Shehab A. Sallam

Copper, nickel and cobalt complexes of Schiff-bases derived from β-diketones

Complexes of CuII, NiII, CoII and FeIII with Schiff-bases derived by condensing o-aminophenol and ethanolamine with dibenzoylmethane, benzoylacetone, acetylacetone and thenoyltrifluoroacetone have been prepared and characterized by elemental analysis, electrical conductivity, magnetic moment, d.t.a. and t.g.a. measurements, i.r., u.v.–vis., e.s.r. and Mössbauer spectra. All the complexes are non-electrolytes. Those with 1:2 metal:ligand ratios have an octahedral or distorted octahedral environment. Square-planar, Td or D2d structures have been proposed for the 1:1 complexes. The Mössbauer spectrum of the FeIII complex confirms its high-spin octahedral stereochemistry.

SCHIFF BASES OF ACETONE DERIVATIVES : SPECTROSCOPIC PROPERTIES AND PHYSICAL CONSTANTS

Summary. Schiff bases of acetylacetone, benzoylacetone, dibenzoylmethane, and thienoyltrifluoroacetone with ethanolamine and 2-aminophenol were synthesized and characterized by elemental analysis, infrared and 1H NMR spectra. Dissociation constants of the synthesized ligands were determined in methanol-water and at an ionic strength of 0.1 M KNO3 at different temperatures; the associated thermodynamic parameters were calculated. Single crystals of one of the ligands were prepared; the X-ray diffraction pattern was analyzed. Thermal analyses of the investigated ligands were performed and correlated with the ligand structure.Zusammenfassung. Schiffsche Basen von Acetylaceton, Benzoylaceton, Dibenzoylmethan und Thienoyltrifluoroaceton mit Ethanolamin und 2-Aminophenol wurden hergestellt und mittels Elementaranalyse, IR-Spektroskopie und 1H-NMR-Spektroskopie charakterisiert. Die Dissoziationskonstanten wurden in Ethanol-Wasser bei einer lonenstärke von 0.1 M KNO3 bei verschiedenen Temperaturen bestimmt; die entsprechenden thermodynamischen Größen wurden berechnet. Das Röntgendiffraktionsmuster eines Einkristalls einer der Verbindungen wurde analysiert. Thermische Untersuchungen wurden durchgeführt und die Ergebnisse mit den Strukturen korreliert.

HPLC method for the simultaneous determination of atenolol and chlorthalidone in human breast milk

A high-performance liquid chromatographic method was optimized and validated for the determination of atenolol and chlorthalidone (CT) in human breast milk. The milk samples were extracted and purified using ACN and phosphoric acid for precipitation of proteins followed by removal of ACN and milk fats by extraction with methylene chloride. The samples were applied, after an extraction procedure, to a cyanide column using a mobile phase consisting of ACN/water (35:65 v/v) and buffered at pH 4.0 with flow rate of 1.0 mL/min. Quantitation was achieved with UV detection at 225 nm using guaifenesin as the internal standard. The effectiveness of protein precipitation and clean up procedure were investigated. The method was validated over the range of 0.3-20 microg/mL for atenolol and 0.25-5 microg/mL for CT.

High-Performance Liquid Chromatographic Determination of Flavoxate Hydrochloride and its Hydrolysis Product

Liquid chromatographic method was presented for the determination of flavoxate hydrochloride (FX) and its hydrolysis product. The method was based on high-performance liquid chromatographic (HPLC) separation of FX from its hydrolysis product on CN column using a mobile phase consisting of acetonitrile-12 mM ammonium acetate (45:55, vol/vol, pH 4.0) with UV detection at 220 nm and flow rate of 1.5 mL min−1. The proposed HPLC method for the determination of FX was utilized to investigate the kinetics of acidic hydrolytic process at different temperatures and to calculate its activation energy. In addition, the proposed HPLC method was used for pH-rate profile study of hydrolysis of FX in Britton–Robinson buffer solutions. The 3-methylflavone-8-carboxylic acid ethyl ester, as impurity of flavoxate hydrochloride, can be separated by the proposed HPLC method.

Lanthanide complexes of D-penicillamine: formation constants, spectral and thermal properties

The complex-formation of lanthanide(III) elements with D-penicillamine have been investigated in acidic and neutral media. The macroscopic protonation constants of the ligand and the formation constants of [Ln.Pen]+, [Ln.Pen2]−, [Ln.Pen.OH] and [Ln.Pen.(OH)2]− complexes were determined from pH-metric data using the BEST computer program. Elemental analyses of the solid complexes indicate formation of 1 : 1 metal : ligand species. The binding sites in the complexes with the possible role of –COO−, –NH2 and –SH groups in the coordination have been discussed using infrared data. The complexes decompose in four steps as shown by their t.g. and d.t.a. analyses. A mechanism of decomposition is proposed which is supported by mass spectral data.

Synthesis and characterization of 3-amino-5-methylisoxazole Schiff bases and their complexes with copper(II), nickel(II) and cobalt(II)

Schiff bases obtained by condensing 3-amino-5-methylisoxazole with salicylaldehyde, 2,3-dihydroxybenzaldehyde, 2,4-dihydroxy-benzaldehyde, 2,5-dihydroxybenzaldehyde or o-hydroxynaphthaldehyde were obtained and characterized by C, H, N analysis, mass, NMR and IR spectra. Copper, nickel and cobalt complexes of the Schiff bases were prepared and characterized using elemental analysis, conductivity measurements, magnetic moments, IR, UV-VIS and ESR spectra, X-ray diffraction, TGA, DTA and DSC thermal analysis. All the complexes are non-electrolytes. ESR spectra show isotropic as well as axial symmetry for the copper complexes. Thermal studies support the formulation of these complexes and showed that they decompose in two or three steps depending on the metal used. Activation energy E a and enthalpies ΔH associated with the decomposition process were calculated and correlated with the complexed metal used.

Lanthanide Complexes with D-Penicillamine Methyl Ester: Formation Constants, Spectral and Thermal Properties

Abstract The complex-formation of the lanthanide(III) cations with D-penicillamine methyl ester have been investigated in acidic and neutral media. The macroscopic protonation constants of the ligand and the formation constants of [Ln·Pme]2+, [Ln·(Pme)2]+, [Ln·Pme·OH]+ and [Ln·Pme·(OH)2] complexes have been determined from pH-metric data using BEST computer program. Species distribution diagrams of the complexes were obtained and plotted using SPE and SPEPLOT computer programs. Elemental analyses of the solid complexes indicate the formation of 1:1 metal:ligand species. Infrared spectra show that coordination takes place through the NH2, the SH and the C=O groups of the ligand. The complexes decompose in four steps as shown by their TG and DTA analysis with the formation of Ln2(SO4)3 as a final product. Activation energy values (ΔEa) are correlated with the atomic radii of the metal ions. The mechanism of the thermal decomposition is proposed.

Synthesis, characterization and toxicity of Cu(II) complexes with metformin Schiff-bases

ABSTRACTCopper complexes of Schiff-bases of metformin with each of salicylaldehyde (HL1); 2,3-dihydroxybenzaldehyde (H2L2); 2,4-dihydroxybenzaldehyde (H2L3); 2,5-dihydroxybenzaldehyde (H2L4); 3,4-d...