Proof of existence of cyclic C4H7+ ions in the dilute gas state

Daughter C4H7-nTn+ ions from the β decay of multitritiated cyclobutane were allowed to react in the gas phase with suitable nucleophiles (H2O, NH3), and the products formed were analyzed by radio gas chromatog. Isolation of comparable amts. of cyclobutyl and cyclopropylcarbinyl derivs. among other products provides direct evidence for the existence of cyclic C4H7+ cations. On the other hand, large yields of linear C4 derivs. demonstrate the facile isomerization of the strained c-C4H7+ cations, either directly, or following their exothermic reaction with the nucleophile.