scholarly journals Structural, Spectral, Thermodynamic and HOMO, LUMO Analysis of 2, 6 dithenobenzene-3-enyl 3, 5 dimethyl piperdine-4-one: A quantum chemical analysis

2021 ◽  
Vol 37 (6) ◽  
pp. 1396-1408
Author(s):  
Sangeetha. R.K ◽  
Ayyappan. S S

In the current work, the vibrational frequencies, infrared intensities, molecular geometry and Raman scattering were determined and investigated using ab initio Hartree–Fock (HF) and density functional methods with a basis set of 6-311++ G (d, p) of the organic molecule under interpretation. The FT-IR and FT-Raman spectra of titled molecule have been recorded in the region 4000-400 cm-1 and 5000-70 cm-1, respectively. The optimized geometry structures (bond lengths and bond angles) achieved using HF shows the best result with the experimental values of the titled molecule. The frontier molecular orbitals help to distinguish chemical responsiveness and molecular kinetic steadiness, thus HOMO-LUMO analysis can be done using the quantum chemistry to improve thermodynamics. The electron density mapping to electrostatic potential surfaces were involved in finding the reactivity sites of the titled compound. With the help of Gauss view 5.0 and Chemcraft packages, the obtained outputs are analyzed. Hyperpolarizability and non-linear optical effect of isolated molecules of NLO materials are observed to be an extensive tool for molecular spectroscopy research. Therefore, for industrial application, Hyperpolarizability of the molecule is also studied.

2019 ◽  
Vol 32 (2) ◽  
pp. 401-407
Author(s):  
M. Dinesh Kumar ◽  
P. Rajesh ◽  
R. Priya Dharsini ◽  
M. Ezhil Inban

The quantum chemical calculations of organic compounds viz. (E)-1-(2,6-bis(4-chlorophenyl)-3-ethylpiperidine-4-ylidene)-2-phenyl-hydrazine (3ECl), (E)-1-(2,6-bis(4-chlorophenyl)-3-methylpiperidine-4-ylidene)-2-phenylhydrazine (3MCl) and (E)-1-(2,6-bis(4-chloro-phenyl)-3,5-dimethylpiperidine-4-ylidene)-2-phenylhydrazine (3,5-DMCl) have been performed by density functional theory (DFT) using B3LYP method with 6-311G (d,p) basis set. The electronic properties such as Frontier orbital and band gap energies have been calculated using DFT. Global reactivity descriptor has been computed to predict chemical stability and reactivity of the molecule. The chemical reactivity sites of compounds were predicted by mapping molecular electrostatic potential (MEP) surface over optimized geometries and comparing these with MEP map generated over crystal structures. The charge distribution of molecules predict by using Mulliken atomic charges. The non-linear optical property was predicted and interpreted the dipole moment (μ), polarizability (α) and hyperpolarizability (β) by using density functional theory.


2016 ◽  
Vol 34 (4) ◽  
pp. 886-904 ◽  
Author(s):  
Meryem Evecen ◽  
Hasan Tanak

AbstractIn this paper, the molecular geometry, vibrational frequencies and chemical shifts of (6-Methoxy-2-oxo-2H-chromen-4-yl)methyl pyrrolidine-1-carbodithioate in the ground state have been calculated using the Hartree-Fock and density functional methods with the 6-311++G(d,p) basis set. To investigate the nonlinear optical properties of the title compound, the polarizability and the first hyperpolarizability were calculated. The conformational properties of the molecule have been determined by analyzing molecular energy properties. Using the time dependent density functional theory, electronic absorption spectra have been calculated. Frontier molecular orbitals, natural bond orbitals, natural atomic charges and thermodynamical parameters were also investigated by using the density functional theory calculations.


A novel heterocyclic chemical entity, 2-(1H-benzo[d]imidazol-2-yl)-3-(3-(4-nitrophenyl)-1-phenyl-1Hpyrazol-4-yl)acrylonitrile) (1f) has been synthesized and characterized. Computational studies were carried out using Gaussian 9 program with DFT/B3LYP/6311(++G) basis set. The structural optimization was computed successfully. Further, HOMO–LUMO analysis promises the incidence of inter electron transfer within the molecule. The theoretically determined hyperpolarizability value is nearly 9.5 times better than standard urea, suggesting its future utility as an efficient NLO optic material or its utility as an effective intermediate to construct better NLO materials


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.


2021 ◽  
Author(s):  
Thangarasu S ◽  
Siva V ◽  
Asath Bahadur S ◽  
Athimoolam S

Abstract In this work, 3-nitroanilinium nitrate (3NAN) has been synthesized and crystallized successfully by solution growth combined with solvent evaporation technique. 3NAN molecular structure has been optimized with Density Functional Theory (DFT) using B3LYP function and Hartree-Fock method with a 6-311 + + G(d,p) basis set. The geometrical parameters of the title molecules have been analyzed. The computed vibrational spectra were compared with experimental result which show appreciable agreement. Thermal stability of the crystal was analyzed with TGA/DTA and the melting points of the salt identified at 209 ºC. HOMO-LUMO energy calculations have shown the charge transfer within the molecu le. The possible pharmaceutical/biological activity of the salts confirmed by the Frontier Molecular Orbital (FMO) analysis have lower band gap value. The antimicrobial activity of grown crystals were tested against certain potentially threatening microbes.


Author(s):  
Virupakshi M. Bhumannavar

Abstract: The structural confirmation of the 1-(4-Bromophenyl)-3-(2-chloro-6-fluorophenyl) prop-2-en-1-one compound is done by experimental techniques. Experimental techniques FTIR, proton NMR, UV-Visible, performed for the compound. The experimentally obtained results are compared with density functional theory obtained results. The decomposition and melting point of the compound is obtained by TGA & DTA. Density functional theory is performed for the 1-(4-Bromophenyl)-3-(2- chloro-6-fluorophenyl) prop-2-en-1-one compound B3LYP/6-311G++(d,p) basis set. Time dependent density functional theory calculated for three different methods B3LYP, Hartree-Fock and CAMB3LYP also employed for the 2C6FBC at 6-311G++(d,p) basis set. Keywords: DFT Study, HOMO-LUMO, FTIR, 1H NMR, TGA/DTA, chalcone


2009 ◽  
Vol 64 (11) ◽  
pp. 745-752 ◽  
Author(s):  
Nergin Günay ◽  
Erdogan Tarcan ◽  
Davut Avcı ◽  
Kadir Esmer ◽  
Yusuf Atalay

The molecular geometry, vibrational spectra, and gauge including atomic orbital (GIAO), individual gauges for atoms in molecules (IGAIM), and continuous set of gauge transformations (CSGT) 1H and 13C chemical shift values of ethyl 6-chloro-2-oxo-2H-chromene-3-carboxylate (C12H9ClO4-(I)) and ethyl 6-bromo-2-oxo-2H-chromene-3-carboxylate (C12H9BrO4-(II)) in the ground state have been calculated by using the Hartree-Fock (HF) and density functional method (B3LYP) with 6- 31G+(d,p) basis set. The results of the optimized molecular structure are presented and compared with the experimental X-ray diffraction. The computed vibrational frequencies were used to determine the types of molecular motions associated with the spectra of the experimental bands observed. Also, calculated 1H and 13C chemical shift values were compared with the experimental ones.


Author(s):  
Dian Alwani Zainuri ◽  
Ibrahim Abdul Razak ◽  
Suhana Arshad

The title chalcone compounds, C27H18O (I) and C33H20O (II), were synthesized using a Claisen–Schmidt condensation. Both compounds display an s-trans configuration of the enone moiety. The crystal structures feature intermolecular C—H...O and C—H...π interactions. Quantum chemical analysis of density functional theory (DFT) with a B3LYP/6–311++G(d,p) basis set has been employed to study the structural properties of the compound. The effect of the intermolecular interactions in the solid state are responsible for the differences between the experimental and theoretical optimized geometrical parameters. The small HOMO–LUMO energy gap in (I) (exp : 3.18 eV and DFT: 3.15 eV) and (II) (exp : 2.76 eV and DFT: 2.95 eV) indicates the suitability of these compounds for optoelectronic applications. The intermolecular contacts and weak contributions to the supramolecular stabilization are analysed using Hirshfeld surface analysis.


2008 ◽  
Vol 63 (10-11) ◽  
pp. 712-720 ◽  
Author(s):  
Davut Avcı ◽  
Adil Başoğlu ◽  
Yusuf Atalay

The molecular geometry, vibrational frequencies, infrared intensities, Raman scattering activities and several thermodynamic parameters of anilinium nitrate in the ground state have been calculated by both Hartree-Fock (HF) and three density functional theory (DFT) methods (B3LYP, BLYP and B3PW91) using the 6-31G(d) basis set. The results of the optimized molecular structure are presented and compared with the experimental X-ray structure. The optimized geometric bond lengths are described very well by the HF method while bond angles are reproduced more accurately by the DFT methods. Comparison between the observed fundamental vibrational frequencies of anilinium nitrate and the results of DFT and HF methods indicates that B3LYP is superior to the scaled HF, BLYP and B3PW91 approaches for molecular vibrational problems. The computed vibrational frequencies are used to determine the types of molecular motions associated with each of the experimental bands observed. In addition, calculated results are related to the linear correlation plot of computed data versus experimental geometric parameters and IR data.


2020 ◽  
Vol 33 (1) ◽  
pp. 231-239
Author(s):  
S. Thangarasu ◽  
V. Siva ◽  
S. Asath Bahadur ◽  
S. Athimoolam

In this work, bis(3-nitroanilinium) sulfate (3NASU) has been synthesized and crystallized successfully by solution growth combined with solvent evaporation technique. The studied salt, 3NASU molecular structure has been optimized with density functional theory (DFT) using B3LYP function and Hartree-Fock method with a 6-311++G(d,p) basis set. The geometrical parameters of 3NASU have been analyzed. The computed vibrational spectra were compared with experimental result which show appreciable agreement. Thermal stability of the crystal was analyzed with TGA/DTA and the melting points of the salt identified at 210 ºC. HOMO-LUMO energy calculations have shown the charge transfer within the molecule. The possible pharmaceutical/biological activity of the salts confirmed by the frontier molecular orbital (FMO) analysis have lower band gap value. The antimicrobial activity of grown crystals were tested against certain potentially threatening microbes.


Sign in / Sign up

Export Citation Format

Share Document