Generation and Structure of Unique Boriranyl Radicals
Generation and Structure of Unique Boriranyl Radicals
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DOI：
10.1021/jacs.7b10788
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发表时间：
2017-11-22
影响因子：
15
通讯作者：
Curran, Dennis P.
中科院分区：
文献类型：
--
作者：
Walton, John C.;McFadden, Timothy R.;Curran, Dennis P.
具有N-杂环卡宾取代基的三元环硼杂环丙烷（boriranes）是通过最近发现的路线制备的。叔丁氧基自由基选择性地从硼原子上夺取氢原子，这使得硼烷基自由基首次能够通过 EPR 光谱进行检测和表征。它们的 EPR 参数表明它们具有平面 pi 特征。通过竞争实验，确定了 H 原子提取的速率常数，发现其比 NHC-硼烷的速率常数低约 2 个数量级。 NHC-硼烷的 B-H BDE 估计约为 95 kcal mol(-1)。
Three-member ring boracyclopropanes (boriranes) with N-heterocyclic carbene substituents were prepared by a recently discovered route. H atoms were selectively abstracted from the boron atoms by t-butoxyl radicals and this enabled boriranyl radicals to be detected and characterized by EPR spectroscopy for the first time. Their EPR parameters indicated they had planar pi-character. From competition experiments, the rate constant for H atom abstraction was determined and found to be about 2 orders of magnitude less than for NHC-boranes. The B-H BDE of an NHC-borirane was estimated to be about 95 kcal mol(-1).