Conformational studies by dynamic nuclear magnetic resonance. Part 24. Gear effect in di-isopropyl-nitrosoamine and -phenyltriazene studied by carbon-13 nuclear magnetic resonance and molecular mechanics
作者:Lodovico Lunazzi、Maurizio Guerra、Dante Macciantelli、Giovanni Cerioni
DOI:10.1039/p29820001527
日期:——
been measured (ΔG‡ 9.7 kcal mol–1) and the structures of the two conformers assigned. Molecular mechanics calculations reproduce all the experimental observations and indicate, in addition, that this dynamic process is not synchronous but follows a two-step pathway. In the case of (2) the existence of the phenomenon could be detected through the interpretation of the selective broadening of one spectral
通过13 C nmr在Pr i 2 NNO(1)和Pr i 2 NNNPh(2)中观察到存在相关的分子内取向(齿轮效应)的证据。在第一种情况下,以92:8的比率检测到两个构象异构体在–120°C下。已测量了相应的激活参数(ΔG ‡ 9.7 kcal mol –1)以及分配的两个构象体的结构。分子力学计算重现了所有实验观察结果,此外,该动态过程不是同步的,而是遵循两步路径。在(2)的情况下,可以通过解释一条光谱线的选择性加宽来检测该现象的存在,并且即使光谱是光谱,也可以测量活化的自由能(ΔG ‡ 10.2 kcal mol –1)没有直接检测到人口少的构象异构体中的一个。