A new solid acid catalyst: the first phosphonate and phosphonic acid functionalised microporous polysilsesquioxanesElectronic supplementary information (ESI) available: Fig. 2 nitrogen sorption isotherm of P2 and Fig. 3 BJH pore size distribution of P2. See http://www.rsc.org/suppdata/cc/b0/b008192m/

Abstract

A novel microporous solid acid, the phosphonic acid modified polysilsesquioxane [(HO)SiCH₂CHPO(OH)₂- CH₂CH₂SiO₂(OH)]_n P2, from the new single precursor compound [(EtO)₃SiCH₂CHPO(OCH₂CH₃) ₂CH₂CH₂- Si(OEt)₃] 1, is reported, along with the catalytic activity of P2 for the pinacol–pinacolone rearrangement.