Shaban E. Ghazy

Characterization and biological studies on Co(II), Ni(II) and Cu(II) complexes of carbohydrazones ending by pyridyl ring

The chelating behavior of ligands based on carbohydrazone core modified with pyridine end towards Co(II), Ni(II) and Cu(II) ions have been examined. The ligands derived from the condensation of carbohydrazide with 2-acetylpyridine (H(2)APC) and 4-acetylpyridine (H(2)APEC). The (1)H NMR, IR data and the binding energy calculations of H(2)APC revealed the presence of two stereoisomers syn and anti in the solid state and in the solution. The (1)H NMR, IR data and the binding energy calculations confirmed the presence of H(2)APEC in one keto form only in the solid state and in the solution. The spectroscopic data confirmed that H(2)APC behaves as a monobasic pentadentate in Co(II) and Cu(II) complexes and as mononegative tetradentate in Ni(II) complex. On the other hand, H(2)APEC acts as a mononegative tridentate in Co(II) complex, neutral tridentate in Ni(II) complex and neutral bidentate in Cu(II) complex. The electronic spectra and the magnetic measurements of complexes as well as the ESR of the copper complexes suggested the octahedral geometry. The bond length and bond angles were evaluated by DFT method using material studio program. The thermal behavior and the kinetic parameters of degradation were determined using Coats-Redfern and Horowitz-Metzger methods. The antioxidant (DDPH and ABTS methods), anti-hemolytic and in vitro Ehrlich ascites of the compounds have been screened.

Heterocyclic substituted thiosemicarbazides and their Cu(II) complexes: synthesis, spectral characterization, thermal, molecular modeling, and DNA degradation studies

Four Cu(II) complexes of N 1-phenyl-N 2-(pyridin-2-yl)hydrazine-1,2-bis(carbothioamide) (H2PPS), N-phenyl-2-(2-(pyridin-2-ylcarbamothioyl)hydrazinyl)-2-thioxoacetamide (H2PBO), N-phenyl-2-(pyridin-2-ylcarbamothioyl)hydrazinecarboxamide (H2APO), and 1-(aminoN-(pyridin-2-yl)methanethio)-4-(pyridin-yl)thiosemicarbazide (H2PPY) have been prepared and characterized by elemental analyses, spectral (infrared (IR), UV-Visible, 1H NMR, and electron spin resonance (ESR)) as well as magnetic and thermal measurements. Varying the substituents on the thiosemicarbazide led to remarkable modifications of the mode of coordination. IR spectral data reveal that the ligands are SN bidentate, NON tridentate, or NSNS tetradendate chelates forming structures in which copper is square-planar or octahedral. ESR spectra of these complexes are quite similar and exhibit an axially symmetric g-tensor parameter with g|  > g ⊥ > 2.0023 revealing an appreciable covalency with d( x 2 –y 2 ) as the ground-state. Bond lengths, bond angles, HOMO, LUMO, and dipole moments have been calculated to confirm the geometry of the thiosemicarbazide derivatives and their corresponding complexes. Proton-ligand dissociation and copper-ligand stability constants of all ligands were calculated pH-metrically. The effect of the compounds on calf thymus DNA was investigated.

Synthesis and spectroscopic characterization of cobalt(II) thiosemicarbazone complexes

Thiosemicarbazone derivatives are formed on reaction between acetophenone, salicylaldehyde, benzophenone and/or 2-hydroxy-4-methoxybenzophenone and thiosemicarbazide or its N4H substituents (ethyl-, phenyl-, and p-chlorophenyl-). The ligands were investigated by elemental analysis and spectral (IR, 1H NMR and MS) studies. The formulas of the prepared complexes have been suggested by elemental analyses and confirmed by mass spectra. The coordination sites of each ligand were elucidated using IR spectra revealing bidentate and tridentate coordination. Different geometries for the complexes were proposed on the basis of electronic spectra and magnetic measurements. The complexes have been analyzed thermally (TG and DTG) and the kinetic parameters for some of their degradation steps were calculated.

Sulfur Containing Reagent for Ion Flotation and Spectrophotometric Determination of Palladium(II)

Abstract The recovery of palladium(II) from acidic aqueous solutions and sea water using 4-phenylthiosemicarbazide (HPTS) and oleic acid surfactant (HOL) has been studied by ionic flotation. Hydrogen ion concentration, foreign ions, temperature and reagent concentrations have been investigated for attaining the maximum efficiency of palladium(II) flotation. HPTS is used to develop a rapid and sensitive method for the spectrophotometric microdetermination of Pd(II). Various analytical parameters have been evaluated. Beers law is obeyed over 2.0–14.5 ppm concentration range. The molar absorptivity of the formed 1:1 species is 0.49 x 104 L mol−1 cm−1 at 300 nm. The ligand protonation constant and the stability constants of its complexes with Pd(II) have been determined potentiometrically. The method is successfully applied to determine directly the added Pd(II) to sea water without flotation. Square-planar geometry was proposed for the isolated solid complex. Also, the flotation mechanism is suggested.

Ligational, analytical and biological applications on oxalyl bis(3,4-dihydroxybenzylidene) hydrazone

The molecular modeling and parameters have been calculated to confirm the geometry of oxalyl bis(3,4-dihydroxybenzylidene) hydrazone, H(6)L. The metal complexes of Cr(3+), VO(2+), ZrO(2+), HfO(2+), UO(2)(2+) and MoO(2)(2+) with H(6)L have been prepared and characterized by partial elemental analysis, spectral studies (electronic; IR), thermal analysis and magnetic measurements. The data suggest the formation of polymer complexes with a unit [Cr(H(4)L)(H(2)O)(3)Cl].H(2)O, [VO(H(4)L)(H(2)O)(2)], [Hf(H(4)L)(H(2)O)].H(2)O [UO(2)(H(4)L)(H(2)O)(2)].2H(2)O [MoO(2)(H(4)L)] and [(ZrO)(2)(H(2)L)-(C(2)H(5)OH)(2)]. The ligand behaves as a dibasic bidentate in all complexes except ZrO(2+) which acts as a tetrabasic tetradentate with the two ZrO(2+) ions. An octahedral geometry was proposed for the Cr(3+), HfO(2+), MoO(2)(2+)and UO(2)(2+) complexes and square pyramid for VO(2+). The Cr(3+) is necessary to degrade the DNA of eukaryotic subject completely; the other complexes have little effect. H(6)L was found suitable as a new reagent for the separation and preconcentration of ZrO(2+) ions from different water samples using flotation technique with satisfactory results.

Flotation separation of mercury(II) from environmental water samples using thiosemicarbazide derivatives as chelating agents and oleic acid as surfactant

Abstract A simple and rapid procedure is developed for the quantitative flotation of mercury(II) from aqueous solutions. Thiosemicarbazide derivatives such as: 1-(amino-N-phenylmethanethio)-4-(pyridine-2-yl)thio-semicarbazide (H2PPS), N-phenyl-2-(pyridine-2-ylcarbamothioyl) hydrazinecarboxamide (H2PBO), 1-(amino(thioformyl)-N-phenylform)-4-(pyridine-2-yl)thiosemicarbazide (H2APO), and 1-(amino-N-(pyri-dine-3-yl)methanethio)-4-(pyridine-2-yl)thiosemicarbazide (H2PPY) are used as organic chelating agents and oleic acid (HOL) as surfactant. The different parameters affecting the flotation process namely, metal ion, ligands and surfactant concentrations, foreign ions (which are normally present in fresh and saline waters), pH and temperature are examined. Nearly 100% of mercury ions are floated at a metal:ligand ratio of 1: 4, pH ~ 4 and at room temperature (~25°C). The procedure was successfully applied to recover Hg2+ ions spiked into some water samples. A flotation mechanism is suggested based on some physical and chemical studies on the solid complexes isolated from aqueous and floated layers.

Spectroscopic, magnetic and thermal studies on complexes of Cu(II) and VO2+ with diacetylmonoxime derivatives: new method for extraction of Cu(II)

The coordination behavior of Cu(II) and VO2+ towards some oximes has been investigated. The isolated complexes were characterized by elemental analysis, molar conductance, magnetic moment, spectra (electronic, IR, ESR and mass) and thermal measurements. The IR spectra showed most ligands are deprotonated during complex formation acting as mononegative bi- or tridentate, binegative tetradentate and neutral tridentate. The magnetic moments and electronic spectra showed octahedral, square pyramidal and square-planar structures for the Cu(II) and VO2+ complexes. The ESR spectra of the complexes are quite similar and exhibit axial symmetric g-tensor parameters with g ∥ > g ⊥ > 2.0023 and confirmed the structures. The TG curves showed decomposition steps and indicate stability of the complexes. The ligands can remove Cu(II) ions from water by flotation technology using oleic acid surfactant with high efficiency.

Cadmium(II) sorption from water samples by powdered marble wastes

Abstract A series of batch adsorption experiments were carried out, with the aim of removing cadmium ions from aqueous solutions and water samples using powdered marble wastes (PMW) as an effective inorganic sorbent. PMW is inexpensive, widespread, and may be considered as environmental problem. The main parameters (i.e. solution pH, sorbent and cadmium concentrations, stirring time, and temperature) influencing the sorption process were investigated. The results obtained for sorption of cadmium ions onto PMW are well described by the Freundlich and Langmuir models. The Dubinin-Radushkevick (D–R) isotherm model was applied to describe the nature of the adsorption of the metal ion; it was found that the adsorption process was chemical in nature. The thermodynamic parameters were also calculated from the Gibbs free energy change (ΔG°), enthalpy (AH°) and entropy (ΔS°). These parameters indicated that the adsorption process of cadmium(II) ions on PMW was spontaneous and endothermic in nature. Under the optimum experimental conditions employed the removal of ca ~100% of Cd2+ ions was attained. The procedure was successfully applied to removal of the cadmium ions from aqueous and various natural water samples. The adsorption mechanism is discussed.

Triethanolamine as a releasing agent for controlling interferences in the atomic absorption spectrometric determination of gold and its use as a collector for the flotation of gold

The interfering effects of a range of organic and inorganic species on the atomic absorption signal of gold have been investigated. These interferences were completely eliminated by adding 6 mmol l–1 triethanolamine (TEA) to both the sample and standard solutions. The role of TEA was extended to the extraction of gold, with 100% recovery, from aqueous solutions, using oleic acid as a surfactant at a pH of 0.5–2.0. A mechanism for the effect of TEA in the flotation and in the atomic absorption investigation was suggested. A simple, sensitive and rapid procedure for flatation and the atomic absorption spectrometric determination of gold in synthetic mixtures and natural waters was elaborated.

Chromium(III) complexes ofd(−)tartaric andl(−) mandelic acids

SummaryThe binary complexes of anhydrous chromium(III) chloride withd(−) tartaric acidl(−) mandelic acids have been characterized by elemental analyses, magnetic susceptibility, vibrational, electronic and circular dichroism spectra. The magnetic susceptibility data are close to the spin only value for a d3 chromium(III) ion. Three (Cr−Cl) vibrational modes in the region 420–290 cm−1 are observed for the formed complexes indicatingC2 local symmetry of ligand atoms around the chromium(III) rather thanC3, which would allow two modes. In the visible spectra, two peaks in the 21052–22222 and 15384–16129 cm−1 range are observed and are assigned to the4A2g→4T1g(F) and4A2g→4T2g transitions. The parameters (Dq, B,β35) place the ligands in the higher end of the spectrochemical series and provide reassurance that the hydroxy acid oxygen complexes to chromium(III) ion. The Cotton effects observed in the spin-forbidden band are assigned to the2E(2Eg),2A2(2T1g) and2E(2T1g), while that in the spin-allowed band are a results of the splitting of the4A2g(4T2g) to4A1(4T2g) and4E(4T2g) transitions. The tartaric acid chelates are likely to befac in terms of ligand carboxylate and/or hydroxy groups since stronger and better defined Cotton effects are observed while mandelic acid chelates are weak suggesting formation of themer structure.