Yu Chin-Yang, Hsu Chia-Chieh, Weng Hsi-Chen
Department of Materials Science and Engineering, National Taiwan University of Science and Technology 43, Section 4, Keelung Road Taipei 10607 Taiwan
RSC Adv. 2018 Apr 3;8(23):12619-12627. doi: 10.1039/c8ra01448e.
Compounds consisting of unsubstituted, monofluoro and difluoro substituted benzothiadiazole bonded to two tetraphenylethenes were successfully prepared by palladium catalyzed Suzuki-Miyaura cross-coupling reaction of their corresponding co-monomers. All compounds exhibited aggregation-induced emission characteristics when the water fraction was higher than 60% in the THF/water mixtures. The emission maximum for the three compounds was blue-shifted when the water content reached 90% compared to that in THF solution. The intensity of emission maximum of difluorinated benzothiadiazole linked with two tetraphenylethenes was 2.5 times higher in 90% water compared to those in THF solution. Surprisingly, two liquid crystal phases with two distinct emission colors were observed only for the compound containing difluorinated benzothiadiazole bonded to two tetraphenylethene. All compounds showed remarkable solvatochromic properties in selected solvents with different polarities. The powder XRD results and mechanochromism of the compounds suggested that the solid state structures can change from one form to another by grinding, fuming or annealing processes.
通过其相应共聚单体的钯催化铃木-宫浦交叉偶联反应，成功制备了由未取代、单氟和二氟取代的苯并噻二唑与两个四苯乙烯键合而成的化合物。当四氢呋喃/水混合物中水的比例高于60%时，所有化合物均表现出聚集诱导发光特性。与在四氢呋喃溶液中相比，当水含量达到90%时，这三种化合物的最大发射波长发生蓝移。与两个四苯乙烯相连的二氟苯并噻二唑在90%水体系中的最大发射强度比在四氢呋喃溶液中高2.5倍。令人惊讶的是，仅对于含有与两个四苯乙烯键合的二氟苯并噻二唑的化合物，观察到具有两种不同发射颜色的两个液晶相。所有化合物在选定的具有不同极性的溶剂中均表现出显著的溶剂化显色特性。化合物的粉末X射线衍射结果和机械变色现象表明，固态结构可通过研磨、熏蒸或退火过程从一种形式转变为另一种形式。
