复旦大学高分子科学系朱亮亮课题组在研究中取得进展，他们在非晶态分子聚集体中实现了可控的光学不对称性。 相关论文10月29日发表在《德国应用化学》杂志上。

通过一种连接胆固醇酯的双联吡咯啉类锌(II)的非晶态超分子结构，研究人员将手性放大的定量控制提高到了一个前所未有的高度。这种由复杂结构单元组成的非晶态分子聚集体表现出镜面对称的手性光学活性。结构单元在不同分子尺度上的合理手性堆积对吸光不对称因子（g abs）的贡献相当大，虽然系统整体上是无序的。强烈而可调的分子聚集程度使溶液中和薄膜中的g abs值从+0.10到+0.31不等，比大多数先前报道过的案例都要高。

在此基础上，可以在外部刺激下实现出色的光学手性开关控制。通过免去结晶材料这一限制，这项工作为在更广泛的手性材料中控制超大光学不对称性奠定了一个普遍适用的设计原则。

据了解，虽然超大光学不对称性常常发生于晶体材料中，由介观排列带来的扭曲经常导致手性光学活性失真。另外，晶态的形成和保持需要复杂的技术工作。然而，在非晶态材料中，要达到较大的手性光学活性仍非常具有挑战性，遑论控制不对称的程度了。

附：英文原文

Title: Controlling Ultra‐Large Optical Asymmetry in Amorphous Molecular Aggregations

Author: Liangliang Zhu, Bin Wu, Hongwei Wu, Yunyun Zhou, Dongxiao Zheng, Xiaoyong Jia, Lei Fang

Issue&Volume:29 October 2020

Abstract: Although ultra‐large optical asymmetry appears in crystalline materials, distractions from the mesoscopic ordering often causes inauthenticity in chiropticity. In addition, the formation and maintenance of crystalline states require complicated technical efforts. In amorphous materials, however, it remained challenging and elusive to achieve large chiropticity, not to mention the control of the degree of asymmetry. Herein, we report the quantitative control of chiral amplification, on amorphous supramolecular structures of cholesteryl‐linked bis(dipyrrinato)zinc(II), to an exceptionally high level. The amorphous molecular aggregations of these complex building blocks exhibit mirror‐image chiropticity. A proper chiral packing of the building block at several molecular scale contributes considerably to the absorptive dissymmetry factor g  abs  , although the system is overall disordered. The intense and tunable aggregation strength renders a variable g  abs  value up to +0.10 and +0.31 in the solution and in film state, higher than those observed in most previously reported cases. On this basis, a superior ON‐OFF switching of chiropticity is realized under external stimuli. By eliminating the demand on material crystallinity, this work establishes a general design principle to control over ultra‐large optical asymmetry on a wider scope of chiral materials.

DOI: 10.1002/anie.202012224

Source: https://onlinelibrary.wiley.com/doi/10.1002/anie.202012224