Bridge Flipping Data from Dynamic 1H‐NMR Spectra of 2,6‐Dimethyl‐[9](3,5)‐Pyridophane and its Pyrylium and N‐Methylpyridinium Analogs

Alexandru T. Balaban, Teodor‐Silviu ‐S Balaban, Makoto Nitta, Nobuhiro Kanomata

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Dynamic 1H‐NMR spectra between room temperature and −90 °C for the title compounds indicate that the flipping of the nonamethylene bridge is slowed down on cooling (ΔGc‡ = 9.8 kcal/mol for the 2/8 methylene groups in the pyridinophane with coalescence temperature Tc = −58 °C) but the pseudorotation persists even at −90 °C. The bridge flipping is somewhat easier in the N‐methylpyridinium (ΔGc‡ = 9.7 kcal/mol, Tc = −63 °C) and in the pyrylophanium perchlorates (ΔGc‡ = 8.9 kcal/mol, Tc = −78 °C).

Original languageEnglish
Pages (from-to)1047-1051
Number of pages5
JournalBulletin des Sociétés Chimiques Belges
Issue number12
Publication statusPublished - 1992


ASJC Scopus subject areas

  • Chemistry(all)

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