scholarly journals Molecular structure, spectroscopic (UV-vis, FT-IR and FT- Raman), conformational aspects of 3t-pentyl-2r,6c-di(naphthalen-1-yl) piperidin-4-one oxime: a comprehensive experimental and DFT study

2017 ◽  
Vol 5 (1) ◽  
pp. 8
Author(s):  
K. Anandhy ◽  
M. Arockia doss ◽  
S. Amala ◽  
S. Mahalakshmi ◽  
G. Rajarajan
Keyword(s):  
Molecular Structure ◽  
Basis Set ◽  
Geometrical Parameters ◽  
Substitution Reactions ◽  
B3lyp Method ◽  
Visible Spectra ◽  
Td Dft ◽  
Ft Ir ◽  
Good Agreement ◽  
Ft Raman

The molecular structure and conformational aspects of 3t-pentyl-2r,6c-di(naphthalen-1-yl)piperidin-4-one oxime (3-PDNPO) were studied by using B3LYP level with 6-31G(d,p) p basis set. The optimized geometrical parameters are in agreement with analogue available single XRD data. The optimized parameters showed that the piperidin-4-one ring adopts chair conformation.The FT- IR and FT-Raman spectra were recorded within the region 4000-400 cm-1 and 4000-10 cm-1, respectively. It was found by experimental wavenumbers and DFT wavenumbers were in good agreement. Electronic properties are investigated using TD-DFT/B3LYP method using 6-31G (d,p) basis set and compared with experimental UV-visible spectra. Additionally, the ΔE gap investigated three phases follows the order of CHCl3 > gas > Methanol. The favourite sites for substitution reactions were evaluated by Mulliken and MEP analyses. From NLO analysis, it is found that the hyperpolarizability values are two times greater than the urea.Our proposed simulation procedure offers an alternative compound with which we can evaluate or design the best candidate NLO material.

scholarly journals Molecular Structure and Vibrational Analysis of 1-Bromo-2-Chlorobenzene Using ab initio HF and Density Functional Theory (B3LYP) Calculations

2011 ◽  
Vol 2011 ◽  
pp. 1-10 ◽  
Author(s):  
G. Shakila ◽  
S. Periandy ◽  
S. Ramalingam
Keyword(s):  
Density Functional ◽  
Vibrational Analysis ◽  
Vibrational Frequencies ◽  
Basis Set ◽  
Geometrical Parameters ◽  
B3lyp Method ◽  
B3lyp Calculations ◽  
Ft Ir ◽  
Experimental Values ◽  
Ft Raman

The FT-Raman and FT-IR spectra for 1-bromo-2-chlorobenzene (1B2CB) have been recorded in the region 4000–100 cm−1 and compared with the harmonic vibrational frequencies calculated using HF/DFT (B3LYP) method by employing 6-31+G (d, p) and 6-311++G (d, p) basis set with appropriate scale factors. IR intensities and Raman activities are also calculated by HF and DFT (B3LYP) methods. Optimized geometries of the molecule have been interpreted and compared with the reported experimental values of some substituted benzene. The experimental geometrical parameters show satisfactory agreement with the theoretical prediction from HF and DFT. The scaled vibrational frequencies at B3LYP/6-311++G (d, p) seem to coincide with the experimentally observed values with acceptable deviations. The theoretical spectrograms (IR and Raman) have been constructed and compared with the experimental FT-IR and FT-Raman spectra. Some of the vibrational frequencies of the benzene are affected upon profusely with the halogen substitutions in comparison to benzene, and these differences are interpreted.

scholarly journals FT-IR, FT-Raman, Homo-Lumo and UV-Visible Spectral Analysis of E-(N′-(1H-INDOL-3YL) Methylene Isonicotinohydrazide)

2017 ◽  
Vol 1 (3) ◽  
pp. 1-37
Author(s):  
D. Sumathi ◽  
H. Saleem ◽  
A. Nathiya ◽  
N. RameshBabu ◽  
D. Usha
Keyword(s):  
Energy Gap ◽  
Solid Phase ◽  
Basis Set ◽  
Excitation Energies ◽  
B3lyp Method ◽  
Td Dft ◽  
Ft Ir ◽  
Experimental Values ◽  
Homo Lumo ◽  
Ft Raman

A combined experimental and theoretical study on molecular and vibrational structure of E-N¢ (ICINH) had been carried out. The FTIR, FT-Raman and UV-Vis spectra of ICINH were recorded in the solid phase. The optimized geometry was calculated by B3LYP method with 6-311++G(d,p) level of basis set. The harmonic vibrational frequencies, IR intensities and Raman scattering activities of the title compound were calculated at same level of theory. The scaled theoretical wavenumber showed very good agreement with the experimental values. The mulliken charges and thermodynamic functions of the ICINH were also performed at same level of theory. NLO and a study on the electronic properties such as excitation energies and wavelength, were performed by TD-DFT approach. HOMO–LUMO energy gap was also calculated and interpreted.

scholarly journals Design, Synthesis, Spectral and Theoretical Studies of Some Picrates

2019 ◽  
Vol 32 (1) ◽  
pp. 174-182
Author(s):  
S. Amala ◽  
G. Rajarajan ◽  
E. Dhineshkumar ◽  
M. Arockia doss ◽  
V. Thanikachalam
Keyword(s):  
Geometrical Parameters ◽  
Slight Effect ◽  
Design Synthesis ◽  
1H And 13C Nmr ◽  
Visible Spectra ◽  
Ft Ir ◽  
Uv Visible ◽  
Small Change ◽  
Experimental Values ◽  
Good Agreement

The structures of newly synthesized compounds (1-3) viz. 3-ethyl-5-methyl-2,6-bis(4- chlorophenyl)piperidin-1-ium picrate (1), 3-ethyl-5-methyl-2,6-bis(4-methylphenyl)piperidin-1-ium picrate (2) and 3-ethyl-5-methyl-2,6-bis(3,4-dimethoxyphenyl)piperidin-1-ium picrate (3) were confirmed by elemental analysis, FT-IR, 1H and 13C NMR. The UV-visible spectra, fluoresence, emission properties of synthesized 1-3 in different solvents were studied. Compounds 1-3 solvatochromic displays a slight effect of the emission and absorption spectrum, indicating a small change in the dipole moment upon excitation of compounds 1-3. All the compounds were investigated by DFT. The theoretical geometrical parameters are in good agreement with experimental values.

scholarly journals Density functional theory study on the molecular structure of loganin

2011 ◽  
Vol 25 (6) ◽  
pp. 287-302 ◽  
Author(s):  
Anoop Kumar Pandey ◽  
Shamoon Ahmad Siddiqui ◽  
Apoorva Dwivedi ◽  
Kanwal Raj ◽  
Neeraj Misra
Keyword(s):  
Molecular Structure ◽  
Density Functional ◽  
Solid Phase ◽  
Density Functional Method ◽  
Functional Method ◽  
Basis Set ◽  
Equilibrium Geometry ◽  
B3lyp Method ◽  
Ft Ir ◽  
Detailed Interpretation

The computational Quantum Chemistry (QC) has been used for different types of problems, for example: structural biology, surface phenomena and liquid phase. In this paper we have employed the density functional method for the study of molecular structure of loganin. The equilibrium geometry, harmonic vibrational frequencies and infrared intensities were calculated by B3LYP/6-311G (d, p) method and basis set combinations. It was found that the optimized parameters obtained by the DFT/B3LYP method are very near to the experimental ones. A detailed conformational analysis was carried out. A detailed interpretation of the infrared spectra of loganin is also reported in the present work. The FT-IR spectra of loganin were recorded in solid phase. The thermodynamic calculations related to the title compound were also performed at B3LYP/6-311G (d, p) level of theory.

scholarly journals Experimental and theoretical studies of 4-[(4-methyl-5-phenyl- 4H1,2,4-triazol-3-yl)sulfanyl]benzene-1,2-dicarbonitrile

2016 ◽  
Vol 35 (2) ◽  
pp. 169
Author(s):  
Ufuk Çoruh ◽  
Reşat Ustabaş ◽  
Hakkı Türker Akçay ◽  
Emra Menteşe ◽  
Ezequiel M. Vazquez Lopez
Keyword(s):  
Molecular Structure ◽  
Density Functional ◽  
Basis Set ◽  
Geometrical Parameters ◽  
X Ray Diffraction ◽  
Functional Theory ◽  
X Ray ◽  
Ft Ir ◽  
Experimental And Theoretical Studies ◽  
Homo Lumo

In this study, 4-[(4-methyl-5-phenyl-4<em>H</em>-1,2,4-triazol-3-yl)sulfanyl]benzene-1,2-dicarbonitrile was synthesized and its molecular structure was characterized by means of FT-IR and X-ray diffraction methods. The crystal is monoclinic and belongs to the P21/n space group. There are three weak intermolecular C-H…N type hydrogen bonds in the molecular structure. The geometrical parameters, vibration frequencies, HOMO–LUMO energies, and molecular electrostatic potential (MEP) map of the compound (3) in ground state were calculated by using density functional theory (DFT/B3LYP) with the 6-311G(d) basis set. Calculated geometrical parameters were compared with X-ray diffraction geometric parameters. On the other hand, theoretical and experimental FT-IR results were also compared.

scholarly journals Scaled Quantum FT-IR and FT-Raman Spectral Analysis of 1-Methoxynaphthalene

2010 ◽  
Vol 7 (2) ◽  
pp. 457-464 ◽  
Author(s):  
M. Govindarajan ◽  
S. Periandy ◽  
K. Ganesan
Keyword(s):  
Force Constants ◽  
Basis Set ◽  
Vibrational Property ◽  
Normal Coordinate ◽  
Vibrational Bands ◽  
Ft Ir ◽  
Raman Spectral ◽  
Raman Spectral Analysis ◽  
Good Agreement ◽  
Ft Raman

The structural and vibrational property of 1-methoxynaphthalene has been studied. The fundamental vibrational frequencies and intensity of vibrational bands were evaluated using B3LYP/6-31G (d, p) basis set and was scaled using various scale factors, which yielded a good agreement between observed and calculated frequencies. The vibrational spectra were interpreted with the aid of normal coordinate analysis. The results of the calculations were applied to simulated spectra of the title compound, which shows excellent agreement with observed spectra. The calculated force constants in vibrational internal coordinates are in closely coincides with the experimentally observed force constants.

Anharmonic vibrational spectral analysis of L-(-)-xylose molecule

2017 ◽  
Vol 16 (07) ◽  
pp. 1750059 ◽  
Author(s):  
Sheeraz Ahmad Bhat ◽  
Mohd Faizan ◽  
Bilal Ahmad Ahanger ◽  
Shabbir Ahmad
Keyword(s):  
Vibrational Analysis ◽  
Simulated Data ◽  
Nbo Analysis ◽  
Basis Set ◽  
Geometrical Parameters ◽  
Homo And Lumo ◽  
Ir And Raman ◽  
Theoretical Results ◽  
Good Agreement ◽  
Ft Raman

In this work, a detailed vibrational analysis of L-(-)-xylose molecule has been carried out. The geometrical parameters and anharmonic spectrum have been calculated and compared with XRD, FTIR (4000–400[Formula: see text]cm[Formula: see text]) and FT-Raman (4000–50[Formula: see text]cm[Formula: see text]) observed data. The simulated data along with IR and Raman intensities were calculated using DFT/B3LYP level of theory in combination with 6-311[Formula: see text]G(d,p) basis set. The experimental and theoretical results are found to be in a good agreement with each other. Moreover, thermodynamic properties, molecular electrostatic potential (MEP) and natural bond orbital (NBO) analysis of L-(-)-xylose are also reported. The calculated HOMO and LUMO energies confirm the charge transfer within the molecule.

scholarly journals Molecular Structure, Vibrational Spectral Investigations (FT-IR and FT-Raman), NLO, NBO, HOMO-LUMO, MEP Analysis of (E)-2-(3-pentyl-2,6-diphenylpiperidin-4-ylidene)-N-phenylhydrazinecarbothioamide Based on DFT and Molecular Docking Studies

2020 ◽  
Vol 11 (4) ◽  
pp. 11833-11855
Keyword(s):  
Molecular Structure ◽  
Thermodynamic Properties ◽  
Density Functional ◽  
Dft Method ◽  
Docking Studies ◽  
Basis Set ◽  
Charge Delocalization ◽  
Vibrational Assignments ◽  
Ft Ir ◽  
Ft Raman

The molecular spectroscopic investigations of (E)-2-(3-pentyl-2,6-diphenylpiperidin-4-ylidene)-N-phenylhydrazine carbothioamide (3-PDPPPHC) are studied. The FT-IR and FT-Raman experimental spectra of the molecule have been recorded in the range of 4000–400 cm−1 and 4000–50 cm−1, respectively. The molecular structure, fundamental vibrational frequencies, and intensities of the vibrational bands were interpreted to aid structure optimizations based on the density functional theory (DFT) method with B3LYP/6-311++G(d,p) level of basis set. The complete vibrational assignments of wavenumbers were made based on total energy distribution (TED). The calculations' results were applied to the title compound's simulated spectra, which show good agreement with observed spectra. The dipole moment, polarizability, and first hyperpolarizability values were also computed. The stability of the molecule analyzing from hyper-conjugative interaction and charge delocalization of the title compounds were studied by NBO analysis. Frontier molecular orbitals (FMOs), molecular electrostatic potential (MEP), and thermodynamic properties were performed. Mulliken charges of the title molecule were also calculated and interpreted. The thermodynamic properties such as heat capacity, entropy, and enthalpy of the title compound were calculated at different gas-phase temperatures. To establish information about the interactions between protein and this novel compound theoretically, docking studies were carried out in detail.

Density functional theory, Comparative vibrational spectroscopic studies, HOMO-LUMO, and NBO analysis of Trichloro isocyanuric acid and Trithio cyanuric acid

2015 ◽  
Vol 8 (3) ◽  
pp. 2197-2221
Author(s):  
Theraviyum Chithambarathanu ◽  
M. Darathi ◽  
J. DaisyMagdaline ◽  
S. Gunasekaran
Keyword(s):  
Density Functional ◽  
Cyanuric Acid ◽  
Nbo Analysis ◽  
Basis Set ◽  
Potential Energy Distribution ◽  
Point Energy ◽  
Isocyanuric Acid ◽  
Ft Ir ◽  
Homo Lumo ◽  
Ft Raman

The molecular vibrations of Trichloro isocyanuric acid (C3Cl3N3O3) and Trithio cyanuric acid (C3H3N3S3) have been investigated in polycrystalline sample at room temperature by Fourier Transform Infrared (FT-IR) and FT-Raman spectroscopies in the region 4000-450 cm-1 and 4000-50 cm-1 respectively, which provide a wealth of structural information about the molecules. The spectra are interpreted with the aid of normal co-ordinate analysis following full structure optimization and force field calculations based on density functional theory   (DFT) using standard B3LYP / 6-311++ G (d, p) basis set for investigating the structural and spectroscopic properties. The vibrational frequencies are calculated and the scaled values are compared with experimental FT-IR and FT-Raman spectra. The scaled theoretical wave numbers shows very good agreement with experimental ones. The complete vibrational assignments are performed on the basis of potential energy distribution (PED) of vibrational modes, calculated with scaled quantum (SQM) method. Stability of the molecule arising from hyper conjugative interactions, charge delocalization has been analyzed using natural bond orbital (NBO) analysis. The results show that change in electron density (ED) in σ* and π* anti-bonding orbitals and second order delocalization   energy (E2) confirm the occurrence of Intra molecular Charge Transfer (ICT) within the molecule. The thermodynamic properties like heat capacity, entropy, enthalpy and zero point energy have been calculated for the molecule. The frontier molecular orbitals have been visualized and the HOMO-LUMO energy gap has been calculated. The Molecular Electrostatic Potential (MEP) analysis reveals the sites for electrophilic attack and nucleophilic reactions in the molecule.

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