13C and 199Hg nuclear magnetic resonance spectroscopic study of alkenemercurinium ions: Effect of methyl substituents on 199Hg chemical shifts

摘要

The long-lived ethylene, cyclohexene, and norbornenemercurinium ions prepared in superacidic, low-nucleophilic media have been studied by ¹³C and ¹⁹⁹Hg NMR spectroscopy. The norbornenemercurinium ion shows temperature-dependent ¹³C and ¹⁹⁹Hg NMR spectra, consistent with equilibration via rapid hydride and Wagner-Meerwin shifts. The ¹⁹⁹Hg NMR shifts of a series of alkylmercury bromides were also obtained in order to elucidate the effect of methyl substituents on ¹⁹⁹Hg NMR chemical shifts.