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

Abstract

Guided by the 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 branches 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.