Adel S. Orabi

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.

Synthesis, characterization and oxidase catalytic activity of vanadium(IV) and oxovanadium(IV) complexes with Schiff base ligands derived from β-diketones

New complexes of vanadium(IV) and oxovanadium(IV) with Schiff base ligands derived from β-diketones and ethanolamine or o-aminophenol have been prepared and characterized by elemental analyses, electrical conductance, magnetic moment measurements, and by i.r., u.v.–vis. and e.p.r. spectroscopy. A distorted octahedral environment was proposed for the vanadium(IV) and oxovanadium(IV) complexes. The spectroscopic results were utilized to compute the important ligand field parameters. Three adduct complexes were isolated owing to the interaction of one oxovanadium complex with Lewis-bases in MeOH. Vanadium(IV) complexes exhibit promising catalytic activity towards the aerobic oxidation of p-phenylenediamine (PPD) to the corresponding semi-oxidized form (PPD+). A linear correlation exists between the oxidase catalytic activity and the Lewis acidity of the central vanadium(IV) ion created by the donating properties of the parent ligand.

Spectral, coordination and thermal properties of 5-arylidene thiobarbituric acids

Synthesis of 5-arylidine thiobarbituric acids containing different functional groups with variable electronic characters were described and their Co(2+), Ni(2+) and Cu(2+) complexes. The stereochemistry and mode of bonding of 5-(substituted benzylidine)-2-TBA complexes were achieved based on elemental analysis, spectral (UV-VIS, IR, (1)H NMR, MS), magnetic susceptibility and conductivity measurements. The ligands were of bidentate and tridentate bonding through S, N and O of pyrimidine nucleolus. All complexes were of octahedral configuration. The thermal data of the complexes pointed to their stability. The mechanism of the thermal decomposition is discussed. The thermodynamic parameters of the dissociation steps were evaluated and discussed.

Physical characteristics, vibrational spectroscopy and normal-coordinate analysis of 2-aminophenol and 2-phenylenediamine complexes

Hg(II) and Cd(II) complexes with 2-aminophenol (Amph) and 2-phenylenediamine (Phda) as ligands were prepared and characterized by elemental analysis, electrical conductivity, thermogravimetric analysis (DTA/TG), X-rays, FT-IR and FT-Raman spectra. The complexes formed can be formulated as [M(L)2/n H2O]/m H2O. The electrical conductivity of 0.001 M DMSO solutions revealed the non-electrolytic behavior of the Amph complexes while Phda complexes behave as a 1:2 electrolyte. DTA analysis reveals the presence of two types of water coordinating as aligned and as water of crystallization. DEa of the stepwise decomposition was evaluated. X-ray powder diffraction studies on the ligands and their complexes are described. The fundamental frequencies of these complexes have been assigned on the basis of normal coordinate calculations, carried out using a generalized valence force field (GVFF). The proposed assignments are discussed in relation to the group frequencies in structurally related molecules and in terms of the computed potential-energy distributions among the symmetry coordinates. # 2002 Elsevier Science Ltd. All rights reserved.

PHYSICO-CHEMICAL PROPERTIES OF Nd(III) AND Er(III) COMPLEXES WITH SOME BIOLOGICAL BUFFER LIGANDS

The new Nd(III) and Er(III) complexes with the zwitterionic buffer ligands N-tris[hydroxymethyl]methyl-3-aminopropanesulfonic acid sodium salt (NaTAPS) and 3-[N,N-bis(2-hydroxyethyl) amino]-2-hydroxypropanesulfonic acid sodium salt (NaDIPSO) have been prepared and characterized by IR, DTA, TG, mass, elemental analyses and electrical conductivity measurements. The Nd(III) complexes may be formulated as [Nd(DIPSO)2H2O)n]NO3· mH2O, where n = 1 and m = 1 for NaDIPSO as ligand while n = 2 and m = 0 for NaTAPS as ligand, [Nd(TAPS)2(H2O)n]NO3. The Er(III) complexes may be described as [Er(DIPSO)2(H2O)n]Cl · mH2O, where n = m = 2 for NaDIPSO as ligand while n = 2 and m = 0 for NaTAPS as ligand. Thermogravemetric studies show that the Er(III) complexes are thermally more stable than the Nd(III) complexes. The electrical conductivity of DMF solutions of these complexes indicate 1:1 electrolytic behavior.

Physical Properties of Some New Uranyl Complexes with Ligands Derived from Acetone

Summary. Uranyl complexes with 1,3-diphenyl-1-(2-hydroxy-anilidino)-1-propylidin-3-one (H2A), 1,3-diphenyl-1-ethanolimine-propylidin-3-one (HB1), 4-phenyl-2-ethanolimino-2-butylidin-4-one (HB2), and 2-ethanolimino-2-pentylidin-4-one (HB3) as ligands were prepared and characterized by elemental analysis, electrical conductivity measurements, magnetic susceptibility determination, mass, IR, and UV/Vis spectroscopy, and thermogravimetry. The complexes can be formulated as [UO2L(H2O)(NO3)]ċnH2O with the exception of UO2-HB1 which has to be written as [UO2L2(H2O)]ċnH2O. The structures of these complexes were fitted using Alchemy III. The thermogravimetric studies suggest the following order of relative thermal stability of the complexes: UO2-H2A>UO2-HB1≈UO2-HB2>UO2-HB3. ΔEact (calculated from the endothermic peaks) of the liberation of H2O of crystallization increases within the order UO2-HB3>UO2-HB1>UO2-HB2>UO2-H2A. The antimicrobial activities of the prepared complexes have been tested.Zusammenfassung. Uranylkomplexe mit 1,3-Diphenyl-1-(2-hydroxy-anilidino)-1-propylidin-3-on (H2A), 1,3-Diphenyl-1-ethanolimin-propylidin-3-on (HB1), 4-Phenyl-2-ethanolimino-2-butylidin-4-on (HB2) und 2-Ethanolimino-2-pentylidin-4-on (HB3) als Liganden wurden hergestellt und mittels Elementaranalyse, Konduktivitäts- und Suszeptibilitätsmessungen, Massen-, IR- und UV/Vis-Spektroskopie sowie Thermogravimetrie charakterisiert. Die Komplexe können als [UO2L(H2O)(NO3)]ċnH2O formuliert werden; eine Ausnahme bildet UO2-HB1, dem die Formel [UO2L2(H2O)]ċnH2O zugeordnet wird. Die Strukturen der Komplexe wurden mit Hilfe des Programms Alchemy III gefittet. Die thermogravimetrischen Untersuchungen legen die Stabilitätsreihenfolge UO2-H2A>UO2-HB1≈UO2-HB2>UO2-HB3 nahe. ΔEact der Freisetzung des Kristallwassers, berechnet aus den endothermen Peaks, steigt in der Reihenfolge UO2-HB3>UO2-HB1>UO2-HB2>UO2-H2A. Die antimikrobielle Aktivität der hergestellten Komplexe wurde untersucht.

Complexes derived from some biologically active ligands

Complexes derived from ampicillin (L1) and amoxicillin (L2) with (Mg(II), Ca(II), Zn(II), Cu(II), Ni(II), Co(II), Ce(III), Nd(III), UO2(VI), Th(IV)) were prepared and characterized by elemental analysis, electrical conductivity measurements, magnetic susceptibility, IR, UV/Vis, and thermogravimetry. The formed complexes can be formulated as (ML(H2O)3(NO3) n ) except for Ce(III) which gave (CeL(H2O)3(Cl)2). The 1H NMR spectra of the Zn(II) complexes are compared to spectra of the ligands. The shift (δ) gave information about the chelating center of the ligands. The ligands and the synthesized complexes, derived from some alkali earth and transition metal ions, were tested as antibacterial reagents. The formed complexes had enhanced activity.

Solvent Extraction and Separation of Thorium(IV) from Chloride Media by a Schiff Base

The Schiff base extractant, (E)-4-(2-hydroxyethylimino)pentan-2-one (AcEt), for thorium(IV) ions was characterized in methylene chloride in chloride media. Analyses of the conventional log10D versus pH and versus log10 thorium ion concentration plots of the extraction equilibrium data reveal that the thorium(IV) ions were extracted as a complex that is characterized by having one ionizable hydrogen ion and a metal:ligand ratio of 1:1. The effects of contact time, A:O phase ratio and temperature on the extraction and stripping were studied. Extraction and stripping isotherms were constructed to determine the theoretical stages of the extraction and stripping processes. The thermodynamic parameters Gibbs energy (∆G°), enthalpy (∆H°) and entropy (∆S°) changes associated with the extraction processes were evaluated. Finally, the optimum parameters of solvent extraction were applied to a chloride leach liquor.Graphical Abstract

Spectral, Magnetic, Thermal, and DNA Interaction of Ni(II) Complexes of Glutamic Acid Schiff Bases

Ni(II) complexes with Schiff bases obtained by condensation of glutamic acid with salicylaldehyde; 2,3-; 2,4-; and 2,5-dihydroxybenzaldehyde; and o-hydroxynaphthaldehyde have been synthesized using the template method in ethanol or ammonia media. They were characterized by elemental analyses, conductivity measurements, magnetic moment, UV, IR, and 1H NMR spectra as well as thermal analysis (TG, DTG, DTA). The Schiff bases are dibasic tridentate or tetradentate donors and the complexes have square planar and octahedral structures. The complexes decompose in two or three steps where kinetic and thermodynamic parameters of the decomposition steps were computed. The interactions of the formed complexes with FM-DNA were monitored by UV and fluorescence spectroscopy.