A novel polyhedron-based metal–organic framework with high performance for gas uptake and light hydrocarbon separation

Abstract

A novel polyhedron-based metal–organic framework [(CH₃)₂NH₂]₂[Zn₃(TADIPA)₂(DMF)₂]·4DMF (JLU-Liu40), which possesses three types of cages with different shapes and sizes, has been successfully synthesized. The framework of JLU-Liu40 is constructed by two inorganic secondary building units (SBUs) of 4-connected square binuclear Zn-paddlewheel and 4-connected tetrahedron mononuclear Zn unit and one organic SBU, which has abundant Lewis basic sites (LBSs), and the framework can be simplified as a pair of 3-connected triangle geometries. Moreover, JLU-Liu40 shows a new (3, 4, 4)-connected topology with the Schläfli symbol {7², 9}₂{7⁴, 8²}. With the benefit of its high density of open metal sites (OMSs) and LBSs, JLU-Liu40 shows good adsorption ability for some small gases such as N₂, CO₂, CH₄, C₂H₆ and C₃H₈. In addition, the theoretical ideal adsorbed solution theory (IAST) calculation indicates that JLU-Liu40 should be a promising material for light gas separation.