基于萘啶二亚胺配体的二硼烷化合物的构筑及性质研究

The design and optoelectronic properties of new BN-substituted polycyclic aromatic hydrocarbons (BN-PAHs) is a very important branch of material science. Meanwhile, the catalyst free transformation of diboron(4) to other useful substrates has also attracted much attention. This project intends to merge these two interesting properties into one structure in the hope of developing a PAHs with new physical and chemical properties. Naphthyridine−diimine (NDI) which is best known as an electron buffer is chosen as ligand to prepare a diboron(4) species−NDI-B2. A series of NDI-B2 featuring different substituents will be synthesized and evaluated for their aromaticy. The physical and chemical properties of those aromatic NDI-B2 will be investigated. The main research topics in this project include: (1) the preparation of NDI-B2 and the impact of the substituents on the aromaticy of the target molecules; (2) study the optoelectronic properties of the aromatic NDI-B2 and the impact of B−B bond on the physical properties of BN-PAHs; (3) investigate the multiple electron oxidation-reduction transformation and catalysts-free reactions. This projects not only offers a new type of BN-PAHs but also demonstrates a potential new way to develop main-group elements centered catalysts and small molecules activation reaction.

硼氮杂多环芳香烃（B,N-PAHs）的开发及光电性质的研究是材料化学的一个重要分支，而二硼烷的无催化剂反应和小分子活化则是当前有机合成领域的研究热点，本项目将B,N-PAHs和二硼烷两个方向进行融合，以期形成一种具有新型物理、化学性质的PAHs体系。萘啶二亚胺（NDI）配体具有出色的电子缓冲效效应，本项目拟合成基于NDI配体的二硼烷(NDI-B2)，并通过尝试不同的取代基筛选出具有芳香性的NDI-B2，最后研究芳香型NDI-B2特有的物理、化学性质。主要研究内容包括：（1）探索NDI-B2化合物的合成路线并研究取代基对芳香性的影响；（2）研究芳香型NDI-B2的光电性质，探讨B−B键的引入对B,N-PAHs光电性质的影响；（3）研究目标化合物的多电子氧化还原反应以及无催化剂反应。本项目不仅有助于新型B,N杂PAHs骨架的开发，同时为基于主族元素的催化剂、小分子活化等领域提供了新思路。

本工作成功制备了基于1,8-萘啶二亚胺配体的双锗烯N4Ge2，其中锗中心为二配位，平面构型。双锗烯N4Ge2的前驱体同样为双锗烯 [N4Ge2Cl2]，前驱体中锗中心为三配位，三角锥构型。理论计算（如：MOs， MBO， NBO等）表面，双锗烯N4Ge2中，两个锗中心没有成键，但是存在超共轭作用；NICS及ACID计算表明，双锗烯N4Ge2具有显著的芳香性。此外，EDA-NOCV表面N4Ge2在其配合物[N4Ge2][Fe2(CO)6] 为二中心六电子配体，这一给电子性质为14族元素首例。