ENERGY-DEPENDENCE OF H-EXCHANGE VERSUS C-C BOND FORMATION IN THE COMPLEX [CH3OH CH2=(CH2)-H-(+.)] - UNIMOLECULAR AND BIMOLECULAR STUDIES

The reactions of the ion-neutral complex [CH3OH CH2CH+{radical dot}2] have been examined by unimolecular and bimolecular approaches. We conclude that the distonic ion CH3OH+ CH2CH2 (1) isomerizes to CH3CH2CH2OH+{radical dot} (5) via the internal ion-molecule reaction [CH3OH CH2CH+{radical dot}2] → [+HOCH2{radical dot}CH2CH3] followed by CC bond formation. Metastable H{radical dot} and H2O losses follow this isomerization. About 60 kJ mol-1 higher (attained by collision-induced dissociation and reaction of CH2CH+{radical dot}2 with CH3OH) CH2OH+ and CH3OH+2 are formed. Hydrogen exchange between oxygen and ethene occurs at this energy, but CC 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 CD3OD+{radical dot} with CH2CH2), H-transfer without exchange occurs. The reactions of [CH3OH CH2CH+{radical dot}2] are thus strongly energy dependent. © 1990.