具有C_(2v)对称性二苯并噻吩衍生物的合成及光学特性

C_(2v) symmetrical dibenzothiophene derivatives: Synthesis and photophysical properties

以二苯并噻吩为原料合成了中间体2，8-二溴二苯并噻吩和2，8-二甲酰基二苯并噻吩，并从这两种化合物出发，分别利用Heck反应和Wittig反应合成了具有C2v对称性的一系列二苯并噻吩衍生物。用核磁共振、红外、质谱等光谱手段表征了新化合物的结构，对这些化合物的光物理特性进行了评价。结果表明：2，8-二[2-（吡啶-4-基）乙烯基]二苯并噻吩（I）的紫外吸收峰随着溶剂极性的增加而出现蓝移现象，而其他化合物的紫外吸收峰随溶剂极性增加往长波方向移动；化合物I具有较低的荧光量子效率；用750-920 nm的飞秒激光激发时化合物I的溶液表现出明显的双光子吸收特性。

Three C2v symmetrical n-conjugated dibenzothiophene derivatives have been synthesized from 2, 8-dibromodibenzothiophene and 2, 8-diformyldibenzothiophene by means of separate Wittig and Heck reactions. Their structures were verified by ^1H-NMR, IR and MS spectra. Investigation of their photophysical properties showed： （1） an abnormal blue-shift in the UV-visible and fluorescence spectra of compound Ⅰ with increasing solvent polarity, whilst red-shifts were observed in the UV-visible spectra of compounds Ⅱ and Ⅲ ; （2） compound Ⅰ possesses low fluorescence quantum yield; （3） compound Ⅰ exhibits significant two photon absorption properties when excited with near IR laser light.