Rational design and synthesis of a task-specific porous organic framework featured azobenzene as a photoresponsive low-energy CO2 adsorbent

An azobenzene-containing porous organic framework (POF) was rationally designed and synthesized via Sonogashira-Hagihara coupling reaction. By virtue of high porous skeleton and azobenzene as light responsive group, this task-specific POF exhibits the reversible stimuli-responsive adsorption property triggered by UV irradiation and heat treatment. The initial Brunauer-Emmet-Teller (BET) surface area of this porous material is 571 m (2) g(-1), while the BET surface area after UV irradiation decreases to 550 m(2) g(-1) along with the reduction of micropores around 0.5 nm and 1.3 nm during the trans to cis isomerization process. Furthermore, CO2 sorption isotherms show a slight decrease, which is caused by the trans to cis conversion of azobenzene side group. It is worth mentioning that CO2 uptakes of POFs are almost constant for three cycles via alternating external stimuli to confirm the excellently reversible switchability of trans-to-cis isomerization.

Automated summary

The azobenzene-containing porous organic framework shows reversible stimuli-responsive adsorption property triggered by UV irradiation and heat treatment. The CO2 uptake remains almost constant during trans-to-cis isomerization, confirming the excellent reversible switchability of the material.