scholarly journals Molecular Structure, Vibrational Spectra and Docking Studies of Abacavir by Density Functional Theory

2017 ◽  
Vol 72 ◽  
pp. 9-27 ◽  
Author(s):  
R. Solaichamy ◽  
J. Karpagam
Keyword(s):  
Title Compound ◽  
Density Functional ◽  
Molecular Geometry ◽  
Nbo Analysis ◽  
Docking Studies ◽  
Basis Set ◽  
Vibrational Assignments ◽  
Molecular Stability ◽  
Homo And Lumo ◽  
Ft Ir

In this study, optimized geometry, spectroscopic (FT-IR, FT-Raman, UV) analysis, and electronic structure analysis of Abacavir were investigated by utilizing DFT/B3LYP with 6-31G(d,p) as a basis set. Complete vibrational assignments and correlation of the fundamental modes for the title compound were carried out. The calculated molecular geometry has been compared with available X-ray data of Abacavir. The calculated HOMO and LUMO energies show that charge transfer occurs within the molecule. The molecular stability and bond strength have been investigated by applying the Natural Bond Orbital (NBO) analysis. The computational molecular docking studies of title compound have been performed.

scholarly journals A Combined Experimental (FT-IR) and Computational Studies of 9-Chloroanthracene

2019 ◽  
Vol 31 (6) ◽  
pp. 1332-1342 ◽  
Author(s):  
KATTAESWAR SRIKANTH ◽  
RAMAIAH KONAKANCHI ◽  
JYOTHI PRASHANTH
Keyword(s):  
Density Functional ◽  
Minimum Energy ◽  
Nbo Analysis ◽  
Docking Studies ◽  
Basis Set ◽  
Protein Targets ◽  
Charge Delocalization ◽  
Fukui Functions ◽  
Homo And Lumo ◽  
Ft Ir

The experimental FT-IR spectral analysis of 9-chloroanthracene has worked out by using density functional theory (DFT). The optimized molecular structure and minimum energy of 9-chloroanthracene has analyzed using DFT/B3LYP functional employing 6-311++G(d,p) basis set. The vibrational frequencies along with IR intensities were computed, scaling was used for a better fit between the experimental and computed frequencies, they agreed with rms error 8.48 cm-1 for 9-chloroanthracene. The NLO behaviour of the molecule is investigated from first-order hyperpolarizability. The HOMO and LUMO energies are evaluated to demonstrate the chemical stability, reactivity of molecule. The MESP over the molecules were plotted to evaluate electron density regions and thermodynamic parameters are calculated. Hyper conjugative interactions and charge delocalization of the molecule study from NBO analysis and Fukui functions are evaluated for 9-chloroanthracene. The molecular docking studies were performed against anticancer protein targets Tyrosinase and HER2.

Quantum Computational, Spectroscopic and Molecular Docking Studies on N-(4-Hydroxyphenyl)picolinamide

2021 ◽  
Vol 6 (3) ◽  
pp. 186-203
Author(s):  
Meenakshi Singh ◽  
Mukesh Kumar ◽  
Neha Singh ◽  
Shikha Sharma ◽  
Neha Agarwal ◽  
...  
Keyword(s):  
Molecular Docking ◽  
Electrostatic Potential ◽  
Density Functional ◽  
Molecular Geometry ◽  
Energy Difference ◽  
Docking Studies ◽  
Basis Set ◽  
Fukui Functions ◽  
Homo And Lumo ◽  
Gibb’S Free Energy

In this work, the quantum computations of newly synthesized N-(4-hydroxyphenyl)picolinamide (4-HPP) is focused. Density functional theory (DFT) was used to perform the quantum calculations. The optimized molecular geometry was obtained using the B3LYP and MP2 methods employing 6-311++G(d,p) basis set, which served as the foundation for all subsequent calculations. The experimental data was compared with the calculated vibrational frequencies and NMR spectra. With the use of the molecular electrostatic potential surface (MEP) and the Fukui functions, the charge distribution, reactive regions and electrostatic potential were displayed. The chemical activity of the 4-HPP was evaluated by the energy difference between HOMO and LUMO. For better understanding of the intermolecular charge transfer (ICT), natural bond order analysis (NBO) was used. At various temperatures, thermodynamic parameters such as Gibb’s free energy, enthalpy and entropy were determined. The electrophilicity index was used to portray the molecule’s bioactivity and molecular docking was used to show the interaction between the ligand and the protein. The nature of the molecule was determined by drug similarity when expecting its application for medical purposes.

scholarly journals Quantum chemical investigation of spectroscopic, electronic and NLO properties of (1E, 4E)-1-(3-nitrophenyl)-5-phenylpenta-1,4-dien-3-one

2018 ◽  
Vol 6 (1) ◽  
pp. 121
Author(s):  
N Benhalima ◽  
S Yahiaoui ◽  
N Boubegra ◽  
M Boulakoud ◽  
Y Megrouss ◽  
...  
Keyword(s):  
Title Compound ◽  
Population Analysis ◽  
Energy Levels ◽  
Visible Spectrum ◽  
Molecular Geometry ◽  
Dft Method ◽  
Nbo Analysis ◽  
Basis Set ◽  
Vibrational Assignments ◽  
Reactivity Descriptors

In the present work the optimized molecular geometry and harmonic vibrational frequencies of chalcone derivative were calculated by DFT/B3LYP method with 6–31G (d,p) basis set. The vibrational assignments were performed on the basis of the potential energy dis-tribution (PED) of the vibrational modes. Natural bond orbital (NBO) analysis has been performed on title compound using B3LYP/6–31G (d,p) and HSEh1PBE /6–31G (d,p) levels in order to elucidate intermolecular hydrogen bonding, intermolecular charge transfer (ICT) and delocalization of electron density. Mulliken atomic charges, natural population analysis (NPA) and atomic polar tensors (APT) were performed. The nonlinear optical properties of the title compound are also calculated and discussed. Molecular electrostatic poten-tial and HOMO-LUMO energy levels are also computed. Ultraviolet–visible spectrum of the title compound has been calculated using TD–DFT method. The molecular orbital contributions were studied by density of states (DOSs). Global reactivity descriptors have been calculated using the HOMO and LUMO to predict compound reactivity.   

scholarly journals Vibrational Spectroscopic Analysis of 10H-Dibenzo[b,e][2,4]oxazine and Investigate their Structural Reactivity by DFT Computations and Molecular Docking Analysis

2020 ◽  
Vol 32 (10) ◽  
pp. 2475-2485
Author(s):  
M. Latha Beatrice ◽  
S. Mary Delphine ◽  
M. Amalanathan ◽  
H. Marshan Robert
Keyword(s):  
Molecular Docking ◽  
Density Functional ◽  
Atomic Orbital ◽  
Nbo Analysis ◽  
Vibrational Frequencies ◽  
Basis Set ◽  
Functional Theory ◽  
Homo And Lumo ◽  
Ft Ir ◽  
Title Molecule

The molecular structure and vibrational spectra of 10H-dibenzo[b,e][2,4]oxazine was calculated with the help of B3LYP density functional theory (DFT) using 6-311G (d,p) basis set. The FT-IR and FT-Raman spectra of title compound were interpreted by comparing the experimental results with the theoretical B3LYP/6-311G (d,p) calculations. The experimental observed vibrational frequencies are compared with the calculated vibrational frequencies and they are in good agreement with each other. Natural bond orbital (NBO) analysis interprets the intramolecular contacts of title molecule. The 1H and 13C NMR chemical movements of the particle have been determined by the gauge independent atomic orbital (GIAO) strategy and contrasted with the experimental outcome. The deciphered HOMO and LUMO energies showed the chemical stability of the molecules. Fukui capacity and natural charge investigation on atomic charges of the title molecule have been discussed. Docking reads were performed for title molecule utilizing the molecular docking programming with fungicidal dynamic PDB’s.

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.

A density functional approach toward structural features and properties of C20…N2X2 (X = H, F, Cl, Br, Me) molecules

2014 ◽  
Vol 13 (04) ◽  
pp. 1450023 ◽  
Author(s):  
Reza Ghiasi ◽  
Morteza Zaman Fashami ◽  
Amir Hossein Hakimioun
Keyword(s):  
Density Functional ◽  
Chemical Shifts ◽  
Geometry Optimization ◽  
Structural Features ◽  
Nbo Analysis ◽  
Basis Set ◽  
Basis Sets ◽  
Basis Set Superposition Error ◽  
Homo And Lumo ◽  
Lowest Unoccupied Molecular Orbitals

In this work, the interaction of C 20 with N 2 X 2 ( X = H , F , Cl , Br , Me ) molecules has been explored using the B3LYP, M062x methods and 6-311G(d,p) and 6-311+G(d,p) basis sets. The interaction energies (IEs) obtained with standard method were corrected by basis set superposition error (BSSE) during the geometry optimization for all molecules at the same levels of theory. It was found C 20… N 2 H 2 interaction is stronger than the interaction of other N 2 X 2 ( X = F , Cl , Br , Me ) with C 20. Highest occupied and lowest unoccupied molecular orbitals (HOMO and LUMO, respectively) levels are illustrated by density of states spectra (DOS). The nucleus-independent chemical shifts (NICSs) confirm that C 20… N 2 X 2 molecules exhibit aromatic characteristics. Geometries obtained from DFT calculations were used to perform NBO analysis. Also, 14 N NQR parameters of the C 20… N 2 X 2 molecules are predicted.

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