π-Conjugated organoboron molecules, which are easy to prepare, stable against moisture, and easy to functionalize, are scarce. Here, we report a one-pot synthesis of an air-stable organoboron compound, dithienooxadiborepine 1 in 17% yield on a 600 mg scale without separation or handling an air-sensitive intermediate. Dithienooxadiborepine 1 showed excellent stability under ambient conditions, allowing conventional column chromatography purification. Functionalization of 1 was realized via direct bromination using NBS and further Stille coupling reactions, giving access to longer π-conjugated molecules 5A and 5B. Single-crystal structures of compounds 4, 5A, and 5B not only unambiguously verified the chemical identity of dithienooxadiborepine 1 but also revealed that both the seven-member oxadiborepine ring and the 5–7–5 fused dithienooxadiborepine ring system are planar. UV–vis absorption and fluorescence emission measurements of 5A and 5B showed bathochromic shifted absorption and emission relative to 1, evidencing good π-conjugation. Cyclic voltammograms of 5A and 5B displayed two reduction peaks corresponding to two electron-accepting events at two boron atoms. These results proved dithienooxadiborepine 1 a potent π-conjugating building block for electron-accepting materials.

中文翻译：

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空气稳定的有机硼化合物，二硫杂恶二硼烷：制备和功能化。

缺乏易于制备，对水分稳定且易于功能化的π共轭有机硼分子。在这里，我们报道了一锅法合成的空气稳定的有机硼化合物，二硫杂恶二硼烷1在600 mg规模上以17％的收率进行合成，而没有分离或处理对空气敏感的中间体。Dithienooxadiborepine 1在环境条件下显示出极好的稳定性，可进行常规柱色谱纯化。通过使用NBS的直接溴化反应和进一步的Stille偶联反应实现了1的功能化，从而可以使用更长的π-共轭分子5A和5B。化合物的单晶结构4，图5A，以及5B不仅明确地验证了二硫杂诺沙地平1的化学性质，而且还揭示了七元的奥沙地丁平环和5–7–5稠合的二硫代恶二硼烷平环系统都是平面的。5A和5B的紫外可见吸收和荧光发射测量结果表明，红移相对于1的吸收和发射发生了位移，证明了良好的π共轭。5A和5B的循环伏安图显示了两个还原峰，分别对应于两个硼原子上的两个电子接受事件。这些结果证明了二硫杂诺沙地平1是一种有效的π结合电子接受材料的构建基块。