标题（中文）：由卤素原子引起的基于1,4-二氢吡啶的荧光分子的增强的压致变色性质

标题（英文）：Enhanced mechanofluorochromic properties of 1,4-dihydropyridine-based fluorescence molecules caused by the introduction of halogen atoms.

刊物名称及期号、页码：CrystEngComm, 2019, 21, 4258–4266. (Front Cover Paper)

作者姓名（中文）：陈亚婷，周一斌，王志强，王梦竹，高文霞，周云兵，刘妙昌，黄小波，吴华悦

作者姓名（英文）：Yating Chen, Yibin Zhou, Zhiqiang Wang, Mengzhu Wang, Wenxia Gao, Yunbing Zhou, Miaochang Liu, Xiaobo Huang* and Huayue Wu*

摘要（英文）：Four cyano(ethoxycarbonyl)methylene-1,4-dihydropyridine (CMD) derivatives were designed and synthesized to study the influence of the halogen atoms on their mechanofluorochromic (MFC) properties. These CMD derivatives are demonstrated to have twisted molecular conformations and display aggregation-induced emission properties. In the crystalline state, the compounds adopt loose J–aggregations and exhibit yellow-green or green solid-state fluorescence. Upon grinding, the original samples of CMD-H, CMD-F, CMD-Cl, and CMD-Br show 21, 60, 61, and 52-nm red shift in the fluorescence spectra, respectively, revealing MFC characteristic. The MFC properties are demonstrated to be due to the crystalline-to-amorphous transition and the red shifts in the fluorescence spectra are attributed to the increased molecular conjugations by the planarization of molecular conformations. The X-ray crystallographic analyses reveal that halogen-substituted CMD derivatives have more twisted conformations and looser stacking arrangements than CMD-H, which is responsible for their higher contrast MFC properties. The work indicates that the introduction of halogen atoms to a specific fluorescent molecule might be used as a simple and feasible route for developing high contrast MFC-active materials.

原文链接： https://doi.org/10.1039/C9CE00348G