Two New 2D and 1D Ni(II) Coordination Polymers Bridged by Vanadium-Substituted Keggin Polyoxotungstophosphates: Hydrothermal Synthesis and Crystal Structure

Two coordination polymers based on vanadium-substituted Keggin polyoxotungstophosphates as bridging ligands, {[Ni(4,4′-bipy)_1.5(OH)(H₂O)]₂[H₃PW₁₀V₂O₄₀]}·4H₂O (4,4′-bpy = 4,4′-bipyridine) 1 and {[Ni(dpa)₂][Ni(dpa)(H₂O)₃]₂[PW₉V₃O₄₀]}·4H₂O (dpa = 2,2′-dipyridylamine) 2, have been obtained by hydrothermal reactions and characterized by elemental analysis, IR, XRD, TGA and single-crystal X-ray Diffraction analysis. Compound 1 is a 2D layered structure built from 1D infinite zigzag {Ni₂(4,4′-bipy)₃(OH)₂(H₂O)₂}_n²⁺ chains bridged via [H₃PW₁₀V₂O₄₀]²⁻ anions. Compound 2 exhibits a one-dimensional chain-like structure constructed from [Ni(dpa)₂]²⁺ fragments bridged via bis-supported Keggin polyoxoanions [Ni(dpa)(H₂O)₃]₂[PW₉V₃O₄₀]²⁻. The two examples demonstrate that vanadium-substituted Keggin polyoxometalates have greater coordination capability.     

Two New Extended Frameworks Constructed from the Sandwiching Polytungstoantimonate Clusters

Two new tungstoantimonates Na₄H₂[{Co(H₂O)₃}₂Co(H₂O)₂W(H₂O)₂ (B-β-SbW₉O₃₃)₂]·33H₂O (1) and H₄[Mn₂(H₂O)₈Mn_3.5(H₂O)₇W_0.5(H₂O)(B-β-SbW₉O₃₃)₂]·20H₂O (2) have been obtained by the routine synthetic reactions in the aqueous solutions and characterized by elemental analysis, IR, TG analysis. Compound 1 is built from the sandwich-type polyoxoanions [{Co(H₂O)₃}₂Co(H₂O)₂W(H₂O)₂(B-β-SbW₉O₃₃)₂]⁶⁻, linked by Na⁺ cations to construct a 1-D chain-like structure. Compound 2 shows an interesting 2-D structure built up from sandwich-type anions [Mn_3.5(H₂O)₇W_0.5(H₂O)(B-β-SbW₉O₃₃)₂]⁸⁻ linked by additional Mn²⁺ ions, which represents the first example of pure inorganic 2-D structure based on the Mn-containing sandwich-type polytungstoantimonate clusters. The electrochemical and photochemical catalysis activities of compounds 1 and 2 have also been investigated.     

A Supramolecular Star-like Tungstoarsenate(V) with Uranyl Cations: [(NH4)12(UO2(H2O))6(UO2(μ2-H2O))6(α-AsW9O34)6]18?

A supramolecular tungstoarsenate(V) containing UO₂ ²⁺ cations has been isolated by reaction of the ammonium salt of lacunary sandwich-type anion [As₂W₁₈(UO₂)₂O₆₈]¹⁴⁻ in aqueous solution of Ce^IV (pH 3.5). The product prepared as NH₄ ⁺ salt, (NH₄)₁₈[(NH₄)₁₂(UO₂(H₂O))₆(UO₂(μ₂-H₂O)₆(α-AsW₉O₃₄)₆]·74H₂O (I), have been characterized by single crystal X-ray diffraction, elemental analysis, IR, and UV/vis spectroscopy. The anion consists on six lacunary α-AsW₉O₃₄ ⁹⁻ anions linked by twelve UO₂ ²⁺ cations which resembles a star (six-member). The single crystal structure of I reveals two types uranium atoms; six uranium atoms in the central of anion form two U₃O₃ trigonal bridging groups in which each uranium atom bounds to three oxygen atoms of one AsW₉ and two bridging water ligands. The other uranium atoms form two equatorial bonds to one AsW₉ and two equatorial bonds to two other AsW₉ fragments. The UV/vis spectroscopy confirms the strong coordination of oxygen atoms of α-AsW₉O₃₄ ⁹⁻ anions to uranyl cations in the equatorial plane.     

Synthesis, structure, and characterization of a 1D monocopper substituted Dawson-type arsenotungstate (H2En)0.5[Cu(En)2]0.5{[Cu(En)2(H2O)]2[Cu(En)2] (α1-As2W17CuO61)} · 8H2O

A new 1D organic-inorganic hybrid monocopper substituted Dawson-type arsenotungstate (H₂En)_0.5[Cu(En)₂]_0.5{[Cu(En)₂(H₂O)]₂[Cu(En)₂](α₁-As₂W₁₇CuO₆₁)} · 8H₂O (I) has been hydrothermally synthesized by the reaction of Na₈[A-α-HAsW₉O₃₄] · 11H₂O, CuCl₂ · 2H₂O, YCl₃, with enthylenediamine (En) and characterized by elemental analyses, IR spectra, UV spectra, powder X-ray diffraction, thermogravimetric analysis, as well as single-crystal X-ray diffraction. Single-crystal structural analysis shows that I displays an interesting 1D chain constructed from [α₁-As₂W₁₇CuO₆₁]⁸⁻ subunits by means of common oxygen atoms and [Cu(En)₂]²⁺ bridges. It should be noted that the structural transformation of the trivacant Keggin polyoxoanion [A-α-AsW₉O₃₄]⁹⁻ to the monovacant Dawson [α-As₂W₁₇O₆₁]¹⁰⁻ polyoxoanion was observed. The TG curve of I exhibits three stages of weight loss.     

Syntheses,crystal structures,and magnetic properties of the banana-shaped tungstophosphates: [M6(H2O)2(PW9O34)2(PW6O26)]17− (MII=NiII,CoII)

Two new banana-shaped tungstophosphates [M₆(H₂O)₂(PW₉O₃₄)₂(PW₆O₂₆)]^{17 ?} (M^II?=?Ni^II, Co^II) incorporating two types of lacunary polyoxometalate units have been synthesized in aqueous solution and characterized by elemental analyses, IR, and UV spectra, and single-crystal X-ray diffraction. Structural analyses show that Na₆H₁₁[Ni₆(H₂O)₂(PW₉O₃₄)₂(PW₆O₂₆)]?·?32H₂O (1) and Na₇H₁₀[Co₆(H₂O)₂(PW₉O₃₄)₂(PW₆O₂₆)]?· 31H₂O (2) are generated from two tri-M^II substituted B-α-[(MOH₂)M₂PW₉O₃₄] Keggin units connected by a hexavacant [PW₆O₂₆]^11? Keggin fragment, leading to the M^II-containing banana-shaped tungstophosphates. Magnetic properties of 2 show decrease of the molar magnetic susceptibility at higher temperatures results from spin-orbit coupling of Co^II and antiferromagnetic interactions whereas the maximum at the lower temperatures is indicative of the ferromagnetic interactions within the trinuclear Co^II spin cluster in the sandwich belt.     

Sandwich-type Uranium-Substituted of Bismuthotungstate: Synthesis and Structure Determination of [Na(UO2)2(H2O)4(BiW9O33)2]13?

The sandwich-type [Na(UO₂)₂(H₂O)₄(BiW₉O₃₃)₂]¹³⁻ uranium (VI) has been synthesized by reacting the trivacant species of B-α-[BiW₉O₃₃]⁹⁻ with and investigated by IR and UV–Vis spectroscopy, and elemental analysis. The X-ray single crystal analysis was carried out on Na₁₃[Na(UO₂)₂(H₂O)₄(BiW₉O₃₃)₂] · 33H₂O (I) which crystallizes in the orthorhombic system, space group Pna2₁ with a = 33.8454(19) ?, b = 21.1484(12) ?, c = 13.2403(7) ?, α = 90°, β = 90°, γ = 90°, and Z = 4. The polyanion consists of two lacunary B-α-[BiW₉O₃₃]⁹⁻ groups which sandwich two uranyl cations and one sodium cation. The uranium atoms adopt distorted pentagonal–bipyramidal coordination, achieved by two equatorial bonds to each BiW₉O₃₃ unit and one external water ligand. The coordination of each uranium atom is evident by the shift of ν_as(W–O_b–W) and ν_as(Bi–O) stretching vibrational bonds. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

A New 1D Chain-like Complex Built Up of Cu-containing Sandwich Tungstogermanate

Two new tungstogermanates K₂Na₁₀[Cu₄(GeW₉O₃₄)₂] · 15.5H₂O (1) and K₄Na₆[Cu_3.5W_0.5(H₂O)₂(GeW₉O₃₄)₂] · 17H₂O (2) have been obtained by the conventional aqueous solution methods and characterized by IR, element analysis, electrochemistry and single-crystal X-ray analysis. Compound 1 is composed of the [Cu₄(GeW₉O₃₄)₂]¹²⁻ anions linked by two equivalent bonds of Cu–O–W, representing the first one-dimensional chain-like structure based on sandwich-type polyoxometalates by direct condensation to form oxo-bridged arrays of clusters. Compound 2 is a sandwich structure, consisting of two trivacant [GeW₉O₃₄]¹⁰⁻ units linked by a [Cu_3.5W_0.5(H₂O)₂] cluster, and the anions are linked by the K⁺ and Na⁺ to form a three-dimensional structure. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

[Ho5(H2O)16(OH)2As6W64O220]25−, ein großes neuartiges Polyoxoanion aus trivakanten Keggin‐Fragmenten

[Ho₅(H₂O)₁₆(OH)₂As₆W₆₄O₂₂₀]^25?, a Large Novel Polyoxoanion from Trivacant Keggin Fragments The novel polyoxotungstate Na₇K₁₈[Ho₅(H₂O)₁₆(OH)₂As₆W₆₄O₂₂₀] · 56 H₂O ( 1 ) was synthesized in aqueous solution and characterized by X‐ray structure analysis, elemental analysis and IR spectroscopy. The anion in 1 represents one of the largest polyoxoanions known yet and exhibits an unusual arrangement of six Keggin units. It consists of six trivacant lacunary α‐B‐(AsW₉O₃₃)^9? Keggin fragments which are connected by a bridging [Ho₅W₁₀(H₂O)₁₆(OH)₂O₂₂]²⁹⁺ unit. The five Ho^III atoms are coordinated by eight oxygen atoms, forming a square‐antiprism.     

Two-dimensional layer architecture assembled by Keggin polyoxotungstate, Cu(II)-EDTA complex and sodium linker: Synthesis, crystal structures, and magnetic properties

Reaction of Keggin polyoxotungstate with copper(II)-EDTA (EDTA=ethylenediamine tetraacetate) complex under mild conditions led to the formation of hybrid inorganic-organic compounds Na₄(OH)[(Cu₂EDTA)PW₁₂O₄₀]·17H₂O (1) and Na₄[(Cu₂EDTA)SiW₁₂O₄₀]·19H₂O (2). The single-crystal X-ray diffraction analyses reveal their two structural features: (1) one-dimensional chain structure consisting of Keggin polyoxotungstate and copper(II)-EDTA complex; (2) Two-dimensional layer architecture assembled by the one-dimensional chain structure and sodium linker. The results of magnetic measurements in the temperature range 300-2 K indicated the existence of ferromagnetic exchange interactions between the Cu^II ions for both compounds. In addition, TGA analysis, IR spectra, and electrochemical properties were also investigated to well characterize these two compounds.     

Structural stability index of heteropoly- and isopolyanions—IV. Application to site-vacant Keggin polyanions,mixed-type Keggin polyanions,some molybdo- and tungsto-vanadates and Jeannin-type polyanion

The theory of structural stability, being based on the number of closed loops per MO₆ octahedral unit in the polyanion-cage, has been applied to a variety of heteropoly- and isopoly-compounds with previously unreported structures. The discussion includes the prediction of the structure of lacunary Keggin heteropoly-compound, Cs₇Na₂[PW₁₀O₃₇]·8H₂O, recently obtained by Knoth and Harlow, the reinvestigation of mixed-type Keggin polyanions, [SiW₉Co₃(H₂O)₃O₃₇]^10? and [SiW₁₁CoO₃₉]^6?, recently prepared by Pope's group, the interpretation of chemical behaviours of some molybdo- and tungsto-vanadates, the structural stabilities of Jeannin-type [As₂W₂₁O₆₉(H₂O)]^6? polyanion and its related compounds, and some remarks on Weakley-type [X(W₅O₁₈)₂]^n? polyanions and Flynn-Stucky-type [X(Nb₆O₁₉)₂]^n? complexes belonging to the hybrid-complex of polyanion.     

Three organic–inorganic hybrid complexes based on the Wells–Dawson polyoxoanion

Three new organic–inorganic hybrid complexes based on the Wells–Dawson polyoxoanion, namely (H₂bpp)[Ni₂(bpp)₂(H₂O)₄(P₂W₁₈O₆₂)]·H₂O 1, [Cu₆(Hbpy)₆(bpy)₃(P₂W₁₈O₆₂)₂]·2H₂O 2 and (Him)₅[Cu(im)₂(P₂W₁₈O₆₂)]·4H₂O 3 [bpp = 1,3-bis (4-pyridyl) propane, bpy = 4,4′-bipyridine, im = imidazole] have been synthesized and characterized. Complex 1 exhibits a three-dimensional (6, 3)-connected framework with anatase topology constructed from [α-P₂W₁₈O₆₂]⁶⁻ clusters and [Ni(bpp)]²⁺ fragments. Each [α-P₂W₁₈O₆₂]⁶⁻ anion links to six nickel atoms through six terminal oxygen atoms from four polar and two equatorial WO₆ octahedra, which shows a novel coordination mode of a Wells–Dawson cluster with a transition-metal atom. Complex 2 displays an interesting one-dimensional double-chain structure built from [α-P₂W₁₈O₆₂]⁶⁻ clusters and [Cu₂(bpy)(Hbpy)₂]²⁺ fragments. To our knowledge, complex 2 represents the first double-chain organic–inorganic hybrid complex based on a Wells–Dawson-type cluster. Complex 3 possesses a one-dimensional zigzag chain structure constructed from [α-P₂W₁₈O₆₂]⁶⁻ anions and [Cu(im)₂]⁺ units through weak Cu···O interactions.     

Two New {P<Subscript>8</Subscript>W<Subscript>49</Subscript>} Wheel-shaped Tungstophosphates Decorated by Co(II), Ni(II) Ions

Two new wheel-shaped tungstophosphates based on 3d-transition metals (Co(II), Ni(II)) ions decorated [P₈W₄₉O₁₈₇]⁴⁰⁻ anion (TM-{P₈W₄₉}), K₄Na₂₂{[Co(H₂O)₂Cl][Co(H₂O)₃]₂[Co(H₂O)₅]_1.5 [Co(H₂O)₃H₄P₈W₄₉O₁₈₇(H₂O)]}·2NaCl·41·5H₂O 1 and Na₃₀{[Ni(H₂O)₃]₂[{Ni(H₂O)₃}_1.5H₃P₈W₄₉O₁₈₇ (H₂O)]}·41.5H₂O 2 have been synthesized by routine synthetic reaction of hexavacant Dawson polyoxonanion [P₂W₁₂O₄₈]¹⁴⁻ with divalent 3d transition-metal ions in aqueous solution. The two compounds are characterized by elemental analysis, IR spectroscopy, TG analysis, electrochemical analysis, and single-crystal X-ray diffraction. Both compounds contain a 2D layer-like structure constructed from 1D chains of wheel-type [P₈W₄₉O₁₈₇]⁴⁰⁻ anions bridged via CoO₆ or NiO₆ units. Cyclic voltammograms and ³¹P NMR analysis suggest that the polyanion [P₈W₄₉O₁₈₇]⁴⁰⁻ of both compounds are stable in aqueous solution (pH = 4).     

Structural stability index of heteropoly- and isopoly-anions—III. Application to site-vacant fragments of keggin and dawson polyanions α-[PW12O

For some site-vacant species of Keggin and Dawson polyanions α-[PW₁₂O₄₀]^3? and α-[P₂W₁₈O₆₂]^6? containing hypothetic     

Mo–V Keggin Structure Compound and Its Electrocatalytic Reduction Toward Bromate

Abstract  

In this paper, the Mo–V Keggin compound 1, KNa₆[VMo₁₂O₄₀]₂(OH)(H₂O)₃₆, had obtained. Single crystal X-ray analysis revealed that there is the nanometer-sized water cube, Na₆(KOH)(H₂O)₃₆, in [VMo₁₂O₄₀]³⁻ Keggin structure. The Na₆(KOH)(H₂O)₃₆ forms one cuboid house with long side of 22.456 ? and short side of 11.228 ?. The cation water cube acts as a “host” and the globular anion [VMo₁₂O₄₀]³⁻ as “guest” which was captured. The cycle voltammetry study showed that above compound had excellent electrocatalytic activity toward the reduction of bromate. Thermogravimetric analysis was in agreement with the crystal data.     

Transition metal substituted polyoxometalates supported on amine-functionalized silica

A series of transition metal substituted polyoxometalates (POM) have been anchored to propylamine-functionalized mesoporous silica (silicaNH₂). These include V, Co and Mn Keggin-type anions such as [PMo₁₀V₂O₄₀]⁵⁻ and [PMo₁₁VO₄₀]⁴⁻, or [SiW₁₁Co^II(H₂O)O₃₉]⁶⁻ and [SiW₁₁Mn^III(H₂O)O₃₉]⁵⁻, and sandwich-type anions, [(PW₉O₃₄)₂ Co ₄ ^II (H₂O)₂]¹⁰⁻ and [(PW₉O₃₄)₂Mn ₄ ^II (H₂O)₂]¹⁰⁻. Experiments at different initial pH_i of aqueous suspension of silica were performed for the Co and Mn substituted Keggin anions. The novel silicaNH₂-POM materials having between 12–17% (w/w) of polyoxometalate were characterized by elemental analysis, solid-state ²⁹Si, ¹³C and ³¹P n.m.r., diffuse reflectance spectroscopy, FTIR spectroscopy, thermal analyses, and BET surface area measurements. The elemental analyses and spectroscopic results pointed to the integrity of POM structures after immobilization on the silica support while the latter one showed a slight decrease of BET surface area. Results of the visible diffuse reflectance spectroscopy for the Co-substituted Keggin anion revealed the coordination of cobalt centers in the cluster with the nitrogen atom of amine groups in modified silica at pH_i ≥ 5.5 or the electrostatic bonding between polyoxoanion and protonated C₃H₆NH ₃ ⁺ group at pH_i = 3.5. For the Co-substituted sandwich anion, external Co centres of the polyoxoanion have coordinated with the amine groups of modified silica under the experimental conditions used. ³¹P MAS n.m.r. showed a shifting of phosphorus atom resonances in H₅[PMo₁₀V₂O₄₀] and H₄[PMo₁₁VO₄₀] to a single resonance at ca. − 4.1 ppm (Δv _1/2 ~ 70 Hz) when these POM were immobilized on the functionalized silica under weak acidic conditions (pH 3), evidencing electrostatic interaction of POM clusters with the C₃H₆NH ₃ ⁺ groups.     

Reactions of trivacant lone-pair-containing tungstobismutate and electrochemical behaviors of its sandwich-type products

We report the crystal structure of dimeric precursor Na₁₂[(Na(H₂O)₂)₆(α-BiW₉O₃₃)₂] (1), and the interaction of this precursor with transition metal ions. Interaction of 1 with Cu²⁺ in neutral medium leads to the formation of a Hervé-type sandwich polyoxoanion [(Cu(H₂O))₃(α-BiW₉O₃₃)₂]^12? (2) in high yield. Interaction of 1 with M²⁺ (M?=?Zn, Ni, Co, Mn) in acidic aqueous medium leads to formation of Krebs-type sandwich polyoxoanions [(M(H₂O)₃)₂(WO)₂(β-BiW₉O₃₃)₂]^10? (3–6). Coordination geometry of the M²⁺ ions, counterions and precursors can affect the structure of products. In our experiments, only the interaction of 1 with Cu²⁺ forms a trisubstituted sandwich-type product. The method using [α-Bi^IIIW₉O₃₃]^9? as starting material is a convenient and effective route for the synthesis of sandwich-type tungstobismutates in high purity and yield. The electrochemical properties of these sandwich-type tungstobismutates in aqueous solution are described.     

Systematic Study of the Interaction Between VIV Centres and Lanthanide Ions MIII in Well Defined {VIV2MIII}{AsIIIW9O33}2 Sandwich Type Clusters: Part 1

A new type of heteropolytungstate is reported that contains in a triangular arrangement one lanthanide f element and two d transition metals in form of heteroatoms. The first example in this series is the monoclinic Na₃K₅[((VO)₂Dy(H₂O)₄K₂(H₂O)₂Na(H₂O)₂)(α-B-AsW₉O₃₃)₂] · 23H₂O (1) which was prepared from an acidified aqueous solution of Na₂WO₄ · 2H₂O, As₂O₃ and VOSO₄ · 5H₂O to which Dy³⁺ ions were added. The single crystal X-ray structure analysis shows that the anion 1a consists of two [α-B-As^IIIW₉O₃₃]⁹⁻ trilacunary Keggin type units linked by two VO²⁺, one Dy³⁺ as well as two K⁺ and one Na⁺ ion, resulting in a sandwich-type structure with idealized C _2v symmetry. The complete magnetochemical analysis shows very interesting magnetic properties, which will be considered in the full series together with the properties of the homologous compounds in due course. Dedicated to Prof. Dieter Fenske on the occasion of his 65th birthday Achim Müller, Joris van Slageren and Bernt Krebs contributed in comparable extent to the paper     

Cyclic Voltammetry Study of the Mn‐Substituted Polyoxoanions [MnII4(H2O)2(H4AsW15O56)2]18− and [((MnIIOH2)MnII2PW9O34)2(PW6O26)]17−: Electrodeposition of Manganese Oxides Electrocatalysts for Dioxygen Reduction

The electrochemical behavior of two manganese (Mn)‐substituted polyoxoanions, the dissymmetrical Dawson sandwich‐type [Mn^II₄(H₂O)₂(H₄AsW₁₅O₅₆)₂]^18? and the Keggin sandwich banana‐shaped [((Mn^IIOH₂)Mn^II₂PW₉O₃₄)₂(PW₆O₂₆)]^17? is investigated. At pH 5, the oxidation of the Mn^II‐centers results in one oxidation wave for [Mn^II₄(H₂O)₂(H₄AsW₁₅O₅₆)₂]^18? and two oxidation waves for [((Mn^IIOH₂)Mn^II₂PW₉O₃₄)₂(PW₆O₂₆)]^17?. To the best of our knowledge, presence of the second Mn‐based wave is rarely observed in the electrochemistry of Mn‐containing polyoxometalates. Deposition of Mn‐oxides electrocatalysts for dioxygen reduction is noticed by cyclic voltammetry, which can be distinguished by the significant positive shift in potentials of the dioxygen reduction reaction.     

Organophosphoryl polyoxotungstates α-[R2PW9O34]5− [R = PhP(S), C6H11P(O), H2NCH(n-Pr)P(O)]

Tetrabutylammonium salts of organophosphoryl derivatives of tungstophosphate of formula α-[R₂PW₉O₃₄]⁵⁻ [R = PhP(S), C₆H₁₁P(O), H₂NCH(n-Pr)P(O)] have been prepared, purified and characterized by elemental analysis, i.r., ³¹P- and ¹⁸³W-n.m.r. spectroscopy. These anions consist of an α-[PW₉O₃₄]⁹⁻ framework on to which are grafted two equivalent organophosphoryl groups through P–O–W bridges; these new species still retain the ‘unsaturated’ Keggin structure. The five-line ¹⁸³W spectra indicates that the hybrid anions possess C _s symmetry in acetonitrile. This revised version was published online in June 2006 with corrections to the Cover Date.     

Comparison between various Keggin and Wells–Dawson sandwich‐type polyoxometalates in catalytic oxidation of cyclooctene and cyclohexene with hydrogen peroxide

The catalytic performance of tetra‐n‐butylammonium salts of Keggin and Wells–Dawson sandwich‐type polyoxotungstates, [M₄(PW₉O₃₄)₂]^m? and [M₄(P₂W₁₅O₅₆)₂]^n? (M = Mn²⁺, Fe³⁺, Co²⁺, Ni²⁺, Zn²⁺), in the oxidation of cyclooctene and cyclohexene with 30% hydrogen peroxide under various conditions was investigated. In comparison, Wells–Dawson sandwich‐type polyoxometalates were found to be less active than Keggin ones. In both of them, those containing Zn and Fe gave higher conversions for different oxidation conditions. These catalysts showed very good reusability in the oxidation reaction. Copyright © 2014 John Wiley & Sons, Ltd.