New Layered Rare‐Earth Hydroxides with Anion‐Exchange Properties

Abstract

We report the synthesis of a new series of layered hydroxides based on rare-earth elements with a composition of RE(OH)2.5Cl(0.5).0.8 H2O (RE: Eu, Tb, etc.) through the homogeneous precipitation of RECl3.x H2O with hexamethylenetetramine (HMT). Rietveld analysis combined with direct methods revealed an orthorhombic layered structure comprising a positively charged layer of [RE(OH)2.5-(H2O)0.8]0.5+ and interlayer Cl- ions. The Cl- ions were readily exchangeable for various anions (NO3-, SO4(2-), dodecylsulfonate, etc.) at ambient temperature. Photoluminescence studies showed that the compounds display typical RE3+ emission. With rare-earth-based host layers and tunable interlayer guests, the new compounds may be of interest for optoelectronic, magnetic, catalytic, and biomedical materials.

Synthesis and Aqueous Colloidal Solutions of RE2(OH)5NO3·nH2O (RE = Nd and La)

“…[1] A family of RE 2 (OH) 5 NO 3 ·nH 2 O was then synthesized under hydrothermal conditions, exhibiting a large ionexchange capacity for a wide range of organic anions. [2] The halide analogues RE 8 (OH) 20 Cl 4 ·nH 2 O and RE 2 (OH) 5 Br· nH 2 O were also presented in recent papers, demonstrating a characteristic layered structure. [3][4][5] Practically, these compounds of the general formula RE 2 (OH) 5 X·nH 2 O, called layered rare-earth hydroxides (LRHs), correspond to m = 0.5 members of the rare-earth hydroxy salts RE(OH) 3-m X m · nH 2 O, where RE = rare earths and X = interlayer anions.…”

Novel Two‐Step Topotactic Transformation Synthetic Route Towards Monodisperse LnOF:Re,3+ (Ln = Y, Pr–Lu) Nanocrystals with Down/Upconversion Luminescence Properties

“…The intercalated anions are uncoordinated in the interlayer gallery and the electrostatic interaction between the charged layers is much weaker compared with the covalent bond, which endow them with high anion exchangeability and unique behavior of exfoliation into individual layers. [ 15 ] Hitherto, researchers have paid much attention to the ion-exchange properties for the intercalated anions, [ 16 ] while sparing little interest to the [Ln 2 (OH) 5 crystal network of polyhedra, which is similar to that of the Y(OH) x F 3-x {0001} plane. Such high structural similarity and the unique layered structure of the LYH greatly favor the ease of the ion-exchange between LYH and Y(OH) x F 3-x .…”

Biohybrid based on layered terbium hydroxide and applications as drug carrier and biological fluorescence probe

“…21 3 2− may arise from HMT decomposition and the CO 2 in the air. [33,34] When the molar ratio of ASA and NaOH is 1:1, the -COOH of ASA is deprotonated. The valence of ASA in ASA-LTbH-1:1 composite is −1, and there exists neutral organic molecules in the composition.…”