scholarly journals A DFT Study on the Stepwise Fluorinated Methylenecyclopropane ⇋ 1-Methylcyclopropene System

2008 ◽  
Vol 63 (1-2) ◽  
pp. 42-48 ◽  
Author(s):  
Salim M. Khalil
Keyword(s):  
Density Functional Theory ◽  
Free Energy ◽  
Dft Calculations ◽  
Density Functional ◽  
Dipole Moments ◽  
Isodesmic Reactions ◽  
Functional Theory ◽  
Substantial Concentration ◽  
Homo Lumo ◽  
Optimized Geometries

Density functional theory (DFT) calculations have been performed to calculate the optimized geometries of stepwise fluorinated methylenecyclopropanes and 1-methylcyclopropenes. Increasing the number of fluorine atoms caused a destabilization of methylenecycopropane. Perfluorinated 1-methylcyclopropene was found to be present in substantial concentration. This is supported by calculations of the Gibbs free energy, isodesmic reactions and orbital energies (HOMO-LUMO). These results are compared with the fluorinated cyclopropanes keto-enol system. Enthalpies, entropies and dipole moments are reported.

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.

Structural and Electronic Properties of Small Silsesquioxanes: A DFT Study

2012 ◽  
Vol 548 ◽  
pp. 281-285 ◽  
Author(s):  
Cheng Gen Zhang ◽  
Ze Min Chen ◽  
Shu Yuan Yu ◽  
Hong Chao Wei
Keyword(s):  
Density Functional Theory ◽  
Dft Calculations ◽  
Electronic Structures ◽  
Density Functional ◽  
Bond Angle ◽  
Functional Theory ◽  
Effect Analysis ◽  
Methyl Group ◽  
Structural And Electronic Properties ◽  
Homo Lumo

Density functional theory (DFT) calculations are performed to investigate the structures of small silsesquioxanes (Si2nO3nX2n) (n=1-5 and X=H, F, Me). The large HOMO–LUMO gaps, which range from 5.41 to 9.17 eV, imply optimal electronic structures for these molecules. Furthermore, the substituent effect analysis indicate that the electron donating methyl group substituents lengthen the Si-O bond and largen the SiOSi bond angle, the electron withdrawing F atom substituents shorten the Si-O bond and lessen the SiOSi bond angle.

A Computational Study on Structures, Stabilities and Electronic Properties of Chloro Silsesquioxanes Si2nO3nCl2n (n=1-5)

2012 ◽  
Vol 190-191 ◽  
pp. 405-408
Author(s):  
Cheng Gen Zhang ◽  
Shu Yuan Yu ◽  
Zong Ji Cao
Keyword(s):  
Density Functional Theory ◽  
Dft Calculations ◽  
Electronic Properties ◽  
Electronic Structures ◽  
Density Functional ◽  
Computational Study ◽  
Functional Theory ◽  
Homo Lumo

Density functional theory (DFT) calculations were performed to investigate the structures of chloro silsesquioxanes Si2nO3nCl2n (n=1-5). Our study focuses on the structures, stabilities, and electronic properties of the chloro silsesquioxanes. The large HOMO–LUMO gaps, which range from 4.54 to 7.39 eV, imply optimal electronic structures for these molecules.

DFT Study on Structures, Stabilities and Electronic Properties of Tert-Butyl Silsesquioxanes Si2nO3n(CMe3)2n (n=1-6)

2012 ◽  
Vol 535-537 ◽  
pp. 1552-1555
Author(s):  
Cheng Gen Zhang ◽  
Shu Yuan Yu ◽  
Hai Mei Zhang
Keyword(s):  
Density Functional Theory ◽  
Dft Calculations ◽  
Electronic Properties ◽  
Electronic Structures ◽  
Density Functional ◽  
Dft Study ◽  
Functional Theory ◽  
Tert Butyl ◽  
Homo Lumo

Density functional theory (DFT) calculations were performed to investigate the structures of tert-butyl silsesquioxanes Si2nO3n(CMe3)2n (n=1-6). Our study focuses on the structures, stabilities, and electronic properties of the tert-butyl silsesquioxanes. The large HOMO–LUMO gaps, which range from 5.68 to 6.99 eV, imply optimal electronic structures for these molecules.

scholarly journals DFT Comparative Study of the Formamide and Fluoro-FormamideTautomers and Their Corresponding Transition States

2021 ◽  
Author(s):  
Ashraf Mansour Al-Msiedeen
Keyword(s):  
Density Functional Theory ◽  
Free Energy ◽  
Vibrational Frequency ◽  
Density Functional ◽  
Transition States ◽  
Mulliken Charge ◽  
Free Energies ◽  
Functional Theory ◽  
The Stability ◽  
Optimized Geometries

Abstract Seventeen tautomers of formamide [NH3CO] and thirty one tautomers of fluoro-formamide [NH2FCO] were examined by density functional theory (DFT) calculations. Five methods of DFT (B3LYP/ 6-311++G, B3LYP/ 6-311++G(2df,2p), B3LYP/cc-pVTZ, wB97X-D/6-311++G(2df,2p) and wB97X-D/ cc-pVTZ) were used to calculate the energies and optimized geometries of formamide tautomers. B3LYP/cc-pVTZ method was determined as the best method and used to calculate relative energies, optimized geometries, mulliken charge distributions, Gibbs free energies and enthalpy of formations of all proposed fluoro-formamide/fluoro-formamidic acid tautomers. Ten transition states of formamide tautomers and nineteen transition states of fluoro-formamide tautomers were determined by vibrational frequency calculations (they have an imaginary value of frequency). Using B3LYP/cc-PVTZ, the relatively small energies of formamide (A1) and formamidic acid (A6) (-446246 and -446193kJ.mol -1 , respectively) participate to it being more stable than other formamide/formamidic acid tautomers, as well as for fluoro-formamide (C1) (-706947 kJ.mol -1 ) and fluoro-formamidic acid (C3) (-706855 kJ.mol -1 ). The stability of fluoro-formamide at carbonyl and at nitrogen was discussed using two thermodynamic calculations: Enthalpy of formation [∆H(298)] and Gibbs free energy (∆G) values, positive ∆G values (59 to 114 kJ mol-1) for fluoro-formamidetautomerism confirms the stability of fluoro-formamide at carbonyl.

DFT Study on Structures, Stabilities and Electronic Properties of Bromo Silsesquioxanes Si2nO3nBr2n (n=1-5)

2012 ◽  
Vol 581-582 ◽  
pp. 349-352
Author(s):  
Shu Yuan Yu ◽  
Cheng Gen Zhang ◽  
Xu Yang
Keyword(s):  
Density Functional Theory ◽  
Dft Calculations ◽  
Electronic Properties ◽  
Electronic Structures ◽  
Density Functional ◽  
Dft Study ◽  
Functional Theory ◽  
Homo Lumo

Density functional theory (DFT) calculations were performed to investigate the structures of bromo silsesquioxanes Si2nO3nBr2n (n=1-5). Our study focuses on the structures, stabilities, and electronic properties of the bromo silsesquioxanes. The large HOMO–LUMO gaps, which range from 4.43 to 6.62 eV, imply optimal electronic structures for these molecules.

scholarly journals Functional Group Effects on the HOMO–LUMO Gap of g-C3N4

Nanomaterials ◽  
2018 ◽  
Vol 8 (8) ◽  
pp. 589 ◽  
Author(s):  
Hao Li ◽  
Zhien Zhang ◽  
Yulu Liu ◽  
Wanglai Cen ◽  
Xubiao Luo
Keyword(s):  
Density Functional Theory ◽  
Dft Calculations ◽  
Band Gap ◽  
Density Functional ◽  
Carbon Nitride ◽  
Functional Group ◽  
Functional Theory ◽  
Metal Free ◽  
Homo Lumo ◽  
Group Effects

Graphitic carbon nitride (g-C3N4) is a promising semiconductor material which has been widely studied in nanoscience. However, the effect of modifying the performance of g-C3N4 is still under debate. In this communication, we show the size and functional group effects on the g-C3N4 using density functional theory (DFT) calculations. It was found that a molecule with six repeated g-C3N4 units (g-C3N4-6) could be the smallest unit that converges to the limit of its HOMO–LUMO gap. Calculations of g-C3N4-6 with varying numbers of substituted C≡N, C=O, and O−H functional groups show that C≡N and C=O could narrow down the HOMO–LUMO gap, while O−H could slightly raise the gap. This study shows that the change of substituents could tune the band gap of g-C3N4, suggesting that rationally modifying the substituent at the edge of g-C3N4-based materials could help to significantly increase the photocatalytic properties of a metal-free g-C3N4.

A Computational Study on Structures, Stabilities and Electronic Properties of Trifluoromethyl Silsesquioxanes Si2nO3n(CF3)2n (n=1-5)

2012 ◽  
Vol 528 ◽  
pp. 91-94 ◽  
Author(s):  
Shu Yuan Yu ◽  
Cheng Gen Zhang ◽  
Ya Lan Wang
Keyword(s):  
Density Functional Theory ◽  
Dft Calculations ◽  
Electronic Properties ◽  
Electronic Structures ◽  
Density Functional ◽  
Computational Study ◽  
Functional Theory ◽  
Homo Lumo

Density functional theory (DFT) calculations were performed to investigate the structures of trifluoromethyl silsesquioxanes Si2nO3n(CF3)2n(n=1-5). Our study focuses on the structures, stabilities, and electronic properties of the trifluoromethyl silsesquioxanes. The large HOMO–LUMO gaps, which range from 5.38 to 8.02 eV, imply optimal electronic structures for these molecules.

scholarly journals Investigation of the Structures and Electronic Properties of 3'-(4-(5-Oxo-5-piperidin-1-yl)-penta-1,3-dienyl)benzo[d][1,3]dioxol-2-yl]Thymidine through DFT Calculations

2011 ◽  
Vol 3 (2) ◽  
pp. 339-345
Author(s):  
M. A. N. Al-Magmoy ◽  
A. H. Essa ◽  
A. J. Hameed
Keyword(s):  
Density Functional Theory ◽  
Dft Calculations ◽  
Electronic Properties ◽  
Ground State ◽  
Density Functional ◽  
Dipole Moments ◽  
Active Molecule ◽  
Functional Theory ◽  
Structural And Electronic Properties

The structural and electronic properties of 3'(4-(5-oxo-5-piperidin1-1-yl)penta-1,3-dienyl)benzo[d][1,3]dioxol-2-yl]-thymidine molecule have been investigated theoretically by performing density functional theory (DFT/3-21G*, 6-31G* and 6-31G**). The geometry of the molecule is optimized, and the electronic properties and relative energies of the molecules have been calculated by density functional theory in the ground state. The resultant dipole moments of the studied molecule are about 5.5, 6.36 and 7.35 Debyes by three levels (3-21G*, 6-31G* and 6-31G**, respectively). This property makes it an active molecule with its environment that is this molecule may interacts with its environment strongly in solution.Keywords:  3'-Azido-3'-deoxythymidine (AZT); Piperine; Density functional theory (DFT); Thymidine.© 2011 JSR Publications. ISSN: 2070-0237 (Print); 2070-0245 (Online). All rights reserved.doi:10.3329/jsr.v3i2.6364                J. Sci. Res. 3 (2), 339-345 (2011)

scholarly journals Charge-Density Induced Discrimination of Halides with a Rigid Dinuclear Copper(II) Complex

2020 ◽  
Author(s):  
Md Mhahabubur Rhaman ◽  
Mohammad Hasan ◽  
Zulfikhar A. Ali ◽  
Douglas Powell ◽  
Ritesh Tandon ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Dft Calculations ◽  
Cell Viability ◽  
Charge Density ◽  
Hela Cells ◽  
Density Functional ◽  
Binding Energies ◽  
Functional Theory ◽  
Dinuclear Copper ◽  
Optimized Geometries

<p>A rigid dinuclear copper(II) complex <b>L</b> based on furan spacers has been synthesized and studied for its binding interactions with halides by colorimetric studies, UV-Vis titrations, and density functional theory (DFT) calculations. Our results from the titration studies demonstrate that <b>L</b> binds each of the halides in the order of fluoride > chloride > bromide > iodide, correlating directly with the charge density of the respective halide. Fully unconstrained DFT geometry optimizations have been carried out on both the isolated <b>L</b> as well as the anion-bound motifs. Binding energies (DE) were calculated for each of the optimized geometries, yielding an attractive DE of -92.39, -27.14, -23.16, and -13.37 kcal/mol for fluoride, chloride, bromide, and iodide, respectively, which is in accord with our experimental results. The compound has been further investigated for its biocompatibility on HeLa cells, demonstrating an excellent cell viability up to 500 µM concentration.</p>

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