The present article reviews the results of solid-state vibrational circular dichroism (SD-VCD) measurements on the crystals of amino acids. The investigated series were Ala, Ile, Leu, Phe, Ser, Val, and Thr. Spectra were recorded for the samples containing both D- and L-enantiomers. The molecular conformation in a crystalline state was compared among the series. Molecule optimization of their conformation under intermolecular interactions in crystalline states was revealed. One noteworthy aspect was that some VCD peaks were remarkably enhanced in comparison with the solution states. This fact was rationalized in terms of vibrationally coupled delocalization in a closely stacked pair. In addition, for a molecule with two asymmetric carbons, the signs of the VCD peaks were determined by the interplay between the two chiral centers. Lastly, the roles of the theoretical approach based on density functional theory calculations were described.

中文翻译：

---

固态振动圆二色性研究晶体状态氨基酸分子的构象。

本文概述了氨基酸晶体上的固态振动圆二色性（SD-VCD）测量结果。研究的系列是Ala，Ile，Leu，Phe，Ser，Val和Thr。记录同时含有D-和L-对映体的样品的光谱。在系列中比较了晶体状态的分子构象。揭示了分子在结晶状态下的分子间相互作用下其构象的分子优化。一个值得注意的方面是，与溶液状态相比，某些VCD峰明显增强。就紧密耦合的一对中的振动耦合离域而言，此事实是合理的。另外，对于具有两个不对称碳原子的分子，VCD峰的符号由两个手性中心之间的相互作用决定。最后，