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首页> 外文期刊>The journal of physical chemistry, A. Molecules, spectroscopy, kinetics, environment, & general theory >Dynamics of 9-hydroxyphenalenone studied by one-dimensional solid-state spin exchange NMR
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Dynamics of 9-hydroxyphenalenone studied by one-dimensional solid-state spin exchange NMR

机译：一维固态自旋交换核磁共振研究9-羟基苯醌的动力学

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摘要

We present a new NMR method to clarify the dynamics of proton tautomerism in solid 9-hydroxyphenalenone. Two C-13 resonance lines influenced by the proton tautomerism have a chemical-shift difference between them, which increases with decreasing temperature. To depict the precise potential curve of the proton tautomerism, the chemical-shift difference when the proton tautomerism is completely frozen is necessary. For solid 9-hydroxyphenalenone and its derivatives, the freezing temperatures are often under -100 degrees C. When the freezing temperatures are below the temperature range in which standard magic angle spinning NMR probes can perform a sample spinning, it is very difficult to obtain the shift difference. The NMR experiments based on this new method are performed at a temperature significantly higher than -100 degrees C at which the proton tautomerism is still active. The new method yields the C-13 spin relaxation rates, the rates for the proton tautomerism, and the populations of the two tautomers. Using the populations and the C-13 chemical-shift difference at that temperature, we determined the chemical-shift difference at the freezing temperature. We also obtained several parameters characterizing the potential profile for the proton dynamics in solid 9-hydroxyphenalenone.
机译：我们提出了一种新的NMR方法来阐明固体9-羟基苯丙酮质子互变异构的动力学。受质子互变异构影响的两条C-13共振线之间的化学位移差随温度降低而增加。为了描绘质子互变异构的精确电位曲线，当质子互变异构完全冻结时，化学位移的差异是必要的。对于固体9-羟基苯丙酮及其衍生物，冷冻温度通常低于-100摄氏度。当冷冻温度低于标准魔角旋转NMR探针可以进行​​样品旋转的温度范围时，很难获得移位差。基于这种新方法的NMR实验是在明显高于-100℃的温度下进行的，在该温度下质子互变异构仍然有效。新方法产生C-13自旋弛豫率，质子互变异构率以及两个互变异构体的总数。使用群体和该温度下的C-13化学位移差异，我们确定了冷冻温度下的化学位移差异。我们还获得了一些参数，这些参数表征了固体9-羟基苯丙烯酮中质子动力学的潜在分布。

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