Two Tetra-Cd^II-Substituted Vanadogermanate Frameworks

Two new tetra-Cd^II-substituted vanadogermanate frameworks {(CdX)₄Ge₈­V^IV₁₀O₄₆(H₂O)­[V^III(H₂O)₂]₄­(GeO₂)₄}·8H₂O (X = ethylene­diamine (en, <b>1</b>) and 1,2-diamino­propane (dap, <b>2</b>)) were hydrothermally prepared and characterized by IR spectra, elemental analysis, powder X-ray diffraction (PXRD), energy-dispersive X-ray spectroscopy (EDX), X-ray photoelectron spectroscopy (XPS), thermogravimetric analysis (TGA), and X-ray single-crystal diffraction. Both are isomorphic, and their 3-D frameworks are made up of tetra-Cd^II-substituted {(CdX)₄Ge₈­V^IV₁₀O₄₆­(H₂O)}^12– fundamental building units interconnected through planar tetra-V^III [V^III₄O₂(H₂O)₈]^8– clusters and tetrahedral GeO₄ bridges. In the unique {(CdX)₄Ge₈­V^IV₁₀O₄₆­(H₂O)}^12– cage, four [Ge₂O₇] dimers and four CdO₄N₂ trigonal prisms are alternately concatenated by μ₃-O bridges to create a round {Ge₈Cd₄O₂₈(X)₄}^16– fragment, five VO₅ groups are linked by sharing edges to generate a pentanuclear [V₅O₁₇] subunit, and then the {Ge₈Cd₄O₂₈(X)₄}^16– fragment is sandwiched by two V₅O₁₇ subunits <i>via</i> sharing O-atoms producing a <i>D</i>_4<i>h</i>-symmetric {(CdX)₄Ge₈­V^IV₁₀O₄₆­(H₂O)}^12– cage with a free water molecule located at the center. As we know, both display unprecedented 3-D organic–inorganic hybrid frameworks built up from the largest number of transition-metal-substituted vanadogermanate {(CdX)₄Ge₈V^IV₁₀O₄₆}^12– cluster shells linked by both GeO₄ tetrahedra and rare [V^III₄O₂(H₂O)₈]^8– clusters. Magnetic measurements reveal the antiferromagnetic couplings within the magnetic vanadium centers

Two Tetra-Cd^II-Substituted Vanadogermanate Frameworks

Two new tetra-Cd^II-substituted vanadogermanate frameworks {(CdX)₄Ge₈­V^IV₁₀O₄₆(H₂O)­[V^III(H₂O)₂]₄­(GeO₂)₄}·8H₂O (X = ethylene­diamine (en, <b>1</b>) and 1,2-diamino­propane (dap, <b>2</b>)) were hydrothermally prepared and characterized by IR spectra, elemental analysis, powder X-ray diffraction (PXRD), energy-dispersive X-ray spectroscopy (EDX), X-ray photoelectron spectroscopy (XPS), thermogravimetric analysis (TGA), and X-ray single-crystal diffraction. Both are isomorphic, and their 3-D frameworks are made up of tetra-Cd^II-substituted {(CdX)₄Ge₈­V^IV₁₀O₄₆­(H₂O)}^12– fundamental building units interconnected through planar tetra-V^III [V^III₄O₂(H₂O)₈]^8– clusters and tetrahedral GeO₄ bridges. In the unique {(CdX)₄Ge₈­V^IV₁₀O₄₆­(H₂O)}^12– cage, four [Ge₂O₇] dimers and four CdO₄N₂ trigonal prisms are alternately concatenated by μ₃-O bridges to create a round {Ge₈Cd₄O₂₈(X)₄}^16– fragment, five VO₅ groups are linked by sharing edges to generate a pentanuclear [V₅O₁₇] subunit, and then the {Ge₈Cd₄O₂₈(X)₄}^16– fragment is sandwiched by two V₅O₁₇ subunits <i>via</i> sharing O-atoms producing a <i>D</i>_4<i>h</i>-symmetric {(CdX)₄Ge₈­V^IV₁₀O₄₆­(H₂O)}^12– cage with a free water molecule located at the center. As we know, both display unprecedented 3-D organic–inorganic hybrid frameworks built up from the largest number of transition-metal-substituted vanadogermanate {(CdX)₄Ge₈V^IV₁₀O₄₆}^12– cluster shells linked by both GeO₄ tetrahedra and rare [V^III₄O₂(H₂O)₈]^8– clusters. Magnetic measurements reveal the antiferromagnetic couplings within the magnetic vanadium centers

Two Tetra-Cd^II-Substituted Vanadogermanate Frameworks

Two new tetra-Cd^II-substituted vanadogermanate frameworks {(CdX)₄Ge₈­V^IV₁₀O₄₆(H₂O)­[V^III(H₂O)₂]₄­(GeO₂)₄}·8H₂O (X = ethylene­diamine (en, <b>1</b>) and 1,2-diamino­propane (dap, <b>2</b>)) were hydrothermally prepared and characterized by IR spectra, elemental analysis, powder X-ray diffraction (PXRD), energy-dispersive X-ray spectroscopy (EDX), X-ray photoelectron spectroscopy (XPS), thermogravimetric analysis (TGA), and X-ray single-crystal diffraction. Both are isomorphic, and their 3-D frameworks are made up of tetra-Cd^II-substituted {(CdX)₄Ge₈­V^IV₁₀O₄₆­(H₂O)}^12– fundamental building units interconnected through planar tetra-V^III [V^III₄O₂(H₂O)₈]^8– clusters and tetrahedral GeO₄ bridges. In the unique {(CdX)₄Ge₈­V^IV₁₀O₄₆­(H₂O)}^12– cage, four [Ge₂O₇] dimers and four CdO₄N₂ trigonal prisms are alternately concatenated by μ₃-O bridges to create a round {Ge₈Cd₄O₂₈(X)₄}^16– fragment, five VO₅ groups are linked by sharing edges to generate a pentanuclear [V₅O₁₇] subunit, and then the {Ge₈Cd₄O₂₈(X)₄}^16– fragment is sandwiched by two V₅O₁₇ subunits <i>via</i> sharing O-atoms producing a <i>D</i>_4<i>h</i>-symmetric {(CdX)₄Ge₈­V^IV₁₀O₄₆­(H₂O)}^12– cage with a free water molecule located at the center. As we know, both display unprecedented 3-D organic–inorganic hybrid frameworks built up from the largest number of transition-metal-substituted vanadogermanate {(CdX)₄Ge₈V^IV₁₀O₄₆}^12– cluster shells linked by both GeO₄ tetrahedra and rare [V^III₄O₂(H₂O)₈]^8– clusters. Magnetic measurements reveal the antiferromagnetic couplings within the magnetic vanadium centers

Novel Three-Dimensional Organic–Inorganic Heterometallic Hybrid Built by Sandwich-Type Tetra-Mn-Substituted Germanotungstates through Mixed 3d and 4f Metal Linkers

The reaction of trivacant Keegin germanotungstate [A-α-GeW₉O₃₄]^10– with Mn²⁺ and Ce⁴⁺ cations in the presence of oxalate ligand under hydrothermal conditions led to the isolation of a novel organic–inorganic hybrid 3d–4f heterometallic germanotungstate K₄Na₄[Ce₂(ox)₃(H₂O)₂]₂{[Mn(H₂O)₃]₂[Mn₄(GeW₉O₃₄)₂(H₂O)₂]·14H₂O (<b>1</b>) (ox = oxalate), which has been characterized by elemental analysis, IR spectroscopy, thermogravimetric (TG) analysis, and single-crystal X-ray crystallography. Interestingly, each tetra-Mn^II-substituted sandwich-type unit acts as 14-dentate ligands to link eight Ce³⁺ centers and six Mn²⁺ centers further into a three-dimensional (3D) architecture. The 3D structure can be considered as two parts: one is the two-dimensional layer formed by sandwich-type [Mn₄(H₂O)₂(GeW₉O₃₄)₂]^12– fragments and Mn²⁺ linkers; the other layer is constructed from Ce³⁺ cations and oxalate bridges, and the two layers are combined together alternately through W–O–Ce–O–W linkers, resulting in the 3D framework. Notably, <b>1</b> exhibits the first 3d–4f 3D organic–inorganic hybrid framework constructed by sandwich-type TM-substituted polyoxoanions and mixed 3d and 4f metal linkers in POM chemistry

Novel Three-Dimensional Organic–Inorganic Heterometallic Hybrid Built by Sandwich-Type Tetra-Mn-Substituted Germanotungstates through Mixed 3d and 4f Metal Linkers

The reaction of trivacant Keegin germanotungstate [A-α-GeW₉O₃₄]^10– with Mn²⁺ and Ce⁴⁺ cations in the presence of oxalate ligand under hydrothermal conditions led to the isolation of a novel organic–inorganic hybrid 3d–4f heterometallic germanotungstate K₄Na₄[Ce₂(ox)₃(H₂O)₂]₂{[Mn(H₂O)₃]₂[Mn₄(GeW₉O₃₄)₂(H₂O)₂]·14H₂O (<b>1</b>) (ox = oxalate), which has been characterized by elemental analysis, IR spectroscopy, thermogravimetric (TG) analysis, and single-crystal X-ray crystallography. Interestingly, each tetra-Mn^II-substituted sandwich-type unit acts as 14-dentate ligands to link eight Ce³⁺ centers and six Mn²⁺ centers further into a three-dimensional (3D) architecture. The 3D structure can be considered as two parts: one is the two-dimensional layer formed by sandwich-type [Mn₄(H₂O)₂(GeW₉O₃₄)₂]^12– fragments and Mn²⁺ linkers; the other layer is constructed from Ce³⁺ cations and oxalate bridges, and the two layers are combined together alternately through W–O–Ce–O–W linkers, resulting in the 3D framework. Notably, <b>1</b> exhibits the first 3d–4f 3D organic–inorganic hybrid framework constructed by sandwich-type TM-substituted polyoxoanions and mixed 3d and 4f metal linkers in POM chemistry

Synergistic Combination of Multi-Zr^IV Cations and Lacunary Keggin Germanotungstates Leading to a Gigantic Zr₂₄-Cluster-Substituted Polyoxometalate

Synergistic directing roles of six lacunary fragments resulted in an unprecedented Zr₂₄-cluster substituted poly­(polyoxotungstate) Na₁₀­K₂₂­[Zr₂₄­O₂₂­(OH)₁₀­(H₂O)₂­(W₂­O₁₀­H)₂­(GeW₉­O₃₄)₄­(GeW₈­O₃₁)₂]·85H₂O (Na₁₀K₂₂·<b>1</b>·85H₂O), which contains the largest [Zr₂₄O₂₂(OH)₁₀(H₂O)₂] (Zr₂₄) cluster in all the Zr-based poly­(polyoxometalate)­s to date. The most remarkable feature is that the centrosymmetric Zr₂₄-cluster-based hexamer contains two symmetry-related [Zr₁₂­O₁₁­(OH)₅­(H₂­O)­(W₂­O₁₀H)­(GeW₉­O₃₄)₂­(GeW₈­O₃₁)]^16– trimers via six μ₃-oxo bridges and was simultaneously trapped by three types of different segments of <i>B</i>-α-GeW₉O₃₄, <i>B</i>-α-GeW₈O₃₁, and W₂O₁₀. The other interesting characteristic is that there are two pairs of intriguing triangular atom alignments: one is composed of the Zr­(2,4,6,8,11) and W21 atoms and the other contains the Ge(1–3), Zr­(3,5,7,9,10,12) and W26 atoms, and the Zr5 atom is inside the triangle; a linking mode is unobserved. The oxygenation reactions of thioethers by H₂O₂ were evaluated when Na₁₀K₂₂·<b>1</b>·85H₂O served as a catalyst. Results show that it is an effective catalyst for oxygenation of thioethers by H₂O₂. The unique redox property of oxygen-enriched polyoxotungstate fragments and Lewis acidity of the Zr cluster imbedded in Na₁₀K₂₂·<b>1</b>·85H₂O provide a sufficient driving force for the catalytic conversion from thioethers to sulfoxides/sulfones

First Tungstoantimonate-Based Transition-Metal–Lanthanide Heterometallic Hybrids Functionalized by Amino Acid Ligands

By the routine aqueous solution method, a series of transition-metal–lanthanide heterometallic tungstoantimonates [Ln­(H₂O)₈]₂­[Fe₄(H₂O)₈(thr)₂]­[B-β-SbW₉O₃₃]₂·22H₂O [Ln = Pr^III (<b>1</b>), Nd^III (<b>2</b>), Sm^III (<b>3</b>), Eu^III (<b>4</b>), Gd^III (<b>5</b>), Dy^III (<b>6</b>), Lu^III (<b>7</b>), thr = threonine] were prepared and structurally characterized by multiple testing techniques. The common structural characteristic of <b>1</b>–<b>7</b> is that they are isomorphous and all consist of a [Fe₄(H₂O)₈(thr)₂­(B-β-SbW₉O₃₃)₂]^6– subunit with two supporting [Ln­(H₂O)₈]³⁺ cations on both sides. It should be pointed out that two thr ligands in the [Fe₄(H₂O)₈(thr)₂­(B-β-SbW₉O₃₃)₂]^6– subunit substitute for two water ligands in the classical [Fe₄(H₂O)₁₀­(B-β-SbW₉O₃₃)₂]^6– polyoxoanion. As far as we know, <b>1</b>–<b>7</b> represents the first organic–inorganic tungstoantimonate hybrids consisting of transition metal and lanthanide cations and amino acid components. The fluorescence behavior of <b>4</b> has been measured and manifests the remarkable fluorescence feature resulting from the emission signature of Eu^III cations. Furthermore, the solid-state electrochemistry and electrocatalytic performances of <b>1</b> have been measured in 0.5 mol L^–1 Na₂SO₄+H₂SO₄ aqueous solution, and the results show that <b>1</b> illustrates comparatively apparent catalytic activities toward the BrO₃^– and H₂O₂ reduction. The magnetic properties of <b>3</b> and <b>6</b> have been studied

Synergistic Combination of Multi-Zr^IV Cations and Lacunary Keggin Germanotungstates Leading to a Gigantic Zr₂₄-Cluster-Substituted Polyoxometalate

Synergistic directing roles of six lacunary fragments resulted in an unprecedented Zr₂₄-cluster substituted poly­(polyoxotungstate) Na₁₀­K₂₂­[Zr₂₄­O₂₂­(OH)₁₀­(H₂O)₂­(W₂­O₁₀­H)₂­(GeW₉­O₃₄)₄­(GeW₈­O₃₁)₂]·85H₂O (Na₁₀K₂₂·<b>1</b>·85H₂O), which contains the largest [Zr₂₄O₂₂(OH)₁₀(H₂O)₂] (Zr₂₄) cluster in all the Zr-based poly­(polyoxometalate)­s to date. The most remarkable feature is that the centrosymmetric Zr₂₄-cluster-based hexamer contains two symmetry-related [Zr₁₂­O₁₁­(OH)₅­(H₂­O)­(W₂­O₁₀H)­(GeW₉­O₃₄)₂­(GeW₈­O₃₁)]^16– trimers via six μ₃-oxo bridges and was simultaneously trapped by three types of different segments of <i>B</i>-α-GeW₉O₃₄, <i>B</i>-α-GeW₈O₃₁, and W₂O₁₀. The other interesting characteristic is that there are two pairs of intriguing triangular atom alignments: one is composed of the Zr­(2,4,6,8,11) and W21 atoms and the other contains the Ge(1–3), Zr­(3,5,7,9,10,12) and W26 atoms, and the Zr5 atom is inside the triangle; a linking mode is unobserved. The oxygenation reactions of thioethers by H₂O₂ were evaluated when Na₁₀K₂₂·<b>1</b>·85H₂O served as a catalyst. Results show that it is an effective catalyst for oxygenation of thioethers by H₂O₂. The unique redox property of oxygen-enriched polyoxotungstate fragments and Lewis acidity of the Zr cluster imbedded in Na₁₀K₂₂·<b>1</b>·85H₂O provide a sufficient driving force for the catalytic conversion from thioethers to sulfoxides/sulfones

Novel One-Dimensional Organic–Inorganic Polyoxometalate Hybrids Constructed from Heteropolymolybdate Units and Copper–Aminoacid Complexes

Two unique organic–inorganic hybrid heteropolymolybdates with copper–aminoacid complexes [Cu­(arg)₂]₂[(CuO₆)­Mo₆O₁₈(As₃O₃)₂]·4 H₂O (<b>1</b>) and [Cu­(arg)₂]₃[TeMo₆O₂₄]·8H₂O (<b>2</b>) (arg = l-arginine) have been prepared under the 110 °C hydrothermal environments and structurally characterized by elemental analyses, IR spectra, thermogravimetric (TG) analyses, and single-crystal X-ray diffraction. <b>1</b> stands for the first one-dimensional (1D) chain organic–inorganic hybrid arsenomolybdate constructed from lantern-shaped [(CuO₆)­Mo₆O₁₈(As₃O₃)₂]^4– units through dinuclear [Cu₂(arg)₄]⁴⁺ connectors, whereas <b>2</b> represents an unprecedented 1D chain organic–inorganic hybrid telluromolybdate built by Anderson-type [TeMo₆O₂₄]^6– fragments via trinuclear [Cu₃(arg)₆]⁶⁺ bridges. Variable-temperature magnetic susceptibilities of <b>1</b> and <b>2</b> have been investigated and both illustrate the weak antiferromagnetic coupling within copper centers mediated by the carboxyl groups of arg ligands. Moreover, the solid-state electrochemical and electrocatalytic properties of <b>1</b> have been carried out in 1 mol L^–1 H₂SO₄ aqueous solution by entrapping it in a carbon paste electrode. <b>1</b> displays apparent electrocatalytic activities toward the reduction of nitrite and bromate

Two Families of Rare-Earth-Substituted Dawson-type Monomeric and Dimeric Phosphotungstates Functionalized by Carboxylic Ligands

Two series of novel organic–inorganic hybrid carboxylated rare-earth-substituted monolacunary Dawson-type phosphotungstate monomers [Hdap]₄­[RE­(H₂O)­(Hpic)₃]­[RE­(Hpic)₂ (α₂-P₂W₁₇O₆₁)]­·21H₂O [RE = Gd^III (<b>1</b>), Tb^III (<b>2</b>), Dy^III (<b>3</b>), Ho^III (<b>4</b>), Er^III (<b>5</b>), Tm^III (<b>6</b>), Yb^III (<b>7</b>), Y^III (<b>8</b>); Hpic = 2-picolinic acid, dap = 1,2-diaminopropane] and dimers [H₂dap]₈­[RE₂(H₂ox)₂­(ox)­(α₂-P₂W₁₇O₆₁)₂]­·25H₂O [RE = Ho^III (<b>9</b>), Er^III (<b>10</b>), Tm^III (<b>11</b>), Yb^III (<b>12</b>), Y^III (<b>13</b>); H₂ox = oxalic acid] have been hydrothermally synthesized and characterized by elemental analyses, IR spectra, thermogravimetric measurements, and X-ray single-crystal diffraction. The monomeric polyoxoanion skeleton of isomorphic <b>1</b>–<b>8</b> is constructed from a monolacunary Dawson-type phosphotungstate implanted by a [RE1­(Hpic)₂]³⁺ cation in the polar position and supported by the other [RE₂(H₂O)­(Hpic)₃]³⁺ cation on the equatorial belt. Interestingly, two kinds of RE cations separately coordinate to two or three Hpic ligands in the form of N–C–C–O–RE containing five-membered ring fashion. The dimeric polyoxoanion backbone of isomorphic <b>9</b>–<b>13</b> is built by two mono-RE substituted Dawson-type phosphotungstate fragments [RE­(H₂ox)­(α₂-P₂W₁₇O₆₁)]^7– joined together by an ox^2– linker. The visible photoluminescence spectra of solid-state <b>2</b>, <b>3</b>, <b>5</b>, and <b>10</b> and the NIR photoluminescence properties for solid-state <b>5</b>, <b>10</b>, <b>7</b>, and <b>12</b> at ambient temperature have been carried out, which are mainly derived from the RE³⁺ f–f electron transitions. Magnetic susceptibility measurements and fitting results of <b>3</b> demonstrate that <b>3</b> is a single-molecule magnet