Topological Evolution in Uranyl Dicarboxylates: Synthesis and Structures of One-Dimensional UO2(C6H8O4)(H2O)2 and ThreeDimensional UO2(C6H8O4)

Two novel uranyl adipates are reported as synthesized via hydrothermal treatment of uranium oxynitrate and adipic acid. Onedimensional UO2(C6H8O4)(H2O)2 (1) [a = 9.6306(6) (angstrom), c = 11.8125(10) (angstrom), tetragonal, P43212 (No. 96), Z = 4] consists of chains of (UO2)O4(H2O)2 hexagonal bipyramids tethered through a linear adipic acid backbone. Three-dimensional UO2 (C6H8O4) (2) [a = 5.5835(12) (angstrom), b = 8.791(2) (angstrom), c = 9.2976(17) (angstrom), (alpha)= 87.769(9) °, (beta)= 78.957(8) °, (gamma)= 81.365(11) °, triclinic, P (No. 2), Z = 2] is produced by decreasing the hydration level of the reaction conditions. This structure contains a previously unreported [(UO2)2O8] building unit cross-linked into a neutral metal-organic framework topology with vacant channels.