一种三态发光的液晶基元合成、自组装及光物理性质  

Synthesis,Self-assembly and Photophysical Properties of A Three-state Highly Emissive Mesogen

作　　者：郑军峰 宫佳鑫 程晓帆 葛云翀 徐鹏 ZHENG Jun-feng;GONG Jia-xin;CHENG Xiao-fan;GE Yun-chong;XU Peng(Department of Applied Chemistry,College of Chemical Engineering,Nanjing Forestry University,Nanjing 210037,China)

机构地区：[1]南京林业大学化学工程学院应用化学系,江苏南京210037

出　　处：《发光学报》2022年第6期869-878,共10页Chinese Journal of Luminescence

摘　　要：聚集导致猝灭(ACQ)分子在单分子态(如稀溶液)高效发光,而聚集诱导发光(AIE)分子在聚集态(如固态)高效发光。这一单态发光的特性严重制约着发光材料的应用。本工作中,我们合成了一种三态(溶液、凝胶、液晶)发光的phasmid液晶基元(PHAgen-12),并考察了其自组装性质与光物理性质。PHAgen-12的两端为一代树枝单元,中间为“二苯基氰基乙烯(AIE)+二苯基丁二炔(ACQ)+二苯基氰基乙烯(AIE)”的刚性核,具有D-A-π-A-D的特征。该分子在普通溶剂(如THF、DCM)中可以溶解;在选择性溶剂烷烃中形成柱状胶束,并可凝胶化;在固态形成六方柱状液晶相,单分子层厚度(~0.44 nm)的单胞内含有~4个分子。PHAgen-12在单分子态表现出ACQ分子的性质,在氯仿中荧光量子产率(QY)为~90.3%;在聚集态表现出AIE性质,PHAgen-12/十二烷凝胶体系(质量百分比为30%)的QY为58.5%,本体液晶态的QY为85.5%。Aggregation-caused quenching(ACQ) and aggregation-induced emission(AIE) molecules are highly emissive only in single molecular and aggregated state,respectively. This singlestate emissive character highly hampers their applications. In this work,we synthesized a three-state(solution,gel and liquid crystal)highly emissive phasmid mesogen(PHAgen-12)and studied its self-assembly and photophysical properties. PHAgen-12 consists of a long rod-like part ended by two Percec-type dendrons. The rod-like core is“cyanostilbene + diphenyl-diacetylene+cyanostilbene”,featuring a D-A-π-A-D type emitter. PHAgen-12 can well dissolve in common solvents such as THF and DCM,form cylindrical micelle and further gel in selective solvents(alkanes),and develop into a hexagonal columnar liquid crystalline phase in bulk state,with four molecules in each monomolecule-thick(~0. 44 nm)hexagonal unit cell. In dilute solution,it behaves like a ACQ molecule with a quantum yield(QY)up to 90. 3 % in CHCl_(3). It renders a strong AIE character in condensed states,with a QY of 58. 5% in PHAgen-12/dodecane gel system(30%(wt))and a QY of 85. 5% in bulk liquid crystalline state.

关 键 词：多态发光 液晶 凝胶 聚集诱导发光(AIE) 聚集导致荧光猝灭(ACQ) 

分 类 号：O753.2[理学—晶体学]