2. Articole

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Author: search.filters.author.Ciumacov, Iurie

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    SYNTHESIS,CHARACTERIZATION,ANDBIOLOGICALPROPERTIESOFTHE COPPER(II)COMPLEXESWITHNOVELLIGAND:N-[4-({2-[1-(PYRIDIN2-YL)ETHYLIDENE]HYDRAZINECARBOTHIOYL}AMINO)PHENYL]ACETAMIDE
    (2023) Rusnac, Roman; Garbuz, Olga; Ciumacov, Iurie; Țapcov, Victor; Hureau, Christelle; Istrati, Dorin; Gulea, Aurelian
    For the first time, a thiosemicarbazone-type ligand containing a paracetamol structural unit was synthesized. Five new coordination compounds based on copper(II) salts: [Cu(L)CH3COO] (1), [{Cu(L)Cl}2]·H2O (2), [Cu(L)H2O·DMF]NO3 (3), [Cu(L)Br] (4), [Cu(L)H2O]ClO4 (5), were obtained, where HL is N-[4-({2-[1-(pyridin-2-yl)ethylidene]hydrazinecarbothioyl}amino)phenyl]acetamide. The new HL was characterized by NMR, FTIR, spectroscopy, and X-ray crystallography. All copper(II) coordination compounds were characterized by elemental analysis, FTIR, EPR spectroscopy, and molar electrical conductivity. Furthermore, single crystal X-ray diffraction analysis elucidated the structures of thiosemicarbazone HL as well as complexes 1–3. All compounds were tested for antimicrobial, antifungal, and antioxidant activities, and their toxicity to Daphnia magna was studied. Biological evaluation has revealed that most of the synthesized compounds demonstrate promising antibacterial, antifungal, and antioxidant activities. In many cases, their antibacterial/antifungal activity is comparable to that of certain drugs used in medicine for these purposes, and in some cases, even surpasses them. HL and complexes 2–5 exhibit antioxidant activity that surpasses that of Trolox. Furthermore, HL and complex 2 display virtually no toxicity to D. magna.
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    COORDINATION COMPOUNDS OF COPPER(II) WITH SUBSTITUTED 3-{[(2-HYDROXYPHENYL)METHYLIDENE]AMINO}PROPANE-1,2-DIOLS
    (2013) Gulea, Aurelian; Ciumacov, Iurie; Graur, Vasilii; Țapcov, Victor
    3-{[(2-Hydroxyphenyl)methylidene]amino}propane-1,2-diol, its 5-chloro-,5-bromo-, 5-nitro-, 3-methoxy derivatives, and 3-{[(2-hydroxynaphthyl- 1)methylidene]amino}propane-1,2-diol react with hydrates of copper(II) chloride, bromide and nitrate in ethanol to form coordination compounds Cu(L)X·nH2O. Template condensation reaction between 3-aminopropane-1,2-diol and 2,3-, 2,4- or 2,5-dihydroxybenzaldehyde in the presence of copper(II) nitrate trihydrate results in similar compounds Cu(L)NO3·nH2O. Structure of some of the condensation products was identified by X-ray analysis. Thermolysis of the substances obtained occurs through the dehydration step (70-90 C) and complete thermal decomposition (290-560 C).
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    SYNTHESIS, STRUCTURE, AND ANTIMICROBIAL ACTIVITY OF COPPER(II) CHELATES CONTAINING IMIDAZOLE AND CONDENSATION PRODUCTS OF α-AMINO ACIDS WITH SALICYLALDEHYDE AND ITS DERIVATIVES
    (2013) Gulea, Aurelian; Lozan-Tîrșu, Carolina; Țapcov, Victor; Ciumacov, Iurie; Janno, E.; Rudic, Valeriu
    Salicylaldehyde, 5-bromo- and 5-nitrosalicylaldehydes, 2- hydroxynaphthalene-1-carbaldehyde, and 2,3-, 2,4-, and 2,5- dihydroxybenzaldehydes reacted with glycine, alanine, and phenylalanine in ethanol in the presence of imidazole (Im) and copper(II) acetate hydrate to give copper(II) chelates with the composition Cu(Im)(L) · nH2O (H2L is the condensation product of the above aldehydes with α-amino acids; n = 0-2). The structure of the complex Cu(Im)(L 1) [H2L1 = 2-(2-hydroxybenzylideneamino)acetic acid] was determined by X-ray analysis. The crystalline structure of [2-(2-hydroxybenzylideneamino)acetato](imidazole)copper is formed by polymeric chains of the Cu(Im)(L1) molecules linked through bridging oxygen atoms in the carboxy groups of the Schiff base ligand. The coordination unit has a distorted tetragonal pyramid configuration, where the pyramid base is composed of the phenol and carboxy oxygen atoms, CH=N nitrogen atom in the ligand H2L1 and imidazole nitrogen atom. The oxygen atom in the carboxy group in the neighboring molecule occupies the apical position of the coordination pyramid. The other coordination compounds also have polynuclear structure with the Schiff base H2L acting as doubly deprotonated tridentate O,N,O-ligand and bridging carboxy groups. Thermal decomposition of the complexes includes their dehydration (70-95 C), while complete thermal decomposition occurs at 360-530 C. The synthesized complexes showed selective antimicrobial activity in the concentration range from 75 to 300 μg/ml against a number of standard strains of Staphylococcus aureus and Escherichia coli.
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    COORDINATION COMPOUNDS OF COBALT, NICKEL, COPPER, AND ZINC WITH 2-BROMO-3-PHENYLPROPENAL BENZOYLHYDRAZONE AND THIOSEMICARBAZONE
    (2009) Samusi, Nina; Ciumacov, Iurie; Țapcov, Victor; Bocelli, Gabrielle; Simonov, Iurie; Gulea, Aurelian
    By X-ray structural analysis the crystal structure of 2-bromo-3- phenylpropenal benzoylhydrazone (HL) was determined. The molecule is not flat. In the crystal the HL molecules form infinite chains with reciprocal van der Waals interaction. 2-Bromo-3-phenylpropenal hydrazone (HL) and thiosemicarbazone (HL') react with cobalt, nickel, copper and zinc chlorides, nitrates and acetates to form coordination compounds of the composition Cu(HL)(L)2 [HL = C6H5-CH=CBr-CH=N-NH-C(O)-C6H 5], MX2•2 HL'•nH2O [M = Co, Ni, Cu, Zn; X = Cl, NO3, HL' = C6H5-CH=CBr-CH=N-NH-C(S) -NH2; n = 0-3], MX2•HL•n H2O [M = Ni, Cu; n = 0, 1], and ML'2•nH2O [M = Co, Ni, Zn; n = 0-3]. The same reactions in the presence of amines (A = C5H 5N, 2-CH3C5H4N, 3-CH 3C5H4N, 4-CH3C5H 4N) afford complexes of the composition CuALCl and MALX•n H 2O [M = Cu, Ni; X = Cl, NO3; n = 0-2]. Structure of the coordination node in the amine-containing copper derivatives is polynuclear, in complexes Cu(HL)(L)2 is octahedral, in other compounds it is tetrahedral. The azomethines (HL and HL') in these complexes behave as bidentate N,O and N,S ligands. Thermolysis of the complexes includes a step of dehydration (60-90°C) and complete thermal decomposition (430-590°C).
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    COORDINATION COMPOUNDS OF COBALT, NICKEL, COPPER AND ZINC WITH THIOSEMICARBAZONE AND 3-PHENYLPROPENAL SEMICARBAZONE
    (2006) Samusi, Nina; Gulea, Aurelian; Țapcov, Victor; Ciumacov, Iurie; Roșu, Tudor
    Hydrates of 3-phenylpropenal thiosemicarbazone (HL•H2O) and semicarbazone (HL'•H2O) react in methanol with cobalt, nickel, copper, and zinc chlorides, nitrates, and acetates to form coordination compounds MX2•2HL•nSolv [M = Co, Ni, Cu, Zn; X = Cl, NO3; HL = C6H5CH=CH-CH=N-NHC(O)NH2; n = 0-3; Solv = H2O, CH3OH], CuX2•HL• nH2O [M = Ni, Cu; n = 0, 1], ML2•nH2O and ML'•nH2O [M = Co, Ni, Zn; HL' = C6H 5CH=CH-CH=N-NHC(O)NH2; n = 0-3]. In the presence of amines (A = C5H5N, 2-CH3C5H4N, 3-CH3C5H4N, and 4-CH3C 5H4N) these reactions yield the complexes Cu(A)LCl•CH3OH and M(A)LX•nH2O [M = Cu, Ni; X = Cl, NO3; n = 0-2]. The copper complexes with the amine ligands are of polynuclear structure, and other complexes are monomeric. Carbazones (HL and HL') are included in the complexes as bidentate N,S-and N,O-ligands. The thermolysis of the complexes involves the stages of removing solvent crystallization molecules (70-90°C), deaquation (150-170°C), and full thermal decomposition (500-580°C).
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    SYNTHESIS, STRUCTURE AND BIOLOGICAL ACTIVITY OF COORDINATION COMPOUNDS OF COPPER, NICKEL, COBALT, AND IRON WITH ETHYL N'-(2-HYDROXYBENZYLIDENE)-N-PROP-2-EN- 1-YLCARBAMOHYDRAZONOTHIOATE
    (2020) Gulea, Aurelian; Usataia, Irina; Graur, Vasilii; Ciumacov, Iurie; Petrenko, Peter; Balan, Greta; Burduniuc, Olga; Țapcov, Victor; Rudic, Valeriu
    N-(Prop-2-en-1-yl)hydrazonocarbothioamide reacts with iodoethane in methanol with further addition of 2-hydroxybenzaldehyde to form hydroiodide of carbamohydrazonothioate (HL·HI). The coordination compounds were obtained by interaction of HL or HL·HI with copper, nickel, cobalt and iron salts CuLХ·nH2O [X = Cl–, Br–, NO3–; n = 0–1], Ni(L)2·HI·CH3OH, Сo(L)2X [X = I–, NO3–] and Fe(L)2NO3. The structures of three complexes were established by single crystal X-ray analysis. The synthesized complexes exhibit selective antimicrobial and antifungal activity against a series of standard microorganisms and fungi in the concentration range of 30–500 μg/mL. In addition, nickel and iron complexes selectively inhibit the growth and proliferation of cancer cells and do not adversely affect normal cells.
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    NICKEL(II) COMPLEXES WITH PENTANE-2,4-DIONE BIS(4-ALLYLTHIOSEMICARBAZONE)
    (2020) Gulea, Aurelian; Graur, Vasilii; Ciumacov, Iurie; Petrenko, Peter; Garbuz, Olga; Țapcov, Victor; Gudumac, Valentin
    Reaction of pentane-2,4-dione with N-(prop-2-en-1-yl)hydrazinecarbothioamide at a 1: 2 molar ratio in ethanol resulted in the formation of a pyrazole derivative. The latter reacted with nickel perchlorate at a 1: 1 molar ratio to form the nickel complex with pentane-2,4-dione bis(4-allylthiosemicarbazone). The same type of nickel complex was obtained as a result of N-(prop-2-en-1-yl)hydrazinecarbothioamide reaction with pentane-2,4-dione and nickel nitrate at a 2: 1: 1 molar ratio. Antimicrobial, antifungal, antioxidant, and anticancer activities of the obtained compounds were studied.
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    SYNTHESIS, STRUCTURE, AND BIOLOGICAL ACTIVITY OF COORDINATION COMPOUNDS OF COBALT(II), NICKEL(II), AND COPPER(II) WITH N-(METHOXYPHENYL)-2-[(5-NITROFURYL)METHYLENE]HYDRAZINE CARBOTHIOAMIDES
    (2019) Gulea, Aurelian; Mitchevici, N.; Ciumacov, Iurie; Petrenko, Peter; Balan, Greta; Burduniuc, Olga; Țapcov, Victor
    4-(2-Methoxyphenyl)-, 4-(3-methoxyphenyl)-, and 4-(4-memoxyphenyl)-2-[(5-mttofuryl)methylene]-hydrazine carboxamide (HL1–3) react with hydrates of cobalt (nickel, copper) chloride (nitrate, acetate) with the formation of the M(HL1–3)2X2 (M = Co2+, Ni2+, Cu2+; X = Cl−, NO3−) and M(L1–3)2 (M = Ni2+, Cu2+) coordination compounds. Structure of the obtained compounds has been studied by means of X-ray diffraction analysis. Their antimicrobial and antifungal activity towards a series of Staphylococcus aureus, Escherichia coli, and yeast-like fungi standard strains has been investigated.
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    SYNTHESIS, STRUCTURE, AND BIOLOGICAL ACTIVITY OF COPPER AND COBALT COORDINATION COMPOUNDS WITH SUBSTITUTED 2-(2-HYDROXYBENZYLIDENE)-N-(PROP-2-EN-1-YL)HYDRAZINE- CARBOTHIOAMIDES
    (2019) Gulea, Aurelian; Graur, Vasilii; Ciumacov, Iurie; Petrenko, Peter A.; Balan, Greta; Burduniuc, Olga; Țapcov, Victor; Rudic, Valeriu
    The reaction of N-(prop-2-en-1-yl)hydrazinecarbothioamide with substituted 2-hydroxybenzaldehydes afforded the corresponding Schiff bases which were used as ligands to obtain copper and cobalt coordination compounds Cu(NL1–6)X · n H2O (X = Cl−, NO3−; n = 0–3), Co(HL2)2NO3, and Co(NL6)2Cl. The structure of the isolated complexes was determined by NMR spectroscopy and X-ray analysis. The complexes were tested for antimicrobial and antifungal activity against S. aureus, E. coli, and yeast-like fungi. Inhibitory effect of the initial thioamides and their complexes against human myeloid leukemia HL-60 cancer cell line was also studied.
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    INTRODUCING N-HETEROAROMATIC BASES INTO COPPER(II) THIOSEMICARBAZON COMPLEXES: A WAY TO CHANGE THEIR BIOLOGICAL ACTIVITY
    (2022) Ulchina, Ianina; Graur, Vasilii; Țapcov, Victor; Ciumacov, Iurie; Garbuz, Olga; Burduniuc, Olga; Ceban, Emil; Gulea, Aurelian
    Three new copper(II) complexes, [Cu(1,10-Phen)(L)] (1), [Cu(2,2’- Bpy)(L)] (2) and [Cu(3,4-Lut)(L)] (3), where H2L=2-[(2,4- dihydroxyphenyl)methylidene]-N-(prop-2-en-1-yl)hydrazine-1- carbothioamide, 1,10-Phen=1,10-phenanthroline, 2,2’-Bpy= 2,2’-bipyridine, 3,4-Lut=3,4-lutidine, have been synthesized and characterized by elemental analysis, FTIR spectroscopy and single crystal X-ray crystallography (1, 2). All compounds are mononuclear. The introduction of a monodentate N-heteroaromatic base (3,4-dimethylpyridine) has led to a significant increase of antimicrobial activity against Gram-negative Escherichia coli and antifungal activity against Candida albicans compared to the pro-ligand and the precursor complex [Cu- (L)H2O]. The introduction of bidentate N-heteroaromatic bases did not lead to such increase of antimicrobial and antifungal activities. Moreover, complex 3 surpasses the inhibitory activity of tetracycline toward Enterobacter cloacae and the inhibitory activity of fluconazole toward Candida parapsilosis and Cryptococcus neoformans. The study of antioxidant activity against cation radicals ABTS* + showed that complexes 1–3 are more active than Trolox, but only introduction of the monodentate Nheteroaromatic base (3,4-dimethylpyridine) led to the increase of antioxidant properties compared to the precursor complex.