Framework desymmetrization enables partial pore space partition in metal-organic frameworks

The pore-space-partition (PSP) has been recognized as a powerful strategy for boosting the uptake capacity of small gas molecules and has seen wide application in reticular chemistry. However, the most successful PSP platform—the partitioned- acs (pacs) net—has followed only one pattern since its inception over a decade ago: one partition agent per partition site, with a general formula of [M 3 O( L1 ) 3 ]( L2 ). This fully partitioned architecture occupies all metal sites, eliminating open metal sites (OMSs) and compromising selectivity. Herein, we introduce a partial PSP concept accessed through a framework desymmetrization strategy. By replacing traditional high-symmetry D 2h ligands with lower-symmetry C 2h ligands (e.g., fumaric acid), we introduce structural distortions into the acs network, breaking the uniformity of partition sites and allowing partition agents to occupy only a fraction of available positions. This provides access to a PSP mechanism, namely part-pacs (partially partitioned- acs ), with a general formula of [M 3 O( L1 ) 3 ]( L2 ) 1/3 . The part-pacs structures retain high acetylene capacity while exhibiting significantly enhanced selectivity compared to their fully partitioned analogues. Specifically, part-pacs-fum-tpa achieves C 2 H 2 /CO 2 separation productivity nearly twice that of its full-pacs counterpart (1.92 mol kg −1 vs 0.98 mol kg −1 ).