Crystallization-Induced Reversal from Dark to Bright Excited States for Construction of Solid-Emission-Tunable Squaraines

作者：Yang, Shuaijun; Yin, Ping-An; Li, Lin; Peng, Qian^*; Gu, Xinggui^*; Gao, Ge; You, Jingsong; Tang, Ben Zhong

来源：Angewandte Chemie - International Edition, 2020, 59(25): 10136-10142.

DOI：10.1002/anie.201914437

• aggregation-induced emission
• crystallization-induced emission
• excited state
• single-crystal to single-crystal
• squaraines

Squaraines (SQs) with tunable emission in the solid state is of great importance for various demands; however a remaining challenge is emission quenching upon aggregation. Herein, a unique SQ, named as CIEE-SQ, is designed to exhibit strong emission in crystal, undergoing crystallization-induced reverse from dark (1)(n+sigma,pi*) to bright (1)(pi,pi*) excited states. Such an excited state of CIEE-SQ can be subtly tuned by molecular conformation changes during the unexpected temperature-triggered single-crystal to single-crystal (SCSC) reversible transformation. Furthermore, co-crystallization between CIEE-SQ and chloroform largely stabilize the (1)(pi,pi*) state, enhancing the transition dipole moment and decreasing the reorganization energy to boost the fluorescence, which is promising in data encryption and decryption.

• 单位
  北京化工大学; 四川大学; 中国科学院