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

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Author: search.filters.author.Gulea, AurelianSubject: search.filters.subject.coordination compounds

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    EXPLORING THE ANTIOXIDANT ACTIVITY OF 1-(PIPERIDIN-1-YL) PROPANE-1,2-DIONE 4-PHENYLTHIOSEMICARBAZONE AND 3d METAL COORDINATION COMPOUNDS WITH THIS LIGAND
    (CEP USM, 2024) Graur, Ianina; Maxim, Mihail; Graur, Vasilii; Tsapkov, Victor; Gulea, Aurelian; Garbuz, Olga
    The new 1-(piperidin-1-yl)propane-1,2-dione 4-phenylthiosemicarbazone (HL) and its 7 coordination compounds [Cu(L)X] (X = Br- (I); Cl- (II); NO3 - (III); CH3COO- (IV); Cl2CHCOO- (V)), [Co(L)2]NO3 (VI), [Fe(L)2]NO3 (VII) have been synthesized and characterized by elemental analysis, FTIR, 1H, 13C NMR spectra and molar electric conductibility. For the obtained compounds it was studied the antioxidant activity towards ABTS•+ radical cation. Uncoordinated 4-phenylthiosemicarbazone HL is the most active one with IC50 14.1 μM. Its activity is higher than that of Trolox which is used in medicine as an antioxidant. Among all the synthesized coordination compounds, the iron(III) complex VII showed the greatest activity. The antioxidant activity of metal complexes is influenced by the anion and the nature of the central metal atom.
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    COORDINATION COMPOUNDS OF COBALT, NICKEL, COPPER, AND ZINC WITH N1,N2 -BIS(PYRIDIN-2-YLMETHYLIDENE)BENZENE-1,2-DIAMINE AND ITS DERIVATIVES
    (2014) Pahonțu, Elena; Gulea, Aurelian; Poirier, Donald; Țapcov, Victor
    o-Phenylenediamine reacts with 2-formyl-, 2-acetyl-, or 2-benzoylpyridine in ethanol in the presence of cobalt, nickel, copper, or zinc chlorides to form monomeric complexes ML1-3Cl2·nH2O {M = Co, Ni, Cu, Zn; L1 = N 1,N 2-bis(pyridin-2-ymethylidene)benzene-1,2-diamine, L2 = N 1,N 2-bis(pyridin-2-ylethylidene) benzene-1,2-diamine, L3 = N 1,N 2-bis[phenyl(pyridin-2-yl)methylidene]benzene-1,2-diamine; n = 0-3}. The condensation products (L1-L3) act in the complexes as tetradentate N,N,N,N-ligands. Thermolysis of the complexes occurs in two stages: dehydration (70-95°C) and complete degradation (320-450°C). At concentrations of 10-5-10-7 M, the complexes inhibit in vitro growth and proliferation of HL-60 human promyelocytic leukemia cells.
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    SYNTHESIS, STRUCTURE, AND BIOLOGICAL ACTIVITY OF COPPER(II), NICKEL(II), COBALT(III), AND IRON(III) COORDINATION COMPOUNDS WITH 2-{2-[(PROP-2-EN-1-YL)CARBAMOTHIOYL]HYDRAZINYLIDENE}PROPANOIC ACID
    (2020) Gulea, Aurelian; Graur, Vasilii; Diurici, E.; Ulchina, Ianina; Bouroș, Pavlina; Balan, Greta; Burduniuc, Olga; Țapcov, Victor; Rudic, Valeriu
    2-Oxopropanoic acid reacts in ethanol with N-(prop-2-en-1-yl)hydrazinecarbothioamide in a 1 : 1 mole ratio to form thiosemicarbazone H2L. Coordination compounds Cu(HL)X [X = Cl–, Br–, NO3–], Cu(H2O)(L), Ni(HL)2, Co(HL)2X [X = Cl–, Br–], and Fe(HL)2X [X = NO3–, Br–] are formed in the reactions of H2L with copper(II), nickel(II), cobalt(II), and iron(III) salts. The reactions of Cu(H2O)(L) with imidazole (Im) and 3,4-dimethylpyridine (3,4-Lut) result in mixed-ligand complexes Cu(A)(L) [A = Im, 3,4-Lut]. The structures of two copper complexes were determined by single crystal X-ray diffraction analysis. The synthesized complexes exhibit selective antimicrobial and antifungal activity in the concentration range of 15.62–1000 μg/mL. The introduction of amines into the inner sphere of copper complexes leads to an increase in the antimicrobial activity.
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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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    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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    SINTEZA COMBINAȚIILOR COORDINATIVE NOI ALE UNOR METALE 3D ÎN BAZA N(4)-(ACETAT DE ETIL) TIOSEMICARBAZONELOR 2-FORMIL ȘI 2-ACETIL PIRIDINEI. PROPRIETĂȚI ANTIOXIDANTE
    (2022) Rusnac, Anna; Garbuz, Olga; Șova, Sergiu; Gulea, Aurelian
    The given work includes the description of methods for the synthesis of new coordinative combinations of Cu(II), Mn(II), Fe(III) Co(III), Ni(II) and Zn(II) with N(4)-(ethyl acetate) thiosemicarbazones of 2-formylpyridine and 2-acetylpyridine. The characterization of the newly synthesized compounds was carried out using 1H NMR, 13C NMR, FTIR spectroscopy, conductivity, and elemental analysis. In addition, the structures of N(4)-(ethyl acetate) thiosemicarbazide and N(4)-(ethyl acetate) thiosemicarbazone 2-acetylpyridine (HL2) were determined using single crystal X-ray diffraction. The antioxidant activity of coordinative combinations was studied and compared with that of free ligands. The most pronounced antioxidant properties are possessed by [Ni(L2)Cl], whose value of IC50=15,05 μM is three times higher than the IC50=46,76 μM of the non-coordinating ligand and about 2,5 times higher than the reference substances Rutin and Trolox.
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    MICROMOLECULAR INHIBITORS OF SUPEROXIDE RADICALS
    (2021) Andronache, Lilia; Pantea, Valeriana; Gulea, Aurelian; Șveț, Inna; Graur, Vasilii; Matcovschi, Valerii; Gamaniuc, Marina; Gudumac, Valentin
    Background: Currently, there is a growing interest in new copper (Cu2+) heterocyclic coordination compounds (CC), isothiosemicarbazide derivates, which demonstrated multiple beneficial properties, but their effect on reactions with free radicals such as the superoxide radical has not been investigated. Material and methods: The action of new micromolecular complexes of copper (Cu2+) chloride and bromide with methyl n- (prop-2-en-1-yl) -2- (pyridin2-ylmethylidene) hydrazine carbimidothioate on capturing activity of the superoxide radical was determined by the spectrophotometric method in vitro experiments. Results: It was established that the micromolecular complexes of copper (II) chloride and bromide with methyl n-(prop-2-en-1-yl)-2-(pyridin-2ylmethylidene) hydrazine carbimidothioate have been found to possess strong superoxide radical inhibitor properties when interacting with a superoxide radical. In addition to this, the IC50 of the studied compounds depends on the nature of the acid-ligand in the internal sphere of the complex and increases in the following sequence: Cl-–Br-. Conclusions: The established property of mentioned compounds is new, because their use as micromolecular inhibitors of superoxide radicals has not been described so far. The synthesized CC expand the arsenal of superoxide radical inhibitors with high biological activity. Their possible significance for the development of new treatment strategies for diseases associated with the overproduction of superoxide radicals is discussed.
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    COORDINATION COMPOUND AS INHIBITOR OF SUPEROXID RADICAL
    (2019) Garbuz, Olga; Pantea, Valeria; Usataia, Irina; Graur, Vasilii; Țapcov, Victor; Sardari, Veronica; Tagadiuc, Olga; Gudumac, Valentin; Gulea, Aurelian
    A fost obținut un nou compus coordinativ biologic activ, nitratul de cupru [2 - ({2 [(ethylsulfanyl) (prop-2-en-1-yl) carbononoimidooyl] -hydrazinylidene} methyl) phenolate], care face parte din clasa isotiosemicarbazidelor metalelor de tranziție.S-a stabilit că acesta exercită proprietăți anti radicalice performante la acțiunea moleculei organice cu radicalul superoxidic. Datorită acestei poroprietăți compusul obținut poate avea o potențială aplicare in medicină in calitate de inhibitor al radicalilor superoxidici in corpul uman, care poate duce la prevenirea deteriorării tesutului cellular, aterosclerozii si carcinogenezei.Compusul coordinativ sintetizat extinde arsenalul inhibitorilor de radicali superoxidici cu activitate biologică importanta.
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    COORDINATION CHEMISTRY IN THE REPUBLIC OF MOLDOVA
    (2009) Bulhac, Ion; Gulea, Aurelian; Batâr, Dumitru
    This article is dedicated to the history of apparition and development of Coordination chemistry in Moldova. The main scientific centres are characterized, as well as their main research directions. The most valuable results in fundamental and applicative research are described, obtained in the field of coordination chemistry in the republic.
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    COPPER(II) COORDINATION COMPOUNDS WITH 2-ACETYLPYRIDINE N4-(BICYCLO[2.2.1]HEPTAN-2-YL)THIOSEMICARBAZONE AS POTENTIAL ANTIBACTERIAL AGENTS
    (CEP USM, 2023) Graur, Vasilii; Graur, Ianina; Gulea, Aurelian; Teleucă, Iulia; Lozan-Tîrșu, Carolina; Bălan, Greta
    The paper presents the synthesis of the new 2-acetylpyridine N4-(bicyclo[2.2.1]hept-2-yl)thiosemicarbazone (HL) and its three copper(II) coordination compounds: [Cu(L)X] (X = NO3- (I), Cl- (II), CHCl2COO- (III)). The obtained compounds were studied by NMR and FTIR spectroscopies, elemental analysis, and molar electric conductibility. The antibacterial activity towards Gram-positive (Staphylococcus aureus, Bacillus cereus) and Gram-negative (Escherichia coli, Acinetobacter baumannii) standard strains was studied for the HL and complexes I-III. The coordination of the HL to the copper(II) atom leads to the increase of activity against almost all microorganisms. Complex I is the most active one towards Gram-positive microorganisms, while complex III is the most active one towards Gram-negative microorganisms. They in many cases surpass the activity of Furacillinum and are practically on the same level as Tetracycline towards Gram-positive microorganisms.