Synthesis and Reactivity of Nitrogen Nucleophiles-Induced Cage-Rearrangement Silsesquioxanes

Novel phthalimide and o-sulfobenzimide-functionalized silsesquioxanes were successfully synthesized via nucleophilic substitution reactions from octakis­(3-chloropropyl)­octasilsesquioxane. Surprisingly, the formation of deca- and dodecasilsesquioxanes cages was discovered during substitution with phthalimide, but only octasilsesquioxane maintained a cage in the o-sulfobenzimide substitution reaction. Moreover, we report the electronic effect of nitrogen nucleophiles to promote cage-rearrangement of inorganic silsesquioxane core for the first time. Structures of products were confirmed by 1H, 13C, and 29Si NMR spectroscopy, ESI–MS analysis, and single-crystal X-ray diffraction.本研究通过亲核取代反应，以八(3-氯丙基)八聚倍半硅氧烷（octakis(3-chloropropyl)octasilsesquioxane）为原料，成功合成了新型邻苯二甲酰亚胺（phthalimide）功能化与邻磺酰苯甲酰亚胺（o-sulfobenzimide）功能化倍半硅氧烷。令人意外的是，在邻苯二甲酰亚胺取代反应过程中，我们发现了十聚和十二聚倍半硅氧烷笼型结构的生成，但在邻磺酰苯甲酰亚胺取代反应中，仅八聚倍半硅氧烷维持了笼型结构。此外，本研究首次报道了氮亲核试剂的电子效应可促进无机倍半硅氧烷核心发生笼型重排。产物结构通过1H、13C及29Si核磁共振波谱法、电喷雾电离质谱（ESI–MS）分析以及单晶X射线衍射得以确证。