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

A unique microporous anionic metal-organic framework, namely Zn(btb)(bbis)·6DMF (1), has been synthesized and structurally characterized [bbis = bis(4-benzylimidazol-ylphenyl)sulfone and Hbtb = 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 Eu, Tb, Dy and Sm afforded lanthanide(iii)-loaded materials. Eu@1 and Tb@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.