Bifunctional ligands containing both carboxylic and sulfonate groups can adopt versatile coordination modes to produce novel metal-organic frameworks (MOFs) with high-dimensional networks and interesting topologies. Using 2,2'-disulfonylbiphenyl-4,4'-dicarboxylic acid (H4L) as a linker and 4,4'-bipyridine (4,4'-bpy) as a co-ligand, two novel 3D CuII MOFs, {[Cu2(L)(4,4'-bpy)2.5(H2O)]·1.7H2O}n, (1), and {[Cu2(L)(4,4'-bpy)2]·DMA·3H2O}n, (2), have been synthesized and structurally characterized by X-ray crystallography (DMA is N,N-dimethylacetamide). MOF (1) shows an unprecedented trinodal 4,4,5-connected topology network with the Schläfli symbol (4.62.73)(43.65.7.8)(6.73.8.10), while MOF (2) indicates a binodal 4,6-connected fsc network with the Schläfli symbol (44.610.8)(44.62). MOFs (1) and (2) were further characterized by elemental analysis, IR spectroscopy, powder X-ray diffraction and thermogravimetric analysis. MOF (1) shows a high water and chemical stability. The proton conductivity of (1) and CO2 adsorption of (2) were also investigated.
Keywords: 2,2′-disulfonylbiphenyl-4,4′-dicarboxylic acid; 4,4,5-connected network; crystal engineering; structural diversity; topology; water and chemical stability.