Functionalized COFs with Quaternary Phosphonium Salt for Versatilely Catalyzing Chemical Transformations of CO2

Currently, it encounters great challenges to accomplish catalyzing various kinds of carbon dioxide(CO2) conversion reactions efficiently with single catalyst, let alone control the interplay among catalytic efficiency and selectivity evenly. Here, we prepared a functional covalent organic framework, [PTPP]X%-TD-COF[PTPP=3-bromopropyltriphenylphosphonium; TD=1,3,5-tri(4-aminophenyl)benzene-1,4-diformylbenzene], by immobilizing the quaternary phosphonium salt onto the skeleton of COFs through a post-synthesis strategy for versatilely catalyzing reduction of CO2 and CO2 fixation on epoxide and aziridine facilely. With the typical features of COFs(such as porosity and ordered structure) and catalytic activity of the quaternary phosphonium salt, [PTPP]X%-TD-COF possesses an intensely synergistic effect for catalyzing the chemical transformations of CO2. Noteworthily, the quaternary phosphonium salt functionalized COFs catalyze the CO2 reduction reaction with amine and phenylsilane to produce formylated and methylated products under gentle reaction conditions with high selectivity and efficiency. Furthermore, [PTPP]X%-TD-COF shows high catalytic ability in CO2 chemical fixation reactions.