Dumbbell-Shaped T8-POSS with Functional Organic Linkers

Abstract

New dumbbell-shaped octasilsesquioxanes (T8-POSS) are obtained by the condensation of organobridged silane precursors with partially condensed T7-triol. The synthesis based on corner-capping proceeds under mild reaction conditions (60 °C in toluene) upon a nucleophilic fluoride-catalyzed condensation of the T7-triol with the alkoxysilyl organics. Two dumbbell-type T8-POSS, one with a non-symmetrical urea-thiourea linker and the other one with a symmetrical malonamide linker, are described. Their formation is monitored by FTIR, their structures are investigated by NMR spectroscopy (1H, 13C and 29Si) and confirmed by mass spectrometry.