The construction of metal-organic frameworks based on 2-(1-hydroxy-ethyl)-3H-benzoimidazole-5-carboxylic acid

Presented here are two novel metal-organic frameworks (MOFs) synthesized by employing a trifunctional imidazolate derivative, 2-(1-hydroxy-ethyl)-3H-benzoimidazole-5-carboxylic acid (H2ebimc) as a ligand. In compound 1, the Zn atoms and ebimc2- ligands were crosslinked to build a wavelike two-dimensional (2D) layer with 3-connected (4.82) topology, with water molecules as terminal ligands coordinated on both sides of the layers. Then, the D-(+)-camphoric acid (H2cam) ligand was introduced into the synthesis system to obtain compound 2. In compound 2, similar topological layers were formed based on Zn2(CO2)3 subunits (SBUs) and then were further pillared by cam2- ligands to construct the final three-dimensional (3D) pillar-layered framework. Moreover, compound 2 exhibited high selectivity of CO2 over N2 and CH4, along with a distinctive framework flexibility triggered by C2H6. Our results highlight the great potential of H2ebimc as a multifunctional ligand for synthesizing MOFs.