Organic–Inorganic Hybrids Based on Monovacant Keggin-type Silicotungstates and 3d-4f Heterometals

A series of organic–inorganic hybrid lacunary Keggin silicotungstate 3d-4f heterometallic derivatives, {[Cu (en)₂]_1.5Ln­[(α-SiW₁₁O₃₉)₂]}₂^20– [Ln = Gd^III for <b>1</b>, Tb^III for <b>2</b>, Dy^III for <b>3</b>, Er^III for <b>4</b>, Lu^III for <b>5</b>], {[Cu­(en)₂]_1.5Ln­[(α-SiW₁₁O₃₉)]}^2– [Ln = La^III for <b>6</b>, Ce^III, for <b>7</b>] and {[Cu­(en)₂(H₂O)]­[Cu­(en)₂]_<i>n</i>Ln­[(α-SiW₁₁O₃₉)₂]}^<i>m</i>− [(Ln, <i>n</i>, <i>m</i>) = (Pr^III, 2, 7) for <b>8</b>, (Sm^III, 3, 5) for <b>9</b>] (en = ethylenediamine) have been successfully synthesized under hydrothermal conditions and further characterized by elemental analyses, inductively coupled plasma atomic emission spectrometry (ICP-AES) analyses, X-ray powder diffraction (XRPD), IR spectra, thermogravimetric (TG) analyses, and single-crystal X-ray diffraction. The common features of <b>1</b>–<b>5</b> and <b>8</b>–<b>9</b> are that they all consist of a sandwich-type [Ln­(α-SiW₁₁O₃₉)₂]^13– polyoxoanion, whereas both <b>6</b> and <b>7</b> consist of the unusual 1:1 [Ln­(α-SiW₁₁O₃₉)]^5– units and [Cu­(en)₂]²⁺ coordination cations. <b>1</b>–<b>5</b> show dimeric structures, and <b>6</b>–<b>9</b> display unprecedented three-dimensional (3D) frameworks, representing the first 3D 3d-4f heterometallic silicotungstates. The features of <b>6</b> and <b>7</b> are that the components are closely packed along the 2₁ screw axis to generate scarce 5-connected network structures with the Schläfli symbol of (4⁸·6²), while <b>8</b> and <b>9</b> exhibit the 4-connected (6⁶) topology and 6-connected (4⁸·5⁴·6³) topology structures, respectively. Furthermore, <b>2</b>, <b>3</b>, and <b>9</b> manifest apparent fluorescence signals, which can be assigned to the characteristic emissions of Tb^III, Dy^III, and Sm^III cations, respectively

Rectangle versus Square Oxalate-Connective Tetralanthanide Cluster Anchored in Lacunary Lindqvist Isopolytungstates: Syntheses, Structures, and Properties

Two types of unique oxalate-connective lanthanide-substituted isopolyoxotungstates, Na₁₀[Ln₂(C₂O₄)­(H₂O)₄(OH)­W₄O₁₆]₂·30H₂O (<b>1</b>) and K₄Na₁₆[Ln­(C₂O₄)­W₅O₁₈]₄·60H₂O (<b>2</b>) (Ln = Eu^III, Ho^III, Er^III, or Tb^III), have been synthesized under conventional aqueous solution conditions and structurally characterized by elemental analyses, IR spectra, single-crystal X-ray diffraction, and thermogravimetric analyses. It should be pointed out that the utilization of different alkaline cations leads to the formation of two structural types. When only Na⁺ ions are present in the system, type <b>1</b> was obtained, while when Na⁺ and K⁺ ions are used, type <b>2</b> was found. Complex <b>1</b> is a double-oxalate-bridging di-Ln substituted Lindqvist dimer with a rectangle tetra-Ln cluster, whereas <b>2</b> is a single-oxalate-connective mono-Ln^III Lindqvist tetramer with square tetra-Ln cluster. As far as we know, such di-Ln substituted Lindqvist fragment in <b>1</b> is observed for the first time. Moreover, <b>2</b> represents the first organic–inorganic hybrid square Ln-substituted isopolyoxotungstate. The solid-state luminescent properties of <b>1-Eu</b>, <b>1-Tb</b>, <b>2-Eu</b>, and <b>2-Tb</b> have been measured. <b>1-Eu</b> and <b>2-Eu</b> display intense, sharp, and narrow emission bands in the orange visible region that originate from the characteristic ⁵D₀ → ⁷F_<i>J</i> transitions, and their fluorescence lifetimes are 1.18 and 1.20 ms, respectively. <b>1-Tb</b> and <b>2-Tb</b> exhibit green photoluminescence mainly derived from ⁵D₄ → ⁷F₅ transitions. The decay behavior of <b>1-Tb</b> can be fitted to a biexponential function with lifetimes of τ₁ = 0.43 ms and τ₂ = 1.25 ms, whereas the decay behavior of <b>2-Tb</b> can be fitted to single exponential function with the lifetime of 1.03 ms. Magnetic susceptibilities of <b>1</b> and <b>2</b> have been measured, and the decline of χ_M<i>T</i> upon cooling for <b>1</b> and <b>2</b> is mostly related to the progressive thermal depopulation of the excited state of Ln cations

Rectangle versus Square Oxalate-Connective Tetralanthanide Cluster Anchored in Lacunary Lindqvist Isopolytungstates: Syntheses, Structures, and Properties

Two types of unique oxalate-connective lanthanide-substituted isopolyoxotungstates, Na₁₀[Ln₂(C₂O₄)­(H₂O)₄(OH)­W₄O₁₆]₂·30H₂O (<b>1</b>) and K₄Na₁₆[Ln­(C₂O₄)­W₅O₁₈]₄·60H₂O (<b>2</b>) (Ln = Eu^III, Ho^III, Er^III, or Tb^III), have been synthesized under conventional aqueous solution conditions and structurally characterized by elemental analyses, IR spectra, single-crystal X-ray diffraction, and thermogravimetric analyses. It should be pointed out that the utilization of different alkaline cations leads to the formation of two structural types. When only Na⁺ ions are present in the system, type <b>1</b> was obtained, while when Na⁺ and K⁺ ions are used, type <b>2</b> was found. Complex <b>1</b> is a double-oxalate-bridging di-Ln substituted Lindqvist dimer with a rectangle tetra-Ln cluster, whereas <b>2</b> is a single-oxalate-connective mono-Ln^III Lindqvist tetramer with square tetra-Ln cluster. As far as we know, such di-Ln substituted Lindqvist fragment in <b>1</b> is observed for the first time. Moreover, <b>2</b> represents the first organic–inorganic hybrid square Ln-substituted isopolyoxotungstate. The solid-state luminescent properties of <b>1-Eu</b>, <b>1-Tb</b>, <b>2-Eu</b>, and <b>2-Tb</b> have been measured. <b>1-Eu</b> and <b>2-Eu</b> display intense, sharp, and narrow emission bands in the orange visible region that originate from the characteristic ⁵D₀ → ⁷F_<i>J</i> transitions, and their fluorescence lifetimes are 1.18 and 1.20 ms, respectively. <b>1-Tb</b> and <b>2-Tb</b> exhibit green photoluminescence mainly derived from ⁵D₄ → ⁷F₅ transitions. The decay behavior of <b>1-Tb</b> can be fitted to a biexponential function with lifetimes of τ₁ = 0.43 ms and τ₂ = 1.25 ms, whereas the decay behavior of <b>2-Tb</b> can be fitted to single exponential function with the lifetime of 1.03 ms. Magnetic susceptibilities of <b>1</b> and <b>2</b> have been measured, and the decline of χ_M<i>T</i> upon cooling for <b>1</b> and <b>2</b> is mostly related to the progressive thermal depopulation of the excited state of Ln cations

Organic–Inorganic Hybrids Based on Monovacant Keggin-type Silicotungstates and 3d-4f Heterometals

A series of organic–inorganic hybrid lacunary Keggin silicotungstate 3d-4f heterometallic derivatives, {[Cu (en)₂]_1.5Ln­[(α-SiW₁₁O₃₉)₂]}₂^20– [Ln = Gd^III for <b>1</b>, Tb^III for <b>2</b>, Dy^III for <b>3</b>, Er^III for <b>4</b>, Lu^III for <b>5</b>], {[Cu­(en)₂]_1.5Ln­[(α-SiW₁₁O₃₉)]}^2– [Ln = La^III for <b>6</b>, Ce^III, for <b>7</b>] and {[Cu­(en)₂(H₂O)]­[Cu­(en)₂]_<i>n</i>Ln­[(α-SiW₁₁O₃₉)₂]}^<i>m</i>− [(Ln, <i>n</i>, <i>m</i>) = (Pr^III, 2, 7) for <b>8</b>, (Sm^III, 3, 5) for <b>9</b>] (en = ethylenediamine) have been successfully synthesized under hydrothermal conditions and further characterized by elemental analyses, inductively coupled plasma atomic emission spectrometry (ICP-AES) analyses, X-ray powder diffraction (XRPD), IR spectra, thermogravimetric (TG) analyses, and single-crystal X-ray diffraction. The common features of <b>1</b>–<b>5</b> and <b>8</b>–<b>9</b> are that they all consist of a sandwich-type [Ln­(α-SiW₁₁O₃₉)₂]^13– polyoxoanion, whereas both <b>6</b> and <b>7</b> consist of the unusual 1:1 [Ln­(α-SiW₁₁O₃₉)]^5– units and [Cu­(en)₂]²⁺ coordination cations. <b>1</b>–<b>5</b> show dimeric structures, and <b>6</b>–<b>9</b> display unprecedented three-dimensional (3D) frameworks, representing the first 3D 3d-4f heterometallic silicotungstates. The features of <b>6</b> and <b>7</b> are that the components are closely packed along the 2₁ screw axis to generate scarce 5-connected network structures with the Schläfli symbol of (4⁸·6²), while <b>8</b> and <b>9</b> exhibit the 4-connected (6⁶) topology and 6-connected (4⁸·5⁴·6³) topology structures, respectively. Furthermore, <b>2</b>, <b>3</b>, and <b>9</b> manifest apparent fluorescence signals, which can be assigned to the characteristic emissions of Tb^III, Dy^III, and Sm^III cations, respectively

Self-Assembly of a Family of Isopolytungstates Induced by the Synergistic Effect of the Nature of Lanthanoids and the pH Variation in the Reaction Process: Syntheses, Structures, and Properties

Three types of new lanthanoid­(Ln)-containing isopolyoxotungstates [H₂N­(CH₃)₂]₆Na₆­[Ln₄(H₂O)₂₂­W₂₈O₉₄H₂]₂<b>·</b>­113H₂O [Ln = Pr³⁺ (<b>1</b>), Nd³⁺ (<b>2</b>), Sm³⁺ (<b>3</b>)], Na₂[Eu­(H₂O)₇]₂­[Eu­(H₂O)₅]₂­[W₂₂O₇₄H₂]<b>­·</b>20H₂O (<b>4</b>), and Na₃H₂[Ln­(H₂O)₄]­[Ln (H₂O)₅]₂­[W₂₂O₇₄H₂]­·36H₂O [Ln = Gd³⁺ (<b>5</b>), Tb³⁺ (<b>6</b>), Er³⁺ (<b>7</b>), Tm³⁺ (<b>8</b>), Yb³⁺ (<b>9</b>), Lu³⁺ (<b>10</b>)] have been obtained by reacting Na₂WO₄­·2H₂O with Ln­(NO₃)₃­·6H₂O in the presence of dimethylamine hydrochloride in the acidic aqueous solution and structurally characterized by elemental analyses, IR spectroscopy, UV spectroscopy, electrospray ionization mass spectrometry (ESI–MS), thermogravimetric (TG) analyses, and single-crystal X-ray diffraction. <b>1</b>, <b>2</b>, and <b>3</b> are isostructural and display a one-dimensional (1-D) chain-like alignment built by hexameric Ln₈-comprising [Ln₄(H₂O)₂₂­W₂₈O₉₄H₂]₂^12– entities via [Ln­(H₂O)₅]³⁺ connectors. The [Ln₄(H₂O)₂₂­W₂₈O₉₄H₂]₂^12– entity consists of two [Ln₄(H₂O)₂₂­W₂₈O₉₄H₂]^6– subunits connected by two W–O–Ln–O–W linkers. Intriguingly, the rare λ-shaped octacosatungstate [W₂₈O₉₄H₂]^18– moiety observed in the [Ln₄(H₂O)₂₂­W₂₈O₉₄H₂]^6– subunit is composed of two undecatungstate [W₁₁O₃₈H]^9– fragments joined through a hexatungstate [W₆O₂₂]^8– fragment by sharing four μ₂-O atoms. In <b>4</b>, 22-isopolytungstate [W₂₂O₇₄H₂]^14– anions are interlinked together by four W–O–Eu1–O–W linkers giving rise to the 1-D chain motif, and then adjacent 1-D chains are further bridged through multiple W–O–Eu2–O–W connectors to engender the two-dimensional extended sheet structure with the 4-connected topology. The isomorphic <b>5</b>–<b>10</b> demonstrate the discrete structure consisting of a [Ln­(H₂O)₄]­[Ln (H₂O)₅]₂­[W₂₂O₇₄H₂]^8– unit. The pH ranges in which <b>3</b>, <b>4</b>, and <b>9</b> are stable in aqueous solution have been examined by virtue of UV and ESI–MS spectra. The solid-state luminescent properties of <b>3</b>, <b>4</b>, and <b>6</b> have been probed at room temperature. <b>3</b> displays the pink emission derived from characteristic emission bands of the Sm³⁺ cations that correspond to transitions from the ⁴G_5/2 excited-state to lower ⁶H_J (<i>J</i> = 5/2, 7/2, 9/2, 11/2) levels, <b>4</b> emits the red light that mainly results from the ⁵D₀ → ⁷F₂ transition of the Eu³⁺ cations, and <b>6</b> manifests the green luminescence mainly originating from the ⁵D₄ → ⁷F₅ transition of the Tb³⁺ cations. Their lifetime decay curves all conform to the single exponential function, affording their lifetimes of 8094.19 ns, 149.00 μs and 384.89 μs, respectively

Tetrahedral Polyoxometalate Nanoclusters with Tetrameric Rare-Earth Cores and Germanotungstate Vertexes

Two novel 1D copper-bridged tetrahedral polyoxometalate nanoclusters with tetrameric rare-earth cores and germanotungstate vertexes, Na₃H₇­[Cu­(en)₂]₅­[Cu­(en)₂­(H₂O)]₂­[RE₄Ge₄­W₄₆O₁₆₄­(H₂O)₃]·<i>n</i>H₂O (RE = Gd^III, <i>n</i> = 25 for <b>1</b>; RE = Y^III, <i>n</i> = 23 for <b>2</b>; en = ethylenediamine), have been hydrothermally synthesized and structurally characterized by elemental analyses, IR spectra, thermogravimetric analysis (TGA), and single-crystal X-ray diffraction. The most prominent structural feature of <b>1</b> and <b>2</b> consists of unprecedented tetrahedral RE-substituted germanotungstate nanoclusters {[(α-Ge­W₁₁O₃₉­RE)₂­(μ₃-WO₄)­(α-Ge­W₁₁O₃₉­RE­(H₂O))]­(μ₄-WO₄)­[α-Ge­W₁₁O₃₉­RE­(H₂O)₂]}^24–, in which four mono-RE^III-substituted Keggin [α-Ge­W₁₁O₃₉­RE­(H₂O)_<i>n</i>]^5– (<i>n</i> = 0, 1, 2) moieties are combined together with the aid of two WO₄^2– connectors. What’s more interesting is that adjacent tetrahedral nanoclusters are interconnected with each other via [Cu­(en)₂]²⁺ bridges, forming a 1D extended chain architecture. To our knowledge, <b>1</b> and <b>2</b> are the first polyoxometalate-based Cu–RE containing 1D chain constructed from tetrahedral RE-substituted germanotungstate nanoclusters and copper–organic bridges. Furthermore, the solid-state electrochemical and electrocatalytic properties of <b>1</b> and <b>2</b> have been carried out in 0.5 mol·L^–1 Na₂SO₄ + H₂SO₄ aqueous solution by entrapping them in a carbon paste electrode. <b>1</b> and <b>2</b> display apparent electrocatalytic activities for the nitrite and bromate reduction

Organocounterions-Assisted and pH-Controlled Self-Assembly of Five Nanoscale High-Nuclear Lanthanide Substituted Heteropolytungstates

Five high-nuclear lanthanide (Ln) substituted heteropolytungstates [H₂N­(CH₃)₂]₁₆Na₉LnH₁₀{[W₁₆Ln₁₀(H₂O)₃₈O₅₀]­[B-α-SeW₉O₃₃]₈}·56H₂O [Ln = La^III (<b>1</b>), Ce^III (<b>2</b>)], [H₂N­(CH₃)₂]₂₂Na₄H₁₂­{[W₁₈Ln₁₀(H₂O)₃₄O₅₆]­[B-α-SeW₉O₃₃]₈}·80H₂O [Ln = La^III (<b>3</b>), Ce^III (<b>4</b>)], and Na₄[H₂N­(CH₃)₂]₁₈H₂₁[Nd­(H₂O)₇]­[W₁₆Nd₁₀O₅₀(H₂O)₃₄­(B-α-AsW₉O₃₃)₈]·60H₂O (<b>5</b>) were prepared by reaction of Na₂WO₄·2H₂O and Ln­(NO₃)₃·6H₂O in the presence of dimethylamine hydrochloride (DMAHC) and Na₂SeO₃ or NaAsO₂ in an aqueous medium. The octameric polyoxoanions {[W₁₆Ln₁₀(H₂O)₃₈O₅₀]­[B-α-SeW₉O₃₃]₈}^38– in <b>1</b> and <b>2</b> are assembled from eight [B-α-SeW₉O₃₃]^8– building blocks linked by 16 extra bridging W^VI centers and ten Ln^III cations, whereas the octameric polyoxoanions {[W₁₈Ln₁₀(H₂O)₃₄O₅₆]­[B-α-SeW₉O₃₃]₈}^38– in <b>3</b> and <b>4</b> are constructed from eight [B-α-SeW₉O₃₃]^8– building blocks joined by 18 additional bridging W^VI centers and ten Ln^III cations [Ln = La^III (<b>3</b>), Ce^III (<b>4</b>)]. The octameric polyoxoanion [W₁₆Nd₁₀O₅₀(H₂O)₃₄­(B-α-AsW₉O₃₃)₈]^40– in <b>5</b> is constituted by eight [B-α-AsW₉O₃₃]^9– building blocks connected by 16 extra bridging W^VI centers and ten Nd^III cations. It should be noted that neighboring {[W₁₆Nd₁₀(H₂O)₃₈O₅₀]­[B-α-AsW₉O₃₃]₈}^46– polyoxoanions in <b>5</b> are further polymerized by two W–O–Nd–O–W linkers into a 1-D chain-like alignment. The thermolysis processes of <b>1</b>, <b>4</b>, and <b>5</b> were investigated by variable-temperature IR spectra, coloration changes, and variable-temperature PXRD patterns. The solid-state NIR luminescence properties of <b>5</b> were systematically studied at room temperature

Organophosphonic Acid-Regulating Assembly of P^V–Sb^III Polyoxotungstate and Its Potential in Building a Dual-Signal Readout Electrochemical Aptasensor for Carcinogen Detection

Template-directed assembly of giant cluster-based nanomaterials is an everlasting theme in cluster science. In this work, ethylenediamine tetramethylphosphonic acid [H8EDTPA = (POCH2(OH)2)4C2H4N2] and [B-α-SbW9O33]9– were, respectively, used as an organic template and an inorganic template to prepare an organophosphonic acid-regulating PV–SbIII-heteroatom-inserted polyoxotungstate aggregate [H2N(CH3)2]5Na11H9[CeW4O10(HEDTPA)SbW15O50][B-α-SbW9O33]2·36H2O (1). Noteworthily, organophosphonic acid ligand not only works as an organic template leading to the assembly of a [HEDTPASbW15O50]14– building block but also further bridges the sandwich-type [CeW4O10(B-α-SbW9O33)2]11– entity. To extend its potential application in electrochemical sensing properties, we prepared a three-dimensional 1@EGO composite (EGO = reduced graphene oxide functionalized by ethylenediamine) with porous architecture and a prominent conducting ability. Furthermore, the 1@EGO composite was explored as a modification material for glassy carbon electrodes to build a dual-signal readout electrochemical aptasensor for carcinogens, which shows much better detection performance for aflatoxin B1 compared with traditional single-signal biosensor

DataSheet1_A mitochondria-targeted nano-platform for pancreatic cancer therapy.docx

Liposome is a conventional drug delivery system which has been widely used in the pharmacy field. However, its applications are greatly restricted in clinical practice by the disadvantages of cholesterol and nonselective distribution. Herein, a novel platform for anti-tumor drug delivery was developed by incorporating an amphiphilic stachydrine-octadecane conjugate (SS) as the mitochondria-targeting molecule onto the triptolide-liposome surfaces (SS-TP LPs). The polyethylene glycol (PEG) and the suitable particle size (about 133 nm) of liposomes facilitated their stabilities, the long half-life in blood and the escape from the rapid elimination. The SS-TP LPs were internalized and accumulated into the mitochondria of cancer cells in a time-dependent manner, followed by triggering permeabilization of the mitochondrial outer membrane by inhibiting Bcl-2, and then further caused greater cancer cell death via releasing cytochrome C and initiating a cascade of caspase 3 reactions. In the Pan02 tumor-bearing mice, the SS-TP LPs showed significant efficacy in inhibiting tumor growth and reducing tumor size but synchronously exhibited specific mitochondria-targeting and much lower subacute toxicity compared with the free TP and TP LPs. Our study suggests that SS-TP LPs can be a promising anticancer drug delivery system for mitochondria-targeted therapy in pancreatic cancer.</p

Novel Plant Growth Regulator Guvermectin from Plant Growth-Promoting Rhizobacteria Boosts Biomass and Grain Yield in Rice

Food is a fundamental human right, and global food security is threatened by crop production. Plant growth regulators (PGRs) play an essential role in improving crop yield and quality, and this study reports on a novel PGR, termed guvermectin (GV), isolated from plant growth-promoting rhizobacteria, which can promote root and coleoptile growth, tillering, and early maturing in rice. GV is a nucleoside analogue like cytokinin (CK), but it was found that GV significantly promoted root and hypocotyl growth, which is different from the function of CK in Arabidopsis. The Arabidopsis CK receptor triple mutant ahk2-2 ahk3-3 cre1-12 still showed a GV response. Moreover, GV led different growth-promoting traits from auxin, gibberellin (GA), and brassinosteroid (BR) in Arabidopsis and rice. The results from a four-year field trial involving 28 rice varieties showed that seed-soaking treatment with GV increased the yields by 6.2 to 19.6%, outperforming the 4.0 to 10.8% for CK, 1.6 to 16.9% for BR, and 2.2 to 7.1% for GA-auxin-BR mixture. Transcriptome analysis demonstrated that GV induced different transcriptome patterns from CK, auxin, BR, and GA, and SAUR genes may regulate GV-mediated plant growth and development. This study suggests that GV represents a novel PGR with a unique signal perception and transduction pathway in plants