Acta Chimica Sinica ›› 2020, Vol. 78 ›› Issue (8): 788-796.DOI: 10.6023/A20050161 Previous Articles     Next Articles



侯斌a, 李晶a, 辛涵申a, 杨笑迪b, 高洪磊a, 彭培珍a, 高希珂a   

  1. a 中国科学院大学 中国科学院上海有机化学研究所 中国科学院有机功能分子合成与组装化学重点实验室 上海 200032;
    b 上海中医药大学 创新中药研究院 上海 201203
  • 投稿日期:2020-05-11 发布日期:2020-06-11
  • 通讯作者: 杨笑迪, 高希珂;
  • 基金资助:

Design, Synthesis and Field Effect Characteristics of Diazulene Diimides Bridged by Aromatic Group

Hou Bina, Li Jinga, Xin Hanshena, Yang Xiaodib, Gao Hongleia, Peng Peizhena, Gao Xikea   

  1. a Key Laboratory of Synthetic and Self-Assembly Chemistry for Organic Functional Molecules, Center for Excellence in Molecular Synthesis, Shanghai Institute of Organic Chemistry, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Shanghai 200032, China;
    b Innovation Research Institute of Traditional Chinese Medicine, Shanghai University of Traditional Chinese Medicine, Shanghai 201203, China
  • Received:2020-05-11 Published:2020-06-11
  • Supported by:
    Project supported by the National Natural Science Foundation of China (Nos. 21522209, 21790362) and the Science and Technology Commission of Shanghai Municipality (Nos. 19XD1424700, 18JC1410600).

Azulene, a bicyclic nonbenzenoid aromatic hydrocarbon, shows completely different physicochemical properties compared with its isomeric naphthalene. Herein, we made use of the diverse reactivity of each position on azulene to design a new synthetic strategy for azulene-based diimides bridged by phenyl or thieno[3,2-b]thiophenyl group, 2-(azulen-2'-yl)-5-(azulen-2''-yl)benzene-1,1':4,1''-tetracarboxylic diimides (AzAzBDI-1/2) and 2-(azulen-2'-yl)-5- (azulen-2''-yl)thieno[3,2-b]thiophene-3,1':6,1''-tetracarboxylic diimide (AzAzTTDI). The key step was double trifluoroacetylation at 1-position of two azulene moieties of the molecule followed by hydrolysis, anhydridization and imidization to obtain the target compounds. The single crystal structure analysis demonstrates that AzAzBDI-2 has twisted molecular backbone. The adjacent two molecules form a dimer through the intermolecular π-π stacking (0.365 nm) between the five-membered ring and the seven-membered ring of two different azulene units. Strong π-π intermolecular interactions (0.355 nm) exist among the dimers to form a slipped one-dimensional (1D) packing motif in the crystal. For three compounds, the optoelectronic properties were investigated by UV-vis absorption spectra and cyclic voltammetry, and their energy levels of highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) and the energy gaps were calculated. The HOMO/LUMO energy levels of AzAzBDI-1, AzAzBDI-2 and AzAzTTDI are -5.56/-3.28 eV, -5.56/ -3.30 eV and -5.57/-3.42 eV, respectively. The end absorptions of AzAzBDI-1, AzAzBDI-2 and AzAzTTDI in thin films show obvious red-shift (13, 13 and 25 nm) relative to those in CHCl3 solution, indicating strong intermolecular interactions in solid state. The charge carrier transport properties of three compounds were studied through organic field-effect transistors (OFETs). Bottom-gate and top-contact OFET devices of AzAzBDI-1, AzAzBDI-2 and AzAzTTDI were fabricated by spin-coated their respective solution on octadecyltrimethoxysilane (OTMS)-treated SiO2/Si substrates. Under nitrogen atmosphere, all of these three compounds displayed electron-dominated ambipolar organic semiconductor characteristics. The electron mobilities of AzAzBDI-1 and AzAzBDI-2 were 0.068 cm2·V-1·s-1 and 0.086 cm2·V-1·s-1 and the hole mobility were 3.1×10-4 cm2·V-1·s-1 and 1.5×10-3 cm2·V-1·s-1, respectively. OFETs based on AzAzTTDI showed the highest electron mobility and hole mobilities of 0.087 cm2·V-1·s-1 and 8.8×10-3 cm2·V-1·s-1, respectively. The X-ray diffraction (XRD) and atomic force microscopy (AFM) studies demonstrate thin films of AzAzBDI-1, AzAzBDI-2 and AzAzTTDI show better crystallinity and form larger size of microstructures by annealing, which is consistent with the enhanced device performance after thermal annealing.

Key words: azulene, nonbenzenoid aromatic hydrocarbon, imides, organic field-effect transistors, organic semiconductor