以2,3,3′,5′-四氟-1,1′-联苯为原料, 在超低温条件下与n-BuLi及CF2Br2反应得到一种新的多卤代联苯类化合物4′-二氟溴甲基-2,3,3′,5′-四氟-4-溴-1,1′-联苯, 利用一步反应同时向分子结构中引入-CF2Br和-Br两个不同的官能团, 简化了反应步骤。用此化合物作为通用中间体, 可以方便地合成多种二氟甲醚桥键类液晶单体, 为此类液晶单体的制备提供了一种新的方法, 文中用上述方法合成了二氟甲醚桥键类液晶单体3PYUQUF, 液晶综合参数测试结果表明, 化合物3PYUQUF的Δｎ值为0.138 0, Δε值为22.63。

A new polyhalogenated biphenyl compound 4-bromo-4′-(bromodifluoromethyl)-2,3,3′,5′-tetrafluoro-1,1′-biphenyl was synthesized from 2,3,3′,5′-tetrafluoro-1,1′-biphenyl by reacting with n-BuLi and CF2Br2 under ultra-low temperature. But, this reaction can be simplified to a one-step reaction by constructing two different functional groups -CF2Br and -Br into the molecular structure. As a general intermediate, this compound can be used to synthesize a variety of difluoromethyl ether bridge-bonded liquid crystal monomers, which provides a new method for the preparation of such liquid crystal monomers. In this paper, the difluoromethyl ether bridge-bonded liquid crystal monomer 3PYUQUF was synthesized by the above methods. The results show that the Δn values of the compound 3PYUQUF was 0.138 0, and the Δε value was 22.63.