硅宾和硼烷活化小分子研究

The activation of small molecules is a key step in synthesis and energy storage. Compared with the broad application of transition metals in the activation of small molecules, the study of main group elements in this fields remains limited. However, whether from the fundamental research of main group chemistry, or from the development of economic and environment friendly novel catalyst systems, the study of main group elements in the field of activation of small molecules certainly will have significant influence on the fundamental element chemistry and catalytic application. This project will proceed from the design and synthesis of novel silylenes and boranes based on cooperative main group element-ligand activation process, and then explore the influence of ligand effect on the activation of small molecules. We plan to achieve the activation of more types of small molecules, such as hydrogen, carbon monoxide, ammonia, especially nitrogen and methane.

小分子活化是合成和能量存储的关键步骤。相对于过渡金属在小分子活化领域的广泛应用，主族元素在这个领域的研究进展明显滞后。但是无论是从主族化学的基础研究角度，还是从新颖、经济性和环境友好催化体系的开发角度，主族元素在小分子活化领域的研究势必对基础元素化学和催化应用产生重大影响。本项目拟从新颖结构硅宾以及基于主族元素-配体协调活化模式的硼烷体系的设计合成入手，探索配体效应对小分子活化的影响因素。通过配体的优化，实现多种小分子，例如氢气、一氧化碳、氨气，尤其是氮气和甲烷的活化。

本项目利用硅宾硼烷加合物在加热条件下的异构化反应，合成了硼氮取代的二溴硅烷，再通过还原反应，制备了硼硅杂环丁烯类似物，它也可以被认为是硼氮取代硅宾的二聚体。晶体结构显示它有一个折叠的B2Si2四元环 (26.2o)，并且对角的硼硅原子距离很短 (2.306(3) Å)。通过理论计算发现两个π电子离域在BSi2三个原子上。实验数据和理论计算结果都证实了硼硅杂环丁烯类似物具有中性同芳香性的性质。对硼硅杂环丁烯类似物反应性也进行了研究，发现它可以与氯化亚铜或氯化氢反应，生成硼硅杂环丁烷类似物。相关结果发表在J. Am. Chem. Soc. 2022, 144, 22446-22450。本项目研究了同芳香性的中性硼硅杂环丁烯类似物的合成、结构和反应性，进一步证实了中性同芳香性的存在，丰富了杂原子芳香性化合物的种类。