The significant isotope effect on hydrogen elimination reaction from 2,3-dimethylbutane (h-DMB) cations was studied by ESR at 77 K. When a h-DMB-SFa(0.6 mol %I) mixture is y-irradiated at 70 K, h-DMB+ ions in addition to h-DMB radicals are produced. When the irradiated mixture is stored at 77 K for 10 min, tetramethylethylene (TME) cations are produced by HZ elimination from h-DMB+ ions. The rate constant for the HZ elimination reaction was measured as 1.1 x s-l at 77 K. When a 2,3-dimethylbutane-2,3-d~ (d-DMB)-SF6 (0.6 mol%) mixture is y-irradiated at 70 K and then stored at 77 K, TME+ ions are scarcely produced upon the storage of the irradiated mixture at 77 K even for 5 days. The rate constant for the DZ elimination reaction from d-DMB+ ions was measured as 6.5 x s-l, which is much smaller than the rate constant for the HZ elimination reaction. The significant isotope effect on the reactions was explained in terms of a model of the tunneling elimination of a hydrogen molecule from a DMB+ ion.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.