G.M. Abu El-Reash

Synthesis, characterization, DFT and biological studies of isatinpicolinohydrazone and its Zn(II), Cd(II) and Hg(II) complexes.

Isatinpicolinohydrazone (H2IPH) and its Zn(II), Cd(II) and Hg(II) complexes have been synthesized and investigated using physicochemical techniques viz. IR, (1)H NMR, (13)C NMR, UV-Vis spectrometric methods and magnetic moment measurements. The investigation revealed that H2IPH acts as binegative tetradentate in Zn(II), neutral tridentate in Cd(II) and as neutral bidentate towards Hg(II) complex. Octahedral geometry is proposed for all complexes. The bond length, bond angle, chemical reactivity, energy components (kcal/mol), binding energy (kcal/mol) and dipole moment (Debyes) for all the title compounds were evaluated by DFT and also MEP for the ligand is shown. Theoretical infrared intensities of H2IPH and also the theoretical electronic spectra of the ligand and its complexes were calculated. The thermal behavior and the kinetic parameters of degradation were determined using Coats-Redfern and Horowitz-Metzger methods. The in vitro antibacterial studies of the complexes proved them as growth inhibiting agents. The DDPH antioxidant of the compounds have been screened. Antitumor activity, carried out in vitro on human mammary gland (breast) MCF7, have shown that Hg(II) complex exhibited potent activity followed by Zn(II), Cd(II) complexes and the ligand.

First row transition metal complexes of (E)-2-(2-(2-hydroxybenzylidene) hydrazinyl)-2-oxo-N-phenylacetamide complexes

Manganese(II), iron(II), cobalt(II), nickel(II), copper(II), and chromium(III) complexes of (E)-2-(2-(2-hydroxybenzylidene)hydrazinyl)-2-oxo-N-phenylacetamide were synthesized and characterized by elemental and thermal (TG and DTA) analyses, IR, UV-vis and (1)H NMR spectra as well as magnetic moment. Mononuclear complexes are obtained with 1:1 molar ratio except [Mn(HOS)(2)(H(2)O)(2)] and [Co(OS)(2)](H(2)O)(2) complexes which are obtained with 1:2 molar ratios. The IR spectra of ligand and metal complexes reveal various modes of chelation. The ligand behaves as a monobasic bidentate one and coordination occurs via the enolic oxygen atom and azomethine nitrogen atom. The ligand behaves also as a monobasic tridentate one and coordination occurs through the carbonyl oxygen atom, azomethine nitrogen atom and the hydroxyl oxygen. Moreover, the ligand behaves as a dibasic tridentate and coordination occurs via the enolic oxygen, azomethine nitrogen and the hydroxyl oxygen atoms. The electronic spectra and magnetic moment measurements reveal that all complexes possess octahedral geometry except the copper complexes possesses a square planar geometry. From the modeling studies, the bond length, bond angle, HOMO, LUMO and dipole moment had been calculated to confirm the geometry of the ligands and their investigated complexes. The thermal studies showed the type of water molecules involved in metal complexes as well as the thermal decomposition of some metal complexes. The protonation constant of the ligand and the stability constant of metal complexes were determined pH-metrically in 50% (v/v) dioxane-water mixture at 298 K and found to be consistent with Irving-Williams order. Moreover, the minimal inhibitory concentration (MIC) of these compounds against Staphylococcus aureus, Escherechia coli and Candida albicans were determined.

Synthesis, spectral characterization and biological evaluation of Mn(II), Co(II), Ni(II), Cu(II), Zn(II) and Cd(II) complexes with thiosemicarbazone ending by pyrazole and pyridyl rings

Here we present the synthesis of the new Mn(II), Co(II), Ni(II), Cu(II), Zn(II) and Cd(II) complexes with chelating ligand (Z)-(2-((1,3-diphenyl-1H-pyrazol-4-yl)methylene) hydrazinyl)(pyridin-2-ylamino)methanethiol. All the complexes were characterized by elemental analysis, IR, (1)H NMR, UV-vis, magnetic susceptibility measurements and EPR spectral studies. IR spectra of complexes showed that the ligand behaves as NN neutral bidentate, NSN mononegative tridentate and NSNN mononegative tetradentate. The electronic spectra and the magnetic measurements suggested the octahedral geometry for all complexes as well as the EPR confirmed the tetragonal distorted octahedral for Cu(II) complex. Cd(II) complex showed the highest inhibitory antioxidant activity either using ABTS method. The SOD-like activity exhibited those Cd(II) and Zn(II) complexes have strong antioxidative properties. We tested the synthesized compounds for antitumor activity and showed that the ability to kill liver (HePG2) and breast (MCF-7) cancer cells definitely.

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.

Transition Metal Complexes from N-Anthranilamido-N′-benzoylthiocarbamide (H2ABTC)

Abstract Complexes of N-anthranilamido-N′-benzoylthiocarbamide (H2ABTC) with Cr(III), Mn(II), Co(II), Ni(II), Cu(II), Zn(II), Cd(II) and UO2(VI) have been synthesized and characterized on the basis of elemental analyses, molar conductivities, spectral (IR and visible) and magnetic studies. IR spectral data show that the ligand behaves in a neutral bidentate, mononegative bidentate or tridentate and binegative tridentate or tetradentate manner. All the complexes are non-electrolytes. Different stereochemistries are proposed for the Cr(III), Mn(II), Co(II), Ni(II) and Cu(II) complexes according to the data of magnetic and electronic spectral measurements. IR data indicate that the carbonyl oxygen of the benzoyl moiety is the backbone of the chelating agent in all the complexes.

Spectral, thermal and magnetic studies of biacetylmonoxime isonicotinoylhydrazone complexes

Abstract The synthesis and characterization of Co(II), Ni(II), Cu(II), Zn(II), Cd(II) and UO2+2 complexes of biacetylmonoxime isonicotinoylhydrazone (BMINH) are reported. Elemental-analysis, magnetic, thermal and spectral (IR, visible and NMR) measurements have been used to characterize the complexes. IR spectral data show that the ligand behaves in a bidentate and/or tridentate manner. An octahedral structure is proposed for the Ni(II) complexes, while a square-planar structure is proposed for both Co(II) and Cu(II) complexes, on the basis of magnetic and spectral measurements.

Structural, DFT and biological studies on Cu(II) complexes of semi and thiosemicarbazide ligands derived from diketo hydrazide

Three new ligands have been synthesized by the addition of an ethanolic suspension of 2-hydrazino-2-oxo-N-phenyl-acetamide to phenyl isocyanate (H2PAPS), phenyl isothiocyanate (H2PAPT) and benzoyl isothiocyanate (H2PABT). The Cu(II) complexes derived from the chloride salt were prepared and characterized by conventional techniques. The isolated complexes were assigned the formulae [Cu(H2PAPS)Cl2(H2O)], [Cu(HPAPT)Cl] and [Cu2HPABT2Cl2(H2O)2](H2O), respectively. The IR spectra of the complexes show that H2PAPS behaves as a neutral tridentate ligand via both CO groups of the hydrazide moiety and a new CN (azomethine) group. H2PAPT behaves as a mononegative tridentate ligand via one CO group of the hydrazide moiety, the thiol CS and a new CN (azomethine) group, and finally H2PABT behaves as a mononegative tetradentate ligand via both CO groups of the hydrazide moiety, an enolized CO group of the benzoyl moiety and the CS group. The vibrational frequencies of the IR spectra of the ligands, which were determined experimentally, are compared with those obtained theoretically from DFT calculations. Also, the bond lengths, bond angles, HOMO, LUMO and dipole moments have been calculated. The calculated HOMO–LUMO energy gap reveals that a change transfer occurs within the molecule. The calculated values of the binding energies indicate that the stabilities of the metal complexes are higher than those of the ligands. Also, the kinetic and thermodynamic parameters for the different thermal degradation steps of the complexes were determined by Coats–Redfern and Horowitz–Metzger methods. Powder XRD indicates the crystalline state and morphology of all the Cu(II) complexes. The antibacterial activities were also tested against Bacillus subtilis and Escherichia coli bacteria. The [Cu(H2PAPS)Cl2(H2O)] complex showed a higher antibacterial effect than the free ligand (H2PAPS), while the other ligands (H2PAPT and H2PABT) showed a higher effect than their Cu(II) complexes. The antitumor activities of the ligands and their Cu(II) complexes have been evaluated against liver (HePG2) and breast (MCF-7) cancer cells. All the ligands were found to display a cytotoxicity better than that of Fluorouracil (5-FU), while the Cu(II) complexes showed very low activity.

Synthesis, biological and comparative DFT studies on Ni(II) complexes of NO and NOS donor ligands.

Three new NOS donor ligands have been prepared by addition ethanolic suspension of 2-hydrazino-2-oxo-N-phenyl-acetamide to phenyl isocyanate (H2PAPS), phenyl isothiocyanate (H2PAPT) and benzoyl isothiocyanate (H2PABT). The Ni(II) complexes prepared from the chloride salt and characterized by conventional techniques. The isolated complexes were assigned the formulaes, [Ni2(PAPS)(H2O)2](H2O)2, [Ni(H2PAPT)Cl2(H2O)](H2O)2 and [(Ni)2(HPABT)2Cl2(H2O)2], respectively. The IR spectra of complexes shows that H2PAPS behaves as a binegative pentadentate via both CO of hydrazide moiety in keto and enol form, enolized CO of cyanate moiety and the CN (azomethine) groups of enolization. H2PAPT behaves as neutral tridentate via both CO of hydrazide moiety and CN (azomethine) group due to SH formation and finally H2PABT behaves as mononegative tetradentate via CO and enolized CO of hydrazide moiety, CO of benzoyl moiety and C=S groups. The experimental IR spectra of ligands are compared with those obtained theoretically from DFT calculations. Also, the bond lengths, bond angles, HOMO (Highest Occupied Molecular Orbitals), LUMO (Lowest Unoccupied Molecular Orbital) and dipole moments have been calculated. The calculated HOMO-LUMO energy gap reveals that charge transfer occurs within the molecule. The theoretical values of binding energies indicate the higher stability of complexes than of ligands. Also, the kinetic and thermodynamic parameters for the different thermal degradation steps of the complexes were determined by Coats-Redfern and Horowitz-Metzger methods. The antibacterial activities were also tested against B. Subtilis and E. coli bacteria. The free ligands showed a higher antibacterial effect than their Ni(II) complexes. The antitumor activities of the Ligands and their Ni(II) complexes have been evaluated against liver (HePG2) and breast (MCF-7) cancer cells. All ligands were found to display cytotoxicity that are better than that of Fluorouracil (5-FU), while Ni(II) complexes show low activity.

Binuclear copper(II), cobalt(II) and Nickel(II) complexes of N1-ethyl-N2-(pyridin-2-yl) hydrazine-1,2-bis(carbothioamide): Structural, spectral, pH-metric and biological studies

Binuclear Cu(II), Co(II) and Ni(II) complexes derived from N(1)-ethyl-N(2)-(pyridin-2-yl) hydrazine-1,2-bis(carbothioamide) (H(2)PET) have been prepared and characterized by elemental analysis, spectral (IR, UV-vis, EI mass, ESR and (1)HNMR) and magnetic measurements. The isolated complexes assigned the general formula, [M(HPET)(H(2)O)(n)Cl](2)·xH(2)O where M=Cu(II), Co(II) and Ni(II), n=2, 1, 0 and x=0, 0.5 and 0, respectively. IR data revealed that the ligand behaves as monobasic tridentate through (CN)(py), (C-S) and new azomethine, (NC)(∗) groups in the Co(II) complex but in Cu(II) complex, the ligand coordinate via both (CS) groups, one of them in thiol form as well as the new azomethine group. In Ni(II) complex, H(2)PET acts as NSNS monobasic tetradente via (CN)(py), (C-S), (CS) and the new azomethine, (NC)(∗) groups. An octahedral geometry is proposed for all complexes. pH- metric titration was carried out in 50% dioxane-water mixture at 298, 308 and 318 °K, respectively and the dissociation constant of the ligand as well as the stability constants of its complexes were evaluated. Also the kinetic and thermodynamic parameters for the different thermal decomposition steps of the complexes were determined by Coats-Redfern and Horowitz-Metzger methods. Moreover, the anti-oxidant, anti-hemolytic, and cytotoxic activities of the compounds have been tested.