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Tunable Aggregation‐Induced Emission of Imidazole Hydrazones by pH and Anions
Author(s) -
Tian Dongjie,
Zheng Xin,
Li Xiaochuan,
Liu Xiaojing,
Zhao Jinhu,
Wang Jianji
Publication year - 2019
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201904259
Subject(s) - imidazole , aggregation induced emission , chemistry , organic chemistry , physics , optics , fluorescence
Aggregation‐induced emission (AIE) materials have drawn great attention for applications as organic light‐emitting diodes (OLED) and probes. The applications are, however, restricted by the complex syntheses and hydrophobic properties. Herein, a one‐step synthesis of an AIE material based on imidazole hydrazone is assessed. Protonation of the imidazole‐H leads to emission color change from yellow to green in the solid state. The emission color is recovered upon imidazole‐H + deprotonation. Moreover, the emission wavelength shifts from 532 to 572 nm by anion exchange. In addition, an enhanced emission ( Φ F up to 22.6 %) was obtained with the Br − anion compared with NTf 2 − , SbCl 5 − , PF 6 − , and OTf − anions. X‐ray crystallography studies together with theoretical calculations show that the enhanced emission of hydrazone salts arises from strong hydrogen bonding between the hydrazone proton and the halide ion (Cl − or Br − ).