Rational design and synthesis of hybrid porous polymers derived from polyhedral oligomeric silsesquioxanes via heck coupling reactions

摘要

Heck coupling reactions are introduced as an efficient method to prepare porous polymers. Novel inorganic-organic hybrid porous polymers (HPPs) were constructed via Heck coupling reactions from cubic functional polyhedral oligomeric silsesquioxanes (POSS), iodinated octaphenylsilsesquioxanes (OPS) and octavinylsilsesquioxanes (OVS) using Pd(OAc)_2/PPh_3 as the catalyst. Here, two iodinated OPS were used, IOPS and p-I_8OPS. IOPS was a mixture with 90% octasubstituted OPS (I_8) and some nonasubstituted OPS (I_9), while p-I_8OPS was a nearly pure compound with ≥99% I_8 and ≥93% para-substitution. IOPS and p-I_8OPS reacted with OVS to produce the porous materials HPP-1 and HPP-2, which exhibited comparable specific surface areas with S_(BET) of 418 ± 20 m~2 g~(-1) and 382 ± 20 m~2 g~(-1), respectively, with total pore volumes of 0.28 ± 0.01 cm~3 g~(-1) and 0.23 ± 0.01 cm~3 g ~(-1), respectively. HPP-1 showed a broader pore size distribution and possessed a more significant contribution from the mesopores, when compared with HPP-2, thereby indicating that IOPS may induce more disorder because of the geometrical asymmetry. HPP-1 and HPP-2 possessed moderate carbon dioxide uptakes of 134 and 124 cm~3 g~(-1) at 1 bar at 195 K, making them promising candidates for CO_2 capture and storage. The synthesized porous polymers may be easily post-functionalized using the retained ethenylene groups. Heck coupling reactions are introduced as an efficient method to prepare novel hybrid porous polymers from cubic functional polyhedral oligomeric silsesquioxanes, iodinated octaphenylsilsesquioxanes, and octavinylsilsesquioxanes. Using the retained ethenylene groups, the resulting porous materials may be easily post-functionalized.