Synthesis, Crystal Structure and Properties of a New 3D Supramolecular Metal-Organic Framework with Stable Tunnels

A flexible polycarboxyl ligand of tetrahydrofuran-2,3,4,5-tetracarboxylic acid (H(4)THFTCA) and a common rigid aromatic ligand of 1,10-phenanthroline (phen) have been successfully co-assembled with Cu(NO3)(2)center dot 3H(2)O to give out a novel 3D supramolecular metal-organic framework (MOF) compound, [Cu-2(THFTCA)(phen)(H2O)(2)center dot CH3CH2OH center dot 3H(2)O] (n) (1), by a solution self-assembly process. Compound 1 has been characterized as a 2D layered coordination polymer constructed by THFTCA(4-) and Cu2+ ions, and the layer present a novel (3.5(2))(3(2).5(3).6(4).7) topological network. Interestingly, the layers are fused each other via strong pi-pi stacking interactions among adjacent ligands of the terminal phen, so that a 3D supramolecular MOF with 1D rhomboidal tunnels array is formed. The thermogravimetric analysis and corresponding powder X-ray diffraction analysis have revealed that the tunnels structure of 1 could be retained after all guest molecules are removed, and the framework could resist the collapse even heating up to 210 A degrees C. An opinion has also been proposed that the larger accessible volume of the guests means the larger stress on the backbone of the MOF after the guests are removed, and the stress is harmful to the stability of the supramolecular porous structure. Finally, the application properties based on the porous structure have also been primarily evaluated.