Aminoalkyl modified polysilsesquioxanes; synthesis, characterisation and catalytic activity in comparison to related aminopropyl modified silicas

Abstract

In this paper we report on the sol–gel synthesis and characterisation (by 29Si CPMAS and SPE MAS, 13C CPMAS NMR and elemental analysis as well as nitrogen sorption porosimetry) of new aminopropylated polysilsesquioxanes of types [(RO)3 − nOn/2SiC6H4SiOn/2(OR)3 − n]x[(RO)3 − nSiOn/2(CH2)3NH2]y and [(RO)3 − nOn/2SiC6H4SiOn/2(OR)3 − n]x[(RO)3 − nSiOn/2(CH2)3NH2]y[(RO)4 − nOn/2Si]z and [(RO)6 − 2nOnSi2C6H4]x[(RO)3 − nSiOn/2(CH2)2NH(CH2)2NH2]y. The catalytic activity of these new polysilsesquioxane supported solid bases in Knoevenagel condensation reactions is described and compared with related aminopropylated silica systems.