- The role of methyl and benzyl substituted dithiocarbazate of 2-acetyl pyridine for the formation of bridged dimeric and unbridged monomeric copper(II) complexes and catecholase mimetic activity of the complexes
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Monomeric [Cu(L1)Cl] (1) and dimeric [Cu(L2)Cl]2 (2) copper(II) complexes, where HL1 = methyl-2-(1-(pyridine-2-yl)ethylidene)-hydrazine-1-carbodithioate and HL2 = benzyl-2-(1-(pyridine-2-yl)ethylidene)hydrazine-1-carbodithioate, have been synthesized and characterized by X-ray crystallography, TGA and spectral methods. Complex 1 crystallizes in a space group P21/n and adopts a square planar environment surrounding the Cu ion, and complex 2 is a triclinic crystal system with space group Pī. Complex 2 is a centrosymmetric dimer where each copper atom forms two chloro bridges and completes five coordination with the tridentate NNS donor. Density functional calculations demonstrate that chloro-unbridged structure of 1 is favored by London dispersion between its layers. It is noticed that the layers are usually packed closely in the solid phase, such attractive interactions are sterically hindered between the layers of 2. Due to the presence of large phenyl group that extend from one layer to the other, the layers cannot slide on top of each other. This leads to the chloro-bridged structure of 2 stabilized by electrostatic interactions between Cu and Cl atoms located at different layers. Both complexes exhibit prominent catecholase activity in methanol following the oxidation of 3,5-di-tert-butyl catechol (DTBC) to the corresponding quinone. Based on the observed turn over frequency of 1 (25.19 h?1) and 2 (10.76 h?1), the monomeric complex demonstrates more catechol mimetic oxidation than the dimer. A plausible mechanism of catecholase activity has been discussed.
- Santra, Ananyakumari,Brandao, Paula,Mondal, Gopinath,Bera, Pradip,Jana, Abhimanyu,Bhattacharyya, Indranil,Pramanik, Chandana,Bera, Pulakesh
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- Heterocyclic dithiocarbazate iron chelators: Fe coordination chemistry and biological activity
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The iron coordination and biological chemistry of a series of heterocyclic dithiocarbazate Schiff base ligands is reported with regard to their activity as Fe chelators for the treatment of Fe overload and also cancer. The ligands are analogous to tridentate heterocyclic hydrazone and thiosemicarbazone chelators we have studied previously which bear NNO and NNS donor sets. The dithiocarbazate Schiff base ligands in this work also are NNS chelators and form stable low spin ferric and ferrous complexes and both have been isolated. In addition an unusual hydroxylated ligand derivative has been identified via an Fe-induced oxidation reaction. X-ray crystallographic and spectroscopic characterisation of these complexes has been carried out and also the electrochemical properties have been investigated. All Fe complexes exhibit totally reversible FeIII/II couples in mixed aqueous solvents at potentials higher than found in analogous thiosemicarbazone Fe complexes. The ability of the dithiocarbazate Schiff base ligands to mobilise Fe from cells and also to prevent Fe uptake from transferrin was examined and all ligands were effective in chelating intracellular Fe relative to known controls such as the clinically important Fe chelator desferrioxamine. The Schiff base ligands derived from 2-pyridinecarbaldehyde were non-toxic to SK-N-MC neuroepithelioma (cancer) cells but those derived from the ketones 2-acetylpyridine and di-2-pyridyl ketone exhibited significant antiproliferative activity.
- Basha, Maram T.,Chartres, Jy D.,Pantarat, Namfon,Akbar Ali, Mohammad,Mirza, Aminul Huq,Kalinowski, Danuta S.,Richardson, Des R.,Bernhardt, Paul V.
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experimental part
p. 6536 - 6548
(2012/09/21)
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- Structural, spectroscopic, and biological aspects of S∩N donor Schiff-base ligands and their chromium(III) complexes
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New chromium(III) complexes are synthesized by classical thermal and microwave (MW)-irradiated techniques. The Schiff bases 2-acetylfuran-S-benzyldithiocarbazate (L1H), 2-acetylthiophene-S-benzyldithiocarbazate (L2H), 2-acetylpyridin
- Shrivastava, Sumit,Fahmi, Nighat,Singh,Singh
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experimental part
p. 1807 - 1819
(2010/12/19)
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- Synthesis and structure-activity relationships of metal-ligand complexes that potently inhibit cell migration
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We screened the National Cancer Institute Diversity Set compound collection for small molecules that affect mammalian cell migration and identified NSC 295642 as an inhibitor of cell motility with nanomolar potency. We found by LC-MS and X-ray crystallogr
- Beshir, Anwar B.,Guchhait, Sankar K.,Gascon, Jose A.,Fenteany, Gabriel
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p. 498 - 504
(2008/09/21)
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- Synthesis, characterization and antimicrobial studies of Sb(III) complexes of substituted thioimines
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Some antimony complexes of a new class of substituted thioimines have been prepared by reacting Ph3Sb (III) with [l-(2-naphthyl) ethyledene] hydrazinecarbodithioic acid phenyl methyl ester (L1H), [l-(2-thienyl) ethyledene] hydrazinecarbodithioic acid phenyl methyl ester (L2H), [l-(2-pyridine) ethyledene] hydrazinecarbodithioic acid phenyl methyl ester (L3H) and [l-(2-furanyl)ethyledene] hydrazinecarbodithioic acid phenyl methyl ester (L4H), in unimolar and bimolar ratios using thermal as well as microwave method. All the new complexes have been characterized by elemental analyses, molecular weight determinations and spectral studies including electronic, IR, 1H and l3C NMR spectra. The spectral data are consistent with the tetra-coordinated and penta-coordinated environments around Sb(IIl). The bidentate ligands coordinate through the nitrogen and sulfur atoms. Free ligands and their metal complexes have been screened for their antimicrobial activity on different species of pathogenic fungi and bacteria and their biological activity is discussed briefly.
- Mahajan, Karuna,Fahmi, Nighat,Singh, Ran Vir
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p. 1221 - 1225
(2008/09/20)
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- Synthesis and antiamoebic activity of new cyclooctadiene ruthenium(II) complexes with 2-acetylpyridine and benzimidazole derivatives
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Reaction of [Ru(η4-C8H12) (CH3CN)2 Cl2] with 2-(2-pyridyl) benzimidazole or Schiff bases derived from 2-acetylpyridine and S-methyldithiocarbazate, S-benzyldithiocarbazate and thiosemicarba
- Bharti, Neelam,Maurya, Mannar R.,Naqvi, Fehmida,Azam, Amir
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p. 2243 - 2245
(2007/10/03)
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- Reactions with Hydrazonoyl Halides XXV. Synthesis of Some New 2,3-Dihydro-1,3,4-thiadiazoles and Arylazothiazoles
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Reaction of hydrazonoyl halides 1, 9-15 with either alkyl carbodithioates 3, 32 and 35 in ethanolic triethylamine afforded the corresponding 2,3-dihydrothiadiazoles 7, 18-24, 34 and 37, respectively. 5-Phenylazothiazoles 17a-c were prepared by reaction of
- Abdelhamid, Abdou O.,Abdel-Riheem, Nadia A.,Emam, Hussein A.
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p. 2323 - 2335
(2007/10/03)
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- Synthetic and biochemical studies of some hydrazine carbodithioic acid derivatives of dioxomolybdenum (VI)
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Some biologically active thioimines, formed by the condensation of heterocyclic aldehydes and ketones with phenylmethyl ester derivative of hydrazine carbodithioic acid and their dioxomolybdenum (VI) complexes have been described.The monomeric complexes a
- Jadon, S. C. Singh,Gupta, Neeti,Singh, R. V.
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p. 733 - 736
(2007/10/03)
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