Novel Fine-Membered Ring Intermediates in Gas Phase Reactions
R A. Loomis, S R. Leone, M K. Gilles
The review considers the role of closed-ring intermediates in chemistry, in general, and focuses on recent experimental and theoretical works that provide compelling evidence for a five-membered ring intermediate in the gas phase. The reactions of oxygen atoms with ethyl iodide and larger alkyl iodides produce HOI and a corresponding ethylenic compound via attack of the oxygen atom at the iodine and closure of the five-membered ring between the oxygen and a hydrogen on the beta-carbon. Detailed results are gathered from infrared chemiluminescence, molecular beam scattering, as well as new kinetics and product yield experiments. The theoretical calculations fully support and characterize the novel reaction mechanism.