Structural diversity in organically templated uranium sulfates

Abstract

The potential of organic amine templates to direct the synthesis of metal sulfate frameworks has been investigated. Eight novel uranyl sulfates have been prepared using a templated uranyl sulfate precursor under hydrothermal conditions. The topologis of the isolated phases vary from the molecular (0-D), to chains (1-D) to layered (2-D) frameworks. [N₄C₆H₂₂]₂[(UO₂)₂(SO₄)₆] (USO-10) is molecular or zero-dimensional. Two different types of one-dimensional uranyl-containing chains have been observed. [N₂C₄H₁₂][UO₂(H₂O)(SO₄)₂] (USO-3), [N₂C₅H₁₄][UO₂(H₂O)(SO₄)₂] (USO-4) and [N₂C₃H₁₂][UO₂(H₂O)(SO₄)₂] (USO-9) contain chains based upon a [UO₂(SO₄)_4/2] backbone. [N₂C₁₀H₁₀][UO₂(SO₄)₂]·H₂O (USO-6) and [N₂C₆H₁₈][(UO₂)₂(H₂O)₃(SO₄)₃] (USO-7) contain chains based upon a [UO₂(SO₄)_3/3] backbone. Two layered or two-dimensional compounds, [N₂C₆H₁₄][UO₂(H₂O)(SO₄)₂] (USO-5) and [N₂C₃H₅]₂[(UO₂)₂(SO₄)₃] (USO-8) have also been isolated. All the new phases have been characterised using a range of physical techniques including single crystal X-ray structure analysis.