Reticular chemistry guided function customization: a case study of constructing low-polarity channel for efficient C3H6/C2H4 separation

Abstract

Guided by principles of reticular chemistry, we have successfully presented the "bending-bridge" strategy, achieving an extraordinary function-targeted assembly by ingeniously redirecting the coordination direction of traditional SBUs. This led to the synthesis of a novel metal-organic framework (MOF), {[CH3NH3][InTPCA]·2H2O·NMF·DMF} (ZJNU-401). The smart design of bending branch within the ligand effectively transformed the tetrahedrally coordinated mononuclear In(III) into a square-planar configuration, thereby avoiding the introduction of open metal sites (OMSs) commonly associated with traditional ssb networks and creating a low-polarity pore surface environment. ZJNU-401 exhibits an optimal pore system that enhances its efficacy for high uptake of C3H6 and C2H6 over C2H4. The remarkable selectivity ratio of C3H6 to C2H4 reaches up to 15.45, alongside efficient one-step purification of C2H4 (> 99.95%) from the mixture of C3H6/C2H4. DFT calculations revealed that multiple O active sites within nonpolar pores provide stronger interactions with both C3H6 and C2H6 compared to those with C2H4.