A Theoretical Study of 2-Substituted Allyl Cations and Anions

1987 ◽  
Vol 42 (7) ◽  
pp. 761-766 ◽  
Author(s):  
Salim M. Khalil
Keyword(s):  
Theoretical Study ◽  
Geometry Optimization ◽  
Allyl Cation ◽  
Allyl Anions ◽  
Complete Geometry Optimization

MINDO-Forces calculations are reported, after complete geometry optimization, for 2-X-allyl cations and anions, where X is O- , OH, NH2, CH3, NO2, CN, CF3, F, CHO.In the case of the allyl cation, it was found that the substituents O- , OH, NH2 are stabilizing, CH3 is slightly stabilizing and all other substituents are destabilizing.In the case of the allyl anions, all the substituents are stabilizing. It was found that the substituents CH3, O- , CN show the amphielectronic behaviour. Calculations predict no (1,3) π interaction in 2-substituted ally cations and anions.

scholarly journals A Theoretical Study of Substituted Cyclopentanones and their Enols

2003 ◽  
Vol 58 (12) ◽  
pp. 738-748 ◽  
Author(s):  
Meisa S. Al-Noeemat ◽  
Reem A. Al-Ma’ani ◽  
Salim M. Khalil
Keyword(s):  
Density Functional Theory ◽  
Density Functional ◽  
Theoretical Study ◽  
Geometry Optimization ◽  
Density Functional Theory Calculations ◽  
Geometrical Parameters ◽  
Free Energies ◽  
Strong Electron ◽  
Functional Theory ◽  
Complete Geometry Optimization

MINDO-Forces calculations with complete geometry optimization have been performed on cyclopentanone and its enol counter part, perfluorination of cyclop entanone and its enol counterpart and X-cyclopentanones and their X-enols, where X is NO2, CF3, CN, OH, NH2 and O−. It was found that ketone is more stable than its enol counterpart. Perfluorination destabilizes ketone on the expense of enol. These results agree with the experimental results and density functional theory calculations. All substituents are destabilizing except O− in the case of cyclopentanone. It was found that NO2 and CF3 behave as strong electron withdrawing groups, CN and NC show amphielectronic behavior, and the substituents OH,NH2 and O− behave as electron releasing groups with O− being strongest. Geometrical parameters, heats of formation, entropies, and Gibbs free energies are reported

Ion solvation by dipolar aprotic solvents. An ab initio study

1987 ◽  
Vol 52 (1) ◽  
pp. 6-13 ◽  
Author(s):  
Petr Kyselka ◽  
Zdeněk Havlas ◽  
Ivo Sláma
Keyword(s):  
Ab Initio ◽  
Geometry Optimization ◽  
Molecular Structures ◽  
Dimethyl Sulphoxide ◽  
Ion Solvation ◽  
Interaction Energies ◽  
Ab Initio Study ◽  
Solvation Energies ◽  
Dipolar Aprotic Solvents ◽  
Complete Geometry Optimization

The paper deals with the solvation of Li+, Be2+, Na+, Mg2+, and Al3+ ions in dimethyl sulphoxide, dimethylformamide, acetonitrile, and water. The ab initio quantum chemical method was used to calculate the solvation energies, molecular structures, and charge distributions for the complexes water···ion, acetonitrile···ion, dimethyl sulphoxide···ion, and dimethylformamide···ion. The interaction energies were corrected for the superposition error. Complete geometry optimization was performed for the complex water···ion. Some generalizations are made on the basis of the results obtained.

MINDO-Forces Study on Substituted Nitromethane ⇋ aci-Nitromethane Tautomerism

2005 ◽  
Vol 60 (1-2) ◽  
pp. 47-53
Author(s):  
Bareehan M. Salim ◽  
Salim M. Khalil
Keyword(s):  
Theoretical Calculations ◽  
Geometry Optimization ◽  
Heats Of Formation ◽  
Geometrical Parameters ◽  
Free Energies ◽  
Electron Densities ◽  
Isodesmic Reactions ◽  
Complete Geometry Optimization

MINDO-Forces calculations with complete geometry optimization have been performed on nitromethane, aci-nitromethane and X-substituted nitromethane and aci-nitromethane (X = F, OH, NH2, CH3, CN, CF3, NO2, CHO). It is found that nitromethane is more stable than aci-nitromethane by 9.337 kcal/mol. This agrees with theoretical calculations. Thermodynamically, substituted aci-nitro tautomers are more stable than the corresponding nitromethane, except in case of the substituent F. Geometrical parameters, heats of formation, electron densities, Gibbs free energies and isodesmic reactions are reported.

Theoretical Study of Si-Rich Transition-Metal Silicides with Double-Graphene-Like Structures

2006 ◽  
Vol 958 ◽  
Author(s):  
Takehide Miyazaki ◽  
Toshihiko Kanayama
Keyword(s):  
Transition Metal ◽  
Theoretical Study ◽  
Layer Structure ◽  
Geometry Optimization ◽  
Energy Calculation ◽  
Total Energy Calculation ◽  
Metal Atoms ◽  
Transition Metal Atoms ◽  
Metal Silicides ◽  
Potential Impact

ABSTRACTWe propose a novel form of graphene-like Si nanostructure based on ab initio total-energy calculation and geometry optimization, (MSi12)n, with M being transition metal atom. It has a three-layer structure, where the two layers of Si atoms in graphene-like positions sandwich another layer of transition metal atoms. The electronic structure may become semiconducting or metallic, depending on the choice of M and arrangement of Si atoms. This hypothetical material can be regarded as a Si-rich phase of transition metal silicide. A potential impact of our finding in forthcoming ultra-scaled Si technology is also discussed.

Mindo-Forces Study on the Keto-Enol Tautomerism of α-Substituted Acetaldehydes XCH2CH=O (X = H, F, Oh, Cn, NH2, NO2, CH3, CF3, OCH3): Comparison with Acetyl Derivatives

2004 ◽  
Vol 59 (12) ◽  
pp. 980-986
Author(s):  
Wasim F. Al-Halasah ◽  
Salim M. Khalil
Keyword(s):  
Theoretical Calculations ◽  
Geometry Optimization ◽  
Substituent Effects ◽  
Geometrical Parameters ◽  
Free Energies ◽  
Electron Densities ◽  
The Stability ◽  
Complete Geometry Optimization

MINDO-Forces calculations with complete geometry optimization have been performed on α- substituted acetaldehydes XCH2CH=O and their enols (X = H, F, OH, CN, NH2, NO2, CH3, CF3, OCH3). All substituents were found to decrease the stability of the acetaldehyde and mostly in the case of electron withdrawing capacity (e. g NO2 and CF3). This agrees with theoretical calculations, except in the case of F. The substituent effects on the stabilities in this study are compared with results obtained from our previous theoretical calculations on acetyl derivatives. Geometrical parameters, electron densities, and Gibbs free energies are reported.

MINDO-Forces Study of Phenyl and Cyclopropyl Substituted Allyl Cations and Anions

1987 ◽  
Vol 42 (3) ◽  
pp. 297-304
Author(s):  
Hayfa M. Jarjis ◽  
Salim M. Khalil
Keyword(s):  
Carbon Atom ◽  
Energy Minimization ◽  
Phenyl Ring ◽  
Terminal Carbon Atom ◽  
Allyl Cation ◽  
Allyl Anions

MINDO-force calculations have been performed on phenyl and cyclopropyl substituted allyl cations and anions with complete energy minimization. It is found that the phenyl ring destabilizes the allyl cations when substituted at the terminal and at the center carbon atom of the cation, while the cyclopropyl ring stabilizes the allyl cation when substituted at the terminal carbon atoms, but destabilizes the cation when substituted at the center carbon atom of the cation. These results agree with the experimental ones. In the case of the allyl anions, it is found that the phenyl ring destabilizes the allyl anions when substituted on the terminal and on the center carbon atoms of the allyl anions, while the cyclopropyl ring stabilizes the allyl anion when substituted on the terminal carbon atom but destabilizes the anion when substituted on the center carbon atom. Also, it is found that both the phenyl and cyclopropyl rings are electron withdrawing when substituted on the allyl anions, while they are electron donating when substituted on the allyl cations.

Analytic gradients, geometry optimization and excited state potential energy surfaces from the particle-particle random phase approximation

2015 ◽  
Vol 17 (2) ◽  
pp. 1025-1038 ◽  
Author(s):  
Du Zhang ◽  
Degao Peng ◽  
Peng Zhang ◽  
Weitao Yang
Keyword(s):  
Excited States ◽  
Potential Energy Surfaces ◽  
Random Phase Approximation ◽  
Theoretical Study ◽  
Random Phase ◽  
Geometry Optimization ◽  
Photochemical Reactions ◽  
Energy Gradient ◽  
State Potential ◽  
Energy Surfaces

The energy gradient for electronic excited states is of immense interest not only for spectroscopy but also for the theoretical study of photochemical reactions.

Theoretical Study on the Influence of Iron Mordant in the Optical Properties of Natural Dyes

2008 ◽  
Vol 587-588 ◽  
pp. 608-612
Author(s):  
M. Carreira ◽  
António Estevao Candeias ◽  
A. Manhita ◽  
C.T. Costa ◽  
P.J. Mendes ◽  
...  
Keyword(s):  
Optical Properties ◽  
Energy Band ◽  
Lower Energy ◽  
Theoretical Study ◽  
Geometry Optimization ◽  
Natural Dyes ◽  
Spin Structures ◽  
Lower Energy Band ◽  
B3lyp Level ◽  
Td Dft

Geometry optimization of free alizarin, purpurin and luteolin and coordinated Fe(II) complexes was performed at DFT/B3LYP level. TD-DFT spectra were also calculated for free and coordinated alizarin and luteolin. For the Fe(II) complexes several spin multiplicities have been calculated and quintuplet spin structures were found to be the most stable. In the luteolin-Fe(II) complex, the coordination of the chromophore with the iron leads to a decrease in the lower energy band. In the case of luteolin complex, a new band emerges due to interactions between the delocalized π electrons of the luteolin molecule with the d metal orbitals.

Theoretical Study on Structural and Electronic Properties of EDOT:SS Oligomers Complex

2015 ◽  
Vol 1131 ◽  
pp. 123-127
Author(s):  
Ampaiwan Marutaphan ◽  
Panida Lorwongtragool ◽  
Chatchawal Wongchoosuk
Keyword(s):  
Electronic Properties ◽  
Polymer Chain ◽  
Density Functional ◽  
Theoretical Study ◽  
Energy Gap ◽  
Average Distance ◽  
Geometry Optimization ◽  
Am1 Method ◽  
Structural And Electronic Properties ◽  
Binding Distance

In this paper, we have reported a theoretical study of the geometric and electronic structures of EDOT:SS oligomers based on semi-empirical Austin model1 (AM1) method and density functional theory at B3LYP/3-21G* level. The effects of polymer chain length of both EDOT and SS on structural and electronic properties including bond length, bond angle, binding distance, charge, the highest occupied orbital (HOMO), the lowest unoccupied molecular orbital (LUMO), and energy gap have been studied from the optimized oligomers which were built by varying repeating unit of monomer as n = 1, 2, 3 and 4. The results show that AM1 is not appropriate for geometry optimization of EDOT:SS system comparing to B3LYP/3-21G* level. The binding distance between H atom on EDOT and O atom on SS tends to close together with the average distance of 2.21 Å. The most positive charges locate at sulfur atoms on EDOT and EDOT:SS. The electrical conductivity of EDOT, SS and EDOT:SS increases when polymer chain is extended.

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