Synthesis and reactivity of nitrogen nucleophiles-induced cage-rearrangement silsesquioxanes

Abstract

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 1 H, 13 C, and 29 Si NMR spectroscopy, ESI-MS analysis, and single-crystal X-ray diffraction. © 2012 American Chemical Society.