Browsing by Subject "SPECTROSCOPIC CHARACTERIZATION"

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    Quantum chemical calculation (electronic and topologic) and experimental (FT-IR, FT-Raman and UV) analysis of isonicotinic acid N-oxide
    (PERGAMON-ELSEVIER SCIENCE LTD) Karaca, C; Atac, A; Karabacak, M
    In this work, the molecular conformation, vibrational and electronic analysis of isonicotinic acid N-oxide (iso-NANO) were presented in the ground state using experimental techniques (FT-IR, FT-Raman and UV) and density functional theory (DFT) employing B3LYP exchange correlation with the 6-311++G(d,p) basis set. The geometry optimization and energies associated possible two conformers (Rot-I and Rot-II) were computed. The vibrational spectra were calculated and fundamental vibrations were assigned on the basis of the total energy distribution (TED) of the vibrational modes, calculated with scaled quantum mechanics (SQM) method and PQS program. The obtained structures were analyzed with the Atoms in Molecules (AIMs) methodology. The computational results diagnose the most stable conformer of iso-NANO as the Rot-I form. Total density of state (TDOS) and partial density of state (PDOS) and also overlap population density of state (OPDOS) diagrams analysis for the most stable conformer (Rot-I) were calculated using the same method. Thermodynamic properties (heat capacity, entropy and enthalpy) of the title compound at different temperatures were calculated. As a result, the optimized geometry and calculated spectroscopic data show a good agreement with the experimental results. (C) 2014 Elsevier B.V. All rights reserved.
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    Rational Synthesis and Characterization of the Mixed-Metal Organometallic Polyoxometalates [Cp*MoxW6-xO18]- (x=0, 1, 5, 6)
    (AMER CHEMICAL SOC) Taban-Çaliskan, G; Fernandes, DM; Daran, JC; Agustin, D; Demirhan, F; Poli, R
    The reaction between the oxometallic complexes Cp*2M2O5 and Na2M'O-4 (M, M' = Mo, W) in a 1:10 molar ratio in an acidic aqueous medium constitutes a mild and selective entry into the anionic Lindqvist-type hexametallic organometallic mixed oxides [Cp*MoxW6-xO18](-) [x = 6 (1), 5 (2), 1 (3), 0 (4)]. All of these compounds have been isolated as salts of nBu(4)N(+) (a), nBu(4)P(+) (b), and Ph4P+ (c) cations and two of them (1 and 3) also with the n-butylpyridinium (nBuPyr(+), d) cation. The compounds have been characterized by elemental analyses, thermogravimetric analyses, electrospray mass spectrometry, and IR spectroscopy. The molecular identity and geometry of compounds 1c, 2a, and 2c have been confirmed by single-crystal X-ray diffraction. Density functional theory calculations on models obtained by replacing Cp* with Cp (I-IV) have provided information on the assignment of the terminal M=O and bridging M-O-M vibrations.