Ligand and Metal Effects on the Stability and Adsorption Properties of an Isoreticular Series of MOFs Based on T‐Shaped Ligands and Paddle‐Wheel Secondary Building Units

Abstract

The synthesis of stable porous materials with appropriate pore size and shape for desired applications remains challenging. In this work a combined experimental/computational approach has been undertaken to tune the stability under various conditions and the adsorption behavior of a series of MOFs by subtle control of both the nature of the metal center (Co²⁺ , Cu²⁺ , and Zn²⁺ ) and the pore surface by the functionalization of the organic linkers with amido and N-oxide groups. In this context, six isoreticular MOFs based on T-shaped ligands and paddle-wheel units with ScD_0.33 topology have been synthesized. Their stabilities have been systematically investigated along with their ability to adsorb a wide range of gases (N₂ , CO₂ , CH₄ , CO, H_2, light hydrocarbons (C₁ -C₄ )) and vapors (alcohols and water). This study has revealed that the MOF frameworks based on Cu²⁺ are more stable than their Co²⁺ and Zn²⁺ analogues, and that the N-oxide ligand endows the MOFs with a higher affinity for CO₂ leading to excellent selectivity for this gas over other species.