Structures and Properties of New Cadmium(II) and Copper(II) Metal-Organic Frameworks Based on Flexible Bridged 1,4-bi(1-Himidazol-1-yl) butane Ligand

Two new metal-organic frameworks (MOFs) based on cadmium(II) ions, 1,2-benzenedicarboxylic acid (BDC), flexible ligand 1,4-bi(1H-imidazol-1-yl) butane (BIIM), coordinated water molecules, [(BIIM)(BDC)(H2O) Cd] 3n (1) and copper(II) ions, BIIM, coordinated water, free thiophene-2,5-dicarboxylate (TDC), free water, {[(BIIM) 4(H2O)(4)Cu-2].(TDC)(2)center dot(H2O)(12)} n (2) are prepared and characterized by X-ray diffraction, thermal gravimetric analysis (TGA), infrared (IR) spectrum and the photoluminescence property for complex (1). The X-ray diffraction analysis reveals that the structures of complexes 1 and 2 are 2D structures through the C-H...pi stacking interactions (for 1) and the BIIM bridging connections (for 2). The IR spectrum for 1 and 2 are presented in the paper, for 1, the strong peaks at 1399 and 1573 cm(-1) are owing to the carboxylic CO(2)(-)symmetry and asymmetry stretching vibrations of BDC. The features of the IR spectrum are consistent with the single crystal structures. The TGA reveal the water is the first lost material from complex, then the ligands removed, and finally the residues of these two complexes are the metal oxide.