Faculty of Chemistry, Tarbiat Moalem University, 49 Mofateh Avenue, 15614 Tehran, Iran.
Spectrochim Acta A Mol Biomol Spectrosc. 2011 Sep;79(5):1798-802. doi: 10.1016/j.saa.2011.05.060. Epub 2011 May 27.
The restricted rotation of p-tolyl moiety in 5,5-dimethyl-3,4-di-p-tolyl-2-cyclopenten-1-one was studied by variable temperature NMR spectroscopy at a temperature range of 218-368 K. A free rotation, in NMR time scale, was observed at temperatures higher than 368 K; while, the rotation froze below 248 K. From dynamic NMR analysis, the Arrhenius energy of activation ΔG‡ was calculated as 56.37 kJ mol(-1). The experimental results were confirmed by theoretical calculation using the density functional theory method B3LYP with basis sets, 6-31G and 6-31+G.
在 218-368 K 的温度范围内，通过变温 NMR 光谱研究了 5,5-二甲基-3,4-二-对甲苯基-2-环戊烯-1-酮中对甲苯基部分的受限旋转。在高于 368 K 的温度下观察到 NMR 时间尺度上的自由旋转，而在低于 248 K 的温度下旋转冻结。通过动态 NMR 分析，计算了阿伦尼乌斯活化能 ΔG‡为 56.37 kJ mol(-1)。实验结果通过使用密度泛函理论方法 B3LYP 与基组 6-31G 和 6-31+G 进行的理论计算得到了证实。
