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Author: search.filters.author.Bulimestru, Ion

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    Sinteza și studiul compușilor coordinativi homo- și heterometalici ai Cu(II) și Bi(III) cu 4-etiltiosemicarbazonele 2-formil și 2-acetilpiridinei
    (CEP USM, 2023) Neguța, Elena; Gulea, Aurelian; Cotovaia, Aliona; Bulimestru, Ion; Bălan, Greta; Șova, Sergiu
    În această lucrare sunt prezentate sinteza și studiul a două serii de compuși coordina- tivi homo- și heterometalici ai Cu(II) și Bi(III) cu 4-etiltiosemicarbazonele 2-formil și 2-acetilpiridinei, cu formulele generale: {Cu(HL)}Cu(edta)•nH2O, {Cu(L)}2Cu(edta)•nH2O în cazul complecșilor homometalici ai Cu(II) și {Cu(L)}Bi(edta)•nH2O (n = 1 - 5), pentru compușii heterometalici Cu(II)-Bi(III). În complecșii sintetizați, 4-etiltiosemicarbazonele 2-formilpiridinei (HFoPyTSC-4Et) și 2-acetilpiridinei (HAcPyTSC-4Et) sunt în formă monodeprotonată (L) sau nedeprotonată (HL), iar edta4- reprezintă ionul etilendiamintetracetat. A fost determinată activitatea antimicrobiană și antifungică a compușilor homo- și heterometalici obținuți. Rezultatele au demonstrat că cea mai mare activitate antimicrobiană a manifestat-o compusul [Cu(AcPyTSC-4Et)Bi(edta)]·5H2O, fiind de cca 76 și 19 ori mai activ decât Furacilina (CMI = 4,67 μg/mL) în cazul tulpinilor Staphylococcus aureus (ATCC 25923) și Bacillus cereus (ATCC 11778), respectiv. Iar împotriva tulpinei Candida albicans, cel mai activ agent antifungic a fost compusul {Cu(AcPyTSC-4Et)}2Cu(edta)·H2O, cu CMI = 0,98 μg/mL, care este de cca 32 de ori mai activ decât Nistatina (CMI = 32,0 μg/ mL).
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    ANTIMICROBIAL AND ANTIFUNGAL ACTIVITY OF CU(II) AND BI(III) COMPLEXES BASED ON AMINOPOLYCARBOXYLATE IONS AND 2-FORMYL AND 2-ACETYLPYRIDINE THIO- SEMICARBAZONES
    (2021) Neguța, Elena; Balan, Greta; Gulea, Aurelian; Bulimestru, Ion
    The biological properties of thiosemicarbazones are often related to metal coordination, which as result affects lipophilicity that controls the rate of entry into the cell. Metal complexes are generally more active than the free ligand, or the metal complex can be a vehicle for activation of the ligand as the cytotoxic agent. Among biologically ac- tive metal compounds, copper (II) complexes with 2-formyl and 2-acetylpyridine thio- semicarbazones proved to be among the most potent antiviral, antitumor and anti-inflam- matory agents. Bismuth compounds have been widely used in medicine for more than two centuries due to their high effectiveness and low toxicity. In the antimicrobial realm, ap- plications have been widespread, due to bismuth antiseptic, astringent, protective, ant- acid, antisecretory and local gastrointestinal properties.
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    PREPARATION OF MIXED-OXIDE MATERIALS FROM HETEROMETALLIC COORDINATION COMPOUNDS
    (Academia de Ştiinţe a Moldovei, 2015) Bulimestru, Ion; Mentre, Olivier; Tancret, Nathalie; Cornei, Nicoleta; Shova, Sergiu; Popa, Nelea; Gulea, Aurelian
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    MAGNETIC STUDY IN SOLUTION OF LANTHANIDE(III)-BISMUTH(III) COORDINATION COMPOUNDS BY MEANS OF NMR SPECTROSCOPY
    (Academia de Ştiinţe a Moldovei, 2012) Gulea, Aurelian; Popa, Nelea; Barba, Alic; Bulimestru, Ion
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    HETEROMETALLIC LANTHANIDE(III)-BISMUTH(III) POLYAMINOPOLYCARBOXYLATE COMPLEXES: SYNTHESIS AND CRYSTAL STRUCTURE
    (Academia de Ştiinţe a Moldovei, 2012) Bulimestru, Ion; Popa, Nelea; Shova, Sergiu; Gulea, Aurelian
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    MOLECULAR PRECURSORS BASED ON HETEROMETALLIC BISMUTH(III)-VO(II) OR -Cu(II) COORDINATION COMPOUNDS
    (Academia de Ştiinţe a Moldovei, 2012) Bulimestru, Ion; Roussel, Pascal; Capet, Frederic; Vannier, Rose-Noelle; Wignacourt, Jean-Pierre; Gulea, Aurelian
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    NEW HETEROPOLYNUCLEAR BI-SM AND BI-HO COMPLEXES WITH ETHYLENEDIAMINETETRAACETIC ACID
    (Academia de Ştiinţe a Moldovei, 2006) Popa, Nelea; Roussel, Pascal; Wignacourt, Jean-Pierre; Bulimestru, Ion; Gulea, Aurelian
    The search for bismuth-lanthanide coordination compounds that could be used as molecular precursors for Bi-Ln-based oxide-type materials displays a wide interest in the relationship with the numerous applications of such inorganic materials as ion conductors (Bi-La, Nd, Sm), ferroelectrics (Bi-Sm, La) or inorganic pigments (Bi-Ho) [1]. When compared with the traditional ceramic route involving oxides of the component metals, these precursor methods actually provide materials displaying a higher homogenity and specific surface area. As an ongoing effort to synthesise new potential precursors for inorganic materials, we have obtained two new heterometallic coordination compounds with ethylenediamine tetraacetate ion as a ligand with the following general formulae: LnBiEdta(NCS)2⋅4H2O (Ln = Sm, Ho). The composition has been confirmed by elemental analysis, TG/TGA study, IR spectroscopy and single crystal X-ray diffraction. The results of X-ray study revealed that the compounds are isomorphous, crystallizing in P21/n space group with the average cell parameters: a = 9.3, b =16.7, c = 14.5 (Å), β=103º. The crystal structure represents a 3D coordination network (see fig.) sustained by the four bridging carboxylate groups of the Edta4- ligand and one of the two NCS- ligands coordinated to Bi through S atom and to Ln through N atom. The second NCS-group is coordinated to Bi ion as a monodentate ligand. Analogous tridimensional structures have been obtained with nitrate ion [2].figureFig. 1. Packing of LnBiEdta(NCS)2⋅4H2O.
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    CRYSTAL STRUCTURE OF [Co(thios) 3 ] 2 [Bidtpa] 2 (NCS)(OH)⋅8H2O
    (Academia de Ştiinţe a Moldovei, 2006) Petrenko, Peter A.; Bulimestru, Ion; Simonov, Yurii A.; Gdaniec, Maria; Gulea, Aurelian
    Bismuth-based mixed-oxides have been studied extensively for a number of potentially useful physical properties like oxygen ion conductivity, ferroelectricity, superconductivity and catalysts in different oxidation processes. The use of bismuth complexes as precursors for new heterometallic oxide systems turned out to be a more effective route compared to traditional ceramic synthesis. Thus, controlled pyrolysis of alkoxide, carboxylate or polyaminopolycarboxylate precursors has frequently been used to synthesize highly dispersed bismuth containing mixed-oxides and solid solutions. Diethylenetriaminepentaacetic acid (H5Dtpa) gives numerous stable complexes with d, f, and p elements, including Bi. Most frequently, complexes with H5Dtpa are more stable than those with its analogues. Recently, we have characterized two heterometallic coordination compounds, [Co(thios)3]2[Bi(Dtpa)]2SO4·6H2O (I) and [Co(thios)3]4[BiDtpa]4⋅(SO4)2⋅20H2O (II) containing complex cations and anions (thios=thiosemicarbazide). In this work we present synthesis and crystal structure of a new heterometallic compound [Co(thios)3]2[BiDtpa]2⋅(NCS)(OH)⋅8H2O (III) (see fig.). The crystal structure of III is built of complex cations [Co(thios)3]3+, three types of anions [Bi(Dtpa)]2-, [NCS]2-, (OH)- and water molecules. The Bi atom coordination polyhedron is a nanohedron and its coordination number is nine. The coordination of Dtpa residues to the bismuth atom gives rise to five glycine and two ethylenediamine metallocycles which are essentially non-planar. The complex cation [Co(thios)3]3+ is a typical Co(III) tristhiosemicarbazide fac-isomer.