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SM ISO690:2012 SÎRBU, Angela, SECU, Mihail, REVENKO, M., BOUROSH, Pavlina. Synthesis and structure of new copper(II) complexes of 5-(methylenetrimetylammonium) salicylaldehyde thiosemicarbazone. In: Materials Science and Condensed Matter Physics, Ed. 7, 16-19 septembrie 2014, Chișinău. Chișinău, Republica Moldova: Institutul de Fizică Aplicată, 2014, Editia 7, p. 170. |
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Materials Science and Condensed Matter Physics Editia 7, 2014 |
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Conferința "Materials Science and Condensed Matter Physics" 7, Chișinău, Moldova, 16-19 septembrie 2014 | ||||||
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Pag. 170-170 | ||||||
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Among the organic reagents used as ligands, thiosemicarbazones have an important role. The importance of these results comes from the fact that an important part of them showed interesting biological properties as: antimicrobial, antitumor, antifungal, etc. Low solubility of thiosemicarbazones and their metal coordination compounds generated some problems. They can be solved by functionalization of coordinating agent with easily ionizable groups. In this context we have carried out the synthesis of new coordination compounds of copper complexes based on 5- (methylenetrimetylamonium)salicylaldehyde thiosemicarbazone ligand ([H2L]Cl). Thus at the interaction of [H2L]Cl with different copper (II) salts in the solutions with pH close to neutral we have obtained three compounds with the formula Cu(HL)Cl2 2.25H2O (1), Cu(HL)Cl(NO3) 2H2O (2) and [Cu(HL)Cl]2SO4 0.75H2O (3). Suitable single crystal for X-ray diffraction were obtained by slow evaporation from water : ethanol mixture (1:3). Single-crystal X-ray diffraction experiments established the crystal structure of 1 – 3 complexes. As a result, it has been found out that all of the three copper (II) complexes are ionic compounds consisting from cationic complex [Cu(HL)Cl]+, anions Cl-, NO3 -, SO4 2- and respective solvation molecules of water. The formally neutral group [HL] is coordinated in 1 – 3 complexes as tridentate ligand through the donor set of atoms O,N,S. Really it is a bipolar ion (Zwitter-ion) with positively charged N(4) atom and negative O(1) (the hydroxyl group is monodeprotonated). Molar ratio of Cu : HL in these compounds is 1:1. The central metal geometry in 1 – 3 complexes is square planar and is occupied by O,N,S atoms of tridentate ligand completed by chloride ion. The interatomic distances of Cu–O, Cu–N, Cu–S and Cu–Cl are within the limits of 1.887(5) – 1.920(3), 1.958(4) – 1.972(5), 2.244(2)- 2.274(2), and 2.237(2) – 2.254(2) Å. As a result of coordination of [HL] with Cu(II), two associated metal cycles appear: one being of five members (CuNNCS), and the second – of six members (CuOCCCN). The cationic complex [Cu(HL)Cl]+ has the same structure in 1 – 3, and due to proton donor groups (-NH2 and -NH) is involved in extended network of hydrogen bonds with anions and water crystallization molecules. |
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