Through-Space C-Br???π Halogen Interaction: Efficient Modulation of Reaction-Based Photochromism and Photoluminescence at Crystalline States for Irradiation Time-Dependent Anti-Counterfeiting

作者：Zhou, Zhibiao; Liu, Qing; Chen, Xian; Xu, Gaoqiang; Wang, Shuodong; Tu, Yujie; Zhang, Jia; Zheng, Xiaoyan; Xiang, Jiannan; Feng, Xing; Zhang, Yang^*; Xie, Sheng^*; Zeng, Zebing^*; Tang, Ben Zhong^*

来源：Advanced Functional Materials, 2021, 31(10): 2009024.

DOI：10.1002/adfm.202009024

• aggregation&#8208
• induced emission
• anti&#8208
• counterfeiting
• halogen&#8208
• &#960
• interaction
• photo&#8208
• responsive solid&#8208
• state materials
• reaction&#8208
• based photochromism

Reaction-based photo-responsive molecular systems have been used as a reliable platform for building intelligent materials, but often suffer from high inactivity in terms of conversion efficiency and reversibility when it comes to solid-state applications. Herein, a class of Spiro-conjugated diphenylindene (DPI) aggregation-induced emission materials that exhibit solid-state photocyclization-based photochromism and photoluminescence, achieved by manipulating through-space C-Br center dot center dot center dot pi halogen interactions is reported. In the crystalline state, the Spiro bridge enables a pair of perpendicularly configured C-Br center dot center dot center dot pi interactions that suppress photoluminescence while activating a highly reversible (>10 000 cycles) and efficient photochromism based on photocyclization. After breaking this intermolecular C-Br center dot center dot center dot pi interaction, for example, by grinding, the solid-state photochromic properties are sensitively de-activated. In addition, this spontaneously reversible photochromism behavior gives a controllable decolorization time (from a few seconds to a few minutes), depending on the light exposure conditions, while displaying a luminescence change. In a proof-of-principle study, these photo-function features demonstrate an attractive potential for novel anti-counterfeiting applications. This work reveals the efficient regulation of C-Br center dot center dot center dot pi halogen interactions for spatial molecular packing, molecular electronic transitions, and chemical transformations, paving the way for the development of solid-state intelligent materials with good reversibility.

• 单位
  北京理工大学; 广东工业大学; y