Xu Xin, Zhu Yi-Kang, Dai Chuan-Ming, Xu Jiaping, Jian Jiwen
Hangzhou Institute of Advanced Studies, Zhejiang Normal University, 1108 Gengwen Road, Hangzhou, Zhejiang, 311231, China.
Xiaoshan Campus, Zhejiang Normal University, 1108 Gengwen Road, Hangzhou, Zhejiang, 311231, China.
Phys Chem Chem Phys. 2024 Apr 3;26(14):11048-11055. doi: 10.1039/d4cp00228h.
The reactivity of pyridine is a complex topic due to its unique electronic structure. The reactions of atomic boron with pyridine molecules in solid neon have been investigated using matrix isolation infrared absorption spectroscopy. Three products (marked as A, B, and C) were observed and characterized through B, D and N isotopic substitution pyridine regents as well as quantum chemical calculations. In the reaction, the ground-state boron atom can attack the lone pair electrons of the nitrogen atom in the pyridine molecule, resulting in the formation of a 1-boropyridinyl radical (A). Alternatively, addition to the aromatic π-system of pyridine can occur in a [1,4] type, leading to the formation of a B[η(1,4)-CHN] complex (B). Under UV-visible light (280 < < 580 nm) irradiation, these two compounds can further undergo photo-isomerization to form BN-embedded seven-membered azaborepin compounds (C). The observation of species A, B, and the subsequent photo-isomerization to species C is consistent with theoretical predictions, indicating that these reactions are kinetically favorable. This research provides valuable insights into the future design and synthesis of corresponding BN heterocyclic derivatives.
由于吡啶独特的电子结构，其反应活性是一个复杂的课题。利用基质隔离红外吸收光谱研究了固态氖中原子硼与吡啶分子的反应。通过硼、氘和氮同位素取代的吡啶试剂以及量子化学计算观察并表征了三种产物（标记为A、B和C）。在该反应中，基态硼原子可以攻击吡啶分子中氮原子的孤对电子，从而形成1-硼吡啶基自由基（A）。或者，吡啶的芳香π体系可以以[1,4]类型发生加成反应，生成B[η(1,4)-CHN]配合物（B）。在紫外-可见光（280＜λ＜580nm）照射下，这两种化合物可进一步发生光异构化反应，形成嵌入BN的七元氮杂硼环化合物（C）。对物种A、B的观察以及随后向物种C的光异构化与理论预测一致，表明这些反应在动力学上是有利的。这项研究为未来相应的BN杂环衍生物的设计和合成提供了有价值的见解。
