Does the cyclohexyl cation exist in the dilute gas state? Direct evidence from a radiolytic study.

The isomeric composition of the gaseous C6HII+ca tions obtained via hydride ion abstraction from c-C6HI2h as been investigated by allowing the charged species to react in the gas phase with water and analyzing the neutral products formed. The nature and the yields of the major products, cyclohexanol, cyclohexanone, and 1-methylcyclopentanol, and their dependence on the pressure and the composition of the gaseous system provide direct evidence for the existence of the cyclohexyl cation in the dilute gas state, with a lifetime in excess of lO-’s, and confirm its facile rearrangement to the more stable 1 -methylcyclopentyl ion.