Synthesis and anion exchange chemistry of new intercalation hosts containing lanthanide cations, Ln 2(OH) 5(NO 3)· xH 2O (Ln=Y, Gd–Lu)

Abstract

A new class of lanthanide containing layered hydroxides, with the composition Ln 2(OH) 5NO 3· xH 2O (Ln=Y, Gd–Lu), has been synthesised via a hydrothermal route. These materials combine the properties of the lanthanides with the flexibility of intercalation hosts and comprise cationic layers containing a single lanthanide cation with charge neutrality maintained by the nitrate anions between the layers. Powder X-ray diffraction (XRD) and TEM studies indicate that they have a monoclinic structure. Additionally, powder XRD data show that Gd 2(OH) 5NO 3· xH 2O is significantly less crystalline than the other phases and it has not yet proved possible to synthesise this phase with any of the larger lanthanides. The capacity of the Ln 2(OH) 5NO 3· xH 2O (Ln=Y, Gd–Lu) materials for anion exchange chemistry has been demonstrated by their facile reactions with a range of inorganic and organic anions, including sulphate, carbonate, aliphatic and aromatic dicarboxylates and disulphonate-forming materials with the general composition Ln 2(OH) 5A 0.5· xH 2O.