含α-二亚胺的低价态、低配位多核Ni–Ni键金属有机化合物的构筑及反应性研究

Metal–metal bonds have attracted considerable attention in the field of organometallic chemistry. Compared to the widely studied dinuclear types, multinuclear metal–metal bonds with low valence and coordination number were still rarely reported because of the increasing difficulties coming from the synthesis. Multinuclear metal–metal bonds with low valence and coordination number not only extend the structures and types of organometallic complexes, but also can greatly promote the applications in catalysis and material science. So far, many related researchers are flocking to this scientific strategy to look forward to playing an important part in the development of multinuclear metal–metal bonds with low valence and coordination number. In this project, the explorations of multinuclear metal–metal bonds will be started from multinuclear Ni–Ni bonds. Based on the previous research, we will continue to design and synthesize the new multinuclear Ni-Ni bonded compounds with low valence and coordination number. Further exploration of the reactivity for these compounds towards inorganic and organic small molecules (such as, N2, O2, H2O and unsaturated hydrocarbons, et al.) is also underway. The electronic structures of the products and the possible reaction mechanisms will be studied by performing DFT computations. This project can enrich the theoretical system in metal–metal bond, and it will play a positive role in promoting the development of organometallic chemistry.

构建金属–金属键化合物是当前金属有机化学的研究热点。与已有的双核金属–金属键相比，低价态、低配位数的多核金属–金属键因为合成难度的成倍增加，迄今该类金属有机化合物仍较为罕见。低价态、低配位数的多核金属–金属键不仅能极大地丰富金属有机化合物的种类和结构，而且还对开发此类化合物在催化、材料科学等领域的发展起到积极的推动作用。因此，向低价态、低配位数的多核金属–金属键这一“战略高地”挺进成为了相关科研人员的奋斗目标。在本项目中，申请者拟以多核Ni–Ni金属键为突破点，在已有的研究基础上，利用α-二亚胺配体去构筑新型低价态、低配位数的多核Ni–Ni键金属有机化合物，结合DFT理论计算结果，探索此类化合物对无机及有机小分子（N2、O2、H2O、不饱和烃等）的反应性，并对其反应机理进行研究。本工作将丰富金属–金属键的理论体系，对金属有机化合物的发展起到积极的推动作用。

低价态、低配位数的多核金属有机化合物是现代化学的一个重要研究领域，在小分子活化和催化方面具有广阔的应用前景。在该项目资金的资助下，申请者和项目组成员基本上按照项目的要求开展工作，研究内容按计划有序进行，取得了一些有意义的成果。本项目中，我们选用空间位阻较大的α-二亚胺配体L (L = [(2,6-iPr2-C6H3)NC(Me)]2, L代表中性的取代基为异丙基的α-二亚胺配体，L•代表−1价的阴离子自由基形式，L2−代表−2价的阴离子形式)，合成了多种镍金属有机化合物，如：含Ni−H键的多核配合物、活化N2配合物及配体自身分解化合物等。通过X-射线晶体学、氢核磁谱图(1H NMR)以及电子顺磁共振(EPR)方法研究了上述化合物的晶体结构、电子构型等。此外，结合我们的实验结果与DFT理论计算，我们研究了所合成的化合物与小分子的反应机理，拓展了金属有机化合物在催化领域的应用。