Department of Chemistry, Catalysis Research Center and Institute of Silicon Chemistry, Technische Universität München , Lichtenbergstraße 4, 85748 Garching bei München, Germany.
J Am Chem Soc. 2017 Oct 18;139(41):14384-14387. doi: 10.1021/jacs.7b08890. Epub 2017 Sep 21.
Homodinuclear multiple-bonded neutral Al compounds, aluminum analogues of alkenes, have been a notoriously difficult synthetic target over the past several decades. Herein, we report the isolation of a stable neutral compound featuring an Al═Al double bond stabilized by N-heterocyclic carbenes. X-ray crystallographic and spectroscopic analyses demonstrate that the dialuminum entity possesses trans-planar geometry and an Al-Al bond length of 2.3943(16) Å, which is the shortest distance reported for a molecular dialuminum species. This new species reacts with ethylene and phenyl acetylene to give the [2+2] cycloaddition products. The structure and bonding were also investigated by detailed density functional theory calculations. These results clearly demonstrate the presence of an Al═Al double bond in this molecule.
在过去的几十年里，同双核多键中性 Al 化合物（烯烃的铝类似物）一直是一个极具挑战性的合成目标。在此，我们报道了一种稳定的中性化合物的分离，该化合物具有由 N-杂环卡宾稳定的 Al=Al 双键。X 射线晶体学和光谱分析表明，二铝实体具有平面构型，Al-Al 键长为 2.3943(16)Å，这是报道的分子二铝物种的最短距离。该新物种与乙烯和苯乙炔反应，得到[2+2]环加成产物。结构和键合也通过详细的密度泛函理论计算进行了研究。这些结果清楚地表明该分子中存在 Al=Al 双键。
