Organic-inorganic hybrid materials constructed from inorganic lanthanide sulfate skeletons and organic 4,5-imidazoledicarboxylic acid

Five different types of the lanthanide sulfate-carboxylates family, [La-2(SO4)( Himdc)(2)( H2O)(2)] 1, [Gd-2( SO4)(2)( Himdc)( H2O)(3)] center dot H2O 2, [Ln(2)( SO4)(2)( Himdc)( H2O)(3)] center dot H2O ( Ln = Gd 3a, Eu 3b), [Eu6Cu( SO4)(6)( Himdc)(4)( H2O)(14)] 4, and [Ln( Himc)(SO4)( H2O)] ( Ln = Eu 5a, Gd 5b, Tb 5c, Dy 5d, Er 5e); H(2)imc = 4-imidazolecarboxylic acid, H(3)imdc = 4,5-imidazoledicarboxylic acid) have been obtained by hydrothermal reactions of Ln(2)O(3), transition metal sulfates and H(3)imdc at 170 degrees C and characterized by means of elemental analyses, IR, TG analysis, luminescence spectroscopy and single crystal X-ray diffraction. The 3D structure of 1 is constructed from alternately linkages of organic {La( Himdc)} layers and inorganic {La2O2(SO4)} layers, with the La atoms as hinges. 2 and 3a/3b both contain alternately arranged 1D left-and right-handed helical {Ln( imdc)} chains bridged by SO42- anions to form a 3D framework with 1D rectangle-like channels along the b axis. The structural differences of 2 and 3a/3b lie in the linkages of the SO42- anions. Complex 4 consists of 2D tubular Eu-sulfate ayers pillared by {Cu( Himdc)(2)} units to generate a 3D network. Complexes 5a-5e possess 2D bamboo-raft-like layer structures based on helical tubes. Interestingly, H(2)imc comes from the in-situ decarboxylation of H(3)imdc in the hydrothermal reactions. The luminescence properties of the complexes 3a, 4, 5a 5c, 5d were investigated in solid state at room temperature.