Beijing National Laboratory for Molecular Sciences, Key Laboratory of Polymer Chemistry and Physics of Ministry of Education, College of Chemistry and Molecular Engineering, Peking University, Beijing, China.
Polymer Materials Research Center, Key Laboratory of Superlight Materials and Surface Technology of Ministry of Education, College of Materials Science and Chemical Engineering, Harbin Engineering University, Harbin, China.
Chirality. 2022 Apr;34(4):574-586. doi: 10.1002/chir.23414. Epub 2022 Jan 10.
Six proline-derived acetylene monomers bearing either two stereocenters (S-mR, S-mS, R-mS, Rac-mS and S-mRac) or one stereocenter (S-mBn) were obtained from commercially available N-(tert-butoxycarbonyl)-prolinal. Under the catalysis of Rh-diene complex, they were converted to the corresponding optically active helical polymers, S-pR, S-pS, R-pS, Rac-pS, S-pRac, and S-pBn. The correlations between configuration and position of stereocenters in pendants with the polymer conformation as well as chiral resolution performance were systematically explored by a combination of nuclear magnetic resonance (NMR), Raman, UV-Vis absorption, electronic/vibration circular dichroism spectroscopies, high-performance liquid chromatography (HPLC), and computational simulation. The configuration of the stereocenter adjacent to polymer mainchain determined the sense of helical conformation and the elution order of analytes, while that of the remote one affected the arrangement of pendants and the scope of analytes that could be discriminated. Among 18 aromatic analytes selected, S-pR could discriminate 10, while S-pS recognized 12. The racemization of adjacent or remote stereocenters greatly reduced the scope of analytes that could be resolved. Based on computer simulations, S-pS had larger recognition space than S-pR, favoring the steric fit with the racemates containing axial chirality. The strength and number of intermolecular hydrogen bondings between enantiomers and CSPs predominantly determined the chiral discrimination.
从商业可得的 N-(叔丁氧羰基)-脯醛出发，得到了 6 个带有两个手性中心（S-mR、S-mS、R-mS、Rac-mS 和 S-mRac）或一个手性中心（S-mBn）的炔丙基脯氨酸衍生物单体。在 Rh-二烯配合物的催化下，它们被转化为相应的手性光学活性螺旋聚合物 S-pR、S-pS、R-pS、Rac-pS、S-pRac 和 S-pBn。通过核磁共振（NMR）、拉曼、紫外-可见吸收、电子/振动圆二色光谱、高效液相色谱（HPLC）和计算模拟的结合，系统地研究了手性中心在侧基的构型和位置与聚合物构象以及手性拆分性能之间的关系。与聚合物主链相邻的手性中心的构型决定了螺旋构象的手性，而远程手性中心的构型则影响了侧基的排列和可以区分的分析物的范围。在所选择的 18 种芳香族分析物中，S-pR 可以区分 10 种，而 S-pS 可以识别 12 种。相邻或远程手性中心的外消旋化大大降低了可以拆分的分析物的范围。基于计算机模拟，S-pS 比 S-pR 具有更大的识别空间，有利于与含有轴向手性的外消旋体的空间适应性。对映体与 CSP 之间的分子间氢键的强度和数量主要决定了手性的区分。
