Intramolecular van der Waals-London Cohesions and Chemical Reactivity: The Transition State in the Bimolecular Nucleophilic Displacement Reaction of Halide Ion with Alkyl Halide

Abstract

The intramolecular London-van der Waals cohesions in the transition states Hal�-. . . CH3 . . . Hal�- in which both halogen atoms are identical should be greater than the following : Hal=F, 0.09 ; Hal=Cl, 0.64 ; Hal=Br, 0.94 ; Hal=I, 1.15 kcal/mole. It is concluded that these cohesions make a significant contribution to the observed increase in the velocity of the above displacement reaction as the polarizability of either entering or leaving halogen atom increases.