N-Heterocyclic Carbene Boranes as Electron-Donating and Electron-Accepting Components of π-Conjugated Systems
作者:Kazuhiko Nagura、Shohei Saito、Roland Fröhlich、Frank Glorius、Shigehiro Yamaguchi
DOI:10.1002/anie.201204050
日期:2012.7.27
Give and take: The introduction of NHC–borane moieties to thiophene‐based π skeletons endows a zwitterionic character, which makes the π system electron‐donating, while the NHC ring acts as an electron‐accepting moiety. The NHC–borane‐substituted thiophene underwent a clean photoisomerization with a drastic color change, however, the expanded bithiophene derivatives were inert to this photoreaction
取舍:将NHC-硼烷部分引入以噻吩为基础的π骨架具有两性离子特性,使π系统具有电子给体性,而NHC环则充当电子接受性部分。NHC-硼烷取代的噻吩经历了干净的光异构化,并发生了剧烈的颜色变化,但是,膨胀的联噻吩衍生物对该光反应呈惰性,显示出低的氧化电位,并在晶体中形成了滑动的π堆积阵列。