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.

Metal halides, solvent effects, phase transfer catalysts, alkylating agent and reaction times were found to have important roles to complete halogen exchange reactions in "one pot" synthesis, starting from octakis(3-chloropropyl)octasilsesquioxane to obtain more reactive halide compounds: octakis(3-bromopropyl)octasilsesquioxane and octakis(3-iodopropyl)octasilsesquioxane. To confirm the complete halogen exchange, the desired products were characterized by (1)H, (13)C and (29)Si NMR spectroscopy, ESI-MS, elemental analysis and single-crystal X-ray diffraction analysis.

Silsesquioxane formation competing with the deprotonation of alcohol solvents in the presence of a strong base to form alkoxides is reported for the first time. Evidently, sodium isopropoxide is formed during the synthesis of the sodium salt of a double‐decker octaphenylsilsesquioxane tetrasilanolate in 2‐propanol as the solvent, which leads to the formation of unexpected cis‐ and trans‐di[(3‐chloropropyl)isopropoxysilyl]‐bridged double‐decker octaphenylsilsesquioxanes after in situ coupling with 3‐chloropropyltrichlorosilane. The desired products were characterized by 1H NMR, 13C NMR, and 29Si NMR spectroscopy; ESI‐MS; and single‐crystal X‐ray diffraction.

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In the title compound, C7H10N2·C7H6O2, the components are linked by an O—H⋯N hydrogen bond. The mean planes of two mol­ecules form a dihedral angle of 78.68 (5)°. The crystal packing exhibits weak non-classical C—H⋯O contacts.