TY - JOUR
T1 - Bridge Flipping Data from Dynamic 1H‐NMR Spectra of 2,6‐Dimethyl‐[9](3,5)‐Pyridophane and its Pyrylium and N‐Methylpyridinium Analogs
AU - Balaban, Alexandru T.
AU - Balaban, Teodor‐Silviu ‐S
AU - Nitta, Makoto
AU - Kanomata, Nobuhiro
PY - 1992
Y1 - 1992
N2 - 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).
AB - 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).
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U2 - 10.1002/bscb.19921011210
DO - 10.1002/bscb.19921011210
M3 - Article
AN - SCOPUS:0343876500
VL - 101
SP - 1047
EP - 1051
JO - Bulletin des Societes Chimiques Belges
JF - Bulletin des Societes Chimiques Belges
SN - 0037-9646
IS - 12
ER -