Ionothermal and Hydrothermal Flux Syntheses of Five New Uranyl Phosphonates

Four
new uranyl phosphonate compounds have been synthesized via
ionothermal flux in the ionic liquids 1-butyl-3-methylimidazolium
chloride ([Bmim]­[Cl]) and 1-ethyl-3-methylimidazolium bromide ([Emim]­[Br]).
[C8H15N2]­[UO2(C6H5PO3H)­(C6H5PO3)] ([Bmim]­[UPhPO]), [C8H15N2]2[(UO2)4(C6H5PO3)3Cl4] ([Bmim]­[UPhPOCl]), [C8H15N2]­[UO2(HO3P­(CH2)3PO3)] (α-[Bmim]­[UC3DPO]), and [C6H11N2]2[(UO2)2(p-C6H4(PO3H)2)3]·2H2O ([Emim]­[UPhDPO])
form one-dimensional chains, two-dimensional sheets, or three-dimensional
frameworks. For comparison, analogous reactions were carried out hydrothermally,
which lead to one new framework structure, [C8H15N2]2[(UO2)5(HO3P­(CH2)3PO3)4] (β-[Bmim]­[UC3DPO]), and one previously characterized tubular uranyl phosphonate. It
was found that the structure is equally dictated by the choice of
flux method, the choice of ligand, and the choice of ionic liquid.