The mixed-ligand strategy to assemble a microporous anionic metal–organic framework: Ln3+ post-functionalization, sensors and selective adsorption of dyes

Abstract

A unique microporous anionic metal–organic framework, namely [Zn₂(btb)₂(bbis)](Me₂NH₂)₂·6DMF (1), has been synthesized and structurally characterized [bbis = bis(4-benzylimidazol-ylphenyl)sulfone and H₃btb = 4,4′,4′′-benzene-1,3,5-triyltribenzoic acid]. This compound exhibits a 4-fold interpenetrated anionic framework with ins topology. The post-synthetic cation exchange of 1 with Eu³⁺, Tb³⁺, Dy³⁺ and Sm³⁺ afforded lanthanide(III)-loaded materials. Eu³⁺@1 and Tb³⁺@1 can be used as the potential luminescent probes in nitrobenzene. The adsorption behavior of 1 towards organic dyes was investigated, revealing rapid and selective separation of methylene blue.