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

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Author: search.filters.author.Pahonțu, ElenaSubject: search.filters.subject.crystal structure

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    SYNTHESIS, CHARACTERIZATION, CRYSTAL STRUCTURE AND ANTIMICROBIAL ACTIVITY OF COPPER(II) COMPLEXES WITH THE SCHIFF BASE DERIVED FROM 2-HYDROXY-4-METHOXYBENZALDEHYDE
    (2015) Pahonțu, Elena; Ilieș, Diana Carolina; Șova, Sergiu; Paraschivescu, Codruța; Badea, Mihaela; Gulea, Aurelian; Roșu, Tudor
    A novel Schiff base, ethyl 4-[(E)-(2-hydroxy-4-methoxyphenyl)methyleneamino] benzoate (HL), was prepared and structurally characterized on the basis of elemental analyses, 1H NMR, 13C NMR, UV-Vis and IR spectral data. Six new copper(II) complexes, [Cu(L)(NO3)(H2O)2] (1), [Cu(L)2] (2), [Cu(L)(OAc)] (3), [Cu2 (L)2Cl2(H2O)4] (4), [Cu(L)(ClO4)(H2O)] (5) and [Cu2(L2S)(ClO4)(H2O)]ClO4·H2O (6) have been synthesized. The characterization of the newly formed compounds was done by IR, UV-Vis, EPR, FAB mass spectroscopy, elemental and thermal analysis, magnetic susceptibility measurements and molar electric conductivity. The crystal structures of Schiff base and the complex [Cu2(L2S)(ClO4)(H2O)]ClO4·H2O (6) have been determined by single crystal X-ray diffraction studies. Both copper atoms display a distorted octahedral coordination type [O4NS]. This coordination is ensured by three phenol oxygen, two of which being related to the μ-oxo-bridge, the nitrogen atoms of the azomethine group and the sulfur atoms that come from the polydentate ligand. The in vitro antimicrobial activity against Escherichia coli ATCC 25922, Salmonella enteritidis, Staphylococcus aureus ATCC 25923, Enterococcus and Candida albicans strains was studied and compared with that of free ligand. The complexes 1, 2, 5 showed a better antimicrobial activity than the Schiff base against the tested microorganisms
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    NOVEL 2-FORMYLPYRIDINE 4-ALLYL-S- METHYLISOTHIOSEMICARBAZONE AND ZN(II), CU(II), NI(II) AND CO(III) COMPLEXES: SYNTHESIS, CHARACTERIZATION, CRYSTAL STRUCTURE, ANTIOXIDANT, ANTIMICROBIAL AND ANTIPROLIFERATIVE ACTIVITY
    (2019) Balan, Greta; Usataia, Irina; Graur, Vasilii; Ciumacov, Iurie; Petrenko, Peter; Gudumac, Valentin; Gulea, Aurelian; Pahonțu, Elena; Burduniuc, Olga
    New zinc (II), copper (II), nickel (II) and cobalt (III) complexes, [Zn (HL)2]I2 (1), [Cu (HL)Cl2] (2), [Cu (HL)Br2] (3), [Cu (HL)(H2O)2](ClO4)2 (4), [Ni (HL)2]I2·H2O (5), [Co(L)2]Cl (6), [Co(L)2]NO3 (7), [Co(L)2]I·[Co(L)2](I3) (8) were obtained with 2-formylpyridine 4-allyl-S-methylisothiosemicarbazone (HL). The isothiosemicarbazone ligand was characterized by NMR (1H and 13C), IR spectroscopy and X-ray diffraction. All the complexes were characterized by elemental analysis, IR, UV–Vis, ESI-MS spectroscopy, molar conductivity, magnetic susceptibility measurements. X-ray diffraction analysis on the monocrystal and powder elucidated the structure of the complexes 1, 5, 7 and 8. The ligand and the complexes were tested for their antioxidant and antimicrobial activity against Staphylococcus aureus, Escherichia coli, Klebsiella pneumoniae and Candida albicans. Also, the antiproliferative properties of these compounds on human leukemia HL-60, human cervical epithelial HeLa, human epithelial pancreatic adenocarcinoma BxPC-3, human muscle rhabdomyosarcoma spindle, large multinucleated RD cells and normal MDCK cells have been investigated. The nickel complex 5 and cobalt complexes 6, 7 showed promising antiproliferative activity and low toxicity.
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    ANTIBACTERIAL, ANTIFUNGAL AND IN VITRO ANTILEUKAEMIA ACTIVITY OF METAL COMPLEXES WITH THIOSEMICARBAZONES
    (Wiley, 2015) Pahonțu, Elena; Julea, Felicia; Rosu, Tudor; Purcarea, Victor; Chumakov, Yurie; Petrenco, Petru; Gulea, Aurelian
    1-phenyl-3-methyl-4-benzoyl-5-pyrazolone 4-ethyl-thiosemicarbazone (HL) and its copper(II), vanadium(V) and nickel(II) complexes: [Cu(L)(Cl)]·C2H5OH·(1), [Cu(L)2]·H2O (2), [Cu(L)(Br)]·H2O·CH3OH (3), [Cu(L)(NO3)]·2C2H5OH (4), [VO2(L)]·2H2O (5), [Ni(L)2]·H2O (6), were synthesized and characterized. The ligand has been characterized by elemental analyses, IR, 1H NMR and 13C NMR spectroscopy. The tridentate nature of the ligand is evident from the IR spectra. The copper(II), vanadium(V) and nickel(II) complexes have been characterized by different physico-chemical techniques such as molar conductivity, magnetic susceptibility measurements and electronic, infrared and electron paramagnetic resonance spectral studies. The structures of the ligand and its copper(II) (2, 4), and vanadium(V) (5) complexes have been determined by single-crystal X-ray diffraction. The composition of the coordination polyhedron of the central atom in 2, 4 and 5 is different. The tetrahedral coordination geometry of Cu was found in complex 2 while in complex 4, it is square planar, in complex 5 the coordination polyhedron of the central ion is distorted square pyramid. The in vitro antibacterial activity of the complexes against Escherichia coli, Salmonella abony, Staphylococcus aureus, Bacillus cereus and the antifungal activity against Candida albicans strains was higher for the metal complexes than for free ligand. The effect of the free ligand and its metal complexes on the proliferation of HL-60 cells was tested.
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    SYNTHESIS, CHARACTERIZATION, CRYSTAL STRUCTURE AND ANTIMICROBIAL ACTIVITY OF COPPER(II) COMPLEXES WITH THE SCHIFF BASE DERIVED FROM 2-HYDROXY-4-METHOXYBENZALDEHYDE
    (Molecular Diversity Preservation International (MDPI), 2015) Pahonțu, Elena; Ilieș, Diana-Carolina; Shova, Sergiu; Paraschivescu, Codruța; Badea, Mihaela; Gulea, Aurelian; Roșu, Tudor
    A novel Schiff base, ethyl 4-[(E)-(2-hydroxy-4-methoxyphenyl)methylene-amino]benzoate (HL), was prepared and structurally characterized on the basis of elemental analyses, 1H NMR, 13C NMR, UV-Vis and IR spectral data. Six new copper(II) complexes, [Cu(L)(NO3)(H2O)2] (1), [Cu(L)2] (2), [Cu(L)(OAc)] (3), [Cu2 (L)2Cl2(H2O)4] (4), [Cu(L)(ClO4)(H2O)] (5) and [Cu2(L2S)(ClO4)(H2O)]ClO4·H2O (6) have been synthesized. The characterization of the newly formed compounds was done by IR, UV-Vis, EPR, FAB mass spectroscopy, elemental and thermal analysis, magnetic susceptibility measurements and molar electric conductivity. The crystal structures of Schiff base and the complex [Cu2(L2S)(ClO4)(H2O)]ClO4·H2O (6) have been determined by single crystal X-ray diffraction studies. Both copper atoms display a distorted octahedral coordination type [O4NS]. This coordination is ensured by three phenol oxygen, two of which being related to the µ-oxo-bridge, the nitrogen atoms of the azomethine group and the sulfur atoms that come from the polydentate ligand. The in vitro antimicrobial activity against Escherichia coli ATCC 25922, Salmonella enteritidis, Staphylococcus aureus ATCC 25923, Enterococcus and Candida albicans strains was studied and compared with that of free ligand. The complexes 1, 2, 5 showed a better antimicrobial activity than the Schiff base against the tested microorganisms.