scholarly journals Comprehensive spectroscopic (FT-IR, FT-Raman, 1H and 13C NMR) identification and computational studies on 1-acetyl-1H-indole-2,3-dione

2017 ◽  
Vol 15 (1) ◽  
pp. 225-237 ◽  
Author(s):  
Maha S. Almutairi ◽  
S. Muthu ◽  
Johanan C. Prasana ◽  
B. Chandralekha ◽  
Alwah R. Al-Ghamdi ◽  
...  
Keyword(s):  
Raman Spectra ◽  
Density Functional ◽  
Energy Gap ◽  
Solid Phase ◽  
Atomic Orbital ◽  
Basis Set ◽  
Potential Energy Distribution ◽  
Charge Delocalization ◽  
Ft Ir ◽  
Ft Raman

AbstractFourier transform infrared (FT-IR) and FT-Raman spectra of 1-acetyl-1H-indole-2,3-dione (N-acetylisatin) were recorded in the solid phase and analyzed. The molecular geometry, vibrational frequencies, infrared intensities, Raman activities and atomic charges were calculated using density functional theory (DFT/B3LYP) calculations with a standard 6-311++G(d,p) basis set. The fundamental vibrational modes of N-acetylisatin were analyzed and fully assigned with the aid of the recorded FT-IR and FT-Raman spectra. The simulated FT-IR and FT-Raman spectra showed good agreement with the experimental spectra. The stability of the molecule, arising from hyper-conjugative interactions and charge delocalization, was analyzed using natural bond orbital (NBO) analysis. The dipole moment (µ), polarization (α) and hyperpolarization (β) values of N-acetylisatin were also computed. The potential energy distribution (PED) was computed for the assignment of unambiguous vibrational fundamental modes. The HOMO and LUMO energy gap illustrated the chemical activity of N-acetylisatin. The energy and oscillator strength were calculated by DFT. Gauge–including atomic orbital NMR (1H and 13C) chemical shift calculations were performed and compared with the experimental values. Thermodynamic properties (heat capacity, entropy and enthalpy) of the compound at different temperatures were also calculated.

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.

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 Synthesis and vibrational spectral (FT-IR, FT-Raman) studies, NLO properties & NBO analysis of (E)-N'(thiophen-2yl methylene)isonicotinohydrazide using quantum chemical method

2018 ◽  
Vol 6 (1) ◽  
pp. 53
Author(s):  
Nathiya A ◽  
Saleem H ◽  
Bharanidharan Bharani ◽  
Suresh M
Keyword(s):  
Molecular Orbital ◽  
Title Compound ◽  
Solid Phase ◽  
Nbo Analysis ◽  
Basis Set ◽  
Excitation Energies ◽  
Charge Delocalization ◽  
Nlo Properties ◽  
Ft Ir ◽  
Ft Raman

FT-IR (4000-400 cm-1) and FT-Raman (3500-50 cm-1) spectra of (E)-N'(thiophen-2yl methylene)isonicotinohydrazide (TMINH) molecule was recorded in solid phase. The optimized geometry was calculated by B3LYP method with 6-311++G(d,p) basis set. The harmonic vibrational frequencies, infrared (IR) intensities and Raman scattering activities of the title compound were performed at same level of theory. The complete vibrational assignments were performed on the basis of the Total energy distribution (TED) of the vibrational modes, calculated with scaled quantum mechanical (SQM) method. The calculated first hyperpolarizability may be attractive for further studies on non-linear optical (NLO) properties of material. Stability of the molecule arising from hyperconjugative interaction and charge delocalization was analyzed using natural bond orbital (NBO) analysis. Highest occupied molecular orbital-Lowest unoccupied molecular orbital (HOMO-LUMO) energy gap explains the eventual charge transfer interactions taking place within the title molecule. A study on the electronic properties, such as excitation energies and wavelengths, were performed by time-dependent (TD-DFT) approach. Molecular electrostatic potential (MEP) provides the information on the electrophilic, nucleophilic and free radical prone reactive sites of the molecule. The thermodynamic properties such as heat capacity, entropy and enthalpy of the title compound were calculated at different temperatures in gas phase. 1H and 13C-NMR chemical shifts of the molecule were calculated using Gauge-independent atomic orbital (GIAO) method.To establish information about the interactions between human cytochrome protein and this novel compound theoretically, docking studies were carried out using Schrödinger software.

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.

Molecular structure, vibrational spectral assignments (FT-IR and FT-RAMAN), NMR, NBO, HOMO–LUMO and NLO properties of 2-nitroacetophenone based on DFT calculations

2016 ◽  
Vol 15 (01) ◽  
pp. 1650007 ◽  
Author(s):  
G. Venkatesh ◽  
M. Govindaraju ◽  
P. Vennila ◽  
C. Kamal
Keyword(s):  
Dft Calculations ◽  
Density Functional ◽  
Chemical Shifts ◽  
Atomic Orbital ◽  
Closed Shell ◽  
Basis Set ◽  
Excitation Energies ◽  
Ft Ir ◽  
Homo Lumo ◽  
Ft Raman

The FT-IR and FT-Raman analyses of 2-nitro acetophenone (2NAP) have been carried out by density functional theory (DFT) calculations based on B3LYP level with 6-31G*/6-311[Formula: see text]G** basis set. The gauge-independent atomic orbital (GIAO) method has been used to get 1H NMR and [Formula: see text]C NMR chemical shifts. From DFT calculations, various parameters such as atomic charges, HOMO–LUMO energies and Dipole moment have been obtained. The molecular electronic potential (MEP) has also been derived for 2NAP. In order to find the electronic excitation energies, oscillator strength and nature of the respective excited states, the closed-shell singlet calculation has been utilized. MOLVIB program has been employed to calculate total energy distribution (TED) and normal coordinate analysis. Natural bond orbital (NBO) analysis has also been carried out by DFT calculations with B3LYP/6-311[Formula: see text]G** basis set.

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.

Theoretical investigation on tautomerism and NLO properties of Salicylideneaniline derivatives

2021 ◽  
Author(s):  
N. Daho ◽  
N. Benhalima ◽  
F. KHELFAOUI ◽  
O. SADOUKI ◽  
M. Elkeurti ◽  
...  
Keyword(s):  
Optical Properties ◽  
Density Functional ◽  
Energy Gap ◽  
Intramolecular Proton Transfer ◽  
Basis Set ◽  
Frontier Molecular Orbital ◽  
Molecular Orbital Calculations ◽  
Visible Absorption ◽  
Charge Delocalization ◽  
Intramolecular Hydrogen

In this work, a comprehensive investigation of the salicylideneaniline derivatives is carried out using density functional theory to determine their linear and non-linear optical properties. Geometry optimizations, for gas and solvent phases, of the tautomers (enol and keto forms) are calculated using B3LYP levels with 6–31G (d,p) basis set . An intramolecular proton transfer, for 1SA-E and 2SA-E, is performed by a PES scan process at the B3LYP/6-31G (d,p) level. The optical properties are determined and show that they have extremely high nonlinear optical properties. In addition, the RDG analysis, MEP, and gap energy are calculated. The low energy gap value indicates the possibility of intramolecular charge transfer. The frontier molecular orbital calculations clearly show the inverse relationship of HOMO–LUMO gap with the first-order hyperpolarizability (β = 59.6471 × 10-30 esu), confirming that the salicylideneaniline derivatives can be used as attractive future NLO materials. Therefore, the reactive sites are predicted using MEP and the visible absorption maxima are analyzed using a theoretical UV–Vis spectrum. Natural bond orbitals are used to investigate the stability, charge delocalization, and intramolecular hydrogen bond.

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 Microwave synthesis of some N-phenylhydrazine-1-carbothioamide Schiff bases

2018 ◽  
Vol 9 (2) ◽  
pp. 74-78 ◽  
Author(s):  
Bushra Kamil Al-Salami
Keyword(s):  
1H Nmr ◽  
Density Functional ◽  
Atomic Orbital ◽  
Calculated Data ◽  
Density Functional Theory Method ◽  
13C Nmr Spectroscopy ◽  
Basis Set ◽  
Functional Theory ◽  
B3lyp Method ◽  
Ft Ir

We have synthesized and characterized a series of carbothioamide derivatived molecules, obtained by reaction of aromatic aldehyde (Anisaldehyde, 9-anthraldehyde, cinnamaldehyde, indole-3-carboxaldehyde, 1-naphthaldehyde and o-vanillin) with an equimolar amount of 4-phenylthiosemicarbazide with microwave irradiation. The synthesized compounds have been characterized by FT-IR, 1H NMR and 13C NMR spectroscopy. Quantum calculations of the physical properties, based on density functional theory method at B3LYP/6-31+G(d,p) level of theory, were performed, by means of the Gaussian 09W set of programs. The theoretical 1H NMR chemical shift results of the studied compounds have been calculated at B3LYP method and standard 6-31+G(d,p) basis set using the standard Gauge-Independent Atomic Orbital approach. The calculated values are also compared with the experimental data available for these molecules. A good linear relationship between the experimental and calculated data has been obtained.

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.

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