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Publication Metadata only Vibrational study on Zn(Pyrimidine)(2)Cl-2, Pyrimidine-Al(OH)(3) and Pyrimidine-(Al(OH)(3))(2) complexes(ELSEVIER SCIENCE BV, PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS, 2008-11-20) Akalın, Elif; AKYÜZ, SEVİM; TR10127; TR46357A molecular modeling analysis was performed via density functional theory (DFT), using B3LYP/6-31++G(d,p) basis set on Zn(PM)(2)Cl-2, PMAI(OH)(3) and PM-(AI(OH)(3))(2) complexes (PM: Pyrimidine) in order to investigate monodentate and bidentate coordination effects on pyrimidine vibrational wavenumbers. The Zn(PM)(2)Cl-2. Complex was synthesized and the FT-IR and FT-Ra spectra were recorded which, when compared to the calculated wavenumbcrs of the model mono- and bidentate Al(OH)(3) Complexes, showed that pyrimidine behaved as a rnonodentate ligand. Anharmonic corrections to the calculated wavenumbers of the Zn(PM)(2)Cl-2 complex were done and the results led to a good overall agreement with the observed wavenurnbers. A complete assignment of the fundamentals was proposed based on the internal mode analysis done by Gaussian03 programme. (C) 2007 Elsevier B.V. All rights reserved.Publication Metadata only Ab Initio and Raman Study of Medium Range Ordering in GeSe2 Glass(Elsevier Science Bv, Po Box 211, 1000 Ae Amsterdam, Netherlands, 2013-08-01) Akalın, Elif; Holomb, R.; Mitsa, V.; Sichka, M.; AKYÜZ, SEVİM; 10127; 46357High resolution Raman spectra of GeSe2 glass were measured and fitted using individual Gaussian components. The structural origin of the components were interpreted using the results of ab initio density functional theory calculations performed on GenSem nanoclusters (n = 2-6, 12; m = 6-9, 12, 14-16, 30) which represent the local structure of GeSe2 glass and on some "defect" GenSem clusters that are thought to be related to the inhomogeneity of the structure at the nanoscale. The calculated vibrational properties of GenSem nanoclusters and their couplings with the short- and medium-range order structure formations in GeSe2 glass are analyzed and discussed. (c) 2013 Elsevier B.V. All rights reserved.Publication Metadata only New Ring-Like Models and ab Initio DFT Study of the Medium-Range Structures, Energy and Electronic Properties of GeSe2 Glass(Taylor & Francis Ltd, 4 Park Square, Milton Park, Abingdon Ox14 4Rn, Oxon, England, 2013-07-01) Akalın, Elif; Holomb, R.; Mitsa, V.; AKYÜZ, SEVİM; 46357; 10127Ab initio DFT calculations were performed on GenSem nanoclusters (n=2, 3, 5, 6, 12; m=6-9, 14, 16, 30) that represent the local structure of GeSe2 glass and on some defect' GenSem clusters that are thought to be related to the inhomogeneity of the structure at the nanoscale. The optimal geometries, total energies and their derivatives as well as the electronic properties of GenSem nanoclusters were calculated using traditional DFT method. In addition, the TD-DFT method has been applied to calculate the electronic band gaps of the clusters. The calculated physico-chemical properties of GenSem nanoclusters and their couplings with the local-and medium-range order structure formations in GeSe2 glass are analysed and discussed.Publication Metadata only Vibrational Analysis of Free and Hydrogen Bonded Complexes of Nicotinamide and Picolinamide(Elsevier, 2006-11-24) Akalın, Elif; AKYÜZ, SEVİM; 46357; 10127Harmonic and anharmonic vibrations of free nicotinamide (NIA) and picolinamide (PIA) molecules together with their hydrogen bonded complexes H2O–NIA and H2O–PIA have been studied by means of density functional method. The calculation results of the vibrational spectra of free molecules have been investigated and are compared to the available experimental spectra. The vibrational wavenumbers of both molecules have also been calculated by polarizable continuum model (PCM) that represents the solvent as a polarizable continuum and places the solute in a cavity within the solvent (water is chosen as the solvent in this study). The results of PCM calculations and the H2O–NIA, H2O–PIA complexes, are used to investigate the H-bonding interactions of both molecules with the water molecule. The harmonic wavenumbers have been scaled by proper factors obtained by comparing the observed versus calculated wavenumbers and it is shown that anharmonic corrections on the vibrational spectra provided a better agreement between the observed and calculated wavenumbers compared to the results obtained by scaling factor method.Publication Metadata only Adsorption and Interaction of 5-fluorouracil with Montmorillonite and Saponite by FT-IR Spectroscopy(ELSEVIER SCIENCE BV, PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS, 2007-05-27) Akalın, Elif; AKYÜZ, SEVİM; AKYÜZ, ZEKİ TANIL; TR46357; TR111424; TR10127Adsorption of 5-fluorouracil (5-FU) on montmorillonite and saponite has been investigated using FT-IR spectrometry. The intercalation of 5-FU within montmorillonite or saponite has been shown by X-ray diffraction to increase the interlayer spacing. In order to investigate interaction of 5-FU with clays, the harmonic and anharmonic vibrational wavenumbers of free 5-FU and 5-FU interacting with AI(OH)3 have been calculated at the DFT/B3LYP level with 6-31 ++G(d,p) basis set by using Gaussian 03 program set. The solution effect on 5-FU was also calculated by using polarizable continuum model (PCM). Experimental and calculated results indicated that 5-FU interacted with clays by direct or indirect coordination (through water molecules) to the Lewis acidic centers. (C) 2006 Elsevier B.V. All rights reserved.