Dynamic Pore Space Partition in Zinc Metal–Organic Frameworks

Increasing the framework connectivity is a useful strategy to tune pore geometry and properties such as gas separation selectivity. Although highly connected frameworks are common for iconic clusters such as M 3 (O/OH) trimers and Zr 6 (O/OH) 8 hexamers, they are rarely seen for Zn 4 O tetramers, one of the most famed MOF building blocks that predates both M 3 and Zr 6 in the MOF field. Here, we demonstrate that pore space partition (PSP) can unlock the potential of Zn 4 O for higher connectivity (>6). We show that on the pore-space-partitioned acs (pacs) platform, zinc-cluster chemistry is diverse and dynamic, yet it can be mapped out semiquantitatively. A large family of Zn x –pacs materials ( x = 2, 3, 4) with 3 different pore-partition mechanisms has been synthesized by applying PSP to the MOF-5-type system. We propose that the difference in the steric effect around 9-connected Zn 3 (OH) and Zn 4 O, exacerbated when the hexagonal c/a ratio is compressed, plays a key role in the discovery of a new pacs family based on 9-connected Zn 4 O. This work significantly broadens the scope of PSP because it no longer requires preoriented open-metal sites. New pacs materials show much better aqueous stability and greatly enhanced C 2 H 2 /C 2 H 4 separation performance than the corresponding nonpartitioned MOF-5-type materials.