Synthesise of (4-Ethynyl-Phenyl)-(4-trifluoromethyl-phenyl)-Diazene, a Novel Intermediate of Azobenzene Liquid Crystal with High Birefrigence

Abstract

In order to obtain an important azobenzene liquid crystal intermediate with phenylacetylene group, Sonogashira coupling reaction was used to preparation the compound. In this paper, the intermediate was synthesized by (4-Iodo-phenyl)-(4-trifluoromethyl-phenyl)-diazene and trimethyl silyl acetylene (TMSA) as raw materials, and then the trimethyl silyl group was removaled under the action of K2CO3. During the synthesis, the optimum reaction conditions were obtained, that the mol ratio of (4-Iodo-phenyl)-(4-trifluoromethyl-phenyl)-diazene and trimethyl silyl acetylene was 1:2, the reaction temperature was 80 oC. Fourier transform infrared spectroscopy (FT-IR) was used to measure the molecular structure of the target compound.