Layered double hydroxides (LDH) intercalated with metal coordination compounds and oxometalates

Rives, V.; Ulibarri, M.A.

doi:10.1016/s0010-8545(98)00216-1

Cited by 824 publications

(500 citation statements)

References 202 publications

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“…These substances comprise an isostructural class of pure inorganic materials capable of exchanging interlamellar counter anions with other anions of interest. [18][19][20] Metal-organic frameworks with extended cationic networks and guest anions are also potential candidates for anion exchange and trapping. 6,[21][22][23][24] In the foregoing examples, the anions are typically bound through weak electrostatic and/or hydrogen bonding interactions.…”

Section: Introductionmentioning

confidence: 99%

Immobilization, Trapping, and Anion Exchange of Perrhenate Ion Using Copper-Based Tripodal Complexes

2011

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Abstract:We describe a multidentate tripodal ligand in which three pendant arms carrying di(2-picolyl)amine units are linked to the ortho-positions of a tris (o-xylyl) scaffold, providing N(CH 2 -o-C 6 H 4 -CH 2 N(CH 2 py) 2 ) 3 (L). Reaction of L with CuCl 2 in the presence of hexafluorophosphate anion afforded blue cubes of [(CuCl) 3 L](PF 6 ) 3 ⋅5H 2 O (1). Crystallographic studies of 1 revealed that the three symmetry-related arms each coordinate a {Cu II Cl} unit, and two molecules of 1 are connected to one another through a Cu(µ-Cl) 2 Cu bridge, extending the molecular structure to form a two-dimensional layer.These 2-D layers pack in an ABCABC… fashion with PF 6 -anions located in between.Reaction of 1 with a stoichiometric amount of perrhenate ion afforded blue plates ofCompound 2 has the same lattice structure of 1, but the tricopper unit backbone now traps one ReO 4 -anion through Coulombic interactions.In addition, three molecules of 2 are bridged by a perrhenate ion forming a Cu 3 (µ 3 -ReO 4 )cluster to give a different 2-D structure, displaying a rare tridentate bridging ReO 4 -mode.Thus in addition to classic perrhenate trapping through weak Coulombic interactions, 2 represents an exceptional example in which the ReO 4 -anion is immobilized in an extended framework through tight covalent interactions. The interlamellar PF 6 -anions in 1 can be exchanged with other anions including perrhenate, perchlorate, or periodate. The structural similarity between perrhenate and pertechnetate makes these materials of potential interest for pertechnetate trapping.3

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Section: Introductionmentioning

confidence: 99%

Immobilization, Trapping, and Anion Exchange of Perrhenate Ion Using Copper-Based Tripodal Complexes

2011

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“…LDHs have been attracting considerable attention as catalytic materials owing to their solid basicity [86] and ability to be modified by various polyacids [92]. Furthermore, mixed oxides formed by the calcination of LDHs can function as solid-base catalysts for many organic reactions.…”

Section: Catalytic Activity Of Ldhsmentioning

confidence: 99%

Geomaterials: their application to environmental remediation

Yamada

Tamura

Watanabe

et al. 2011

Science and Technology of Advanced Materials

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Geomaterials are materials inspired by geological systems originating from the billion years long history of the Earth. This article reviews three important classes of geomaterials. The first one is smectites-layered silicates with a cation-exchange capacity. Smectites are useful for removing pollutants and as intercalation compounds, catalysts and polymer nanocomposites. The second class is layered double hydroxides (LDHs). They have an anion-exchange capacity and are used as catalysts, catalyst precursors, sorbents and scavengers for halogens. The third class of geomaterials is zeolites-microporous materials with a cation-exchange capacity which are used for removing harmful cations. Zeolite composites with LDHs can absorb ammonium and phosphate ions in rivers and lakes, whereas zeolite/apatite composites can immobilize the radioactive iodine. These geomaterials are essential for environmental remediation.

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“…[15][16][17] Layered double hydroxides (LDHs) or hydrotalcite-like compounds are a large family of two-dimensional (2D) anionic clay materials represented by the general formula of [M1-x 2+ Mx 3+ (OH)2] x+ [Ax/n] n-·mH2O, where M 2+ and M 3+ are di-and trivalent metal cations, A n-is the counteranion and x = 0.17-0.33 defines the M 3+ /(M 2+ +M 3+ ) ratio. [18][19][20] The interlayer anions are linked within the positively charged host layer by means of electrostatic forces and hydrogen bonding interactions via the interlayer water molecules or hydroxyl groups. [21,22] LDHs can provide a flexible confined space that can be adjusted by changing the size and the structure of a guest molecules.…”

Section: Introductionmentioning

confidence: 99%

Classical Keggin Intercalated into Layered Double Hydroxides: Facile Preparation and Catalytic Efficiency in Knoevenagel Condensation Reactions

Jia

Fang

Zhang

et al. 2015

Chemistry A European J

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Abstract:The family of polyoxometalate (POM) intercalated layered double hydroxides (LDHs) composite materials has shown great promise for the design of functional materials with numerous applications. It is known that intercalation of the classical Keggin polyoxometalate (POM) of [PW12O40] 3-(PW12) into layered double hydroxides (LDHs) is very unlikely to take place by conventional ion exchange methods due to spatial and geometrical restrictions. In this paper, such intercalated compound of Mg0.73Al0.22(OH)2 [PW12O40]0.04·0.98H2O (Mg3Al-PW12) has been successfully obtained by adopting a spontaneous flocculation method. The Mg3Al-PW12 has been fully characterized using a wide range of methods (XRD, SEM, TEM, XPS, EDX, XPS, FT-IR, NMR, BET). XRD patterns of Mg3Al-PW12 exhibit no impurity phase usually observed next to the (003) diffraction peak. Subsequent application of the Mg3Al-PW12 as catalyst in Knoevenagel condensation reactions of various aldehydes and ketones with Z-CH2-Z' type substrates (ethylcyanoacetate and malononitrile) at 60 o C in mixed solvents (Vipropanol:Vwater = 2 : 1) demonstrated highly efficient catalytic activity. The synergistic effect between the acidic and basic sites of the Mg3Al-PW12 composite proved to be crucial for the efficiency of the condensation reactions. Additionally, the Mg3Al-PW12 catalysed Knoevenagel condensation of benzaldehyde with ethyl cyanoacetate demonstrated the highest turnover number (TON) of 47980 reported so far.

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Layered double hydroxides (LDH) intercalated with metal coordination compounds and oxometalates

Cited by 824 publications

References 202 publications

Immobilization, Trapping, and Anion Exchange of Perrhenate Ion Using Copper-Based Tripodal Complexes

Immobilization, Trapping, and Anion Exchange of Perrhenate Ion Using Copper-Based Tripodal Complexes

Geomaterials: their application to environmental remediation

Classical Keggin Intercalated into Layered Double Hydroxides: Facile Preparation and Catalytic Efficiency in Knoevenagel Condensation Reactions

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