Ab Initio Study of Solvent Effects on Rate of 1,3-Dipolar Cycloadditions of Benzonitrile Oxide and Various Dipolarophiles

Ab initio molecular orbital calculations have been used to investigate the structures and the transition states of 1,3-dipolar cycloadditions between benzonitrile oxide with ethylene, cyclopentene, acrylonitrile and tetracyanoethylene in heptane and water: calculations reveal enhanced hydrogen bonding of a water molecule to the transition states for the cycloaddition 1,3-dipolar of reaction of benzonitrile oxide with cyclopentene, the optimal interaction energies being 0.7 kcal/mol more favourable for hydrogen bonding to the oxygen atom in the transition states than for the reactants.

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Ab Initio Calculation of Thermodynamic and Kinetic Quantities for 1,3-Dipolar Cycloadditions of Benzonitrile Oxide with Various Dipolarophiles

Journal of Chemical Research ◽

10.3184/030823402103171979 ◽

2002 ◽

Vol 2002 (6) ◽

pp. 279-281 ◽

Cited By ~ 3

Author(s):

E. Rajaian ◽

M. Monajjemi ◽

M.R. Gholami

Keyword(s):

Ab Initio ◽

Molecular Orbital ◽

Rate Constant ◽

Thermodynamic Stability ◽

Ab Initio Calculation ◽

Transition States ◽

Molecular Orbital Calculations ◽

Free Energies ◽

Energy Calculations ◽

Dipolar Cycloadditions

Ab initio molecular orbital calculations have been used to investigate the structures and transition states of 1,3-dipolar cycloadditions between benzonitrile oxide with ethylene, acrylonitrile, tetracyanoethylene and cyclopentene. Geometry optimisations and energy calculations were performed with RHF/6–31G*//RHF/6–31G* in each case. Calculation of vibrational frequencies permitted computation of the enthalpies, Gibbs free energies and rate constant of reactions. Cycloadditions of 1,3-dipolar benzonitrile oxide with electron-poor dipolarophiles have higher rates and lower thermodynamic stability than with other dipolarophiles.

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Ion solvation by dipolar aprotic solvents. An ab initio study

Collection of Czechoslovak Chemical Communications ◽

10.1135/cccc19870006 ◽

1987 ◽

Vol 52 (1) ◽

pp. 6-13 ◽

Cited By ~ 2

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.

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Molecular structure and intramolecular hydrogen bonding in 4,6-dinitroresorcinol and 2,5-dinitrohydroquinone from ab initio molecular orbital calculations

Journal of Molecular Structure THEOCHEM ◽

10.1016/s0166-1280(96)04859-2 ◽

1997 ◽

Vol 393 (1-3) ◽

pp. 121-126 ◽

Cited By ~ 6

Author(s):

Konstantin B. Borisenko ◽

Charles W. Bock ◽

István Hargittai

Keyword(s):

Molecular Structure ◽

Hydrogen Bonding ◽

Ab Initio ◽

Molecular Orbital ◽

Intramolecular Hydrogen Bonding ◽

Molecular Orbital Calculations ◽

Intramolecular Hydrogen

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An ab initio study on the insertion reactions of CH [X2II] with NH3, H2O, and HF

Canadian Journal of Chemistry ◽

10.1139/v96-100 ◽

1996 ◽

Vol 74 (6) ◽

pp. 910-917 ◽

Cited By ~ 13

Author(s):

Zhi-Xiang Wang ◽

Ruo-Zhuang Liu ◽

Ming-Bao Huang ◽

Zhonghua Yu

Keyword(s):

Ab Initio ◽

Electron Correlation ◽

Lower Energy ◽

Energy Surface ◽

Molecular Orbital Calculations ◽

Ab Initio Study ◽

Insertion Reactions ◽

Moller Plesset ◽

Ch Radical ◽

Water Hydrogen

The mechanisms of the reactions of CH (X2II) with NH3, H2O, and HF have been studied by means of ab initio molecular orbital calculations incorporating electron correlation with Møller–Plesset perturbation theory up to the second order. For each of the three CH reactions, the insertion path has been found in the potential energy surface; in the calculated insertion path there exists an intermediate complex prior to the transition state that has a lower energy than the reactants. Energetic results indicate that insertion paths are favourable channels for these CH reactions, which is in line with proposals based on kinetic experiments. Key words: CH radical, ammonia, water, hydrogen fluoride, reaction mechanism.

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