德国萨尔大学Schfer Andr团队报道了锂铝双金属二茂金属。相关研究成果于2024年5月14日发表在《自然—化学》。

具有两个相同金属原子夹在两个η5键合的环戊二烯基环之间的，双金属二茂金属是一类狭窄的化合物，具有代表性的例子是二锌茂碳烯和双铍烯。

该文中，眼人员报道了一种异双金属二茂金属的合成和结构表征，它可以通过锂和亚铝基片段与五异丙基环戊二烯基配体的异源偶联来获得。Al–Li键具有高离子特性，并得益于环戊二烯基配体的异丙基之间的分散相互作用。

一个关键的合成步骤是分离环戊二烯基亚铝单体，这也使得能够对该物种进行结构表征。除了通过单晶X射线衍射分析进行结构鉴定外，还通过溶液和固态的多核NMR光谱对这两种化合物进行了表征。此外，对锂-铝杂双金属二茂金属与N-杂环卡宾和不同杂等位烯的反应性研究表明，Al–Li键很容易断裂。

附：英文原文

Title: A lithium–aluminium heterobimetallic dimetallocene

Author: Bischoff, Inga-Alexandra, Dans, Sergi, Thoni, Philipp, Morgenstern, Bernd, Andrada, Diego M., Mller, Carsten, Lambert, Jessica, Gieelmann, Elias C. J., Zimmer, Michael, Schfer, Andr

Issue&Volume: 2024-05-14

Abstract: Homobimetallic dimetallocenes exhibiting two identical metal atoms sandwiched between two η5 bonded cyclopentadienyl rings is a narrow class of compounds, with representative examples being dizincocene and diberyllocene. Here we report the synthesis and structural characterization of a heterobimetallic dimetallocene, accessible through heterocoupling of lithium and aluminylene fragments with pentaisopropylcyclopentadienyl ligands. The Al–Li bond features a high ionic character and profits from attractive dispersion interactions between the isopropyl groups of the cyclopentadienyl ligands. A key synthetic step is the isolation of a cyclopentadienylaluminylene monomer, which also enables the structural characterization of this species. In addition to their structural authentication by single-crystal X-ray diffraction analysis, both compounds were characterized by multinuclear NMR spectroscopy in solution and in the solid state. Furthermore, reactivity studies of the lithium–aluminium heterobimetallic dimetallocene with an N-heterocyclic carbene and different heteroallenes were performed and show that the Al–Li bond is easily cleaved.

DOI: 10.1038/s41557-024-01531-y

Source: https://www.nature.com/articles/s41557-024-01531-y