设计合成了含有酰亚胺结构单元的氮杂和硫杂稠五环共轭分子1和2,并对它们的物理化学性质进行了研究.实验结果显示酰亚胺基团的引入不仅使得分子具有良好的溶解性,而且有效地降低分子的HOMO和LUMO能级.化合物1的单晶结构显示其共轭核具有良好的平面性.单晶中,化合物1通过强的π-π相互作用形成二聚体,二聚体之间存在强的氢键相互作用.基于化合物2的薄膜场效应晶体管表现出p-型场效应晶体管行为,其最高迁移率为2.75×10^-3cm^2·V^-1·s^-1。
Five-ring fused azo- and thio-aromatic compounds 1 and 2 containing imide substituent were designed and synthesized. 3,4-Dibromo-1-(2-ethylhexyl)-1H-pyrrole-2,5-dione reacted with lithium indyl and benzothiophene-3-boronic acid respectively, affording intermediates 3 and 4. Compound 3 was intramolecular cyclized in the presence of Pd Cl2 to give target compound 1. And compound 2 was prepared through intramolecular cyclization of intermediate 4 by means of photochemical ringclosure reaction and oxidation. The physicochemical properties of compounds 1 and 2 were thoroughly investigated with TGA, UV-vis absorption spectra and cyclic voltammetry. Experimental results showed the introduction of imide substituent not only increased the solubility of compounds 1 and 2, but also decreased their energy levels of the highest occupied molecular orbital(HOMO) and the lowest unoccupied molecular orbital(LUMO). The HOMO/LUMO energy levels of compounds 1 and 2 are-5.58/-2.25 e V and-6.04/-3.51 e V respectively. Single crystals of compound 1 were grown through solvent evaporation method in the mixture of dichloromethane and petroleum ether. Single crystal structure revealed compound 1 has a planar conjugated core and forms dimmer in the crystal. Strong π-π intermolecular interactions exist in the dimmer, and hydrogen bonds(NH…O=C) are observed among dimmers. The charge carrier mobilities of compounds 1 and 2 were investigated through thin film transistors. The transistors were fabricated with top-contact/bottom-gate device configurations. And thin films were deposited in vacuum on octadecyltrichlorosilane(OTS)-modified Si/Si O2 substrates. Transistors performance of compound 2 displays obvious p-type performance with a mobility of 2.75×10^-3 cm^2·V^-1·s^-1. However, compound 1 exhibited no organic field-effect transistor(OFET) behavior. In order to understand the different device performances of compounds 1 and 2, their thin films were investigated by atomic force microscopy(AFM) and X-ray diff