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Al Manşūrah, Egypt

(E)-3-(2-(2-hydroxybenzylidene)hydrazinyl)-3-oxo-n(thiazole-2-yl) propane-mide (H2L) has been prepared and its structure confirmed by elemental analysis, IR and 1HNMR spectroscopy. It has been used to produce diverse complexes with Ni(II), Co(II) and Cu(II) ions. The complexes obtained have been investigated by thermal analysis, spectral studies (IR, UV-visible, ESR), and magnetic measurements. IR spectra suggest that the H 2L acts as a bidentate ligand coordinating via (CN)1 and (OH)phenolic or deprotonated enolized carbonyl oxygen (CO) 1. The electronic spectra of the complexes and their magnetic moments provide information about geometries. The room temperature solid state ESR spectra of the Cu(II) complexes show dx2-y2 as a ground state, suggesting tetragonally distorted octahedral or square-planar geometries around Cu(II) centre. The molar conductance measurements proved that the complexes are non-electrolytes. The bond length, bond angle, HOMO, LUMO, dipole moment and charges on the atoms have been calculated to confirm the geometry of the ligand and the investigated complexes. Also, thermal properties and decomposition kinetics of all compounds are investigated. The interpretation, mathematical analysis and evaluation of kinetic parameters (Ea, A, ΔH, ΔS and ΔG) of all thermal decomposition stages have been evaluated using Coats-Redfern and Horowitz-Metzger methods. Finally, the antimicrobial activity has been tested. © 2011 Elsevier B.V. All rights reserved. Source


This paper presents a combined experimental and computational study of novel Mn(II), Ni(II), Cu(II), Zn(II) and Cd(II) complexes of (E)-2-((3-hydroxynaphthalen-2-yl)methylene)-N-(pyridin-2-yl) hydrazinecarbothioamide (H 2L). The complexes have been characterized by elemental analyses, spectral (IR, UV-Vis, 1H NMR and 13C NMR), magnetic and thermal studies. Theoretical calculations have been performed to obtain IR spectra for the ligand and its complexes using AM1, MM, Zindo/1 and PM3 methods. Satisfactory theoretical-experimental agreements were achieved by the MM method for the ligand and PM3 for the metal complexes. Additional information is obtained from bond length calculations for all compounds by two methods, AM1 and MM. It was observed that the M-S bond length is longer than that of M-N in the Cu(II), Cd(II) and Mn(II) complexes and the M-O bond length is shorter than that of M-N in the case of the Ni(II) complex, and the same is noticed in the Zn(II) complex which contains M-O, M-N and M-S bonds and their bond lengths have the order M-S > M-N > M-O. DOS calculations were carried out by the MM (ADF) method for the ligand and the Cu complex, from which we concluded that the thiol form of the ligand is more active than thione form and this explains why most of the complexation is in that form. Also, valuable information is obtained from the calculation of molecular parameters for all compounds carried out by previous methods of calculation (electronegativity of the coordination sites, net dipole moment of the metal complexes, values of heat of formation and binding energy), which proved that the complexes are more stable than the ligand. The IR spectra show that H 2L is coordinated to the metal ions in a mono, bi or tridentate manner. Furthermore, the kinetic and thermodynamic parameters for the different decomposition steps were calculated using the Coats-Redfern and Horowitz-Metzger methods. Finally, biochemical studies showed that complexes 3 and 4 have a powerful and complete degradation effect on DNA. © 2012 Elsevier Ltd. All rights reserved. Source


El-Gammal O.A.,Mansoura University | Abu El-Reash G.M.,Mansoura University | Ghazy S.E.,Mansoura University | Yousef T.,Mansoura Laboratory
Journal of Coordination Chemistry | Year: 2012

Four Cu(II) complexes of N 1-phenyl-N 2-(pyridin-2-yl) hydrazine-1,2-bis(carbothioamide) (H 2PPS), N-phenyl-2-(2-(pyridin-2- ylcarbamothioyl)hydrazinyl)-2-thioxoacetamide (H 2PBO), N-phenyl-2-(pyridin-2-ylcarbamothioyl)hydrazinecarboxamide (H 2APO), and 1-(aminoN-(pyr-idin-2-yl)methanethio)-4-(pyridin-yl)thiosemicarbazide (H 2PPY) 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. © 2012 Taylor & Francis. Source


Abu El-Reash G.M.,Mansoura University | El-Gammal O.A.,Mansoura University | El-Gamil M.M.,Mansoura Laboratory
Spectrochimica Acta - Part A: Molecular and Biomolecular Spectroscopy | Year: 2013

Cr(III), Mn(II) and Fe(III) complexes derived from the quadruple potential dithione heterocyclic thiosemicarbazide ligand (H2PET) have been prepared and characterized by conventional techniques. The isolated complexes were assigned the formulae, [Cr(HPET)(H2O)2Cl 2]·3H2O, [Mn(HPET)(H2O)Cl]2 and [Fe(HPET)(H2O)2Cl2]·H2O, respectively. IR data revealed that the ligand behaves as monobasic bidentate through (CN)py and (CS) groups in both Cr(III) and Fe(III) complexes. In the binuclear Mn(II) complex, H2PET acts as NSNS monobasic tetradente via (CN)py, (CS), (CS) and the new azomethine, (NC)* groups. An octahedral geometry for all complexes was proposed. The bond lengths, bond angles, HOMO, LUMO and dipole moment have been calculated by DFT using materials studio program to confirm the geometry of H2PET and its metal complexes. The ligand association constant and the stability constants of its complexes in addition to the thermodynamic parameters were calculated from pH metrically at 298, 308 and 318°K in 50% dioxane-water mixture, respectively. Also, the kinetic and thermodynamic parameters for the different thermal degradation steps of the complexes were determined by Coats-Redfern and Horowitz-Metzger methods. Moreover, the anti-oxidant (using ABTS and DPPH methods), anti-hemolytic, and cytotoxic activities of the compounds have been tested. © 2012 Elsevier B.V. All rights reserved. Source


Yousef T.A.,Mansoura Laboratory | Abu El-Reash G.M.,Mansoura University | El-Gammal O.A.,Mansoura University | Bedier R.A.,Mansoura University
Journal of Molecular Structure | Year: 2012

A new series of [Co(HPTP)Cl(H2O)2], [Cu(HPTP)Cl], [Cd(HPTP)Cl](H2O)4, [Fe(PTP)Cl(H2O) 2](H2O), [UO2(HPTP)(OAc)(H2O) 2] complexes of Schiff-bases derived from 4-(2-pyridyl)-3- thiosemicarbazide and pyruvic acid (H2PTP) have been synthesized and characterized by spectroscopic studies. Schiff-base exhibit thiol-thione tautomerism wherein sulfur plays an important role in the coordination. The coordination possibility of the Schiff-bases towards metal ions have been proposed in the light of elemental analyses, spectral (IR, UV-vis, 1H NMR, 13C NMR and ESR), magnetic and thermal studies. IR spectra show that H2PTP is coordinated to the metal ions in a mono or binegative tridentate manner. The electronic spectra of the complexes and their magnetic moments provide information about geometries. The room temperature solid state ESR spectra of the Cu(II) complexes show dx2- y2 as a ground state, suggesting square-planar geometry around Cu(II) center. The molecular parameters: total energy, binding energy, isolated atomic energy, electronic energy, heat of formation, dipole moment, HOMO and LUMO were calculated for the ligand and its complexes. Furthermore, the kinetic and thermodynamic parameters for the different decomposition steps were calculated using the Coats-Redfern and Horowitz-Metzger methods. Also, the optical band gap (Eg) of the metal complexes has been calculated. The optical transition energy (Eg) is direct and equals 3.25, 3.26, 3.34 and 3.27 eV for Co, Cu, Fe and U complexes, respectively. The synthesized ligand, in comparison to its metal complexes is screened for its antibacterial activity against bacterial species, Bacillus thuringiensis, Staphylococcus aureus, Pseudomonas aeruginosa and Escherichia coli. The activity data show that the metal complexes to be more potent/antibacterial than the parent Schiff base ligand against one or more bacterial species. Finally, the biochemical studies showed that, Cu, Cd and Fe complexes have powerful and complete degradation effect on DNA. © 2012 Elsevier B.V. All rights reserved. Source

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