A Theoretical Study of Substituted Stepwise Fluorinated Cyclopropanone Keto-Enol System

2003 ◽  
Vol 58 (12) ◽  
pp. 749-755
Author(s):  
Abdullah El-Alali ◽  
Ali A. Marashdeh ◽  
Salim M. Khalil
Keyword(s):  
Theoretical Study ◽  
Dipole Moments ◽  
Heats Of Formation ◽  
Geometrical Parameters ◽  
Free Energies ◽  
Isodesmic Reactions ◽  
Orbital Energies ◽  
Substantial Concentration ◽  
Homo Lumo ◽  
Complete Optimization

MINDO-Forces calculations have been performed with complete optimization of the geometries on stepwise fluorinated cyclopropanones and their enols. Increase in the number of fluorine atoms causes destabilization of cyclopropanone. Perfluorinated enol was found to be present in substantial concentration, as was mentioned in previous work. This is supported by calculations of Gibbs free energies and isodesmic reactions. Geometrical parameters, heats of formation, electron densities, dipole moments and orbital energies (HOMO-LUMO) are reported.

A Theoretical Study of Fulvene Radical Anions

1991 ◽  
Vol 46 (3) ◽  
pp. 247-255 ◽  
Author(s):  
Salim M. Khalil ◽  
Hayfa M. Jarjis
Keyword(s):  
Theoretical Study ◽  
Dipole Moments ◽  
Heats Of Formation ◽  
Geometrical Parameters ◽  
Radical Anions ◽  
Optimization Of Geometry ◽  
Stabilization Effect ◽  
Complete Optimization ◽  
Spin Densities

AbstractMINDO-Forces calculations have been performed, with complete optimization of geometry on fulvene and X-fulvene radical anions, where X is OH, NH2, CH3, NO,2 CN, F, dimethyl and cyclopropyl. A twisted structure with angle 5° was found for fulvene anion. All substituents are stabilizing. The stabilization effect is more pronounced in the case of NO2, and very weak in the case of CH3. It was found that the substituents CH3 and CN show amphielectronic behaviour. Geometrical parameters, heats of formation, dipole moments, electron and spin densities are reported

MINDO-Forces Study on the Substituent Effect in the Keto-Enol Tautomerism of Acetyl Derivatives

2004 ◽  
Vol 59 (4-5) ◽  
pp. 299-308
Author(s):  
Wasim F. Al-Halasah ◽  
Ali Mahasnah ◽  
Salim M. Khalil
Keyword(s):  
Vinyl Alcohol ◽  
Substituent Effect ◽  
Theoretical Calculations ◽  
Geometry Optimization ◽  
Heats Of Formation ◽  
Geometrical Parameters ◽  
Free Energies ◽  
Orbital Energies ◽  
Homo Lumo ◽  
Complete Geometry Optimization

MINDO-Forces calculations with complete geometry optimization have been performed on acetaldehyde, vinyl alcohol and acetyl derivatives CH3COX(X=H, F, OH, CN, NH2, NO2 , CH3 , CF3,OCH3). It was found that acetaldehyde is more stable than vinyl alcohol by 10.451 kcal/mol. Thermodynamically, keto tautomers are more stable than their enol counterparts. This agrees with theoretical calculations. The electron releasing substituents tend to stabilize keto tautomers, while the electron withdrawing substituents tend to destabilize the keto tautomers, relative to the parent. Geometrical parameters, heats of formation, electron densities, Gibbs free energies and orbital energies (HOMO-LUMO) are reported.

A Theoretical Study of Monosubstituted Fulvenes

1990 ◽  
Vol 45 (6) ◽  
pp. 799-806 ◽  
Author(s):  
Hayfa M. Jarjis ◽  
Salim M. Khalil
Keyword(s):  
Dipole Moment ◽  
Double Bond ◽  
Theoretical Study ◽  
Heats Of Formation ◽  
Exocyclic Double Bond ◽  
Geometrical Parameters ◽  
Electron Densities ◽  
Orbital Energies ◽  
Optimization Of Geometry ◽  
Complete Optimization

AbstractMINDO-forces calculations have been done after complete optimization of geometry on X-monosubstituted fulvenes, where X is OH, NH2 , CH3, NO2, CN, F, dimethyl and cyclopropyl. It was found that all the substituents are stabilizing. The electron releasing substituents increase the dipole moment at the exocyclic double bond while the electron withdrawing ones increase the dipole moment at the endocyclic diene. Geometrical parameters, heats of formation, orbital energies and electron densities are reported.

A Theoretical Study of Fulvene Radical Cations

1988 ◽  
Vol 43 (5) ◽  
pp. 485-493
Author(s):  
Salim M. Khalil
Keyword(s):  
Radical Cation ◽  
Theoretical Study ◽  
Dipole Moments ◽  
Radical Cations ◽  
Heats Of Formation ◽  
Geometrical Parameters ◽  
Electron Densities ◽  
Optimization Of Geometry ◽  
Complete Optimization

MINDO-Forces calculations have been performed, after complete optimization of geometry, on fulvene molecule, fulvene and X-fulvene radical cations, where X is OH, NH2, CH3, NO2, CN and F. A twisted structure with angle 5° was found for fulvene radical cation. The substituents OH, NH2, CH3, CN and F are stabilizing. NO2 is slightly stabilizing. Geometrical parameters, heats of formation, dipole moments and electron densities are reported.

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.

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 A Theoretical Study of Substituted Cyclobutanones and Their Enols

2004 ◽  
Vol 59 (11) ◽  
pp. 838-844
Author(s):  
Mohammad I. Sway ◽  
Iyad D. Al-Shawabkeh ◽  
Salim M. Khalil
Keyword(s):  
Free Energy ◽  
Gibbs Free Energy ◽  
Theoretical Study ◽  
Theoretical Calculations ◽  
Heats Of Formation ◽  
Geometrical Parameters ◽  
Electron Densities ◽  
Complete Optimization ◽  
Electron Withdrawing Substituents

MINDO-Forces calculations have been performed with complete optimization of the geometry on cyclobutanone and its enol counterpart, perfluorination of cyclobutanones and enol counterparts, and X-cycolobutanones and their X-enols, where X is NO2, CF3, CN, OH, NH2 and F. It was found that ketone is more stable than its enol counterpart. Perfluorination destabilizes ketone on the expense of enol. These results agree with experimental and theoretical calculations. Electron releasing substituents (NH2, OH, F) stabilize cyclobutanone, while electron withdrawing substituents (CF3, NO2) destabilize it. CN substituents have almost no effect on the stabilization of this keto-enol system. Geometrical parameters, heats of formation, electron densities and Gibbs free energy are reported

Theoretical study on thermochemical parameters and IR spectra of chlorinated isomers of nitrobenzene

2013 ◽  
Vol 91 (10) ◽  
pp. 999-1008 ◽  
Author(s):  
Ibrahem Altarawneh ◽  
Mohammednoor Altarawneh ◽  
Saleh Rawadieh
Keyword(s):  
Experimental Data ◽  
Heat Capacity ◽  
Ir Spectra ◽  
Theoretical Study ◽  
Enthalpies Of Formation ◽  
Geometrical Parameters ◽  
Free Energies ◽  
Calculated Enthalpy ◽  
Standard Enthalpies Of Formation ◽  
Thermochemical Parameters

Thermochemical and geometrical parameters and internal rotation barriers of all chlorinated nitrobenzene isomers were calculated with the G3MP2B3 composite method. Standard entropies, standard Gibbs free energies of formation, standard enthalpies of formation, and heat capacities were calculated and compared with their corresponding available experimental data. Our calculated enthalpy values agree well with the corresponding experimental data. The temperature dependence of entropy and heat capacity has been analysed. All isomers with ortho-chlorine substituents were found to be less stable than other corresponding isomers. Rotational barriers and distortions of the benzene rings were incorporated in the calculations of values for entropy and heat capacity. The IR spectra were calculated and found to be in reasonable agreement with the experimental spectra.

THEORETICAL STUDY OF NEUTRAL AND IONIC SinO(n = 1-13) CLUSTERS

2009 ◽  
Vol 23 (18) ◽  
pp. 3729-3738
Author(s):  
YU-HONG ZHU ◽  
BAO-XING LI ◽  
FANG-SHU LIANG ◽  
JIE XU
Keyword(s):  
Density Functional ◽  
Theoretical Study ◽  
Dipole Moments ◽  
Basis Set ◽  
Electronic Charge ◽  
Full Potential ◽  
Mulliken Population ◽  
Consistent Field ◽  
Self Consistent Field ◽  
Homo Lumo

A systematic theoretical study of the structural properties and stabilities for neutral Si n O (n = 1-13) clusters and their ions has been carried out using the full-potential linear-muffin-tin-orbital molecular-dynamics (FP-LMTO-MD) method and the Amsterdam Density Functional (ADF) program with TZ2P basis set in conjunction with self-consistent field (SCF). Their ionization potentials (IPs), electron affinities (EAs), dipole moments μ, constant volume heat capacity Cv are computed. Based on the Mulliken population analyses, it is found that part of electronic charge is transferred from the Si atoms into the oxygen atom. Compared with other structures, the adsorption structures with an edge or a surface O atom are more stable. Calculations also show that the Si n O clusters with larger HOMO–LUMO gap exhibit high stability.

Theoretical Study of the Effect of Different α-Substituents on the Acetaldimine-Vinylamine Tautomeric System

2004 ◽  
Vol 59 (6) ◽  
pp. 382-388
Author(s):  
Hamzeh S. M. Al-Omari
Keyword(s):  
Free Energy ◽  
Proton Transfer ◽  
Gibbs Free Energy ◽  
Theoretical Study ◽  
Semiempirical Method ◽  
Heats Of Formation ◽  
Geometrical Parameters

The Acetaldimine-Vinylamine tautomeric system has been studied by employing the MNDO semiempirical method. The imine structure was found to be energetically favorable, as indicated by the calculated heats of formation, Gibbs free energy, LUMO and HOMO, and charges. The substitution of F, Cl, CN, CH3, CF3, NO2 and BH2 at the α-position was found to affect the geometrical parameters. F and Cl substituents are found to favor the imine formation, while CF3, NO2, CN2 and BH2 favor the amine formation. The proton transfer in this tautomeric system is found to be easier (ΔH = 5.224 kcal/mol) than that in the keto-enol tautomeric system (ΔH = 11.1 kcal/mol).

Sign in / Sign up

Export Citation Format

Share Document