Constructing Alkali Metal–Organic Frameworks with High Porosity Utilizing a High-Connectivity Organic Linker

Alkali metal-organic frameworks (AMOFs) hold considerable promise for a broad spectrum of applications, benefiting from their low toxicity and lightweight. However, the construction of AMOFs with permanent porosity remains a significant challenge due to the tendency of alkali metals to coordinate with polar solvents, thereby forming coordination polymers with low dimensionality. Here, we introduce a connectivity-regulated approach for the synthesis of porous AMOFs by using highly connected organic linkers. Following this strategy, we have constructed AMOFs (denoted as HIAM-112-Li/Na/K/Rb/Cs) using the entire group of alkali metals (Li, Na, K, Rb, and Cs) and an octacarboxylate linker. In particular, HIAM-112 K/Rb/Cs demonstrate record-high porosities among K-, Rb-, and Cs-based coordination networks, respectively. By evaluating their separation performance for the selected gas mixtures, we demonstrate that these highly porous AMOFs hold a strong potential in adsorption-related fields.