(Z)‑1,2-Di(1-pyrenyl)disilene: Synthesis, Structure, and Intramolecular Charge-Transfer Emission

(Z)-1,2-Di­(1-pyrenyl)­disilene containing bulky 1,1,3,3,5,5,7,7-octaethyl-s-hydrindacen-4-yl (Eind) groups has been obtained as purple crystals by the reductive coupling reaction of the corresponding dibromosilane with lithium naphthalenide. An X-ray crystallographic analysis revealed an Eind- and pyrenyl-meshed molecular gear around the disilene core adopting the Z configuration, in which the two pyrenyl groups intramolecularly interact through the π–π stacking with a distance of 3.635 Å between the centers of the two pyrene rings. The disilene π-system exhibits a π­(Si–Si) → π*­(pyrene) intramolecular charge-transfer (ICT) fluorescence at room temperature, whose wavelengths depend on the solvent polarity. The photophysical properties are theoretically supported by computational studies including excited-state calculations.(Z)-1,2-二(1-芘基)二硅烯（带有大位阻的1,1,3,3,5,5,7,7-八乙基-s-氢茚满-4-基（Eind）基团），通过相应二溴硅烷与萘锂的还原偶联反应，以紫色晶体形式制备得到。X射线晶体衍射分析显示，围绕二硅烯核心、由Eind基团与芘基构成的分子齿轮结构呈Z构型，其中两个芘基通过分子内π-π堆积相互作用，两个芘环的中心间距为3.635 Å。该二硅烯的π体系在室温下展现出π(Si–Si)→π*(芘)型分子内电荷转移（intramolecular charge-transfer, ICT）荧光，其发射波长随溶剂极性发生变化。其光物理性质通过包含激发态计算在内的理论计算研究得到了佐证。