Magdy H. Seada

Metal chelates of azo-pyridazine dyes: Chelating tendencies of benzoylacetone-monohydrazone-3-hydrazino-4-benzyl-6-phenylpyridazine (bahp)

The synthesis, acid-base equilibria and metal-ion chelating tendencies of BAHP are reported. From potentiometric equilibrium measurements of hydrogen-ion concentration at 30 degrees and ionic strength 0.10M (KNO(3)), in 75% dioxan-water medium, the values of the stability constants of some BAHP complexes with transition, non-transition and lanthanide ions have been evaluated. Probable structures of the metal chelates are inferred from the electronic absorption spectra and infrared examination of the solid copper complex. The use of BAHP as an analytical reagent for the spectrophotometric determination of copper, nickel and cobalt ions is discussed.

Metal chelates of azo-pyridazine dyes-II : Chelating tendencies of diacetyl-, benzil- and benzoylethane-monohydrazone-3-hydrazino-4-benzyl-6-phenylpyridazine

Abstract The diacetyl-(DAHP), benzil-(BHP) and benzoylethane-(BEHP) derivatives of 3-hydrazino-4-benzyl-6-phenylpyridazine have been prepared and characterized. Their acid-base properties and their equilibria with transition metal ions in 75% dioxan-water solvent at 30°C have been investigated by pH titrimetry. The role of proton and metal ion solvation by the organic solvent has been discussed in view of the results obtained for the lanthanide-BHP systems in different media. Probable structures of the metal chelates are given based on potentiometric data and spectral results for the solid copper chelates. The possibility of forming MHL species were inferred from electronic absorption measurements at different pH values. The use of BHP as an analytical reagent for the determination of copper spectrophotometrically or as a metallochrom indicator in the complexometric titration of Cu(II) ion is also discussed.

Metal chelates of azo-pyridazine dyes III chelating tendencies of pyruvic and hippuric monohydrazone-3-hydrazino-4-benzyl-6-phenylpyridazine

The synthesis and quantitative equilibrium studies of two new azo-pyridazine ligands, namely the pyruvic (PHP) and hippuric (HipHP) acid derivatives are described in detail. Their acid-base and metal-ligand equilibrium constants in 75% dioxan-water solvent at 30 °C have been calculated from potentiometric and spectrophotometric data. The probable structures are inferred from electronic and vibrational spectral results. Evidence is presented for the formation of protonated complexes withPHP.ZusammenfassungDie Synthese und quantitative Gleichgewichtsuntersuchungen von zwei neuen Azo-pyridazin-Liganden, die von Brenztraubensäure (PHP) bzw. Hippursäure (HipHP) abzuleiten sind, werden im Detail beschrieben. Die entsprechenden Säure-Base- und Metall-Ligand-Gleichgewichtskonstanten in 75% Dioxan-Wasser bei 30 °C wurden aus potentiometrischen und spektrophotometrischen Daten ermittelt. Die wahrscheinlichen Strukturen wurden von Elektronen- und IR-spektroskopischen Daten abgeleitet. Es sind Beweise vorhanden, daß mitPHP protonierte Komplexe gebildet werden.

Complexing behavior of 3-(p-, m- and o-hydroxybenzylidene-amino) -4,6-dimethyl-1H-pyrazolo[3,4-b] pyridine(p-, m- and o-HDMPP) with lanthanides and some of transition metals

The stability constants of the complexes between a series of lanthanide(III), UO[sub 2](II), Cu(II), Ni(II) and Co(II) cations and p-, m- and o-HDMPP ions have been measured using potentiometric methods. The formation constants for o-HDMPP is larger than those for m- and p-HDMPP. The results are explained in terms of the differences in the dentate character of these ligands. The coordination sites on o-HDMPP are inferred through the study of infrared spectra, elemental analysis and conductance for o-HDMPP-Cu(II) chelate. 31 refs., 4 figs., 2 tabs.

Synthesis, Characterization and ِAntimicrobial Activities of Some New Heterocyclic Schiff Bases Derived from Thiocarbohydrazide

The reaction of prazolobenzothienopyrimidine-3-carbaldehyde 1 with thiocarbohydrazide afforded the Schiffs base 3. The latter compound reacted with some electrophilic reagents to give 1,2,4-triazoles 4-6 and 1,2,4-triazines 7-9. Treatment of compound 3 with 2-cyano-3,3-bis(methylthio)acrylonitrile gave the corresponding 5-amino-4-cyano-3-methylthiopyrazole derivative 11. The reaction of pyrazole 11 with carbon disulfide afforded dithioxopyrazolopyrimidine 12. Acylation of compound 11 by using acetic anhydride yielded acetamide 13. On the other hand, the cyclocondensation of pyrazole 11 with acetic anhydride in pyridine yielded pyrazolopyrimidine derivative 14. The reactivity of compound 11 towards formamide and phenylisothiocyanate to give the pyrazolopyrimidines 15 and 16 was studied. The newly synthesized compounds were screened for their antimicrobial activity.