An Octacarboxylate-Linked Sodium Metal-Organic Framework with High Porosity

Alkali metal-based metal-organic frameworks (MOFs) with permanent porosity are scarce because of their high tendency to coordinate with solvents such as water. However, these MOFs are lightweight and bear gravimetric benefits for gas adsorption related applications. In this study, we present the successful construction of a microporous MOF, designated as HIAM-111, built solely on sodium ions by using an octacarboxylate linker. The structure of HIAM-111 is based on 8-connected Na₄ clusters and exhibits a novel topology with an underlying 3²,4²,8-c net. Remarkably, HAM-111 possesses a robust and highly porous framework with a BET surface area of 1561 m²/g, significantly surpassing that of the previously reported Na-MOFs. Further investigations demonstrate that HIAM-111 is capable of separating C₂H₂/CO₂ and purifying C₂H₄ directly from C₂H₄/C₂H₂/C₂H₆ with high adsorption capacities. The current work may shed light on the rational design of robust and porous MOFs based on alkali metals.