厦门大学江云宝团队报道了通过二维同手性螺旋的形成自发结晶拆分螺旋构建块。相关研究成果发表在2022年5月31日出版的《德国应用化学》。

自发结晶拆分导致砾岩晶体仍然是一个重大挑战。

该文中，研究人员建议在至少两个维度上形成正交的同手性超分子螺旋，以实现自发结晶拆分。因此，提出了一种设计原理，即将手性物种制成螺旋构造块，以实现螺旋形成。

作为概念证明，乙酰丙氨酸被选为螺旋短氮杂肽，其N-氨基硫脲衍生物含有β-转结构，在苯硫脲芳香环上进一步引入卤素原子。因此，合成的折叠物种能够通过转弯结构进行分子间氢键和卤素键，分别在二维形成正交的分子间氢键和卤素键超分子螺旋，并在结晶时进行手性拆分。而其对应物含有弱卤素键或无卤素原子的F-取代基，在外消旋化合物中结晶。

附：英文原文

Title: Spontaneous Resolution of Helical Building Block through the Formation of Homochiral Helices in Two Dimensions

Author: Xiang Lin, Bohan Kou, Jinlian Cao, Peimin Weng, Xiaosheng Yan, Zhao Li, Yun-Bao Jiang

Issue&Volume: 2022-05-31

Abstract: Spontaneous resolution leading to conglomerate crystals remains a significant challenge. Here we propose to form orthogonal homochiral supramolecular helices in at least two dimensions to allow the spontaneous resolution. A designing rationale is accordingly suggested that the chiral species is made into helical building blocks to allow the helix formation. As a proof-of-the-concept, acetylalanine was chosen to be made into a helical short azapeptide, its  N  -amidothiourea derivative containing a β-turn structure, to which a halogen atom was further introduced at the phenylthiourea aromatic ring. The resultant folded species is therefore enabled to undergo both the intermolecular hydrogen and halogen bonding across the turn structure to form orthogonal intermolecular hydrogen bonded and halogen bonded supramolecular helices in two dimensions, respectively, and undergoes chiral resolution upon crystallization. While their counterpart containing an F-substituent of weak halogen bonding or no halogen atom, crystallizes in the racemic compounds.

DOI: 10.1002/anie.202205914

Source: https://onlinelibrary.wiley.com/doi/10.1002/anie.202205914