Browsing by Author "Bocelli, Gabriele"

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CRYSTAL STRUCTURES OF COPPER (II) COMPLEXES WITH 5-CHLORINE- AND 5-BROMINE-SUBSTITUTED N-ETHANOLSALICYLIDENIMINES
(Academia de Ştiinţe a Moldovei, 2006) Chumakov, Yurii; Tsapkov, Victor I.; Bocelli, Gabriele; Antosyak, B.; Gulea, Aurelian
The condensation products of alcanolimines with aldehydes and ketons form the biologically active coordination compounds with ions of transition metals differing in composition, structure and properties. In this respect, the synthesis of biometal complexes with similar ligands and investigations of the structural features of these compounds are of great interest from scientific and practical standpoints. Therefore the crystal structures of bis-{4-bromo-2-[(2-hydroxy-ethylamine)methyl]phenole}copper (I), bis-{4-chloro-2-[(2-hydroxy-ethylamine)-methyl]phenole}copper (II) have been studied. Crystals of I are monoclinic, a = 13.237(3), b = 4.589(1), c = 21.010(4) Å, space group P21/c, Z =2, R = 0.036. Crystals of II are also monoclinic, a = 4.994 (1), b = 17.034 (3), c = 10.723 (2) Å, space group P21/n, Z =2, R = 0.066. In I and II the metal atom is situated at symmetry center. In I the copper atom coordinates two singly deprotonated bidentate molecules of 4-bromo-2-[(2-hydroxy-ethylamine)-methyl]phenol through the phenolic oxygen atoms and azomethine nitrogen atoms. The donor atoms form the distortion square around the central atom due to center of symmetry. In II the copper atom coordinates two singly deprotonated bidentate molecules of 4-chloro-2-[(2-hydroxy-ethylamine)-methyl]phenol through the phenolic oxygen atoms and azomethine nitrogen atoms. The coordination polyhedron of the central atom is an extended tetragonal bipyramid with the phenolic oxygen atoms and azomethine nitrogen atoms in its base. Both axial vertexes of bipyramid are occupied by the oxygen atoms of aminealcohol groups of adjacent complexes connected with the initial complex by symmetry center. In turn the oxygen atoms of amine alcohol groups of initial complex are located in coordination bipyramid apexes of neighboring complexes and thus forming the infinite polymeric chains along a axis.
CRYSTAL STRUCTURES OF NITRATO-COPPER(II) COMPLEXES COMPRISING 4,4’ -BIPYRIDYL AND SALICYLIDEN- OR NAPHTHALIDENAMINOETHANOL
(Academia de Ştiinţe a Moldovei, 2006) Chumakov, Yurii; Petrenko, Peter A.; Tsapkov, Victor I.; Bocelli, Gabriele; Gulea, Aurelian
Copper (II) nitrate with 2-[2-(hydroxyethylimino)-methyl]-phenol (H2L), 2-[2(hydroxyethylimino)-methyl]-naphtol (H2L1) and heterocyclic amines has been found to generate polynuclear coordination compounds with antimicrobial properties. It was established that polynuclear complexes are formed depending on the nature of the proton-accepting agent, pH and temperature of the reaction mixture. The structure of these compounds, dentate number of the nitrate group, physicochemical properties and antimicrobial activity are determined by the nature of these amines. It was of great interest to study how the replacement of different amines by 4,4’-bipyridyl (Bipy) affects the complex structure. In connection with this, we have synthesized complexes [Cu3(Bipy)3(H2O)2(HL)2(NO3)4]n (I) and [Cu2(Bipy)(HL1)2(NO3)2] (II), where L = 2-[(2-Hydroxy-ethylimino)methyl]-phenol, L1 = 1-[(2-Hydroxyethylimino)methyl]-naphthalen-2-ol, and determined their crystal structures by X-ray diffraction analysis. The crystal structure I consists of polymeric bands [Cu3(Bipy)3(H2O)2(HL)2(NO3)4] along [001] direction. The coordination polyhedra of Cu(1) and of Cu(2) are tetragonal bipyramids. The basic structural unit of II is the binuclear complex [(HL1)(NO3)Cu(Bipy)Cu(NO3)(HL1)] which forms the crystal structure II by means of multiple hydrogen bonds.