Browsing by Author "Bîrcă, Maria"

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    COMBINAȚII COORDINATIVE ALE CUPRULUI(II) CU ({(2 [(PIRIDIN-2-IL)METILIDEN]HIDRAZINCARBOTIOIL} AMINO) ACETAT DE ETIL CU PROPRIETĂȚI ANTIOXIDATIVE
    (CEP USM, 2024) Bîrcă, Maria; Rusnac, Anna; Garbuz, Olga; Evtodienco, Carolina; Gulea, Aurelian
    In this work, ethyl 2-isothiocyanatoacetate and [(hydrazinecarbotyoyl)amino]ethyl acetate, which are precursors of thiosemicarbazones, were synthesized.Based on these compounds, the synthesis of two new thiosemicarbazones ethyl 2-(2-(pyridin-2-ylmethylene)hydrazinecarbothioamido)acetate (Hl1) and ethyl 2-(2-(1-(pyridin-2-yl)-ethylidene)hydrazinecarbothioamide)acetate (Hl2) with yields between 85-88%. The thiosemicarbazones obtained were confrmed using 1H and 13C-nMR and FTIR spectroscopy. For the frst time, 8 coordination compounds were obtained based on thiosemicarbazone (Hl1 - Hl2) and Cu(II) salts: [Cu(l1)Br], [Cu(l1)(H2O)Cl], [Cu(l1)nO3], [Cu(l1)(H2O)ClO4], [Cu(l2)Br], [Cu(l2)(H2O)Cl], [Cu(l2)nO3], [Cu(l2)(H2O) ClO 4]. The composition of the synthesized coordination compounds was determined by elemental metal analysis and IR spectroscopy.For the synthesized compounds, the antioxidant capacity was evaluated by means of the aBTs method. In which ethyl 2-(2-(pyridin-2-ylmethylene)hydrazinecarbothioamido)acetate (Hl1) and ethyl 2-(2-(1-(pyridin-2-yl)ethylidene)hydrazinecarbothioamido)acetate (Hl2) were shown to exhibit the best results compared to the reference substance Trolox.
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    COMPUȘI COORDINATIVI AI FIERULUI(III) CU UNELE TIOSEMICARBAZONE N(4) – SUBSTITUITE ALE DERIVAȚILOR SALICIL ALDEHIDEI ȘI CINAM ALDEHIDEI
    (CEP USM, 2024) Bîrcă, Maria; Rusnac, Roman; Gulea, Aurelian
    In this paper, the purpose of synthesis of Fe(III) coordination compounds with some N(4)-substituted thiosemicarbazones of salicyl aldehyde and cinnam aldehyde derivatives was pursued: which contain as a radical in the N(4) position: tert-butyl, cyclohexyl; allyl, methyl. The structure of thiosemicarbazones HnL1-5 was confirmed by FTIR spectroscopy and TLC analysis, melting point and NMR spectra. Based on the above-mentioned ligands, 5 coordination combinations were obtained, the research of which was carried out with the help of infrared spectroscopy. All synthesized compounds are being researched for their biological properties: antimicrobial and antifungal, as well as antioxidant capacities.
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    COMPUȘII COORDINATIVI AI CU(II), NI(II) ȘI CO(III) 3D CU TIOSEMICARBAZIDELE SUBSTITUITE
    (CEP USM, 2022-11-10) Bîrcă, Maria; Ţapcov, Victor; Garbuz, Olga; Borta, Ioana; Gulea, Aurelian
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    FORMATIVE ASPECTS OF THE CHEMICAL CALCULATION PROBLEMS FROM THE PERSPECTIVE OF FOCUSING ON STUDENTS' INTERESTS
    (Academia de Ştiinţe a Moldovei, 2017) Bîrcă, Maria; Prisăcaru, Irina; Zacuțelu Maria2, Maria
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    IN VITRO ANTILEUKEMIA ACTIVITY (HL-60 CELLS), OF SOME 3d METAL COMPLEXES. CHEMICAL SYNTHESIS AND STRUCTURE – ACTIVITY RELATIONSHIP
    (Academia de Ştiinţe a Moldovei, 2006) Gulea, Aurelian; Poirier, Donald; Roy, Jenny; Stavila, Vitalie; Bulimestru, Ion; Tsapkov, Victor; Bîrcă, Maria; Popovschi, Lilia
    28 years after the first approval of cisplatin in the clinic against a number of cancer diseases, cisplatin and related compounds continue to be among the most efficient anticancer drugs used so far. Efforts are focused to develop novel platinum- and non-platinum-based antitumor drugs to improve clinical effectiveness, to reduce general toxicity and to broaden the spectrum of activity. Thiosemicarbazones and their transition metal complexes demonstrated potent cytotoxic activity against a series of murine and human suspended cultured tumor cells. The aim of our communication is to report the synthesis of novel 3d metal complexes with some di- and tri-dentate ligands containing N, O and S donor atoms which have different electronic and geometrical structure confirmed by elemental and thermal analyses, molar conductance, magnetic measurements, IR and NMR data. In order to investigate the antileukemia activity 27 metal complexes were tested as inhibitors of HL60 cells growing. It was established that the nature, electronic structure and coordination number of the central atom, the geometric configuration of metal complexes and the nature of the ligands (donor atoms) are important in biological activity prediction. In investigated series of complexes the most active are those having a copper (II) or a cobalt (II) species. For the octahedral environment of the cobalt complexes the electronic configuration is important Co2+ ( 3d7 ) > Co3+ ( 3d6 ). This different activity can be explained by the fact that in solutions Co2+ complexes with inner coordination sphere lifetime of the ligands 10-4 - 10-5 s are more labile in comparison with the inert Co3+ complexes (lifetime 103 – 105 s). Copper (II) complexes with different type of electronic hybridisation and geometric structure produce also different activity. We find that a square planar Cu2+ complexes have essential activity. The activity of such square planar complexes is influenced also by the nature of the ligand donor atoms. In fact complexes with coordinated ligands containing N, O and S chelate donor atoms are essentially more active than complexes including inner sphere only nitrogen or oxygen. In this case the presence of coordinated ligand containing sulphur donor atom is indicated. If sulphur ligand donor atom is blocked by CH3 group the biological activity became unsignificant.
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    SINTEZA , PROPRIETĂŢILE FIZICO - CHIMICE, ANTIOXIDATIVE Ș I ANTITUBERCULOASE ALE COMPUȘILOR COORDINATIVI AI UNOR METALE 3D CU IZONICOTINOILHIDRAZONA 2 - HIDROXI - 3 - METOXIBENZALDEHIDA
    (CEP USM, 2020) Bîrcă, Maria; Cotovaia, Aliona; Țapcov, Victor; Garbuz, Olga; Crudu, Valeriu; Gulea, Aurelian
    În lucrare sunt prezentate sinteza și studiul proprietăţilor antituberculoase și al activității antioxidative 13 compuși coordinativi noi ai Cr3+, Mn2+, Fe3+, Co3+, Ni2+, Cu 2+, Zn2+ cu izonicotinoilhidrazona 2-hidroxi-3-metoxibenzaldehida (H2L). Ligandul (H2L) a fost obținut la condensarea hidrazidei acidului izonicotinic cu 2-hidroxi-3 -metoxibenzaldehida.Structura acestui ligand a fost stabilită folosind analiza cu raze X. Compușii sintetizați manifestă activitate antituberculoasă și antioxidativă pronunțată.
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    STUDIEREA PRIN METODA ANALIZEI TERMICE COMPLEXE A PARTICULARITĂŢILOR PROCESELOR DE DESHIDRATARE A MOSTRELOR DE CIUPERCI ŞI RĂDĂCINI DE HREAN USCATE
    (CEP USM, 2009) Bîrcă, Maria; Gulea, Aurelian; Lupașco, Andrei; Ţapcov, Victor; Andronic, Olesea; Isac–Guțu, Tatiana; Cotovaia, Aliona
    L’ augmentation continue de la demande du marché de produits végétaux séchés de haute qualité exige l’étude duprocessus de leur déshydratation. À cette fin, un certain nombre d’échantillons de produits végétaux pour le séchageont été traités avec différents régimes des microondes. Pour étudier les propriétés de la matière séchée on a réalisé uneanalyse thermique complexe (thermogravimétrie, thermogravimétrie différentielle, thermo-graphie et analyse thermique différentielle) des processus de déshydratation thermique d’échantillons. Les données expérimentales obtenues (l’ordrede réaction, l’énergie d’activation, le facteur pré-exponentiel, la constante de vitesse et l’entropie) indiquent que leursvaleurs sont proches des paramètres des procédés de déshydratation de systèmes décrits dans la littérature et a permisd’établir les conditions optimales pour l’obtention des champignons et des racines de raifort séchés avec la plus grande durée de stockage
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    STUDY OF MAGNETIC AND ANTIOXIDATIVE PROPERTIES OF SOME BIOMETAL COORDINATION COMPOUNDS OF o-VANILLIN ISONICOTINOYLHYDRAZONE
    (Academia de Ştiinţe a Moldovei, 2015) Gulea, Aurelian; Tsapkov, Victor I.; Bîrcă, Maria; Cotovaia, Aliona; Gudumac, Valentin; Garbuz, Olga; Petcenco, I.; Malic, Elena
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    SYNTHESIS AND BIOLOGICAL ACTIVITY OF COPPER(II) COMPLEXES OF 2-FORMYLPYRIDINE 4-(DIMETHYLPHENYL)THIOSEMICARBAZONES
    (Academia de Ştiinţe a Moldovei, 2012) Sargun, Artur; Jalbă, Angela; Lozan-Tîrşu, Carolina; Gulea, Aurelian; Sofroni, Larisa; Stefan-van Staden, Raluca-Ioana; Bîrcă, Maria
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    SYNTHESIS, STRUCTURE, AND ANTITUBERCULOUS PROPERTIES OF COPPER COORDINATION COMPOUNDS WITH 2-HYDROXY-3- METHOXYBENZALDEHYDE ISONICOTINOYLHYDRAZONE
    (Academia de Ştiinţe a Moldovei, 2015) Gulea, Aurelian; Tsapkov, Victor I.; Bîrcă, Maria; Cotovaia, Aliona; Crudu, Valeriu; Eftodii, Sergiu; Malic, Elena