Yazar "Sundaraganesan, N." seçeneğine göre listele
Listeleniyor 1 - 7 / 7
Sayfa Başına Sonuç
Sıralama seçenekleri
Öğe Experimental, theoretical calculations of the vibrational spectra and conformational analysis of 2,4-di-tert-butylphenol(PERGAMON-ELSEVIER SCIENCE LTD, 2012) Kalaichelvan, S.; Sundaraganesan, N.; Dereli, O.; Sayin, U.In the present work, we reported a combined experimental and theoretical study on conformational stability, molecular structure and vibrational spectra of 2,4-di-tert-butylphenol (2,4-DTBP). The FT-IR (400-4000 cm(-1)) and FT-Raman spectra (50-3500 cm(-1)) of 2,4-DTBP were recorded. The molecular geometry, harmonic vibrational frequencies and bonding features of 2,4-DTBP in the ground-state have been calculated by using the density functional BLYP/B3LYP methods. The energy calculated by time-dependent density functional theory (TD-DFT) result complements with the experimental findings. The calculated highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO) energies show that charge transfer occurs within the molecule. Finally the calculation results were compared with measured infrared and Raman spectra of the title compound which showed good agreement with observed spectra. (C) 2011 Elsevier B.V. All rights reserved.Öğe FT-IR, FT-Raman spectra, density functional computations of the vibrational spectra and molecular conformational analysis of 2,5-di-tert-butyl-hydroquinone(PERGAMON-ELSEVIER SCIENCE LTD, 2011) Subramanian, N.; Sundaraganesan, N.; Dereli, O.; Turkkan, E.The purpose of finding conformer among six different possible conformers of 25-di-tert-butyl-hydroquinone (DTBHQ), its equilibrium geometry and harmonic wavenumbers were calculated by the B3LYP/6-31G(d,p) method. The infrared and Raman spectra of DTBHQ were recorded in the region 400-4000 cm(-1) and 50-3500 cm(-1), respectively. In addition, the IR spectra in CCl(4) at various concentrations of DTBHQ are also recorded. The computed vibrational wavenumbers were compared with the IR and Raman experimental data. Computational calculations at B3LYP level with two different basis sets 6-31G(d,p) and 6-311++G(d,p) are also employed in the study of the possible conformer of DTBHQ. The complete assignments were performed on the basis of the potential energy distribution (PED) of the vibrational modes, calculated using VEDA 4 program. The general agreement between the observed and calculated frequencies was established. (C) 2011 Elsevier B.V. All rights reserved.Öğe FT-IR, FT-Raman spectra, density functional computations of the vibrational spectra and molecular geometry of butylated hydroxy toluene(PERGAMON-ELSEVIER SCIENCE LTD, 2011) Babu, P. Chinna; Sundaraganesan, N.; Dereli, O.; Turkkan, E.The FT-IR spectrum of 2,6-di-tert-butyl-4-methylphenol [butylated hydroxy toluene] was recorded in the region 4000-400 cm(-1). The FT-Raman spectrum of butylated hydroxy toluene was also recorded in the region 3500-50 cm(-1). The molecular structure and vibrational frequencies of butylated hydroxy toluene (BHT) have been investigated with combined experimental and theoretical study. Two stable conformers of the title compound were obtained from the result of geometry optimizations of these possible conformers. The conformer 1 is (approximately 2.6 kcal/mol) more stable than conformer 2. Geometry optimizations and vibrational frequency calculations were performed by BLYP and B3LYP methods using 6-31G(d), 6-31G(d,p) and 6-31+G(d,p) as basis sets. The scaled frequencies were compared with experimental spectrum and on the basis of this comparison; assignments of fundamental vibrational modes were examined. Comparison of the experimental spectra with harmonic vibrational wavenumbers indicates that B3LYP/6-31G(d) results are more accurate. Predicted electronic absorption spectra of BHT from TD-DFT calculation have been analyzed and compared with the experimental UV-vis spectrum. The calculated HOMO and LUMO energies show that the charge transfer occurs within the molecule. (C) 2011 Elsevier B.V. All rights reserved.Öğe Molecular structure and vibrational spectra of 4-phenylsemicarbazide by density functional method(ELSEVIER, 2011) Dereli, O.; Sudha, S.; Sundaraganesan, N.In this paper, combined experimental and theoretical study on molecular and vibrational structure of 4-phenylsemicarbazide (4PSC) were reported. The Fourier transform infrared (FT-IR) spectrum of 4PSC was recorded in the region 4000-400 cm(-1). Fourier transform Raman (FT-Raman) spectrum of 4PSC was also recorded in the region 3500-50 cm(-1). Semi-empirical PM3 method was used for conformational distribution of possible conformers. The molecular geometry and vibrational frequencies of the most stable conformer of 4PSC in the ground state have been calculated by using the density functional BLYP and B3LYP methods with 6-31G(d) and 6-31G(d,p) as basis sets. The optimized geometrical parameters obtained from theoretical calculations show good agreement with the XRD experimental values. The ground state energies, dipole moments and thermodynamic parameters have also been computed. The calculated and scaled frequencies were compared with experimental values and on the basis of this comparison and PED data assignments of fundamental vibrational modes were examined. The differences between the observed and BLYP/6-31G(d) scaled wavenumber values of most of the fundamentals are very small. (C) 2011 Elsevier B.V. All rights reserved.Öğe Molecular Structure and Vibrational Spectra of Alpha-Benzoinoxime by Density Functional Method(MAIK NAUKA/INTERPERIODICA/SPRINGER, 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 Synthesis, FT-IR, FT-Raman, dispersive Raman and NMR spectroscopic study of a host molecule which potential applications in sensor devices(PERGAMON-ELSEVIER SCIENCE LTD, 2012) Kurt, M.; Karabacak, M.; Okur, S.; Sayin, S.; Yilmaz, M.; Sundaraganesan, N.The solid phase FT-IR, FT-Raman and dispersive Raman spectra of the host molecule which potential applications in sensor devices have been recorded in the region 400-4000 and 50-3500 cm(-1), respectively. The spectra were interpreted in terms of fundamentals modes, combination and overtone bands. The structure of the molecule was optimized and the structural characteristics were determined by density functional theory (DFF) using B3LYP method with 6-31G(d) basis set. The vibrational frequencies were calculated for the studied molecule by DFT method, and compared with the experimental frequencies, which yield good agreement between observed and calculated frequencies. Finally the calculation results were applied to simulate infrared and Raman spectra of the compound. Obtained these spectra also showed good agreement with observed spectra. The dipole moment, linear polarizability and first hyperpolarizability values were also computed. The linear polarizability and first hyperpolarizability of the studied molecule indicate that the compound is a good candidate of nonlinear optical materials. Crown Copyright (C) 2012 Published by Elsevier B.V. All rights reserved.Öğe Vibrational Spectral and Quantum Chemical Investigations of Tert-Butyl-Hydroquinone(ELSEVIER, 2012) Dereli, Ö.; Erdoğdu, Y.; Güllüoğlu, M. T.; Türkkan, E.; Özmen, 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.
