Facultatea de Chimie şi Tehnologie Chimică / Faculty of Chemistry and Chemical Technology

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Author: search.filters.author.Ciumacov, IurieSubject: search.filters.subject.X ray diffraction

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    Synthesis, structure and properties of some 3d-element complexes with 2-[2-(hydroxybenzylidene)-amino]-2-hydoxymethylpropane-1,3-diol [Articol]
    (2004) Țapcov, Victor; Ciumacov, Iurie; Antoșciac, Boris; Bocelli, Gabrielle; Samusi, Nina; Gulea, Aurelian
    2-[2-(Hydroxybenzylidene)-amino]-2-hydoxymethylpropane-1,3-diol (HL) reacts with cobalt, nickel, copper and zinc chlorides, bromides and acetates in water-ethanol solutions and gives MLX·nH2O and ML 2·nH2O complexes (M = Co, Ni, Cu, Zn; X = Cl, Br; n = 0-5). Single crystals of CuLBr were grown, and its crystal structure was determined by X-ray diffraction analysis. The crystals are tetragonal, a = 17.024(2), c = 8.720(2) Å, space group P421c, Z = 8, R 1 = 0.0349. In the structure of this complex, the copper atom coordinates the deprotonated HL molecule. The coordination polyhedron of the central atom is an elongated tetragonal pyramid. Its base is built of the imine nitrogen atom, phenolic and alcoholic oxygen atoms, and bromine atom. The apex of the pyramid is occupied by the bromine atom of the adjacent complex connected with the initial complex by the plane of sliding reflection. Thus, the crystal contains infinite chains of complexes running along the c axis, the complexes being united by both bridging bromine atoms and O-H⋯O hydrogen bonds. The conclusions on the compositions and structures of the remaining compounds were made on the basis of elemental and combined thermal analyses, IR spectroscopy, and magnetic chemistry data. The copper halide complexes were found to have dimeric, and the other metal complexes monomeric, structures. In the synthesized complexes, the azomethine HL can function as a bidentate or tridentate ligand. The thermolysis of the coordination compounds proceeds through the stages of elimination of crystal water molecules (75-90°C) or inner-sphere water molecules (145-155°C) and complete thermal destruction (485-550°C).
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    Crystal structures of nitrato-{2-[2-(1-pyridine-2-ylethylidene)hydrazine]-1,3-benzothiazolo}aquacopper and chloro-{2-[2-phenyl(pyridine-2-ylethylidene)hydrazine]-1,3-benzothiazolo}copper [Articol]
    (2015) Ciumacov, Iurie; Paholnițcaia, Anastasia; Petrenko, Peter A.; Țapcov, Victor; Poirier, Donald; Gulea, Aurelian
    Two crystal modifications of nitrato-{2-[2-(1-pyridine-2-ylethylidene)hydrazine]-1,3-benzothiazolo}aquacopper (I and II) and two modifications of chloro-{2-[2-phenyl(pyridine-2-ylethylidene)hydrazine]-1,3-benzothiazolo}copper (III and IV) have been synthesized and studied by X-ray diffraction. In structures I and II, the copper atoms coordinate a monodeprotonated molecule of the organic ligand, nitrate ions, and a water molecule. In crystals of I, the complexes are monomeric, whereas complexes II are linked via nitrate ions to form polymeric chains. In both structures the coordination polyhedron of the copper atom can be described as a distorted tetragonal bipyramid—(4 + 1 + 1) in I and (4 + 2) in II. These coordination polyherdra have different compositions. In structures III and IV, the metal atoms coordinate a monodeprotonated {2-[2-phenyl(pyridine-2-ylethylidene)hydrazine]-1,3-benzothiazole molecule and chloride ions. In III the complex-forming ion has square-planar coordination geometry, whereas structure IV consists of centrosymmetric dimers with two bridging chlorine atoms. It was found that nitrato-{2-[2-(1-pyridine-2-ylethylidene)hydrazine]-1,3-benzothiazolo}aquacopper possesses antitumor activity.