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 − nO_n/2SiC₆H₄SiO_n/2(OR)_3 − n]_x[(RO)_3 − nSiO_n/2(CH₂)₃NH₂]_y and [(RO)_3 − nO_n/2SiC₆H₄SiO_n/2(OR)_3 − n]_x[(RO)_3 − nSiO_n/2(CH₂)₃NH₂]_y[(RO)_4 − nO_n/2Si]_z and [(RO)_6 − 2nO_nSi₂C₆H₄]_x[(RO)_3 − nSiO_n/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.