Synthesis,Crystal Structure and Fluorescence Properties of a Terbium(Ⅲ) Complex with Biphenyl-2,3,3',5'-tetracarboxylic Acid

A new terbium complex based on biphenyl-2,3,3',5'-tetracarboxylic acid(H_4bptc) has been synthesized, {Tb(Hbptc)(H_2O)_4]×H_2O}n(1). Its structure was determined by single-crystal X-ray diffraction analysis and further characterized by elemental analysis, IR spectra and TG analyses. Title complex crystallizes in monoclinic, space group P21/n with a = 14.090(2), b = 8.0824(13), c = 15.5591(17) ?, V = 1775.4(5) ?~3, Mr = 576.22, D_c = 2.156 g/cm3, μ(Mo Kα) = 4.059 mm~(-1), F(000) = 1128, Z = 4, the final R = 0.027 and w R = 0.0726 for 3296 observed reflections(I 2σ(I)). Complex 1 exhibits a 2 D layer structure, and such layers are further united together into a three-dimensional supramolecular structure through π···π interaction and intricate hydrogen bonding. The fluorescence excitation and emission spectroscopy of 1 showed that H4 bptc is a kind of highly efficient sensitizer for terbium(Ⅲ) ion. The title complex also displays efficient ligand sensitized luminescence in the visible region with long lifetime of 2.02 ms in the solid state.