Linker Enantiomericity Engineering in Reticular Frameworks for Architecting Robust Materials with Synergetic Open...

Chiral linkers offer built-in enantiomericity capable of regulating pore microenvironments or even net dimensions and topologies of the resulting reticular frameworks. Whereas it has been established that enantiopure and racemic linkers can form significantly different structures upon metal directed coordination assembly, such examples are still extremely rare and occur largely through serendipity rather than rational design. In this work, guided by the intrinsically chiral topology concept established in reticular frameworks and the Wallach's rule that racemic crystals are denser than chiral ones in supramolecular systems, we target a unique example where enantiopure linker gives a homochiral 3D porous and robust framework (S-TAMOF-3D) with intrinsically chiral (10,3)-a srs topology while the racemic linker exclusively produces a 2D dense and non-porous layered structure (race-TAMOF-2D), upon crystallization with Cu ions in water at room temperature. This experimental observation points to the fact that linker enantiomericity could lead to structural diversity much greater than has hitherto been suspected. Moreover, the activated S-TAMOF-3D shows triangle-shaped cavities decorated with exposed open Cu²⁺ sites, which work synergistically to bind SF₆ molecules with outstanding SF₆/N₂ separation performance, as validated by extensive sorption and breakthrough experiments as well as theoretical simulations. Our work suggests that beyond molecular systems, Wallach's rule can also be leveraged to guide the design of extended reticular materials that otherwise are unachievable via traditional linker engineering strategies, thus offering a new methodology for architecting reticular materials with enhanced functions.