Synthesis and structure of [C 6H 14N 2][(UO 2) 4(HPO 4) 2(PO 4) 2(H 2O)]·H 2O: An expanded open-framework amine-bearing uranyl phosphate

Abstract

A new open-framework compound, [C 6H 14N 2][(UO 2) 4(HPO 4) 2(PO 4) 2(H 2O)]·H 2O, ( DUP-1) has been synthesized under mild hydrothermal conditions. The resulting structure consists of diprotonated DABCOH 2 2+ (C 6H 14N 2 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 UO 7 units. [C 6H 14N 2][(UO 2) 4(HPO 4) 2(PO 4) 2(H 2O)]·H 2O possesses five crystallographically unique U centers. U(VI) is present here in both six- and seven-coordinate environments. The DABCOH 2 2+ cations are held within the channels by hydrogen bonds to both two uranyl oxygen atoms and a μ 2-O atom. Crystallographic data (193 K, Mo Kα, λ=0.71073 Å): DUP-1, monoclinic, P2 1/ 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>2 σ( I).