Synthesis and structure of [C6H14N2][(UO2)4(HPO4)2(PO4)2(H2O)]·H2O: An expanded open-framework amine-bearing uranyl phosphate

Abstract: A new open-framework compound, [C6H14N2][(UO2)4(HPO4)2(PO4)2(H2O)]·H2O, (DUP-1) has been synthesized under mild hydrothermal conditions. The resulting structure consists of diprotonated DABCOH2 2+ (C6H14N2 2+) cations and occluded water molecules occupying the channels of a complex uranyl phosphate three-dimensional framework. The anionic lattice contains uranophane-like sheets connected by hydrated pentagonal bipyramidal UO7 units. [C6H14N2][(UO2)4(HPO4)2(PO4)2(H2O)]·H2O possesses five crystallographically unique U centers. U(VI) is present here in both six- and seven-coordinate environments. The DABCOH2 2+ cations are held within the channels by hydrogen bonds to both two uranyl oxygen atoms and a μ 2-O atom. Crystallographic data (193K, Mo Kα, λ=0.71073Å): DUP-1, monoclinic, P21/n, a=7.017(1)Å, b=21.966(4)Å, c=17.619(3)Å, β=90.198(3)°, Z=4, R(F)=4.76% for 382 parameters with 6615 reflections with I>2σ(I). [Copyright &y& Elsevier]