initials: RM
authors.lastname: Younes
mesh_terms: D000447:Aldehydes; D001391:Azo Compounds / Q000737:chemistry; D004553:Electric Conductivity; D007202:Indicators and Reagents; D008024:Ligands; D008670:Metals / Q000737:chemistry*; D011199:Potentiometry; D011522:Protons; D011804:Quinolines / Q000737:chemistry*; D013055:Spectrophotometry, Infrared; D013696:Temperature; D013816:Thermodynamics
chemical_list: D000447:Aldehydes; D001391:Azo Compounds; D007202:Indicators and Reagents; D008024:Ligands; D008670:Metals; D011522:Protons; D011804:Quinolines