Synthesis and Characterization of B-Heterocyclic π-Radical and Its Reactivity as a Boryl Radical
Synthesis and Characterization of B-Heterocyclic π-Radical and Its Reactivity as a Boryl Radical
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DOI：
10.1021/ja3094372
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发表时间：
2012-12-12
影响因子：
15
通讯作者：
Nozaki, Kyoko
中科院分区：
文献类型：
--
作者：
Aramaki, Yoshitaka;Orniya, Hideki;Nozaki, Kyoko
报道了稳定、持久的重氮硼环中性自由基3的首次分离和全表征。碱稳定的二氟硼烷2的还原提供了作为中性分子的自由基3，其具有一个连接到一个氟原子和两个氮原子上的平面sp(2)硼原子。ESR谱和密度泛函计算表明，未成对的电子在六元环上离域。由于与单占据分子轨道相关的电子跃迁，3具有特征的红色，因为UV-Vis光谱显示在498 nm处有最大吸收。虽然密度泛函计算表明，与六元环中的氮和碳原子相比，自由基3在硼原子上的自旋密度相对较低，但当与苯醌或过氧化苯甲酰反应时，3以碱稳定的硼自由基的形式反应。
The first isolation and full characterization of the stable, persistent diazaboracyclic neutral radical 3 is reported. Reduction of base-stabilized difluororoborane 2 provided radical 3 as a neutral molecule having a planar sp(2) boron atom attached to one fluorine and two nitrogen atoms. ESR spectroscopy and DFT calculations indicated that the unpaired electron is delocalized over the six-membered ring. Because of an electronic transition related to the singly occupied molecular orbital, 3 has a characteristic red color, as UV-vis spectroscopy showed an absorption maximum at 498 nm. Although DFT calculations suggested that radical 3 has relatively low spin density on the boron atom in comparison with the nitrogen and carbon atoms in the six-membered ring, 3 reacted as a base-stabilized boryl radical when treated with benzoquinone or benzoyl peroxide.