Browsing by Author "Melnic, Elena"

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    CRYSTAL STRUCTURE AND HIRSHFELD SURFACE ANALYSIS OF 2,4-DIAMINO-6-PHENYL-1,3,5-TRIAZIN-1-IUM PERCHLORATE
    (CEP USM, 2024) Craciun, Nicoleta; Melnic, Elena; Fonari, Marina; Chişca, Diana
    Synthesis and characterization of new organic salt, 2,4-diamino-6-phenyl-1,3,5-triazin- 1-ium perchlorate (LH)(ClO4), in which NH ···O(N) hydrogen bonds play an essential role in stabilizing the crystal structure, were highlighted in the present study. The crystal structure was determined using single-crystal X-ray diffraction analysis, which reveals that the title compound crystallizes in the monoclinic centrosymmetric space group P21/c and contains one cation and one anion in the asymmetric unit. The unit cell parameters are a =13.8011(13) Å, b = 5.0674(5) Å, c = 16.6411(13) Å, and β = 91.930(9)˚. Also, the composition C9H10ClN5O4, of the discussed compound was confirmed by FTIR spectroscopy. From this research a decisive influence of hydrogen bonds on stability of the reported crystal is evidenced. The distribution of all types of intermolecular interactions was assessed by the Hirschfeld surface analysis method.
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    Effect of the nature of the anion on the composition and structure of cobalt complex with monoethanolamine [Articol]
    (2013) Cotovaia, Aliona; Șova, Sergiu; Melnic, Elena; Simonov, Iurie; Gulea, Aurelian; Pahonțu, Elena
    A number of products formed in reactions of cobalt(II) salts with monoethanolamine (HEtm) in a neutral medium were synthesized and studied. X-Ray diffraction study showed that the nitrate and acetate form the dimers [Co(HEtm)3][Co(Etm)3](NO3)3 and [Co(HEtm)3][Co(Etm)3](CH3COO)3 · 8H2O, respectively. In chloride solutions, cobalt is partially oxidized to give the trinuclear complex [CoII{Co III(Etm)3}2]Cl3 · H 2Etm · 2H2O. The reaction of the chelate [Co(Etm)3] · 3H2O with nitric acid is accompanied by complete protonation of the coordinated aminoethanolate ions, and the reaction with formic acid involves complete replacement of the coordinated ligand by acid residue anions and water molecules to give the coordination polymer {Co2(μ-HCOO)4(H2O)4} n .