Acta Chimica Sinica ›› 2022, Vol. 80 ›› Issue (10): 1376-1384.DOI: 10.6023/A22070288 Previous Articles     Next Articles


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

殷东a, 商宏怡a, 余文浩a,b, 向仕凯a, 胡平a, 赵可清a, 冯春a,*(), 汪必琴a,*()   

  1. a 四川师范大学化学与材料科学学院 成都 610066
    b 四川大学高分子科学与工程学院 成都 610065
  • 投稿日期:2022-07-01 发布日期:2022-09-06
  • 通讯作者: 冯春, 汪必琴
  • 基金资助:
    国家自然科学基金(21772135); 国家自然科学基金(21871195); 国家自然科学基金(51773140)

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

Dong Yina, Hongyi Shanga, Wenhao Yua,b, Shikai Xianga, Ping Hua, Keqing Zhaoa, Chun Fenga(), Biqin Wanga()   

  1. a College of Chemistry and Materials Science, Sichuan Normal University, Chengdu 610066
    b College of Polymer Science & Engineering, Sichuan University, Chengdu 610065
  • Received:2022-07-01 Published:2022-09-06
  • Contact: Chun Feng, Biqin Wang
  • Supported by:
    National Natural Science Foundation of China(21772135); National Natural Science Foundation of China(21871195); National Natural Science Foundation of China(51773140)

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 and π-π interactions 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 exhibiting both liquid crystalline and gelling properties. This investigation sheds light on the potential applicability of the triazole-modified triphenylene 2,3-dicarboxyimides as promising multifunctional materials.

Key words: discotic liquid crystal, self-assembly, organogels, triphenylene 2,3-dicarboxylic ester, triphenylene 2,3-dicar- boxyimide, 1,2,3-triazole