Intramolecular reorganization 1. Deprotonation of toluene with the CH2CN– anion: an analysis in the framework of a gas phase model

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I. A. Romanskii

Russian Chemical Bulletin, International Edition, Vol. 57, No. 9, pp. 1842—1849, September, 2008


A mechanism is proposed of intramolecular reorganization leading to equalization of the

energies of reactants and products in a nonequilibrium proton transfer reaction. The model

proposed allows one to extend a conventional quantum chemical treatment to gas phase proton

transfer. Taking the reaction of toluene deprotonation with the CH2CN– anion (a conjugate

base of acetonitrile) as an example, it was shown that the activation energy and its components

can be determined from direct  ab initio calculations. The effect of disbalance of structural

changes relative to the "equilibrium" proton transfer is considered.

 

Intramolecular reorganization

2.* The Brønsted correlation for a series of gas phase reactions

of deprotonation of para substituted toluene derivatives with the СH2CN– anion

 

Russian Chemical Bulletin, International Edition, Vol. 57, No. 9, pp. 1850—1857, September, 2008

 

A proton transfer model proposed earlier that includes equalization of energies of the reac

tant and product by an intramolecular mechanism was used to study gas phase reactions of

deprotonation of para substituted toluene derivatives (substituents were NH2, OH, CH3, H, Cl,

NC, CN, and NO2) with the СH2CN– anion. The energy parameters of the reactions were

determined from ab initio calculations. The Brønsted correlation based on the results obtained

was analyzed in the framework of conventional quantum chemical formalism (the Marcus

equation). The problem of disbalance of the changes in the geometry of the activated complex

relative to its position on the reaction coordinate was considered taking some geometric param

eters of the system as examples.

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