Fast Reaction Studies of Carbocations in Solution

The pulse radiolysis method has been used to generate and study a series of fivecarbocations, consisting of phenylcarbenium ions and cyclopropylphenylcarbenium ions, in chlorocarbon solvents. Rate constants for the reactions of these substituted carbenium ions with various nucleophiles such as halide ions, alkyl amines, amonia and water, have been determined. The observed reactivity trends (or, in some cases, lack thereof) with successive substitution are discussed in relation to steric and electronic effects. Comparison of these reactivities with observations from solvolysis experiments is discussed. Solvent effects are observed.