Modulating Microenvironments of Nanocages in MOFs for Controllable Propylene Adsorption

Nanocages of metal-organic frameworks (MOFs) are critical for gas separation by accommodating the target molecules through some specific interactions. However, traditional temperature- and pressure-swing adsorption by using MOFs is energy-intensive to modulate the adsorptive interactions. Herein, we use anthracene as the photoresponsive switch (PRS) to modulate the microenvironments of nanocages in MOFs by light for controllable gas adsorption of MOFs. Irradiation with 365 nm of light makes anthracene dimerize, which forms an unfit microenvironment and decreases the uptake of gases. Irradiation with 254 nm light or heating recovers the dimer of anthracene to the monomer, which weakens the negative impact of anthracene on gas adsorption. The change of binding energy between the framework of nanocage and the guest molecule by molecular simulation reveals the distinctive effects of polymerized/unpolymerized anthracene on gas adsorption. This work gives clues to the development of advanced adsorbents for controllable gas separation.