中国科学院化学研究所刘冰研究组报道了用圆盘状单体同步聚合和自组装的均匀单畴液晶六方棒。相关论文发表在2025年3月11日出版的《美国化学会杂志》上。

本文报道了三苯（TP）衍生单体通过同步聚合和自组装（SPSA）可以得到高度均匀的六方棒。这些棒具有单畴柱状液晶结构，其中由堆叠的TPs形成的柱沿棒的长轴排列。杆的长度/直径比可以在很宽的范围内调整。分析了多环芳烃实现SPSA的关键因素，阐明了形成机理。特别是，该课题组观察到成功的SPSA发生在较高的临界温度以下，这可能是由于侧链和主链之间的微相分离不足，这应该是SPSA的一般原则。

此外，小组证明了TP单元的柱状堆叠显著促进了单重态激发态到三重态激发态的系统间交叉，从而在室温下同时发出荧光和磷光。这项工作可以扩展到更广泛的多环芳烃，以调节其自组装和发光特性。

据了解，多环芳烃（PAHs）由于其独特的光学、电学和磁学性质，其纳米结构的制备具有很高的吸引力。然而，通过自组装制造均匀且定义良好的多环芳烃纳米结构仍然是一个重大挑战。

附：英文原文

Title: Uniform Single-Domain Liquid Crystalline Hexagonal Rods by Synchronized Polymerization and Self-Assembly Using Disc-Shaped Monomers

Author: Minchao Li, Yuanxin Ma, Jing Li, Xiaoli Zhang, Zihao Xu, An-Chang Shi, Bing Liu

Issue&Volume: March 11, 2025

Abstract: The fabrication of nanostructures from polycyclic aromatic hydrocarbons (PAHs) is highly attractive owing to their unique optical, electrical, and magnetic properties. However, the creation of uniform and well-defined PAH nanostructures by self-assembly still remains a significant challenge. Herein, we report that highly uniform hexagonal rods can be obtained from triphenylene (TP)-derived monomers by synchronized polymerization and self-assembly (SPSA). These rods have a single-domain columnar liquid crystalline structure in which columns formed from stacked TPs are along the long axis of the rods. The length/diameter ratios of the rods can be tuned over a wide range. Key factors to achieve SPSA of PAHs were analyzed, and the formation mechanism was clarified. In particular, it is observed that successful SPSA occurs below an upper critical temperature, which could be attributed to insufficient microphase separation between the side chains and the main chains and should be a general principle for SPSA. Furthermore, we demonstrate that the columnar stacking of TP units significantly promotes the intersystem crossing of the singlet excited state to the triplet excited state, resulting in simultaneous fluorescence and phosphorescence emission at room temperature. This work may be extended to a wide range of PAHs to regulate their self-assembly and light emission properties.

DOI: 10.1021/jacs.4c17729

Source: https://pubs.acs.org/doi/abs/10.1021/jacs.4c17729