Browsing by Author "Sundaraganesan, N"

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    The infrared, Raman, NMR and UV spectra, ab initio calculations and spectral assignments of 2-amino-4-chloro-6-methoxypyrimidine
    Cinar, Z; Karabacak, M; Cinar, M; Kurt, M; Babu, PC; Sundaraganesan, N
    The 2-amino-4-chloro-6-methoxypyrimidine abbreviated as ACMP have been investigated by both the experimental and theoretical methods; through this work we provide the essential fact about the structural and vibrational insights. The optimized molecular structure, atomic charges, vibrational frequencies and ultraviolet spectral interpretation of ACMP have been studied by performing DFT/B3LYP/6-311++G(df,pd) level of theory. The FT-IR, FT-Raman spectra were recorded in the region 4000-400 cm(-1) and 4000-50 cm(-1) respectively. The UV absorption spectrum of the compound that dissolved in ethanol and water solution were recorded in the range of 200-400 nm. The scaled wavenumbers are compared with the experimental values. The difference between the observed and scaled wavenumber values of most of the fundamentals is very small. Based on the UV spectrum and TD-DFT calculations, the electronic structure and the assignments of the absorption bands were carried out. The H-1, C-13 and DEPT 135 nuclear magnetic resonance (NMR) chemical shifts of the molecule were calculated using with the Gauge Including Atomic Orbital (GIAO) method and compared with experimental results. Besides, molecular electrostatic potential (MEP), frontier molecular orbitals (FMO) analysis were investigated using theoretical calculations. (C) 2013 Elsevier B.V. All rights reserved.
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    The spectroscopic (FT-IR, FT-Raman, UV and NMR) first order hyperpolarizability and HOMO-LUMO analysis of dansyl chloride
    Karabacak, M; Cinar, M; Kurt, M; Poiyamozhi, A; Sundaraganesan, N
    The solid phase FT-IR and FT-Raman spectra of dansyl chloride (DC) have been recorded in the regions 400-4000 and 50-4000 cm(-1), respectively. The spectra have been interpreted in terms of fundamentals modes, combination and overtone bands. The structure of the molecule has been optimized and the structural characteristics have been determined by density functional theory (B3LYP) method with 6311++G(d,p) as basis set. The vibrational frequencies were calculated for most stable conformer and were compared with the experimental frequencies, which yield good agreement between observed and calculated frequencies. The infrared and Raman spectra have also been predicted from the calculated intensities. H-1 and C-13 NMR spectra were recorded and H-1 and C-13 nuclear magnetic resonance chemical shifts of the molecule were calculated using the gauge independent atomic orbital (CIAO) method. UV-Visible spectrum of the compound was recorded in the region 200-600 nm and the electronic properties HOMO and LUMO energies were measured by time-dependent TD-DFT approach. Nonlinear optical and thermodynamic properties were interpreted. All the calculated results were compared with the available experimental data of the title molecule. (C) 2013 Elsevier B.V. All rights reserved.
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    Experimental and theoretical FTIR and FT-Raman spectroscopic analysis of 1-pyrenecarboxylic acid
    Karabacak, M; Cinar, M; Kurt, M; Babu, PC; Sundaraganesan, N
    The title molecule 1-pyrenecarboxylic acid (1PCA) has been characterized by FTIR, FT-Raman, NMR and UV-Vis spectral analyses. The molecular geometry, harmonic vibrational modes, the corresponding wavenumbers and IR intensities of 1PCA were calculated by DFT method with 6-311G(d,p) basis set. The assignments of the fundamentals were proposed on the basis of total energy distribution (TED) calculations. The calculated C-13 and H-1 NMR chemical shifts using gauge including atomic orbitals (GIAOs) approach are in good agreement with the observed chemical shifts. The polarizability and first order hyperpolarizability of the title molecule were calculated and interpreted. Using TD-DFT method, the electronic transitions have been compared with the experimental wavelengths. The molecular electrostatic potential map was used for prediction of possible hydrogen and oxygen bonding sites IPCA molecule. (C) 2013 Elsevier B.V. All rights reserved.
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    FT-IR, FT-Raman, dispersive Raman, NMR spectroscopic studies and NBO analysis of 2-Bromo-1H-Benzimidazol by density functional method
    Sas, EB; Kurt, M; Karabacak, M; Poiyamozhi, A; Sundaraganesan, N
    In this study, geometrical optimization, FT-IR (4000-400 cm(-1)), FT-Raman (4000-40 cm(-1)), dispersive Raman (4000-40 cm-1) spectroscopic analysis, electronic structure and H-1 and C-13 nuclear magnetic resonance (NMR) studies of 2-Bromo-1H-Benzimidazol (abbreviated as 2Br1HB) were undertaken by utilizing DFT/B3LYP with 6-311+G(d,p) basis set. The results of the calculations were applied to simulate spectra of the title compound, which show good agreement with observed spectra. Complete vibrational assignments, analysis and correlations of the fundamental modes for 2Br1HB compound were carried out. Stability of the molecule arising from hyperconjugative interactions, charge delocalization was analyzed using natural bond orbital (NBO) analysis. The molecule orbital contributions were studied by using the total density of states (TDOS), partial density of states (PDOS), and overlap population density of states (OPDOS). The electronic properties like HOMO-LUMO energies and molecular electrostatic potential (MEP) analysis were reported. The calculated HOMO and LUMO energies shows that charge transfer interactions take place within the molecule. Mulliken population analysis on atomic charges was also calculated. Good correlation between the experimental H-1 and C-13 NMR chemical shifts in DMSO solution and calculated gauge-including atomic orbital (GIAO) shielding tensors were found. (C) 2014 Elsevier B.V. All rights reserved.
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    Synthesis and spectroscopic characterization on 4-(2,5-di-2-thienyl-1H-pyrrol-1-yl) benzoic acid: A DFT approach
    Kurt, M; Sas, EB; Can, M; Okur, S; Icli, S; Demic, S; Karabacak, M; Jayavarthanan, T; Sundaraganesan, N
    A complete structural and vibrational analysis of the 4-(2,5-di-2-thienyl-1H-pyrrol-1-yl) benzoic acid (TPBA), was carried out by ab initio calculations, at the density functional theory (DFT) method. Molecular geometry, vibrational wavenumbers and gauge including atomic orbital (CIAO) C-13 NMR and H-1 NMR chemical shift values of (TPBA), in the ground state have been calculated by using ab initio density functional theory (DFT/B3LYP) method with 6-311G(d,p) as basis set for the first time. Comparison of the observed fundamental vibrational modes of (TPBA) and calculated results by DFT/B3LYP method indicates that B3LYP level of theory giving yield good results for quantum chemical studies. Vibrational wavenumbers obtained by the DFT/B3LYP method are in good agreement with the experimental data. The study was complemented with a natural bond orbital (NBO) analysis, to evaluate the significance of hyperconjugative interactions and electrostatic effects on such molecular structure. By using TD-DFF method, electronic absorption spectra of the title compound have been predicted and a good agreement with the TD-DFF method and the experimental one is determined. In addition, the molecular electrostatic potential (MEP), frontier molecular orbitals analysis and thermodynamic properties of TPBA were investigated using theoretical calculations. (C) 2015 Elsevier B.V. All rights reserved.