New Luminescent Three-Dimensional Zn(II)/Cd(II)-Based Metal–Organic Frameworks Showing High H2 Uptake and CO2 Selectivity Capacity

Abstract

Three new three-dimensional (3D) luminescent metal–organic frameworks (MOFs), namely, [Zn2(L)2]·2DMA·3H2O (1), [Zn2(L)2]·H2O (2), and [Cd2(L)2]·H2O (3) [H2L = 2-(imidazol-1-yl)terephthalic acid], have been solvothermally synthesized by using d10 metal ions Zn(II)/Cd(II) and H2L in different solvent systems, which have been well characterized by elemental analysis, Fourier transform infrared spectroscopy, powder X-ray diffraction, and thermogravimetric analysis. As influenced by the different solvents and metal ions, single-crystal X-ray diffraction shows that 1 is a three-dimensional (3D) microporous framework with one-dimensional (1D) pores (10.85 × 8.79 A2) based on the [Zn2(μ2-COO)4] secondary building units, and 2 and 3 are two 3D isostructural networks composed by 1D zigzag chains, which are further connected by L2– ligands into dense packing structures. Topology analyses reveal that 1 can be simplified as a binodal (6,3)-connected ant topological net with a point symbol of (44·63·83)(48·62), and 2 a...