Synthesis, Structures, and Luminescent Properties of Uranyl Terpyridine Aromatic Carboxylate Coordination Polymers

Six novel uranyl terpyridine aromatic carboxylate coordination polymers, [UO2(C6H2O4S)(C15H11N3)] (1), [UO2(C6H2O4S)(C15H10N3Cl)]center dot H2O (2), [UO2(C8H4O4)(C15H11N3)] (3), [UO2(C8H4O4)(C15H10N3Cl)] (4), [UO2(C12H6O4)(C15H11N3)] (5), and [UO2(C12H6O4)(C15H10N3Cl)] (6), were synthesized under solvothermal conditions and characterized by single-crystal and powder X-ray diffraction and luminescence and UV-vis spectroscopy. Compounds 1, 2,, and 5 crystallize as molecular uranyl dimers, whereas compounds 3, 4, and 6 contain ladder motifs of uranyl centers. Fluorescence spectra of 1-4 show characteristic UO22+ emission, wherein bathochromic and hypsochromic shifts are noted as a function of organic species. In contrast, uranyl emission from 5 and 6 is quenched by the naphthalene dicarboxylic acid linker molecules.