Cross-Interaction Constant and Intrinsic Reaction Barrier

摘要

The cross second-derivative of the activation energy,ツG× , with respect to the two component thermodynamic barriers, ツGⅹ_X and ツGⅹ_Y, can be given in terms of a cross-interaction constant (CIC), モ_XY (ヱ_XY), and also in terms of the intrinsic barrier,ツG×。 , with a simple relationship between the two: モ_XY = -1/(6ツG×。). This equation shows that the distance between the two reactants in the adduct (TS, intermediate, or product) is inversely related to the intrinsic barrier. An important corollary is that the Ritchie N₊ equation holds (for which モ_XY = 0) for the reactions with high intrinsic barrier. Various experimental and theoretical examples are presented to show the validity of the relationship, and the mechanistic implications are discussed.