Structural, vibrational (FTIR and FT-Raman), NMR, UV–vis spectral analysis, and DFT study of 2-(6-oxo-2-thioxotetrahydropyrimidin-4(1H)-ylidene) hydrazine carboxamide

2017 ◽  
Vol 95 (5) ◽  
pp. 580-589 ◽  
Author(s):  
N. Kalaiarasi ◽  
S. Manivarman
Keyword(s):  
Density Functional ◽  
Nbo Analysis ◽  
Basis Set ◽  
Geometrical Parameters ◽  
Mulliken Population ◽  
Functional Theory ◽  
Charge Delocalization ◽  
Homo Lumo ◽  
Spectral Characterizations ◽  
Ft Raman

Vibrational and spectral characterizations of 2-(6-oxo-2-thioxo tetrahydro pyrimidin-4(1h)-ylidene) hydrazine carboxamide (OTHHPYHC) were experimentally presented for the ground state using FTIR and FT-Raman and theoretically presented by density functional theory (DFT) using B3LYP correlation function with the basis set 6-31G(d,p). The geometrical parameters, energies, and wavenumbers have been obtained. The fundamental assignments were performed on the basis of total energy distribution. The first order hyperpolarizability (β0) and relative properties (β, α0, and Δα) were calculated using B3LYP/6-31G(d, p) method. Solidity of the molecule due to hyperconjugative interactions and charge delocalization has been analysed using natural bond orbital (NBO) analysis. The charge distribution and electron transfer from bonding to antibonding orbitals and electron density in the σ* and π* antibonding orbitals confirms interaction within the molecule. In addition to this, Mulliken population and HOMO–LUMO analysis have been used to support the information of structural properties.

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.

scholarly journals Spectroscopic, Electronic and Optical Properties of 4-Nitroimidazole using DFT Calculations

2020 ◽  
Vol 33 (1) ◽  
pp. 83-88
Author(s):  
S. Jeyavijayan ◽  
Palani Murugan
Keyword(s):  
Density Functional ◽  
Energy Gap ◽  
Dft Method ◽  
Nbo Analysis ◽  
Spectroscopic Techniques ◽  
Functional Theory ◽  
Raman Spectroscopic ◽  
Homo Lumo ◽  
Total Energy Distribution ◽  
Ft Raman

Theoretical and experimental vibrational spectra of 4-nitroimidazole were studied by FTIR, FT-Raman spectroscopic techniques and density functional theory (DFT) method. The contributions of the different modes to each wavenumber were confirmed using total energy distribution (TED). The optimized parameters and thermodynamic properties of 4-nitroimidazole have been computed. The charge transfer interactions of the molecule were explained from the small value of HOMO-LUMO energy gap. The NBO analysis, Mulliken’s plot and MEP studies of the molecule have also been reported.

scholarly journals Structural, Vibrational, Quantum Chemical Calculations, Thermal and Antimicrobial Studies On Nitrate Salt Of 3-Nitroaniline

2021 ◽  
Author(s):  
Thangarasu S ◽  
Siva V ◽  
Asath Bahadur S ◽  
Athimoolam S
Keyword(s):  
Density Functional ◽  
Basis Set ◽  
Experimental Result ◽  
Frontier Molecular Orbital ◽  
Geometrical Parameters ◽  
Functional Theory ◽  
Hartree Fock ◽  
Antimicrobial Studies ◽  
Evaporation Technique ◽  
Homo Lumo

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.

scholarly journals Structural and Vibrational Studies (FT-IR, FT-Raman) of Voglibose Using DFT Calculation

2016 ◽  
Vol 64 ◽  
pp. 45-62 ◽  
Author(s):  
R. Solaichamy ◽  
J. Karpagam
Keyword(s):  
Charge Transfer ◽  
Density Functional ◽  
Energy Gap ◽  
Chemical Shifts ◽  
Nbo Analysis ◽  
Biological Properties ◽  
Basis Set ◽  
Potential Energy Distribution ◽  
Charge Delocalization ◽  
Ft Raman

In the present study, we report on the Molecular structure and infrared (IR) and FT-Raman studies of Voglibose (VGB) as well as by calculations based on the density functional theory (DFT) approach; utilizing B3LYP/6-31G(d,p) basis set. The targeted interpretation of the vibrational spectra intended to the basis of calculated potential energy distribution matrix (PED) utilizing VEDA4 program. Stability of the molecule arising from hyperconjugative interactions and charge delocalization was studied using natural bond orbital (NBO) analysis. The results show that change in electron density in the σ∗and π∗antibonding orbitals and E2energies confirm the occurrence of intramolecular charge transfer within the molecule. The UV-Visible and NMR spectral analysis were reported by using TD-DFT and gauge GIAO approach respectively and their chemical shifts related to TMS were compared. The lowering of HOMO and LUMO energy gap appears to be the cause for its enhanced charge transfer interactions. Besides, molecular electrostatic potential (MEP) analysis was reported. Due to different potent biological properties, the molecular docking results are also reported.

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 Synthesis, spectral characterization, molecular structure, HOMO-LUMO, MEP and NLO analysis of some (E)-N-(4-Fluoro-3-Phenoxybenzylidene)- substituted benzenamines

2016 ◽  
Vol 4 (2) ◽  
pp. 27
Author(s):  
G. Jesu Retna Raj ◽  
P. Jayanthi ◽  
M. Sekar
Keyword(s):  
Density Functional ◽  
Basis Set ◽  
Spectral Studies ◽  
Geometrical Parameters ◽  
Atomic Charges ◽  
Functional Theory ◽  
1H And 13C Nmr ◽  
Vibrational Bands ◽  
Homo Lumo ◽  
Vibrational Wavenumbers

In this work, (E)-N-(4-Fluoro-3-Phenoxybenzylidene)-substituted benzenamines (1-6) have been synthesized and characterized by IR, 1H and 13C NMR spectral studies. Density functional theory (DFT) has been used to optimize geometrical parameters, atomic charges, vibrational wavenumbers and intensity of vibrational bands. The molecular properties HOMO-LUMO, MEP and atomic charges of carbon, nitrogen and oxygen were calculated using B3LYP/6-311G (d, p) basis set. The polarizability and first order hyperpolarizability of the title Compounds were calculated and interpreted.

scholarly journals The effect of the fused-ring substituent on anthracene chalcones: crystal structural and DFT studies of 1-(anthracen-9-yl)-3-(naphthalen-2-yl)prop-2-en-1-one and 1-(anthracen-9-yl)-3-(pyren-1-yl)prop-2-en-1-one

2018 ◽  
Vol 74 (5) ◽  
pp. 650-655 ◽  
Author(s):  
Dian Alwani Zainuri ◽  
Ibrahim Abdul Razak ◽  
Suhana Arshad
Keyword(s):  
Density Functional ◽  
Energy Gap ◽  
Basis Set ◽  
Geometrical Parameters ◽  
Quantum Chemical Analysis ◽  
Functional Theory ◽  
Intermolecular Contacts ◽  
Fused Ring ◽  
Crystal Structural ◽  
Homo Lumo

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.

scholarly journals Structural, Vibrational, Quantum Chemical Calculations, Thermal and Antimicrobial Studies on Sulphate Salt of 3-Nitroaniline

2020 ◽  
Vol 33 (1) ◽  
pp. 231-239
Author(s):  
S. Thangarasu ◽  
V. Siva ◽  
S. Asath Bahadur ◽  
S. Athimoolam
Keyword(s):  
Density Functional ◽  
Basis Set ◽  
Experimental Result ◽  
Frontier Molecular Orbital ◽  
Geometrical Parameters ◽  
Functional Theory ◽  
Hartree Fock ◽  
Antimicrobial Studies ◽  
Evaporation Technique ◽  
Homo Lumo

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.

scholarly journals Molecular structure, NBO analysis, first hyper polarizability, and homo-lumo studies of π-extended tetrathiafulvalene (EXTTF) derivatives connected to π-nitro phenyl by density functional method

2018 ◽  
Vol 6 (1) ◽  
pp. 114
Author(s):  
Tahar Abbaz ◽  
Amel Bendjeddou ◽  
Didier Villemin
Keyword(s):  
Density Functional ◽  
Density Functional Method ◽  
Nbo Analysis ◽  
Functional Method ◽  
Total Charge ◽  
Linear Optics ◽  
Functional Theory ◽  
Non Linear Optics ◽  
Homo And Lumo ◽  
Homo Lumo

In these study we have been obtained the structural properties of (exTTF) derivatives 1-4 by using B3LYP/6-31G(d,p) of Density Functional Theory (DFT) utilizing Becke three exchange functional and Lee Yang Paar correlation functional. The calculation of first hyperpolarizability shows that the molecules are attractive molecules for future applications in non-linear optics. Molecular electrostatic potential (MEP) at a point in the space around a molecule gives an indication of the net electrostatic effect produced at that point by the total charge distribution of the molecule. The calculated HOMO and LUMO energies show that charge transfer occurs within these molecules. 

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