Pyramidic columnar mesophases lend themselves to a variety of dynamic studies by solid-state NMR methods. In the present work we emphasized the use of ~(13)C MAS and rotor synchronized 2D exchange experiments for measuring molecular reorientation within the columns in columnar structures. Several other applications of ~(13)C MAS NMR to study discotic liquid crystals can be envisioned. One relates to density modulation within columnar mesophases. The stacking of discotic molecules into columnar structure may pose packing problems because of.the incommensurability of aliphatic and aromatic moieties. Under certain conditions this may lead to density modulation within the columns. Such modulations may lead to inhomogeneous line broadening of ~(13)C MAS spectra and thus provide a tool for the investigation of the phenomenon. Related effects on the deuterium NMR of discotic mesophases were found in columnar mesophases related to derivatives of rufigallol. Another application of ~(13)C MAS NMR to dynamics in discotic mesophases relates to dipolar recoupling. In most cases the observed carbons are coupled to nearby protons and strong decoupling of the ~(13)C-~1H dipolar interaction is required to observe narrow lines. In the presence of motion, when the rate of the process is of the order of the decoupling field the effect of the latter is destroyed. This results in lines broadening, thus providing another tool for rate measurements. It is likely that the molecular reorientation rate in many discotic columnar mesophases fall in this time scale.
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机译：金字塔酰胺柱状中间蛋白酶通过固态NMR方法赋予了各种动态研究。在本工作中，我们强调使用〜（13）C MAS和转子同步的2D交换实验来测量柱状结构中柱内的分子重新定位。可以设想〜（13）C MAS NMR的其他几种应用可以设想偶然液晶。一种涉及柱状中间蛋白酶内的密度调节。将光盘分子的堆叠成柱状结构可能是由于脂肪族和芳香部分的不可甲状腺性能造成包装问题。在某些条件下，这可能导致列内的密度调制。这种调制可能导致〜（13）C MAS光谱的不均匀线宽，因此提供了用于调查该现象的工具。在与Rufigallol的衍生物有关的柱状中间蛋白酶中发现了对光学乳腺癌的氘NMR的相关效果。 〜（13）C MAS NMR在光盘中间蛋白酶类中动态的另一个应用涉及偶极循环。在大多数情况下，观察到的碳结合在附近的质子上，并且需要强烈的去耦〜（13）C-〜1H双极相互作用来观察窄线。在运动的存在下，当过程的速率是解耦场的顺序时，后者的效果被破坏。这导致线条扩大，从而为速率测量提供另一种工具。许多椎间盘柱状蛋白酶中的分子重新定向率可能落在此时间尺度上。
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