title: Potentiometric, spectrometric, thermal and conductimetric studies on some 3-phenyl-4-(arylazo)-5-pyrazolones and their complexes with divalent cobalt metal ion.
abstract: 3-phenyl-4-arylazo-5-pyrazolones (I-IV) have been synthesized and characterized by elemental, infrared (IR), ultraviolet and visible spectra (UV-Vis), proton nuclear magnetic resonance (1H NMR) and Mass spectra. It has been proved that these compounds exhibit a keto-enol tautomerism in solution. The donor character of the substituent increases the enol form. The ionization constants of the investigated ligands have been determined potentiometrically and found to decrease in the order OCH(3)(IV)>CH(3)(III)>H(I)>Cl(II). The Co(II) complexes of the investigated 3-phenyl-4-arylazo-5-pyrazolones (I-IV) have been prepared and characterized by elemental and thermal analyses as well as by IR, UV-Vis, electronic transition, potentiometric, conductimetric and magnetic measurements. The data suggest octahedral geometry for Co(II) (1:1) complexes and tetrahedral for Co(II) (2:3) complexes.
authors.affiliation: Faculty of Science, Chemistry Department, Cairo University, Giza, Egypt.
authors.forename: H B
authors.initials: HB
authors.lastname: Hassib
authors.forename: S A
authors.initials: SA
authors.lastname: Abdel-Latif
mesh_terms: D003035:Cobalt / Q000378:metabolism*; D004553:Electric Conductivity; D006358:Hot Temperature; D008024:Ligands; D009682:Magnetic Resonance Spectroscopy; D013058:Mass Spectrometry; D011199:Potentiometry; D011720:Pyrazoles / Q000737:chemistry* / Q000378:metabolism; D047069:Pyrazolones; D013055:Spectrophotometry, Infrared
chemical_list: D008024:Ligands; D011720:Pyrazoles; D047069:Pyrazolones; C038362:pyrazolone; D003035:Cobalt