Browsing by Author "Cecal, Alexandru"

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    INVESTIGATION OF GEOMETRICAL AND CONFORMATIONAL ISOMERS OF COBALT(II) BIS(DIPHENYLACETATO)-BIS(G -PICOLINATE) BY DYNAMIC NMR SPECTROSCOPY AND MOLECULAR MECHANICS
    (2001) Novițchi, Ghenadie; Cecal, Alexandru; Gulea, Aurelian
    Cobalt(II) bis(diphenylacetato)-bis(γ-picolinate) is synthesized and its geometrical and conformational isomers are investigated using dynamic NMR and molecular mechanics methods. The complex in the solution is shown to exist as cis and trans isomers, which are detected at 263 K in the course of a slow intermolecular ligand exchange. At T < 223 K, the intramolecular rotation of the phenyl radicals about the -O2C-CH(Ph)2 and -O2CCH(Ph)-Ph bonds slows, which results in the formation of different conformers. The energies of the retarded intermolecular exchange and of the retarded rotation of the phenyl radicals were calculated from 1H NMR and molecular mechanics data.
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    USE OF SOME CATALYSTS IN RADIOLYTICAL SPLIT OF WATER
    (2002) Cecal, Alexandru; Paraschivescu, Andrei; Gulea, Aurelian; Palamaru, Mircea; Iordan, Alexandra; Popa, Karin; Craus, Mihai
    The present paper deals with the study of catalyzed water radiolysis under the influence of γ-rays emitted by a 60Co source (Λ = 3 × 104 Ci) with a dose rate of 8.3 kGy/h, for hydrogen production. Thirty-one solid inorganic compounds, insoluble in water, were tested as catalysts. They belong to: coordination compounds of some metallic ions with organic ligands based on salycilaldehyde or naphthalenaldehyde derivatives, mixed oxides, RhCl3 supported on a Al2O 3 layer and bimetallic compounds with EDTA ligand. The released hydrogen quantity, determined by mass spectrometry, was approximately 7-35 times greater than the one produced by simple radiolysis of water, in the absence of catalysts.