Porous Siloxane–Organic Hybrid with Ultrahigh Surface Area through Simultaneous Polymerization–Destruction of Functionalized Cubic Siloxane Cages

A novel hierarchically porous, hyper-cross-linked siloxane–organic hybrid (PSN-5) has been synthesized by Friedel–Crafts self-condensation of benzyl chloride-terminated double-four-ring cubic siloxane cages as a singular molecular precursor. Simultaneous polymerization of the organic functional groups and destruction of the siloxane cages during synthesis yielded PSN-5, which has an ultrahigh BET surface area (∼2500 m2 g–1) and large pore volume (∼3.3 cm3 g–1) that to our knowledge are the highest values reported for siloxane-based materials. PSN-5 also shows a high H2 uptake of 1.25 wt % at 77 K and 760 Torr.