Accurate measurement of the optical activity of alanine crystals and determination of their absolute chirality
Accurate measurement of the optical activity of alanine crystals and determination of their absolute chirality
复制标题
准确测量丙氨酸晶体的光学活性并测定其绝对手性
DOI：
10.1016/j.jpcs.2017.01.024
复制
发表时间：
2017
影响因子：
4
通讯作者：
Masahito Tanaka and Toru Asahi
中科院分区：
文献类型：
--
作者：
Kazuhiko Ishikawa;Yukana Terasawa;Masahito Tanaka and Toru Asahi
波长依赖性的丙氨酸晶体中的手性光学性质的测量迄今为止是不成功的，使用传统的光谱技术。我们描述了我们的尝试，以测量L-和D-丙氨酸晶体的旋光性的波长依赖性沿着每个晶轴，并确定丙氨酸晶体的绝对手性的绝对结构相关的旋光性使用的X-射线衍射仪和一个广义的高精度通用旋光仪。我们成功地精确测量了该方向的旋光色散<010>，表明d-丙氨酸晶体的旋光是右旋的，而-丙氨酸晶体的旋光是左旋的，从而确定了绝对手性。此外，与溶液中的旋光性的比较表明，丙氨酸晶体中的旋光性不仅在值上不同，而且在符号上也不同。这些结果使我们得出结论，在结晶状态下的旋光功率不应该是简单的分子旋光功率值的总和。我们提出了一个理论的必要性，其中包含的分子相互作用的贡献，在晶体中，为了计算的结晶状态的旋光功率。
Wavelength dependence measurements of the chiroptical properties in alanine crystals have so far been unsuccessful using conventional spectroscopic techniques. We describe our attempts to measure the wavelength dependence of the optical activity in L- andD-alanine crystals along each crystallographic axis, and to determine the absolute chirality of alanine crystals by correlating the absolute structure to the optical activity using an x-ray diffractometer and a generalized high accuracy universal polarimeter. We have succeeded in accurately measuring the optical rotatory dispersion in the <010> direction, which shows that the optical rotation of thed-alanine crystal is dextrorotatory and that of thel-alanine crystal is laevorotatory, thereby determining the absolute chirality. Furthermore, comparison with the optical activity in solution shows that the optical activity in alanine crystals is different not only in value, but also in the sign. These results have led us to conclude that the optical rotatory power in the crystalline state should not be simply the summation of molecular optical rotatory power values. We propose the necessity of a theory, which contains the contribution of molecular interactions within the crystal, in order to calculate the optical rotatory power of the crystalline state.