Prediction of rate constants of S N 2 reactions by the multicomponent QSPR method

Abstract

299 One of the most important parameters of any reac� tion is its rate constant. However, when dealing with a chemical reaction, a researcher faces the necessity to consider the contributions of many components that form the reaction system: the solvent, substrate, and reagent. The reaction rate also dramatically depends on pressure and temperature. The problem of prediction of chemical reaction rate constants has long attracted the attention of researchers, and considerable progress has been achieved in this respect. For many reaction series, spe� cific models have been constructed that consider the effect of different reagent parameters. Such models are characterized by high correlation coefficients but can� not be thought of as universal [1, 2]. Therefore, it is of interest to construct a unified model that could predict, with an acceptable accuracy, the rate constants of nucleophilic substitution at a sat� urated carbon atom on the basis of the structures of all the reagents involved, no matter what class of com� pounds they belong to. Consideration of such a complicated problem from the standpoint of QSPR (quantitative structure–prop� erty relationship) methodology necessitates using the multicomponent QSPR (MQSPR) approach, which was previously successfully applied to predicting the solvation free energy, which depends on the structure of two substances, the solute and the solvent [3].