Publications by authors named "Rafat M El-Khatib"

The current research focuses on the treatment of Cr(III), Fe(III) and Cu(II) metal ions with aryl hydrazone ligand named (E)-4-(((diphenylmethylene)hydrazono)methyl)benzene-1,3-diol (DPHB) to afford four novel solid complexes with high yields. Different characterization approaches, including infrared, UV-visible, and NMR spectroscopies, elemental analyses, and thermal gravimetric analysis (TGA), revealed that all mononuclear crystalline metal chelates with good thermal stability had a six-coordination with octahedral geometry. Density Functional Theory (DFT) computations were used and provided a reasonable explanation for these metal chelates' electrical and structural features.

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The complexes of Fe(II), Cd(II) and Zn(II) with Schiff base derived from 2-amino-3-hydroxypyridine and 3-methoxysalicylaldehyde have been prepared. Melting points, decomposition temperatures, Elemental analyses, TGA, conductance measurements, infrared (IR) and UV-Visible spectrophotometric studies were utilized in characterizing the compounds. The UV-Visible spectrophotometric analysis revealed 1:1 (metal-ligand) stoichiometry for the three complexes.

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Three new nano sized Cu(II), Co(II) and Ni(II) complexes of imine ligand derived from the condensation of 2-amino-3-hydroxypyridine and 3-methoxysalicylaldehyde have been prepared and investigated using various chemical techniques such as NMR, elemental analysis, molar conductance, IR, electronic spectra, TGA and magnetic moment measurements. The obtained chemical analysis data showed that the synthesis of 1:1 (metal:ligand) ratio and octahedral geometry was proposed on the basis of magnetic moment and spectral data studies except the Cu(II) complex which is tetrahedral geometry. Nano-sized particles of the investigated complexes were prepared by sonochemistry method.

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In recent years, great interest has been focused on Fe(II) Schiff base amino acid complexes as cytotoxic and antitumor drugs. Thus a series of new iron(II) complexes based on Schiff bases amino acids ligands have been designed and synthesized from condensation of 5-bromosalicylaldehyde (bs) and α-amino acids (L-alanine (ala), L-phenylalanine (phala), L-aspartic acid (aspa), L-histidine (his) and L-arginine (arg)). The structure of the investigated iron(II) complexes was elucidated using elemental analyses, infrared, ultraviolet-visible, thermogravimetric analysis, as well as conductivity and magnetic susceptibility measurements.

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In this study, new Fe(II) Schiff base amino acid chelates derived from the condensation of o-hydroxynaphthaldehyde with L-alanine, L-phenylalanine, L-aspartic acid, L-histidine and L-arginine were synthesized and characterized via elemental, thermogravimetric analysis, molar conductance, IR, electronic, mass spectra and magnetic moment measurements. The stoichiometry and the stability constants of the complexes were determined spectrophotometrically. Correlation of all spectroscopic data suggested that Schiff bases ligands exhibited tridentate with ONO sites coordinating to the metal ions via protonated phenolic-OH, azomethine-N and carboxylate-O with the general formulae [Fe(HL)2]·nH2O.

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Rate constants for base hydrolysis of both coumarin and thiocoumarin have been studied in different binary aqueous-methanol mixtures at temperature range from 288 to 313 K. The activation parameters of the reactions were evaluated. Moreover, the change in the activation barrier of the investigated compounds from water to water-methanol mixtures were estimated from the kinetic data.

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