Three novel indium MOFs derived from dicarboxylate ligands: Syntheses, structures and photoluminescent properties

The self-assembly of InCl3 with 1,4-phenylenediacetic acid (1,4-H2pda), 1,3-benzendicarboxylic acid (1,3-H2bdc) and 1,4-cyclohexanedicarboxylic acid (1,4- H2chdc) generates three new In(III) MOFs, (Me2NH2)[In(cis-1,4-pda)2] (1), HIn(1,3-bdc)2·2DMF (2) and In(OH)(trans-1,4-chdc) (3) (Me2NH=dimethylamine, DMF=N, N'-dimethylformamide). Compound 1 displays a novel 1D no-planar double chain. Although a mixture of cis- and trans-1,4-H2pda was used, the product of compound 1 is a single phase with only cis-pda2− ligands. Compound 2 possesses a 2D square lattice with sql topology. Interestingly, in compound 2, the 4-connected building unit containing InO6 octahedron is firstly occurred in In-MOFs. Compound 3 is built up from the infinite metal-oxide chains cross-linked by trans-1,4-chdc2− to form 3D framework with rhombus-shaped channels. Furthermore, compounds 1–3 present intense solid-state fluorescent emissions at room temperature. - Graphical abstract: Three new In-MOFs based on different dicaboxylate acids display 1D chain, 2D layer and 3D open-framework, respectively and show strong luminescence emissions at room temperature. Highlights: ► Three new indium metal-organic frameworks have been solvothermal synthesized. ► The structural variation is attributed to the diverse coordination modes of ligands. ► Compounds 1–3 exhibit 1D double chain, 2D layer and 3D open-framework, respectively. ► These compounds exhibit strong solid-state luminescence emission at room temperature.