Synthesis, structure and luminescent property of a binuclear terbium complex [Tb2(Hsal)8(H2O)2][(Hphen)2]•2H2O

A binuclear terbium complex [Tb-2(Hsal)(8)(H2O)(2)] . [(Hphen)(2)] . 2H(2)O 1 (Hsal = o-HOC6H4CO2-, phen = 1,10-phenanthroline) was synthesized and characterized by elemental analysis, molar conductance, IR, UV-VIS, X-ray powder diffraction, Thermogravimetric analysis and fluorescence. Its structure was determined by X-ray single crystal diffraction. In the dimeric anion [Tb-2(Hsal)(8)(H2O)(2)](2-), two terbium atoms are connected by four bidentate bridging carboxylate groups. Each Tb atom is eight-coordinated to four bidentate bridging carboxylate groups, one bidentate chelating carboxylate groups, one monodentate carboxylate group as well as one water molecule. The mono-protonated phen does not coordinate to the Tb atom directly. Hydrogen bonds, pi-pi stacking interactions and electrostatic attractions result in the formation of a two-dimensional supramolecular structure. The solid-state luminescence behavior of 1 was studied. Compared with binary terbium salicylate Tb(Hsal)(3)(H2O)(2) . 2H(2)O, it emits a relatively weak green light under the excitation of UV light, which may be attributed to the formation of extensive pi-electron conjugation systems in the structure. (C) 2003 Elsevier B.V. All rights reserved.