Observation by UV-visible and NMR spectroscopy and theoretical confirmation of 4-isopropyltropolonate ion, 4-isopropyltropolone (Hinokitiol), and protonated 4-isopropyltropolone in acetonitrile

Masashi Hojo, Tadaharu Ueda, Michitaka Ike, Kei Okamura, Taku Sugiyama, Masato Kobayashi, Hiromi Nakai

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Protonated 4-isopropyltropolone (H2L+) was produced by the addition of methanesulfonic or trifluoromethanesulfonic acid to 4-isopropyltropolone (hinokitiol: HL) dissolved in a protophobic aprotic solvent, acetonitrile, with poor solvation of anions and cations. The formation was confirmed by UV-visible and 13C NMR spectroscopy as well as theoretical calculations using the Gaussian03 quantum chemistry package. The 13C chemical shifts of all C-atoms in the seven-membered ring were properly assigned for H2L+ and HL as well as for the deprotonated species, L-. The influence of residual water in the organic solvent was regarded as negligible because such a water is in the "dihydrogen ether" condition.

Original languageEnglish
Pages (from-to)1986-1989
Number of pages4
JournalJournal of Chemical and Engineering Data
Issue number5
Publication statusPublished - 2010 May 13


ASJC Scopus subject areas

  • Chemistry(all)
  • Chemical Engineering(all)

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