Rapid Microwave Synthesis and Purification of Porous Covalent Organic Frameworks

A study was conducted to demonstrate rapid microwave synthesis and purification of porous covalent organic frameworks (COF). The COFs were synthesized under microwave heating conditions by preparing in a 3:2 molar ratio solution of 1,4-benzenediboronic acid (BDBA) and 2,3,6,7,10,11- hexahydroxytriphenylene (HHTP) in a 1:1 mixture of mesitylene. The mixture was sealed under nitrogen in a 35 mL glass microwave tube and heated by microwave irradiation at 100 °C with stirring for 20 minutes at a power of 20 W, using a CEM S-Class Explorer 96-position microwave reactor attached with a digital camera. It was observed that a gray precipitate was formed in the reaction vessel, while the supernatant solution turned purple, due to the formation of an oxidized form of HHTP. The gray-purple powder was filtered under nitrogen and washed with acetone that had been dried over 5 Å molecular sieves.