α-ring, and β-ring carbons in 13C-NMR spectra of N-substituted 2,4,6-trimethylpyridinium salts III are anisochronous. Dynamic NMR spectroscopy affords appreciably higher activation enthalpies ΔG≠ for rotation around the N(sp2)C(sp3) bond than ΔG≠ for the analogously substituted mesityl derivatives, in agreement with the shorter C than the CC bond.
N-取代的2,4,6-三
甲基吡啶鎓盐III的1 H-NMR光谱中的α-甲基和β质子,13 C-NMR光谱中的α-甲基,α-环和β-环碳原子是等时的。动态NMR光谱比类似取代的
均三甲苯基衍
生物的ΔG≠提供了更高的活化焓ΔG≠(围绕N(sp 2)activationC(sp 3)键旋转),与C短于CC键相一致。