Metal-organic architectures of silver(I), cadmium(II), and copper(II) with a flexible tricarboxylate ligand

Three novel metal-organic architectures, [Ag-3(bta)]center dot 1.5H(2)O (1), [Cd-3(bta)(2)(H2O)(7)]center dot 5H(2)O (2), and [Cu-11(bta)(6)(Hbta)(2)-(H2O)(10)]center dot 29H(2)O (3), were obtained by reactions of the corresponding metal salts with a flexible tripodal ligand, benzene-1,3,5-triacetic acid (H(3)bta), and their structures were determined by single-crystal X-ray diffraction studies. The results revealed that, in complexes 1 and 2, the carboxylate groups of the bta(3-) ligand adopted varied coordination modes to link metal atoms and further to form three-dimensional structures with open channels occupied by water molecules, while in complex 3, for the first time, the flexible H3bta acted as a secondary building unit to generate a novel nanometer-sized metallocage, which is composed of a Cu-II paddle wheel (square secondary building units) and bta(3-)/Hbta(2-) organic links (triangular secondary building units). The photoluminescence properties of complexes 1 and 2 were investigated, and the results showed that 2 exhibited photoluminescence in the solid state at room temperature.