三唑环修饰的苯并菲二羧酸酯和酰亚胺:合成、液晶及凝胶性  

Synthesis,Mesomorphism and Gelation Properties of Triazole-Modified Triphenylene 2,3-Dicarboxylic Esters and 2,3-Dicarboxyimides

作　　者：殷东 商宏怡 余文浩[1,2] 向仕凯 胡平[1] 赵可清[1] 冯春[1] 汪必琴[1] Yin Dong;Shang Hongyi;Yu Wenhao;Xiang Shikai;Hu Ping;Zhao Keqing;Feng Chun;Wang Biqin(College of Chemistry and Materials Science,Sichuan Normal University,Chengdu 610066;College of Polymer Science&Engineering,Sichuan University,Chengdu 610065)

机构地区：[1]四川师范大学化学与材料科学学院,成都610066 [2]四川大学高分子科学与工程学院,成都610065

出　　处：《化学学报》2022年第10期1376-1384,共9页Acta Chimica Sinica

基　　金：国家自然科学基金(Nos.21772135,21871195,51773140)资助。

摘　　要：在盘状液晶分子外围柔性链中引入功能不同的基团,是设计和合成具有良好液晶性能化合物的常用策略.本工作从苯并菲2,3-二甲酸和酸酐出发,通过亲核取代和点击反应,分别合成了两类三唑环修饰的苯并菲二羧酸酯和苯并菲酰亚胺化合物.热重分析仪(TGA)测试表明,新制备的主要中间产物与目标化合物失重为5%时的温度在274~389℃之间,均表现出良好的热稳定性.我们通过差示扫描量热法(DSC)、偏光显微镜(POM)和变温X射线衍射(XRD)实验对这些化合物的热力学行为和介晶性进行了研究.除三唑环修饰的酯3a和3b无液晶性外,主要中间产物(2和5)与三唑环修饰的酰亚胺产物(6a和6b)均有一个六方柱状液晶相.此外,制备的以三唑为桥联基团的酰亚胺二聚体10为室温液晶,具有173℃的液晶范围.XRD证实了该二聚体中存在有序度不同的两种柱状液晶相(Colh1和Colh2).另外,由于三唑环的引入,三唑环修饰的酯类和酰亚胺两类化合物在某些有机溶剂中都能形成有机凝胶.其中,二聚体10在1,2-二氯乙烷和1,4-二氧六环中表现出优异的凝胶能力,其临界凝胶浓度(CGC)可低至1mg/m L.相比之下,不含三唑环的中间产物2和5则不能形成凝胶,表明三唑环之间的偶极-偶极作用和液晶刚性核π-π堆积的协同作用对于超分子凝胶的形成起着重要的作用.因此,同时表现出液晶和凝胶性质的三唑环修饰的苯并菲2,3-二酰亚胺分子具有成为一种多功能材料的潜在应用价值.The introduction of different functional groups at the periphery chains of discotic liquid crystals is a general strategy for the design and synthesis of new promising mesomorphic materials.Starting from triphenylene 2,3-dicarboxylic acid and anhydride,two kinds of triazole-modified triphenylene 2,3-dicarboxylic esters and 2,3-dicarboxyimides were synthesized via nucleophilic substitution and subsequent Cu-catalyzed azide-alkyne click reactions.Thermogravimetric analysis(TGA)measurements indicated that the prepared precursors and desired compounds exhibit good thermal stability with the temperatures of 5%weight loss in the range of 274~389℃.The thermal behavior and mesomorphism of these compounds were studied by differential scanning calorimetry(DSC),polarised optical microscopy(POM)and variable temperature X-ray diffraction(XRD)experiments.With the exceptions of esters 3a and 3b,which both show a single crystalline phase with a rather high melting temperature,the key precursors(2 and 5)and two triazole-modified imides(6a and 6b)all exhibit enantiotropic hexagonal columnar phase.Besides,the prepared triazole-bridged imide dimer 10 is a room temperature liquid crystalline material and has a wider mesophase range of 173℃from 8℃up to 181℃.XRD confirmed the existence of two columnar mesophases with different degrees of order in dimer 10,unambiguously characterized as Colh1 and Colh2.Due to the triazole moieties,additionally,all the triazole-modified esters and imides can form organogels in some organic solvents.Notably dimer 10 exhibits strong gelation ability in 1,2-dichloroethane or 1,4-dioxane with a very low critical gel concentration(1 mg/mL).In comparation,the precursor compounds 2 and 5,which do not possess any triazole ring in structure show no tendency to gelate,indicating that the strong dipole-dipole andπ-πinteractions between the triazole rings play an important role in the formation of the gel.Thus triazole-modified triphenylene 2,3-dicarboxyimides represent an interesting example of molecules

关 键 词：盘状液晶 自组装 有机凝胶 苯并菲2 3-二羧酸酯 苯并菲2 3-二酰亚胺 1 2 3-三唑 

分 类 号：O753.2[理学—晶体学] O622O648.17