Energy dependence of H-exchange versus CC bond formation in the complex [CH 3OH CH 2CH + [rad]2]: unimolecular and bimolecular studies

Abstract

The reactions of the ion—neutral complex [CH 3OH CH 2CH + 2] have been examined by unimolecular and bimolecular approaches. We conclude that the distonic ion CH 3OH + CH 2CH 2 ( 1) isomerizes to CH 3CH 2CH 2OH + ( 5) via the internal ion—molecule reaction [CH 3OH CH 2CH + 2] → [ +HOCH 2 CH 2CH 3] followed by CC bond formation. Metastable H and H 2O losses follow this isomerization. About 60 kJ mol −1 higher (attained by collision-induced dissociation and reaction of CH 2CH + 2 with CH 3OH) CH 2OH + and CH 3OH + 2 are formed. Hydrogen exchange between oxygen and ethene occurs at this energy, but CC bond formation does not. Hydrogen atoms exchange by interconversion of ion-neutral complexes rather than by isomerizations involving formation of distonic ions. At 33 kJ mol −1 higher still (reaction of CD 3OD + with CH 2CH 2), H-transfer without exchange occurs. The reactions of [CH 3OH CH 2CH + 2] are thus strongly energy dependent.