One-dimensional uranium(VI) coordination polymers with pyridinecarboxylate ligands

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Date
2016-07-27
Journal Title
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Publisher
Elsevier B.V.
Abstract
A method to produce picolinate ligand in situ under hydrothermal conditions has been used to synthesize four uranyl hydroxyl, oxo- and oxohydroxyl picolinato complexes. (UO2)(OH)(Pic) (1) (HPic = picolinic acid) contains 7-fold coordinated uranyl hydroxyl dimers linked through μ2-bridging Pic ligands forming a one-dimensional (1D) polymer. (NH4)[(UO2)3(O)2(OH)(Pic)2] (2) consists of 7-fold coordinated uranyl oxohydroxyl trinuclear units linked through both μ2- and μ3-Pic ligands forming a 1D polymer. (NH4)[(UO2)2(O)2(Pic)] (3) is constructed with 7-fold coordinated uranyl oxo-dinuclear units linked through oxo- and μ3-Pic ligands forming a 1D polymer. (NH4)[(UO2)4(O)2(OH)2(Pic)2(INT)]·H2O (4) (HINT = isonicotinic acid) is made of 7-fold coordinated uranyl oxohydroxyl tetranuclear units linked through both Pic and INT ligands forming a 1D polymer. All four polymers are thermal robust to 350 °C. Raman spectroscopy confirmed the presence of uranyl ion and Pic ligand. In addition, red enhanced fluorescence emissions have been observed for both 1 and 4. The synthesis method, with the advantage of controlling uranyl hydrolysis and generating ligand in situ, provides a more reliable way to make new coordination polymers of carboxylate ligands with various uranyl hydrolysis species. © 2016 Elsevier Ltd.
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Keywords
Uranium, Polymers, Ligands, Picolinic acid, Raman spectroscopy, Ions
Citation
Shepherd, N. D., Zhang, Y., Karatchevtseva, I., Price, J. R., Kong, L., Scales, N., & Lumpkin, G. R. (2016). One-dimensional uranium (VI) coordination polymers with pyridinecarboxylate ligands. Polyhedron, 113, 88-95. doi:10.1016/j.poly.2016.04.028
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