Controllable synthesis of isoreticular pillared-layer MOFs based on N-rich triangular prism building units: gas adsorption and luminescent properties

Abstract

A series of isoreticular MOFs (1–4) with rare lon topologies have been rationally synthesized using the ligand benzotriazole-5-carboxylic acid and auxiliary aromatic dicarboxylic ligands based on novel double secondary building units (SBUs) and trigonal-prism building units. On the other hand, MOFs 1–4 all adopt pillared-layer structures based on the same honeycomb layers, and then the neighboring layers are linked together through the ditopic carboxylate pillars. They all exhibit similar constructions but different pore characteristics (volumes and surfaces), owing to convertible ditopic ligands pillaring the same layers. Notably, they all possess a certain degree of air and water stability and CO₂ uptake capacity. In addition, we researched the luminescence properties of MOFs 1–4. We found that MOF 2 can be used as a fluorescent probe for exhibiting a clear fluorescent enhancement “turn on” response for H₂O and a fluorescence quenching “turn-off” response for nitrobenzene (NB).