B(sp²)–B(sp³) diborane species based on bis(catecholato)diboron and N‐heterocyclic carbenes (NHCs) underwent catechol/bromide exchange selectively at the sp³‐hybridized boron atom. The reduction of the resulting 1,1‐dibromodiborane adducts led to reductive coupling and isolation of doubly NHC‐stabilized 1,2‐diboryldiborenes. These compounds are the first examples of molecules exhibiting π‐electron delocalization over an all‐boron chain.

中文翻译：

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Diboryldiborenes：π-共轭B4链等电于丁二烯阳离子

基于双（邻苯二酚）二硼和N-杂环卡宾（NHC）的B（sp ²）–B（sp ³）乙硼烷物种在sp ³杂交的硼原子上选择性地进行了邻苯二酚/溴化物交换。生成的1,1-二溴二硼烷加合物的减少导致NHC稳定的双1,2-二硼基二硼烷的还原偶联和分离。这些化合物是在全硼链上表现出π电子离域的分子的第一个例子。