Polarographic Behaviour of Some 3-Pyridylazo Dyes

183-18

Polarographic Behaviour of Some 3-Pyridylazo Dyes

183-18

حسابات ثوابت الاستقرار لمتراكبات اللنثانيدات مع الآزو- بيتا- داي كيتونات

The stability constants of the complexes between the trivalent lanthanide series of cations and series of azo-B-diketone ligands are reported. The measurements were conducted at 30°C and zero ionic strength (free KN03), in 100 % methanol. The relation between the overall stability constant (Log B;) and atomic number of lanthanide elements, shows a gadolinium-break. The relation between (Log Bz) and the basicity of the studied ligands ( 2 pKi + pKz) are, also discussed. The overall stability values obtained reflected a great affinity of the organic ligands for chelation with lanthanide ions.‏‏ قد ورث ثوابت الاستقرار لمتراكبات كاتيونات اللنثانيدات الثلاثية مع بعض ليجاندات الآزو - بيتا - داي كيتون . واجريت القياسات عند ٣٠ ‏م وعند تركيز ايوني مقداره صفر باستخدام ١٠٠٠ ‏% ميثانول . وقد اظهرت العلاقة بين محصلة ثابت الاستقرار ‏ (loj B2) وبين الاعداد الذرية للنثانيدات منطقة منظمة عند الجاد ولينيوم . كما نوقشت العلاقة بين (loj B2) وقاعديه الليجاندات المدروسة وشرحت قيم ثوابت الاتزان . وقد اظهرت الدراسة من خلال حساب قيم ثوابت الاستقرار القابلية الكبيرة لليجاندات المستخدمة لتكوين متراكبات مع ايونات اللنثانيدات

Original scientific paper

Potentiometric and spectrophotometric studies of the complexation of Schiff-base hydrazones containing the pyrimidine moiet

Potentiometric and spectrophotometric studies of the complexation of Schiff-base hydrazones containing the pyrimidine moiety

Three Schiff-base hydrazones (ONN donors) were prepared by condensation of 2-amino-4-hydrazino-6-methylpyrimidine with 2-hydroxyacetophenone, 2-methoxybenzaldehyde and diacetyl to yield 2-OHAHP, 2-OMeBHP and DHP, respectively. The structures of these ligands were elucidated by elemental analysis, UV, IR, 1H-NMR and mass spectra. The metalligand stability constants of Mn2+, Fe3+, Co2+, Ni2+, Cu2+, Zn2+, Cd2+, UO22+ and Th4+ chelates were determined potentiometrically in two different media (75 % (v/v) dioxanewater and ethanolwater) at 283, 293, 303 and 313 K at an ionic strength of 0.05 M (KNO3). The thermodynamic parameters of the 1:1 and 1:2 complexes were evaluated and are discussed. The dissociation constants of 2-OHAHP, 2-OMeBHP and DHP ligands and the stability constants of Co2+, Ni2+ and Cu2+ with 2-OHAHP were determined spectrophotometrically in 75 % (v/v) dioxanewater

Structural characterization of immobilized-polysiloxane iminobis (N-diethylenediamineacetamide) ligand system

Insoluble porous solid polysiloxane immobilized ligand system bearing chelating ligand group of the general formula P(CH2)3N[CH2CONH(CH2)2NH(CH2)2NH2]2 (where P represents [SiO]n polysiloxane network) has been prepared by the reaction between the polysiloxane immobilized diethyliminodiacetate ligand system, P(CH2)3N(CH2CO2Et)2 and diethylenetriamine in toluene. The XPS and FTIR results showed that all ethylacetate groups (COOEt) are converted into the amide groups (NCO). The new functionalized ligand system exhibits high capacity for the uptake of the metal ions (Mn2+, Fe3+, Co2+, Ni2+, Cu2+ and Zn2+). Complexation of the prepared ligand system for these metal ions at the optimum conditions was found in the order: Cu2+>Ni2+>Fe3+>Co2+>Mn2+>Zn2+. This ligand system shows higher capacity toward the metal ions than its iminiodiactate precursor which we have been