scholarly journals Fukui Function Analysis and Optical, Electronic, and Vibrational Properties of Tetrahydrofuran and Its Derivatives: A Complete Quantum Chemical Study

2015 ◽  
Vol 2015 ◽  
pp. 1-11 ◽  
Author(s):  
Apoorva Dwivedi ◽  
Vikas Baboo ◽  
Abhishek Bajpai
Keyword(s):  
Molecular Electrostatic Potential ◽  
Function Analysis ◽  
Quantum Chemical Study ◽  
Chemical Study ◽  
Basis Set ◽  
Potential Surfaces ◽  
Vibrational Assignments ◽  
Optical And Electronic Properties ◽  
Homo Lumo ◽  
Complete Quantum

The spectroscopic, optical, and electronic properties of tetrahydrofuran and its derivatives were investigated by FTIR techniques. We have done a comparative study of tetrahydrofuran and its derivatives with B3LYP with 6-311 G (d, p) as the basis set. Here we have done a relative study of their structures, vibrational assignments, and thermal, electronic, and optical properties of ttetrahydrofuran and its derivatives. We have plotted frontier orbital HOMO-LUMO surfaces and molecular electrostatic potential surfaces to explain the reactive nature of tetrahydrofuran and its derivatives.

Comparative study of DFT/B3LYP, B3PW91, and HSEH1PBE methods applied to molecular structures and spectroscopic and electronic properties of flufenpyr and amipizone

2015 ◽  
Vol 93 (10) ◽  
pp. 1147-1156 ◽  
Author(s):  
D. Avcı ◽  
S. Bahçeli ◽  
Ö. Tamer ◽  
Y. Atalay
Keyword(s):  
Gas Phase ◽  
Electronic Absorption ◽  
Molecular Electrostatic Potential ◽  
Biological Activities ◽  
Molecular Structures ◽  
Basis Set ◽  
Potential Surfaces ◽  
Ir Frequencies ◽  
Homo Lumo ◽  
C Nmr

The optimized molecular structures, conformational analyses, vibrational (IR) frequencies and their assignments, maximum electronic absorption wavelengths (gas phase and in ethanol solvent), 1H and 13C NMR chemical shift values (gas phase and in CDCl3 solvent), HOMO−LUMO analysis, molecular electrostatic potential surfaces, and nonlinear optical properties of flufenpyr (C14H9ClF4N2O4) and amipizone (C14H16ClN3O) compounds that have many biological activities have been calculated using the DFT/B3LYP, B3PW91, and HSEH1PBE methods with the 6-311G(d,p) basis set in the ground state. A comparison among the results calculated at the mentioned levels indicates that the HSEH1PBE calculations give usually greater values compared with the others in terms of vibrational frequencies, the maximum electronic absorption wavelengths, and HOMO−LUMO energy gaps of the title compounds.

scholarly journals Structural, Electronic, and Vibrational Properties of Isoniazid and Its Derivative N-Cyclopentylidenepyridine-4-carbohydrazide: A Quantum Chemical Study

2014 ◽  
Vol 2014 ◽  
pp. 1-15 ◽  
Author(s):  
Anoop kumar Pandey ◽  
Abhishek Bajpai ◽  
Vikas Baboo ◽  
Apoorva Dwivedi
Keyword(s):  
Density Functional ◽  
Quantum Chemical Study ◽  
Chemical Study ◽  
Basis Sets ◽  
Ground State Structure ◽  
Vibrational Modes ◽  
Functional Theory ◽  
Complete Assignment ◽  
Experimental Values ◽  
Homo Lumo

Isoniazid (Laniazid, Nydrazid), also known as isonicotinylhydrazine (INH), is an organic compound that is the first-line medication in prevention and treatment of tuberculosis. The optimized geometry of the isoniazid and its derivative N-cyclopentylidenepyridine-4-carbohydrazide molecule has been determined by the method of density functional theory (DFT). For both geometry and total energy, it has been combined with B3LYP functionals having LANL2DZ and 6-311 G (d, p) as the basis sets. Using this optimized structure, we have calculated the infrared wavenumbers and compared them with the experimental data. The calculated wavenumbers by LANL2DZ are in an excellent agreement with the experimental values. On the basis of fully optimized ground-state structure, TDDFT//B3LYP/LANL2DZ calculations have been used to determine the low-lying excited states of isoniazid and its derivative. Based on these results, we have discussed the correlation between the vibrational modes and the crystalline structure of isoniazid and its derivative. A complete assignment is provided for the observed FTIR spectra. The molecular HOMO, LUMO composition, their respective energy gaps, and MESP contours/surfaces have also been drawn to explain the activity of isoniazid and its derivative.

scholarly journals Crystal structure, DFT and Hirshfeld surface analysis of 2-amino-4-(2-chlorophenyl)-7-hydroxy-4H-benzo[1,2-b]pyran-3-carbonitrile

2019 ◽  
Vol 75 (11) ◽  
pp. 1638-1642
Author(s):  
M. Beemarao ◽  
S. Silambarasan ◽  
A. Jamal Abdul Nasser ◽  
M. Purushothaman ◽  
K. Ravichandran
Keyword(s):  
Surface Analysis ◽  
Molecular Electrostatic Potential ◽  
Energy Levels ◽  
Hirshfeld Surface ◽  
Intramolecular Interactions ◽  
Hirshfeld Surface Analysis ◽  
Maximum Deviation ◽  
Potential Surfaces ◽  
Compound C ◽  
Homo Lumo

The benzopyran ring of the title compound, C16H11ClN2O2, is planar [maximum deviation = 0.079 (2) Å] and is almost perpendicular to the chlorophenyl ring [dihedral angle = 86.85 (6)°]. In the crystal, N—H...O, O—H...N, C—H...O and C—H...Cl hydrogen bonds form inter- and intramolecular interactions. The DFT/B3LYP/6-311G(d,p) method was used to determine the HOMO–LUMO energy levels. The molecular electrostatic potential surfaces were investigated by Hirshfeld surface analysis and two-dimensional fingerprint plots were used to analyse the intermolecular interactions in the molecule.

scholarly journals Xrd, Quantum Chemical, Vibrational, Thermal and Antifungal Activity Analysis on 3-Nitroanilinium Hydrogen Oxalate

2019 ◽  
Vol 9 (1S3) ◽  
pp. 319-323
Keyword(s):  
Density Functional ◽  
Density Functional Method ◽  
Functional Method ◽  
Basis Set ◽  
Frontier Molecular Orbital ◽  
Geometrical Parameters ◽  
Vibrational Assignments ◽  
Hartree Fock ◽  
Homo Lumo ◽  
Good Agreement

3-nitroanilinium hydrogen oxalate has been crystallized successfully by solvent evaporation method. Optimized molecular geometrical parameters and the vibrational assignments of 3NAOX has been calculated by using Hartree-Fock (HF) and density functional method (B3LYP) with 6-311++G (d, p) basis set. The computational analysis showed good agreement with the experimental data. The energy and various parameters were obtained by HOMO–LUMO plot. The apparent pharmaceutical/biological activity of the salt confirmed by lower band gap value obtain from the Frontier Molecular Orbital (FMO) analysis. Thermal properties of 3NAOX were analyzed by TGA/DTA. The grown crystals were involved in an antimicrobial activity against certain potentially threatening microbes which shows that grown crystal screened the bacteria.

Studies of intramolecular H-bond interactions and solvent effects in the conformers of glycolic acid — A quantum chemical study

2018 ◽  
Vol 17 (01) ◽  
pp. 1850009 ◽  
Author(s):  
Mahendiraprabu Ganesan ◽  
Nirmala Vedamanickam ◽  
Selvarengan Paranthaman
Keyword(s):  
Solvent Effects ◽  
Density Functional ◽  
Glycolic Acid ◽  
Chemical Potential ◽  
Quantum Chemical Study ◽  
Chemical Study ◽  
Basis Set ◽  
Chemical Hardness ◽  
Geometrical Parameters ◽  
Water Media

In this work, density functional theory is applied to understand the conformational stability and solvent effects on glycolic acid conformers in different solvents. In addition, the role of intramolecular hydrogen bond (H-bond) interactions in the stability of conformers are investigated. The molecular geometries of selected conformers are optimized using B3LYP and PBE0 functionals with 6-311[Formula: see text]G(d,p) basis set. The effects of solvent on the geometrical parameters, relative stability, dipole moment, chemical hardness, chemical potential, etc. are studied for the conformers of glycolic acid. Our calculations show that the order of stability of the SSC and AAT conformers does not change in liquid phase. However, the energy of SSC and AAT conformers is very close to each other in water media. In water media, strong intramolecular H-bond interaction is present in AAT conformer which causes the energy of AAT conformer to be very close to that of SSC conformer. This may be due to the influence of water media.

Alkyl versus hydrogen substitution: an abinitio study of the addition of hydroxide to formaldehyde and to acetone

1989 ◽  
Vol 67 (1) ◽  
pp. 176-182 ◽  
Author(s):  
C. I. Bayly ◽  
F. Grein
Keyword(s):  
Quantum Chemical Study ◽  
Chemical Study ◽  
Energy Difference ◽  
Basis Set ◽  
Secondary Minimum ◽  
Energy Curve ◽  
Co Addition ◽  
Hydrogen Substitution ◽  
Acetone System ◽  
Reaction Profile

The reaction profiles of the anionic nucleophilic addition of hydroxide to formaldehyde (system I) and to acetone (system II) were studied using theoretical abinitio methods. Calculations were carried out using the 4-31G basis set augmented with polarization and diffuse functions on some atoms. Electron correlation calculations were performed at the MP2 (frozen core), MP2, and MP4 levels for system I and at the MP2 (frozen core) level for system II. For both systems a local energy maximum was found at a C—OH distance of 2.5 Å. The barrier maximum was at lower energy than the separated reactants (−17.2 kcal/mol for system I and −5.6 kcal/mol for system II). This type of reaction profile is in accordance with a previous study on a prototype reaction. The energy difference between the barrier maximum and the secondary minimum (towards the reactants) was very small for system I (0.7 kcal/mol), but higher for system II (5.4 kcal/mol). The geometries of the two systems differed significantly in the region of the reaction coordinate containing the barrier and the secondary minimum. Keywords: quantum chemical study, addition of OH− to H2CO, addition of OH− to (CH3)2CO, alkyl versus hydrogen substitution, potential energy curve.

Synthesis, Molecular Structure, HOMO-LUMO and Spectroscopic Investigation of (E)-1-(2,4-Dichloro-5-fluorophenyl)-3-(2,6-dichlorophenyl)prop-2-en-1-one: A DFT Based Computational Exploration

2020 ◽  
Vol 5 (3) ◽  
pp. 242-248
Author(s):  
Vishnu A. Adole ◽  
Ravindra H. Waghchaure ◽  
Thansing B. Pawar ◽  
Bapu S. Jagdale ◽  
Kailas H. Kapadnis
Keyword(s):  
Molecular Structure ◽  
Spectroscopic Investigation ◽  
Density Functional ◽  
Dft Method ◽  
Basis Set ◽  
Spectroscopic Techniques ◽  
Vibrational Assignments ◽  
Computational Exploration ◽  
Title Molecule ◽  
Homo Lumo

In present study, the synthesis, molecular structure, HOMO-LUMO and spectroscopic investigation of (E)-1-(2,4-dichloro-5-fluorophenyl)-3-(2,6-dichlorophenyl)prop-2-en-1-one (CFPCP) is reported. The structure of the title compound was affirmed based on FTIR, 1H NMR & 13C NMR spectroscopic techniques. The computational examination has been performed by employing density functional theory (DFT) method at B3LYP/6-311G++(d,p) basis set. The geometry of the title molecule has been optimized and established at the same level of theory. The various structural and quantum chemical parameters have been investigated for the title molecule at the 6-311G++(d,p) basis set. To explore the electron distribution, Mulliken atomic charges and molecular electrostatic potential surface are discussed. Besides, vibrational assignments were made and the scaled frequencies have been compared with the experimental frequencies. For the investigation of the absorption wavelength, excitation energy and the oscillator strength TD-DFT method using B3LYP/6-311G++(d,p) basis set is used. Some thermochemical functions have also been investigated using harmonic vibrational frequencies.

Sign in / Sign up

Export Citation Format

Share Document