Ionothermal synthesis of a metal-organic framework constructed by magnesium(II) and 4,4′-oxybis(benzoic acid) ligand

By using the ionic liquid 1-butyl-2,3-dimethylimidazolium bromide ([Bmmim]Br) as solvent and reactant, a magnesium(II) metal complex, namely, [Bmmim][Mg3(oba)3(obaH)] (1) (obaH2 = 4,4′-oxybis(benzoic acid)) has been synthesized ionothermally, which represents the first Mg(II)-oba metal-organic framework. Single-crystal X-ray analysis indicated that the structure of 1 featured a three-dimensionally anionic framework of [Mg3(oba)3(obaH)]nn−. Photoluminescence measurements revealed that 1 exhibited strong emission at 387 nm ascribed to ligand-to-metal charge transfer.

Graphical abstractWe report on the ionothermal synthesis of a magnesium metal-organic framework, namely [Bmmim][Mg3(oba)3(obaH)] (1) (obaH2 = 4,4′-oxybis(benzoic acid), [Bmmim] = 1-butyl-2,3-dimethylimidazolium). The structure of 1 features a three-dimensionally (3D) anionic framework. Thermal stability and photoluminescent property of 1 have also been studied.Figure optionsDownload full-size imageDownload as PowerPoint slideHighlights► Ionothermal synthesis is firstly applied in the preparation of Mg-oba MOF. ► The current compound is the first Mg-MOF built from the obaH2 ligand. ► Compound 1 exhibits strong light emission at 387 nm (λex = 285 nm) in the solid state at room temperature.