Department of Applied Chemistry, Faculty of Science and Engineering, Chuo University , 1-13-27 Kasuga, Bunkyo-ku, Tokyo 112-8551, Japan.
J Am Chem Soc. 2016 Oct 5;138(39):12787-12790. doi: 10.1021/jacs.6b08714. Epub 2016 Sep 26.
A stable bismabenzene was synthesized, isolated, and structurally characterized. The prospective aromaticity of this heavy benzene, bearing a sixth-row element, was examined by X-ray crystallography and NMR and UV-vis spectroscopy, as well as theoretical DFT calculations. Structural analysis of this bismabenzene revealed a planar ring containing unsaturated Bi-C and C-C bonds. As bond alternations could not be observed, these results are consistent with the formal criteria of aromaticity. Theoretical calculations also support the aromatic nature of this bismabenzene, which reacted with an alkyne to form the corresponding [4+2] cycloadduct, thus demonstrating a small yet tangible aromatic stabilization energy.
合成、分离并结构表征了一种稳定的双苯。通过 X 射线晶体学、NMR 和 UV-vis 光谱以及理论 DFT 计算研究了这种含有第六周期元素的重苯的潜在芳香性。这种双苯的结构分析表明，它含有一个平面环，其中包含不饱和的 Bi-C 和 C-C 键。由于没有观察到键交替，这些结果与芳香性的正式标准一致。理论计算也支持这种双苯的芳香性质，它与炔烃反应形成相应的 [4+2] 环加成产物，从而证明了存在微小但可衡量的芳香稳定能。
