Synthesis, Crystal Structure and Photoluminescent Property of Metal-Organic Frameworks with Mixed Carboxylate and Imidazole-Containing Ligands.

Three new metal-organic frameworks (MOFs), namely [Zn(tib)(PDC)] ( 1), [Zn3(tib)2(CHDC)3]·8H2O ( 2) and [Zn3(tib)2(BTC)2]·4.95H2O ( 3) were synthesized by hydrothermal reactions of ZnCl2 with 1,3,5-tris(1-imidazolyl)benzene (tib) and different carboxylate ligands of 2,6-pyridinedicarboxylic acid (H2PDC), 1,4-cyclohexanedicarboxylic acid (H2CHDC) and 1,3,5-benzenetriacetic acid (H3BTC), respectively. The complexes were characterized by IR, thermogravimetric analysis, single crystal and powder X-ray diffractions. Complex 1 has a binuclear structure, in which one imidazole group of tib is free of coordination, while 2 has three-dimensional (3D) framework with the CHDC-Zn microcycles filled into the tib-Zn 3D net, and 3 is a 2-fold interpenetrating 3D framework with the interconnection of two one-dimensional (1D) chains formed by BTC-Zn and tib-Zn, respectively. The different structures of 1- 3 are resulted from the distinct carboxylate ligands. In addition, complexes 1- 3 show obvious emissions at room temperature in the solid state. [ABSTRACT FROM AUTHOR]