An unusual highly connected 3D net with hydrophilic pore surface

An unusual highly connected 3D framework, [K2Cd3(OBA)4(H2O)2(DMF)2](H2O)2 (1) that contains three windows along separate dimensions, has been constructed from a flexible V-shaped ligand 4,4′-oxydibenzoic acid (H2OBA) and a infinite linear {K2Cd3(COO)8}n cluster under solvothermal conditions. Owing to the existence of a polar Ccarboxyl–Ocore–Ccarboxyl moiety in the ligand and the coordinated hydrophilic DMF molecule, a hydrophilic environment is generated at the pore surface. Compound 1 shows high adsorption capacity for polar molecules, such as methanol (7.83%), ethanol (7.13%) and water (13.37%), but exhibits very low uptake capacity for non-polar molecules like methane (0.49%) and cyclohexane (0.68%). Furthermore, its luminescent properties including the quantum yield and lifetime value have also been investigated.