Synthesis of Acid-Base-Resistant 3D MOF-Network with Ligand Containing a Concave Backbone and Convex Binding Sites

A new ligand design is reported, combining a concave-shaped backbone and convex binding sites. The combination of a C2-linked 1,2,3-trisubstituted arene (concave connection) and meta-COOH side arm binding sites (convex shape) was prepared and applied to the preparation of extended frameworks. With the formation of different SBUs, the binding cation plays a crucial role. While Co²⁺ gave the 1D linear polymer, Cd²⁺ produced 3D porous networks with a new (3,3-c) topology. The resulting MOF showed excellent stability toward water, acids, and bases (pH = 2-11), highlighting the potential applications in aqueous solution based on this new ligand design concept.