Browsing by Author "Novițchi, Ghenadie"

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    HETEROMETALLIC COMPOUNDS WITH THE BINUCLEAR COMPLEX ANION [CR2 (OH)(AC)(NTA)2 ]2– : SYNTHESIS AND STRUCTURE
    (2009) Ciornea, Victor; Șova, Sergiu; Novițchi, Ghenadie; Ganju, Dumitru; Cajeva, Olga; Gulea, Aurelian; Simonov, Iurie
    Heterometallic compounds BaCr2(OH)(Ac)(Nta)2 • 4H2O (I) and [Fe(L)3][Cr2(OH)(Ac)(Nta) 2] • nH2O (L is Bipy (II) and Phen (III); Bipy is, αα′-bipyridine, Phen is o,o′-phenanthroline, Ac - is acetate ion, Nta is nitrilotriacetate ion; n = 8 (II) and 6.25 (III)) are synthesized. According to the X-ray diffraction data, compounds II and III have ionic structures built of the isolated complex cations [Fe(L) 3]2+, binuclear complex anions [Cr2(OH)(Ac) (Nta)2]2-, and crystallization water molecules. The magnetic properties of compounds II and III in the interval from 2 to 300 K confirm assumptions on the diamagnetic character of [Fe(L)3] 2+ and indicate the antiferromagnetic interaction between the chromium atoms in the dimeric fragment [Cr2(OH)(Ac)(Nta) 2]2-.
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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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    IRON(III) COMPLEXES WITH DITOPIC MACROCYCLES BEARING CROWN-ETHER AND BIS(SALICYLIDENE) ISOTHIOSEMICARBAZIDE MOIETIES
    (2023) Arion, Vladimir; Palamarciuc, Oleg; Șova, Sergiu; Novițchi, Ghenadie; Rapta, Peter
    The main aims of this work were the synthesis and characterization of iron(III) complexes with a ditopic ligand H2L consisting of a bis(salicyl- idene)isothiosemicarbazide moiety with a N2O2 binding site and a crown-ether (O6) moiety. A series of high-spin iron(III) complexes, i.e., [FeIIILClBa(CH3OH)(H2O)0.5(ZnCl4)] (1), [FeIIILCl] (2), [FeIIIL(N3)] (3) and [(FeIIIL)2O] (4), were synthesized. The complexes were characterized by mass spectrometry, IR and UV–Vis spectroscopy, variable temperature (VT) mag- netic susceptibility measurements, Mössbauer spectroscopy, single crystal X-ray diffraction and cyclic voltammetry.
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    MAGNETIC INVESTIGATION OF AN UNUSUAL DISSYMMETRIC BINUCLEAR MANGANESE CARBOXYLATE COMPLEX
    (2006) Novițchi, Ghenadie; Costes, Jean-Pierre; Popovschi, Lilia; Șova, Sergiu; Gulea, Aurelian
    The magnetic susceptibility (χT) of an unusual dissymmetric binuclear manganese corboxylate complex has been measured from 2 to 300K. The magnetic data which have been fitted with help of the Heisenberg Dirac Van Vleck HDVV spin-exchange Hamiltonian H = −J S1S2ur ur, indicate that an antiferromagnetic interaction equal to J = -0.90(1) cm-1 is present. A correlation between J values and Mn-H2 O-Mn angles has been tempted.