Synthesis and Crystal Structures of New Lanthanide Hydroxyhalide Anion Exchange Materials, Ln2(OH)5X • 1.5H2O (X = Cl, Br; Ln = Y, Dy, Er, Yb)

A family of layered lanthanide hydroxyhalide intercalation hosts, Ln(2)(OH)(5)X center dot 1.5H(2)O (X = Cl, Br; Ln = Y, Dy, Er, Yb), has been synthesized under hydrothermal conditions and their crystal structure determined. These are the first structures for the m = 1 members of the Ln(2)(OH)(6-m)(A)(m)center dot nH(2)O family of intercalation hosts to be determined. Reaction mixtures with Ln = Yb always yield a biphasic product which adopts an orthorhombic or monoclinic crystal structure. In both cases the layer composition is [Yb-2(OH)(5)(H2O)(1.5)](+) and the Yb is eight or nine coordinated to bridging hydroxide anions and coordinated water molecules. Charge balancing halide anions are located in the interlayer gallery. The orthorhombic structure is adopted by the other chloride host lattices and the monoclinic one by Y-2(OH)(5)Br center dot 1.5H(2)O. These materials have been shown to undergo facile room temperature anion exchange reactions with a range of organic dicarboxylates.