Basheir A. El-Shetary

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.

Ligational behavior of thiosemicarbazone, semicarbazone and thiocarbohydrazone ligands towards VO(IV), Ce(III), Th(IV) and UO2(VI) ions: synthesis, structural characterization and biological studies.

Mono- and binuclear VO(IV), Ce(III), Th(IV) and UO(2)(VI) complexes of thiosemicarbazone, semicarbazone and thiocarbohydrazone ligands derived from 4,6-diacetylresorcinol were synthesized. The structures of these complexes were elucidated by elemental analyses, IR, UV-vis, ESR, (1)H NMR and mass spectra as well as conductivity and magnetic susceptibility measurements and thermal analyses. The thiosemicarbazone (H(4)L(1)) and the semicarbazone (H(4)L(2)) ligands behave as dibasic pentadentate ligands in case of VO(IV) and UO(2)(VI) complexes, tribasic pentadentate in case of Ce(III) complexes and monobasic pentadentate in case of Th(IV) complexes. However, the thiocarbohydrazone ligand (H(3)L(3)) acts as a monobasic tridentate ligand in all complexes except the VO(IV) complex in which it acts as a dibasic tridentate ligand. The antibacterial and antifungal activities were also tested against Rhizobium bacteria and Fusarium-Oxysporium fungus. The metal complexes of H(4)L(1) ligand showed a higher antibacterial effect than the free ligand while the other ligands (H(4)L(2) and H(3)L(3)) showed a higher effect than their metal complexes. The antifungal effect of all metal complexes is lower than the free ligands.

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.

Determination of some lanthanide ions by conductometric and spectrophotometric measurements of their hydrazo-5-pyrazolone complexes

Abstract A series of complexes of 1-phenyl-3-methyl-4( x -phenylhydrazo)-5-pyrazolone [where x = 2-OCH 3 (i), 2-COOH (ii), 2-OH-5-Cl (iii), 2-OH-5-CH 3 (iv), and 2-SO 3 Na-4-CH 3 (v)] with trivalent lanthanide ions, Ln (III) were investigated and used for determination of these ions by conductometric and spectral measurements. The results indicate the probable formation of 1:1 and 1:2 chelates (metal:ligand). Solid chelates were isolated and their structures established by elemental analysis and infrared spectral data. The hydrazo stretching frequency of NHN = appeared in the range 1535 to 1520 cm −1 , the carbonyl band from 1670 to 1650 cm −1 , ν M − N from 575 to 565 cm −1 , and ν M − O from 530 to 510 cm −1 . Ln (III) coordinate with hydrazo-5-pyrazolone derivatives to form chelate rings with benzenoid type resonance through π-bonding from the metal to the ligand. The Yb 3+ complexes with 2-hydroxy-5-methyl (iv) derivative were also investigated in solutions by spectrophotometric studies and were very useful in the microdetermination of this element.

Synthesis and Characterization of New Transition and Actinide Metal Complexes of a Hydrazone Ligand. Mixed‐Ligand Complexes, Pyrolysis Products, and Biological Activity

Abstract The chelating properties the hydrazone ligand 2‐carboxyphenylhydrazo‐ethylcyanoacetate (H2L) have been studied. A new series of binary mononuclear complexes were prepared from the reaction of the hydrazone ligand (H2L) with the metal ions, Cd(II), Cu(II), Ni(II), Co(II), Th(IV), and UO2(VI), in the presence of LiOH as a deprotonating agent. The binary Cu(II) complex of H2L was reacted with the ligands 1,10‐phenanthroline or 2‐aminopyridine to form mixed‐ligand complexes. The binary complexes of Cu(II) and Ni(II) are suggested to have octahedral configurations. The Cd(II) and Co(II) complexes are suggested to have tetrahedral and/or square‐planar geometries, respectively. The Th(IV) and UO2(VI) complexes are suggested to have octahedral and dodecahedral geometries, respectively. The mixed‐ligand complexes have octahedral configurations. Also, new complexes were obtained pyrolytically as the previous complexes decompose through several isolable as well as non‐isolable intermediates during heating. The structures of all complexes and the corresponding thermal products were elucidated by elemental analyses, conductance, IR and electronic absorption spectra, magnetic moments, 1H NMR and TG–DSC measurements, as well as by mass spectroscopy. The ligand and some of the metal complexes were found to activate the enzyme pectinlyase.

Determination of stability constants of some substituted 4-pyrazolone dyes containingo-methoxy,o-carboxy, ando-nitro groups with trivalent lanthanide ions

The relative stabilities of the metal derivatives of hydrazo pyrazolone dyes containingortho -OCH3, -COOH, and -NO2 groups have been measured potentiometrically in 75% (v/v) dioxane—water mixture at 30 °C and <0.1 ionic strength. The stability constant of their 1:1 and 1:2 chelates with twelve trivalent lanthanide ionsLn(III) have also been determined. The effects of substituents on the hydrazo-moiety of the ligand on the equilibria are discussed. The affinity of different ligands for complexation with lanthanide ions reaches its highest value withortho-carboxyphenylhydrazopyrazolone. The data were correlated and the results were used to explain the stabilization of such chelates by dative π-bonding betweenLn(III) and the ligand.ZusammenfassungEs wurden die relativen Stabilitäten der Metallderivate von Hydrazopyrazolon-Farbstoffen mitortho-OMe, -COOH und -NO2 potentiometrisch in 75% (v/v) Dioxan—Wasser bei 30 °C und einer Ionenstärke <0.1 bestimmt. Die Stabilitätskonstanten der 1:1 und 1:2 Chelate mit zwölf trivalenten LanthanidenionenLn(III) wurden ebenfalls gemessen. Die Substituenteneffekte werden diskutiert. Dabei zeigeno-Carboxyphenylhydrazopyrazolone die höchste Affinität zu Lanthanidenionen. Die Daten werden miteinander korreliert und die Resultate auf der Basis einer dativen π-Bindung zwischenLn(III)-Ion und dem Liganden diskutiert.

Thermodynamics, formation constants, spectrophotometry and infrared spectroscopy of complexes between some divalent metal ions and 3-hydrazino-6-phenylpyridazine and related ligands

Abstract The stepwise formation constants of complexes of Cu(II), Ni(II), Co(II), Mn(II), Zn(II), Cd(II) and UO 2 (II) ions with 3-hydrazino-6-phenylpyridazine (HPP) and its condensation products with benzil (BHPP) and p -methoxyacetophenone ( p -MeOAHPP) were determined in a 75% (v/v) dioxane-water mixture at μ = 0.05 M (KNC 3 ). The effect of temperature (at 10, 20, 30 and 40 °C) was also examined for Cu(II) and UO 2 (II)-BHPP complexes. The overall changes in Δ G , Δ H and Δ S have been calculated. The solid complexes of Cu(II)-, Co(II)- and Ni(II)-BHPP were prepared and examined by elemental analysis and IR spectroscopy. Analysis of the data indicates chelation of the BHPP ligand through the nitrogens of both hydrazone and the pyridazine ring and the carbonyl oxygen group. The spectrophotometric studies were performed on solutions of Cu(II), Ni(II) and Co(II) with BHPP in order to obtain the optimum pH values for complex formation. The compositions of the chelates formed were determined. Analytical determinations of the micro amounts of Cu(II), Ni(II) and Co(II) were also done using BHPP as the complexing agent.

Thermodynamics and formation constants of trivalent lanthanide metal ions with 3-hydrazino-6-phenylpyridazine and other related derivative ligands

Abstract Complexes of trivalent lanthanide metal ions with 3-hydrazino-6-phenylpyridazine (HPP) and its condensation products with benzil (BHPP) and p -methoxyacetophonone ( p -MeOPHPP) have been investigated by pH-metric titration in 75% (v/v) dioxane-water medium at 30 °C. The proton ligand stability constant (p K H ) and formation constants (log K 1 and log β) were calculated. Moreover, the effects of ionic strength (0, 0.05, 0.1 and 0.15), temperature (20, 30 and 40°C) and the dielectric constant (50, 60 and 75%, v/v, dioxane-water) were evaluated for some selected lanthanide(III)-BHPP complexes. The overall changes in Δ G , Δ H and Δ S were evaluated, and the relation Z 2 / r vs. log K 1 of lanthanide comnlxes was examined.

Azo Complexes of Cu(II), Co(II), Ni(II), Cd(II), Th(IV), and UO2(VI) Ions. Mixed‐Ligand Complexes, Pyrolysis Products and Biological Activity

Abstract The reactions of azo ligand, 2‐[2′‐carboxyphenylazo]‐5,5‐dimethyl‐1,3‐cyclohexane‐dione, (H2L), with the metal ion Cd(II), Cu(II), Ni(II), Co(II), Th(IV), or UO2(VI) in the presence of LiOH as a deprotonating agent, yielded binary mononuclear complexes. The binary Cu(II) complex reacts with the ligands 1,10‐phenanthroline or 2‐aminopyridine to form mixed‐ligand complexes. All the binary complexes of Cd(II), Cu(II), and Ni(II) have octahedral configurations, while the Co(II) complex is square‐planar. The binary complexes of Th(IV) and UO2(VI) have distorted dodecahedral geometries. The mixed‐ligand complexes have octahedral configurations. Thermal studies on these complexes showed the possibility of obtaining new complexes pyrolytically, where the complexes decompose through several isolable as well as non‐isolable intermediates during heating. The structures of all complexes and the corresponding thermal products were elucidated by elemental analyses, conductance, IR and electronic absorption spectra, magnetic moments, 1H NMR and TG–DSC measurements as well as by mass spectroscopy. The ligand and some of the complexes were found to activate the enzyme pectinlyase.

Complexation of uranyl (UO2+2) and thorium (Th4+) with arylbis( 5-hydroxy-3-methyl-1-phenylpyrazol-4-yl) methanes

Abstract The thermodynamic parameters of complexes of UO2(II) and Th(IV) cations with arylbis(5-hydroxy-3-methyl-1-phenylpyrazol-4-yl) methanes and other derivatives have been measured in 75% (v/v) methanol-water and 0.10 M KNO3 using potentiometry. Comparison of the experimental and calculated (using the modified Born equation) values of ΔG indicates the inner sphere nature of all the complex systems. The solid complexes were isolated and characterized by elemental analysis, conductance, infrared spectra, and by TG, DTG and DTA measurements. The ligands behave towards the metal ion as monobasic bidentate ligands.