scholarly journals Density Functional Theory Study on Conformers of Benzoylcholine Chloride

2013 ◽  
Vol 2013 ◽  
pp. 1-10 ◽  
Author(s):  
Mustafa Karakaya ◽  
Fatih Ucun ◽  
Ahmet Tokatlı
Keyword(s):  
Density Functional Theory ◽  
Ground State ◽  
Density Functional ◽  
Atomic Orbital ◽  
Nbo Analysis ◽  
Vibrational Frequencies ◽  
Molecular Structures ◽  
Basis Set ◽  
Functional Theory ◽  
B3lyp Method

The optimized molecular structures and vibrational frequencies and also gauge including atomic orbital (GIAO)1H and13C NMR shift values of benzoylcholine chloride [(2-benzoyloxyethyl) trimethyl ammonium chloride] have been calculated using density functional theory (B3LYP) method with 6-31++G(d) basis set. The comparison of the experimental and calculated infrared (IR), Raman, and nuclear magnetic resonance (NMR) spectra has indicated that the experimental spectra are formed from the superposition of the spectra of two lowest energy conformers of the compound. So, it was concluded that the compound simultaneously exists in two optimized conformers in the ground state. Also the natural bond orbital (NBO) analysis has supported the simultaneous exiting of two conformers in the ground state. The calculated optimized geometric parameters (bond lengths and bond angles) and vibrational frequencies for both the lowest energy conformers were seen to be in a well agreement with the corresponding experimental data.

scholarly journals DFT Study of the Molecular and Electronic Structure of Metal-Free Tetrabenzoporphyrin and Its Metal Complexes with Zn, Cd, Al, Ga, In

2022 ◽  
Vol 23 (2) ◽  
pp. 939
Author(s):  
Alexey V. Eroshin ◽  
Arseniy A. Otlyotov ◽  
Ilya A. Kuzmin ◽  
Pavel A. Stuzhin ◽  
Yuriy A. Zhabanov
Keyword(s):  
Density Functional Theory ◽  
Density Functional ◽  
Electronic Absorption Spectra ◽  
Nbo Analysis ◽  
Molecular Structures ◽  
Basis Set ◽  
Ionic Character ◽  
Functional Theory ◽  
Metal Free ◽  
Zinc Cadmium

The electronic and molecular structures of metal-free tetrabenzoporphyrin (H2TBP) and its complexes with zinc, cadmium, aluminum, gallium and indium were investigated by density functional theory (DFT) calculations with a def2-TZVP basis set. A geometrical structure of ZnTBP and CdTBP was found to possess D4h symmetry; AlClTBP, GaClTBP and InClTBP were non-planar complexes with C4v symmetry. The molecular structure of H2TBP belonged to the point symmetry group of D2h. According to the results of the natural bond orbital (NBO) analysis, the M-N bonds had a substantial ionic character in the cases of the Zn(II) and Cd(II) complexes, with a noticeably increased covalent contribution for Al(III), Ga(III) and In(III) complexes with an axial –Cl ligand. The lowest excited states were computed with the use of time-dependent density functional theory (TDDFT) calculations. The model electronic absorption spectra indicated a weak influence of the nature of the metal on the Q-band position.

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.

Ab Initio Hartree-Fock and Density Functional Theory Study on Molecular Structures, Energies, and Vibrational Frequencies of 2-Amino-3-, 4-, and 5-Nitropyridine

2010 ◽  
Vol 65 (1-2) ◽  
pp. 107-112 ◽  
Author(s):  
Yusuf Sert ◽  
Fatih Ucun ◽  
Mustafa Böyükata
Keyword(s):  
Experimental Data ◽  
Density Functional Theory ◽  
Ab Initio ◽  
Density Functional ◽  
Vibrational Frequencies ◽  
Geometric Parameters ◽  
Molecular Structures ◽  
Basis Set ◽  
Functional Theory ◽  
Hartree Fock

AbstractThe molecular structures, vibrational frequencies, and corresponding vibrational assignments of 2-amino-3-, 4-, and 5-nitropyridine have been calculated by using ab initio Hartree-Fock (HF) and density functional theory (B3LYP) methods with 6-311++G(d,p) basis set level. The calculated vibrational frequencies and optimized geometric parameters (bond lengths and bond angles) were found to be in well agreement with the experimental data. The comparison of the observed and the calculated results showed that the scaled B3LYP method is superior to the scaled HF method for both the vibrational frequencies and the geometric parameters. For well fitting the calculated and the experimental frequencies we used scale factors obtained from the ratio of the frequency values of the strongest peaks in the calculated and the experimental spectra. These obtained scales seem to cause the better agreement of the gained vibrations to the experimental data.

scholarly journals Structural and spectroscopic characterization and DFT studies of 2-amino-1,10-phenanthrolin-1-ium chloride

2019 ◽  
Vol 10 (2) ◽  
pp. 95-101
Author(s):  
Sebile Işık Büyükekşi ◽  
Namık Özdemir ◽  
Abdurrahman Şengül
Keyword(s):  
Density Functional Theory ◽  
Electronic Absorption ◽  
13C Nmr ◽  
Density Functional ◽  
Electronic Absorption Spectra ◽  
Chemical Shifts ◽  
Atomic Orbital ◽  
Basis Set ◽  
Functional Theory ◽  
1H And 13C Nmr

A versatile synthetic building block, 2-amino-1,10-phenanthrolin-1-ium chloride (L∙HCl) was synthesized and characterized by IR, 1H and 13C NMR DEPT analysis, UV/Vis and single-crystal X-ray diffraction technique. The molecular geometry, vibrational wavenumbers and gauge including atomic orbital (GIAO), 1H and 13C NMR chemical shifts values of the title compound in the ground state were obtained by using density functional theory (DFT/B3LYP) method with 6-311++G(d,p) basis set and compared with the experimental data. Electronic absorption spectrum of the salt was determined using the time-dependent density functional theory (TD-DFT) method at the same level. In the NMR and electronic absorption spectra calculations, the effect of solvent on the theoretical parameters was included using the default model with DMSO as solvent. The obtained theoretical parameters agree well with the experimental findings.

Density Functional Theory Based Modeling of the Corrosion on Iron Surfaces

2013 ◽  
Vol 58 (2) ◽  
pp. 321-323 ◽  
Author(s):  
N. Nunomura ◽  
S. Sunada
Keyword(s):  
Density Functional Theory ◽  
Density Functional ◽  
Atomic Orbital ◽  
Atomic Layer ◽  
Iron Surface ◽  
Basis Set ◽  
Water Molecules ◽  
Aqueous Corrosion ◽  
Functional Theory ◽  
Adsorption Of Water

In order to understand the first steps of the aqueous corrosion of iron, we have performed density functional theory (DFT) based calculations for water molecules and pre-covered oxygen on iron surface. The surface structure is modeled by iron atomic layer and vacuum region, and then oxygen atom and water molecules are displaced on the surface. Self consistent DFT calculations were performed using a numerical atomic orbital basis set and a norm-conserve pseudopotential method. According to our calculations, with increasing surface oxygen coverage, the iron surface is found to be not activated, which leads to a feeble adsorption of water molecules on iron surface. Our results show that the surface covered oxygen exerts an influence on the adsorption of water molecules on iron surface.

scholarly journals Molecular Geometry, NLO, MEP, HOMO-LUMO and Mulliken Charges of Substituted Piperidine Phenyl Hydrazines by Using Density Functional Theory

2019 ◽  
Vol 32 (2) ◽  
pp. 401-407
Author(s):  
M. Dinesh Kumar ◽  
P. Rajesh ◽  
R. Priya Dharsini ◽  
M. Ezhil Inban
Keyword(s):  
Density Functional Theory ◽  
Density Functional ◽  
Chemical Reactivity ◽  
Molecular Geometry ◽  
Basis Set ◽  
Functional Theory ◽  
B3lyp Method ◽  
Reactivity Descriptor ◽  
Homo Lumo ◽  
Optimized Geometries

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.

Binding Energies of Organic Charge-Transfer Complexes Calculated by First-Principles Methods

1998 ◽  
Vol 63 (8) ◽  
pp. 1223-1244 ◽  
Author(s):  
Cordula Rauwolf ◽  
Achim Mehlhorn ◽  
Jürgen Fabian
Keyword(s):  
Density Functional Theory ◽  
Charge Transfer ◽  
Ground State ◽  
Density Functional ◽  
Binding Energies ◽  
Basis Set ◽  
Dispersion Energy ◽  
Functional Theory ◽  
Basis Set Superposition Error ◽  
Donor And Acceptor

Weak interactions between organic donor and acceptor molecules resulting in cofacially-stacked aggregates ("CT complexes") were studied by second-order many-body perturbation theory (MP2) and by gradient-corrected hybrid Hartree-Fock/density functional theory (B3LYP exchange-correlation functional). The complexes consist of tetrathiafulvalene (TTF) and related compounds and tetracyanoethylene (TCNE). Density functional theory (DFT) and MP2 molecular equilibrium geometries of the component structures are calculated by means of 6-31G*, 6-31G*(0.25), 6-31++G**, 6-31++G(3df,2p) and 6-311G** basis sets. Reliable molecular geometries are obtained for the donor and acceptor compounds considered. The geometries of the compounds were kept frozen in optimizing aggregate structures with respect to the intermolecular distance. The basis set superposition error (BSSE) was considered (counterpoise correction). According to the DFT and MP2 calculations laterally-displaced stacks are more stable than vertical stacks. The charge transfer from the donor to the acceptor is small in the ground state of the isolated complexes. The cp-corrected binding energies of TTF/TCNE amount to -1.7 and -6.3 kcal/mol at the DFT(B3LYP) and MP2(frozen) level of theory, respectively (6-31G* basis set). Larger binding energies were obtained by Hobza's 6-31G*(0.25) basis set. The larger MP2 binding energies suggest that the dispersion energy is underestimated or not considered by the B3LYP functional. The energy increases when S in TTF/TCNE is replaced by O or NH but decreases with substitution by Se. The charge-transferred complexes in the triplet state are favored in the vertical arrangement. Self-consistent-reaction-field (SCRF) calculations predicted a gain in binding energy with solvation for the ground-state complex. The ground-state charge transfer between the components is increased up to 0.8 e in polar solvents.

scholarly journals Graphite as A Hydrogen Storage in Fuel Cell System: Computational Material Study for Renewable Energy

2017 ◽  
Vol 17 (2) ◽  
pp. 103
Author(s):  
Rahmat Gunawan ◽  
Cynthia Linaya Radiman ◽  
Muhamad Abdulkadir Martoprawiro ◽  
Hermawan K. Dipojono
Keyword(s):  
Density Functional Theory ◽  
Hydrogen Storage ◽  
Density Functional ◽  
Alkali Metals ◽  
Correlation Energy ◽  
Atomic Orbital ◽  
Hydrogen Gas ◽  
Basis Set ◽  
Functional Theory ◽  
Orbital Contribution

The Hydrogen storage based-graphite materials have been investigated theoretically via Density Functional Theory (DFT) approach. The native graphite was compared to the modified graphite, namely the intercalation graphite (GICs, graphite intercalated compounds). Here the GICs was intercalated by alkali metals (Li, Na and K). The electronic structures, energetics and atomic orbital contributions of hydrogen-graphite system, GICs, and hydrogen-GICs were studied by calculation approach of gradient corrected PBE (Perdew-Burke-Ernzerhof) for recovery of exchange-correlation energy. The calculation was supported by using basis set of the plane waves whereas the computation of electron-core by using Ultrasoft Vanderbilt pseudopotential. The computational calculation provides four main studies i.e. molecular geometry relaxation, determination of electronic bands structure of energy, energy state density (DOS) and atomic orbital contribution by charge density differences.Keywords: Density Functional Theory, hydrogen gas, graphite intercalated material

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