Hindered rotation around the N(sp2)-C(sp3) single bond in 2,4,6-trimethyl-N-alkylpyridinium cations:H DNMR analysist
作者:Alexandru T. Balaban、Cornelia Uncuţ/a、Mihai Elian、Filip Chiraleu、Antonie Dinculescu
DOI:10.1016/s0040-4020(01)83508-0
日期:1984.1
6-trimethylpyridinium salts 2. Dynamic NMR spectroscopy demonstrates appreciably higher activation free energies ΔG# for rotation around the N(sp2)-C(sp3 bond than ΔG# for the analogously substituted mesityl derivatives, in agreement with the shorter N-C bond distance than for the C-C bond.
1 H NMR光谱中2,6-甲基和3,5-质子的成对化学位移不等价,以及13 C NMR中2,6-甲基,2,6-环和3,5-环碳的成对化学位移不等价光谱,观察到N-烷基-2,4,6-三甲基吡啶鎓盐2。动态NMR光谱相当高的活化自由能Δ演示ģ #周围的N(SP旋转2)-C(SP 3键比ΔG#为类似于取代的异亚丙基衍生物,在具有比用于CC键较短NC键距离协议。