Liquid Crystal Institute and Chemical Physics Interdisciplinary Program, Kent State University, Kent, OH, 44242, USA.
Materials and Manufacturing Directorate, Air Force Research Laboratory, Wright-Patterson AFB, OH, 45433, USA.
Angew Chem Int Ed Engl. 2018 Feb 5;57(6):1627-1631. doi: 10.1002/anie.201712781. Epub 2018 Jan 9.
Supramolecular approaches toward the fabrication of functional materials and systems have been an enabling endeavor. Recently, halogen bonding has been harnessed as a promising supramolecular tool. Herein we report the synthesis and characterization of a novel halogen-bonded light-driven axially chiral molecular switch. The photoactive halogen-bonded chiral switch is able to induce a self-organized, tunable helical superstructure, that is, cholesteric liquid crystal (CLC), when doped into an achiral liquid crystal (LC) host. The halogen-bonded switch as a chiral dopant has a high helical twisting power (HTP) and shows a large change of its HTP upon photoisomerization. This light-driven dynamic modulation enables reversible selective reflection color tuning across the entire visible spectrum. The chiral switch also displays a temperature-dependent HTP change that enables thermally driven red, green, and blue (RGB) reflection colors in the self-organized helical superstructure.
超分子方法在功能材料和系统的构建中具有重要意义。最近，卤键被用作一种有前途的超分子工具。本文报道了一种新型光驱动手性轴分子开关的合成与表征。光活性卤键手性开关能够在掺杂非手性液晶（LC）主体时诱导自组装、可调谐的螺旋超结构，即胆甾相液晶（CLC）。作为手性掺杂剂的卤键开关具有高螺旋扭曲力（HTP），并且在光异构化时其 HTP 发生显著变化。这种光驱动的动态调控使得整个可见光谱范围内的反射颜色能够实现可逆选择性调谐。手性开关还表现出随温度变化的 HTP 变化，使得在自组装螺旋超结构中能够实现红、绿、蓝（RGB）反射颜色的热驱动。
