Further evidence for the stability of methylenechloronium ylide, H 2 CCIH. A neutralization‐reionization ion‐dissociation experiment

Recent theoretical and experimental studies are in conflict with our previous neutralization–reionization evidence for the surprising stability of simple ylides such as H 2 CCIH. Neutralization of [H 2 CCIH] + ˙ ions from CICH 2 COOH with Hg followed by reionization of the resulting neutral molecules with O 2 produces intense [CCIH 3 ] + ˙ parent ions. Collisionally activated dissociation of these mass‐selected ions shows that 47 ± 5% are the [H 2 CCIH] + ˙ isomer. This demonstrates that stable H 2 CCIH molecules can be formed by neutralization, surviving intact for the lifetime of the experiment (10 −6 s). Field ionization conditions effective in ionizing excited argon atoms do not produce appreciable ionization of the neutrals from [H 2 CCIH] + ˙, suggesting that the stable H 2 CCIH neutrals are not Rydberg state molecules.