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Öğe Analysis of the xylenol isomers by femtosecond laser time of flight mass spectrometry(Canadian Science Publishing, 2018) Kepceoglu, A.; Koklu, N.; Gundogdu, Y.; Dereli, O.; Kilic, H. S.Xylenol is a phenolic chemical substance having two methyl groups and one hydroxyl group attached to a benzene ring and has six isomers. 2,4-xylenol is the only isomer of the xylenol molecule that is in the liquid phase while the remaining isomers are all in crystal form at room temperature. In the scope of this study, we have experimentally investigated ionization and dissociation properties of xylenol isomers. All experiments were carried out by using a time of flight mass spectrometry (TOF-MS) system coupled with a femtosecond laser system. The laser pulse power-dependent multiphoton ionization of xylenol isomers was investigated by using IR (800 nm) femtosecond laser pulses having a pulse width of similar to 90 fs in duration and laser intensities changing from 2.6 x 10(13) to 2.6 x 10(14) W/cm(2). Theoretically, molecular orbitals (LUMO+1, LUMO, HOMO, HOMO-1), vertical and adiabatic ionization energies were calculated using density functional theory (DFT) with B3LYP functional and 6-311++G(d,p) basis set by following geometry optimization and performing conformational analysis.Öğe Experimental and Theoretical Vibrational Spectroscopic Study of Zinc (II) Halide Complexes of 4-Acetylpyridine(Gazi Univ, 2017) Erdogdu, Y.; Sertbakan, T. R.; Dereli, O.; Gulluoglu, M. T.; Yurdakul, S.In the present work, we present a detailed experimental and theoretical study of the zinc (II) halide complexes of 4-acetylpyridine (abbreviated as 4-Ap) (Zn (L)(2) X-2, [where L: C7OH7N; X: Cl, Br and I]). The infrared and Raman spectra of the zinc (II) halide complexes of 4-Ap have been recorded between 400-4000 cm(-1) and 5-3500 cm(-1) regions, respectively. The analysis of the FT-IR and FT-Raman spectra indicates that some structure-spectra correlations. For a given series of isomorphous complexes, the sum of the differences between the values of the vibrational modes of uncoordinated 4-Ap was found to increase in order of second ionization potentials of metal. The molecular geometry and vibrational frequencies of the zinc (II) halide complexes of 4-Ap in the ground state have been calculated by using the Density Functional Method (B3LYP) with LANL2DZ and SDD as basis sets. A complete assignment of the fundamentals was proposed based on the total energy distribution (TED) calculation.Öğe Molecular structure and spectral investigations of 3,5-Di-tert-butyl-o-benzoquinone(Elsevier, 2017) Yilmaz, M.; Aydin, B.; Dogan, O.; Dereli, O.Conformational analysis of 3,5-Di-tert-butyl-o-benzoquinone molecule was performed and two stable conformers were determined by B3LYP/6-311++G(d,p). Using the most stable one, molecular structural parameters, vibrational frequencies were calculated by B3LYP/6-311++G(d,p), B3LYP/6-31G(d) and BLYP/6-31G(d,p) levels of theory. The FT-IR spectrum of the compound was recorded in the region 4000-550 cm(-1). The Raman spectrum was also recorded in the region 3500-100 cm(-1). Calculated results were compared with experimental counterparts. The best results were obtained from B3LYP/6-311++G(d,p) calculations. Experimental C-13 and H-1 NMR data of tittle compound were taken from literature and the calculated results compared with these data. Vibrational and NMR band assignments were performed. HOMO-LUMO energies, molecular electrostatic potentials and thermodynamic properties were also given for further investigations of our structure. (C) 2016 Elsevier B.V. All rights reserved.Öğe Molecular Structure and the EPR Calculation of the Gas Phase Succinonitrile Molecule(Amer Inst Physics, 2017) Kepceoglu, A.; Kilic, H. S.; Dereli, O.Succinonitrile (Le. butanedinitrile) is a colorless nitrile compound that can be used in the gel polymer batteries as a solid-state solvent electrolytes and has a plastic crystal structure. Prior to the molecular structure calculation of the succinonitrile molecule, the conformer analysis were calculated by using semi empirical method PM3 core type Hamiltonian and eight different contbrmer structures were determined. Molecular structure with energy related properties of these confomiers having the lowest energy was calculated by using DFT (B3LYP) methods with 6-311++G(4) basis set. Possible radicals, can be formed experimentally. were modeled in this study. EPR parameters of these model radicals were calculated and then compared with that obtained experimentally.Öğe Molecular structure and vibrational spectra of 7-Ethoxycoumarin by density functional method(Elsevier, 2013) Sarikaya, E. Karakas; Dereli, O.; Erdogdu, Y.; Gulluoglu, M. T.In the present study, as a result of detailed conformational search of the 7-Ethoxycoumarin, four different conformers of (7EC) have been obtained. The FT-IR and Raman spectra of 7EC were recorded in the region 4000-400 cm(-1) and 3500-50 cm(-1), respectively. Vibrational frequences of the title compound were calculated by B3LYP method using 6-311++G(d,p) basis sets. The calculated vibrational frequences were analyzed and compared with experimental results. Characteristic vibrational bands of the pyrone ring, methylene and CO groups have been identified. (c) 2013 Elsevier B.V. All rights reserved.Öğe Molecular structure and vibrational spectra of 7-Methoxy-4-mehylcoumarin by density functional method(Elsevier, 2013) Sarikaya, E. Karakas; Dereli, O.In the present study, as a result of detailed structural and conformational analysis of the 7-Methoxy-4-methylcoumarin, two different conformers have been obtained. The FT-IR and Raman spectra were recorded in the region 4000-400 cm(-1) and 3500-50 cm(-1), respectively. Vibrational frequences of the title compound were calculated by Becke3-Lee-Yang-Parr (B3LYP) functional using 6-311++G(d,p) basis sets. The ground state energies and dipole moments have also been computed. The calculated and scaled frequencies were compared with experimental values and on the basis of this comparison and total-energy distribution data assignments of fundamental vibrational modes were examined. The differences between the observed and scaled wavenumber values of most of the fundamentals are very small. (C) 2013 Elsevier B.V. All rights reserved.Öğe Molecular Structure and Vibrational Spectra of Alpha-Benzoinoxime by Density Functional Method(Pleiades Publishing Inc, 2014) Dereli, O.; Erdogdu, Y.; Gulluoglu, M. T.; Sundaraganesan, N.; Turkkan, E.; Sayin, U.; Ozmen, A.In the present study, an exhaustive conformational search of the Alpha-benzoinoxime has been performed. The FT-IR spectrum of this compound was recorded in the region 4000-400 cm(-1). The FT-Raman spectrum was also recorded in the region 3500-50 cm(-1). Vibrational frequences of the title compound were calculated by B3LYP method using 6-311++G(d, p) basis set. The calculated vibrational frequences were analysed and compared with experimental results.Öğe Radiation Damage Centers in Cholesteryl Heptanoate(Polish Acad Sciences Inst Physics, 2013) Sayin, U.; Can, C.; Turkkan, E.; Dereli, O.; Ozmen, A.; Yuksel, H.Cholesterol takes part significantly in many biological mechanisms and as important component for manufacture of bile acids, steroid hormones, and several fat-soluble vitamins. To determine magnetic properties of cholesteryl heptanoate (C34H58O2) which is an important cholesteryl ester in human life and new technology, the single crystals of cholesteryl heptanoate were grown by slow evaporation of concentrated ethyl acetate solution and the grown single crystals were irradiated at room temperature with Co-60 gamma ray. The radical produced by gamma irradiation has been investigated in the range of temperatures 123-330 K for different orientations of the crystal in a magnetic field by EPR. Radiation damage center was attributed to radical (C) over dotH(alpha)CH(2 beta). The g factor and hyperfine coupling constants have slight dependence on temperature and evident dependence on the orientation of the magnetic field. Determined g factor and hyperfine coupling constants for the radical (C) over dotH(alpha)CH(2 beta) were found to be anisotropic with the average values g(av) = 2.0036, (a(CH alpha))(av) = 14.52 G, (a(CH2 beta))(av) = 25.78 G.Öğe Study on molecular structure and vibrational spectra of 5,7-dimethoxycoumarin using DFT: A combined experimental and quantum chemical approach(Pleiades Publishing Inc, 2014) Sarikaya, E. Karakas; Dereli, O.Conformational analysis of 5,7-Dimethoxycoumarin was performed and two stable conformers were obtained. The difference between the total energies of these conformers was 1.4698 kcal/mol and the difference between the zero point corrected energies was nearly zero. Vibrational frequencies of these conformers were calculated by B3LYP method using 6-311++G(d, p) basis sets and compared with experimentally recorded FT-IR and Raman spectra. Vibrational assignments were made by calculated total energy distributions. Time dependent density functional theory calculations were done by the same level of theory in order to investigate low-lying excited state and obtained results were compared with the maximum absorbtion peak value of experimental UV-visible spectrum.Öğe Theoretical (DFT) and experimental (FT-IR, FT-Raman, FT-NMR) investigations on 7-Acetoxy-4-(bromomethyl)coumarin(Pleiades Publishing Inc, 2015) Erdogdu, Y.; Saglam, S.; Dereli, O.An analysis of the results of the structural and spectroscopic studies of 7-Acetoxy-4-(bromomethyl) coumarin (7A4BMC) molecule were performed by FT-IR, FT-Raman, FT-NMR and quantum chemical calculations. The FT-IR and FT-Raman spectra of 7A4BMC were recorded in the 400-4000 and 50-3500 cm(-1) region, respectively. The molecular conformations of 7A4BMC were computed at the B3LYP/6-311++G(d,p) level of theory. Molecular structure and spectral calculations were calculated by means of B3LYP with 6-311++G(d,p), cc-pVDZ and cc-pVTZ basis sets. The whole vibrational characteristics of the 7A4BMC molecule are given.Öğe Vibrational spectral and quantum chemical investigations of tert-butyl-hydroquinone(Elsevier, 2012) Dereli, O.; Erdogdu, Y.; Gulluoglu, M. T.; Turkkan, E.; Ozmen, A.; Sundaraganesan, N.The Fourier transform infrared (FT-IR) and micro-Raman spectra of tert-butyl-hydroquinone were recorded in the region 4000-400 cm(-1) and 4000-50 cm(-1), respectively. Conformational space was scanned with molecular mechanic simulations. All other calculations were performed by B3LYP/6-311G++(d,p) level of theory. The molecular structure and vibrational frequencies of the title compound were calculated and compared with experimental spectra. Theoretical vibrational spectra of the title compound were interpreted by means of TEDs. Predicted electronic absorption spectrum of tert-butylhydroquinone from TD-DFT calculation was analyzed and compared with the experimental UV-visible spectrum. (C) 2012 Elsevier B.V. All rights reserved.
