Polyoxometalate-Dicarboxylate Hybrid Dimers with {SiWCr} Nodes: Syntheses, Structures, and Mass Spectrometric Characterization.

The current study describes a new family of hybrid dimers constructed from secondary building blocks based on a dichromium-substituted silicodecatungstate, {SiWCr}, and flexible dicarboxylate ligands of varied lengths. All five polyoxometalate-organic hybrid compounds exhibit an entropically favored, cyclic dimer motif that contains just two {SiWCr} clusters─the minimum to form a closed loop, linked by two aliphatic dicarboxylates, as revealed by single-crystal X-ray diffraction. Due to the kinetic inertness of such Cr-based hybrid dimers, ESI-MS has become a particularly useful technique for the characterization of these paramagnetic, NMR-unfriendly systems.

Functionalized polyoxometalates enable fast ion transport in solid-state batteries at room temperature.

The coupling of functionalized inorganic polyoxometalates with polymer electrolytes leads to considerably enhanced mechanical properties and faster ion transport (1.1 × 10 S cm) at room temperature. The assembled Li/Li symmetric cell displays excellent stability in a 3000 h cycling test and a Li/LiFePO cell exhibits superior cycling performance over 250 cycles.

Atomically Precise Silver Clusters Stabilized by Lacunary Polyoxometalates with Photocatalytic CO Reduction Activity.

The syntheses of atomically precise silver (Ag) clusters stabilized by multidentate lacunary polyoxometalate (POM) ligands have been emerging as a promising but challenging research direction, the combination of redox-active POM ligands and silver clusters will render them unexpected geometric structures and catalytic properties. Herein, we report the successful construction of two structurally-new lacunary POM-stabilized Ag clusters, TBA H Ag (DPPB) (CH CN) [Ag (Si W O ) ] ⋅ 10CH CN ⋅ 9H O ({Ag (Si W O ) }, TBA=tetra-n-butylammonium, DPPB=1,4-Bis(diphenylphosphino)butane) and TBA H Ag Na (H O) [Ag (Si W O ) ] ⋅ 8CH CN ⋅ 10H O ({Ag (Si W O ) }), using a facile one-pot solvothermal approach. Under otherwise identical synthetic conditions, the molecular structures of two POM-stabilized Ag clusters could be readily tuned by the addition of different organic ligands.

Polyoxometalate-Organic Hybrid "Calixarenes" as Supramolecular Hosts.

Calixarenes are among the most useful and versatile macrocycles in supramolecular chemistry. The one thing that has not changed in the 80 years since their discovery, despite numerous derivatizations, is their fully organic, covalent scaffolds. Here, we report a new type of organic-inorganic hybrid "calixarenes" constructed by means of coordination-driven assembly.

A Macrocyclic Polyoxomolybdate with Phosphate and Phosphonate Linkers: Synthesis, Structure, and Proton Conductivity.

A coordination macrocycle composed of eight identical [PMoO] ({PMo}) clusters connected by both organic tetraphosphonates and inorganic phosphates, (CNH)(NH)H[(PMoO)(CPONH)(PO)Cs(MoO(HO))] (CNH = imidazolium), is presented here. The primary building block, {PMo}, is a tetravacant Keggin-type phosphomolybdate that has never been observed before. The compound shows a high proton conductivity of 9.

{Mo W }: Polyoxometalate Cages Shaped by π-π Interactions.

Here we report the formation of giant {Mo W } polyoxometalate cages templated by π-conjugated planar ligands. Their inorganic shells incorporate arrays of 18 stacked aromatic carboxylates, such as 1,3,5-benzenetricarboxylate or 5-nitroisophthalate, and the assembly is stabilized by multiple π-π interactions. NMR data confirmed that the cages are stable in solution and the inner aromatic templates can be postsynthetically replaced by selected aliphatic dicarboxylates, paving the way for endo-functionalization and exploration of the reactivities within the cage cavities.

A bimodal type of AgPd Plasmonic Blackbody Nanozyme with boosted catalytic efficacy and synergized photothermal therapy for efficacious tumor treatment in the second biological window.

Nanozymes are promising for precise cancer treatment, but are typically limited in terms of the low catalytic efficiency and the complexity in tumor microenvironment (TME). Herein, we describe a bimodal type of AgPd plasmonic blackbody (AgPd PB) nanozyme of compact sizes (< 30 nm), which presents not only boosted enzyme efficacy but also efficient photothermal therapy (PTT) for synergized therapy through tissue-penetrating light in the second biological window (1000-1700 nm). The synthesized hyperbranched AgPd PB nanozymes possess intense and broadband localized surface plasmonic resonance absorption of 400-1300 nm, entailing prominent photothermal efficiency (η = 45.

Timing matters: pre-assembly post-assembly functionalization of a polyoxovanadate-organic cuboid.

The pre-assembly and post-assembly approaches in the functionalization of a polyoxovanadate-organic cuboid, [{VS}(QPTC){V}], are discussed. We have shown that the two pathways have led to distinctly different systems, with either an expanded or contracted interior void space, when phenylphosphonate is introduced at different stages of the self-assembly. One leaves the cuboid framework largely intact, whereas the other results in a compact, twisted cuboid.

Metal-Organic Cages with {SiW Ni } Polyoxotungstate Nodes.

A tritopic, Ni-substituted Keggin cluster, {SiW Ni }, assembles with rigid dicarboxylate linkers to give rise to a set of discrete, POM L -type structures (POM={SiW Ni }) with defined interior voids. The outcome of coordination-driven self-assemblies of these polyhedral cages-from fused dimers to trigonal prisms-was found to be sensitive to bend angles of the ditopic ligands, which vary from 122° to 180°. These polyoxotungstate-based metal-organic polyhedra, when coupled with [Ru(bpy) ]Cl as a photosensitizer and triethanolamine as the electron donor, serve as highly effective catalysts for CO reduction, with turnover numbers up to 328 and CO selectivity as high as 96.

Macrocyclic Polyoxometalates: Selective Polyanion Binding and Ultrahigh Proton Conduction.

The rational development of an anion templation strategy for the construction of macrocycles has been historically limited to small anions, but large polyoxoanions can offer unmatched structural diversity and ample binding sites. Here we report the formation of a {Mo Fe } macrocycle by using the Preyssler anion, [NaP W O ] ({P W }), as a supramolecular template. The {Mo Fe } macrocycle displays selective anion binding behavior in solution.

High-Sensitivity Sensing of Divalent Copper Ions at the Single Upconversion Nanoparticle Level.

Single-nanoparticle-level sensing allows us to measure individual molecular interactions and probe environmental stimuli at nanometer-scale resolution. Despite these premises, limited success has been met hitherto due to the demanding challenge to distinguish a dimmed signal from a noisy background. Here, we describe an approach for high-sensitivity single-nanoparticle-level sensing of divalent copper (Cu) ions through near-infrared-to-visible upconversion luminescence against a near-null background.

How to not build a cage: endohedral functionalization of polyoxometalate-based metal-organic polyhedra.

Introducing functionalities into the interior of metal-organic cage complexes can confer properties and utilities ( catalysis, separation, drug delivery, and guest recognition) that are distinct from those of unfunctionalized cages. Endohedral functionalization of such cage molecules, for decades, has largely relied on modifying their organic linkers to covalently append targeted functional groups to the interior surface. We herein introduce an effective coordination method to bring in functionalities at the metal sites instead, for a set of polyhedral cages where the nodes are formed polyoxovanadate clusters, [V O(OCH)(μ-SO)(COO)].

Pentadecanuclear Fe-Containing Polyoxometalate Catalyst for Visible-Light-Driven Generation of Hydrogen.

The structurally new, carbon-free pentadecanuclear Fe-containing polyoxometalate, Na[NaFe(OH)(PO)(A-α-SiWO)]·85HO (Na-), was synthesized using a facile one-pot, solution-based synthetic approach and systematically characterized by various spectroscopic techniques. Single-crystal X-ray diffraction reveals that the title complex is composed of two [Fe(A-α-SiWO)] fragments and two [Fe(A-α-SiWO)] fragments stabilized by four PO linkers in a tetrameric style with idealized point group symmetry. When coupling with (4,4'-di-butyl-2,2'-dipyridyl)-bis(coumarin)-iridium(III) hexafluorophosphate ([Ir(coumarin)(dtbbpy)][PF]) photosensitizer and triethanolamine (TEOA) sacrificial electron donor, polyoxoanion effectively catalyzed hydrogen production with a minimally optimized TON of 986, which represents, to our knowledge, one of the highest values among known Fe-substituted POM-catalyzed hydrogen production systems.

Bridging Polyoxometalate-Based Mn Cubane Clusters with Inorganic Phosphates: Structural Transformation and Magnetic Properties.

The mixed-valent tetramanganese MnMn (Mn) cubane clusters have been at the forefront of molecular magnetism and biomimetic catalysis research for decades. Incorporating robust polyoxometalates to Mn cubanes significantly improves their stability and aqueous solubility, while providing a great platform for studying their deposition onto selected surfaces during device fabrication. In this work, we discovered that the terminal carboxylate ligands in these polyoxometalate-based [MnMnO] magnetic clusters can be partially or completely replaced by inorganic phosphate/polyphosphate groups.

In situ self-assembled cationic lanthanide metal organic framework membrane sensor for effective MnO and ascorbic acid detection.

Developing portable membrane sensors to accurately detect the biomolecule ascorbic acid (AA) is extremely important for food safety and human health. Herein, we successfully design and synthesize a novel cationic metal organic framework (Eu-pbmc, Hpbmc = 2-(pyridine-2-yl)-1H-benzimidazole-5-carboxylic acid) and assemble polyacrylonitrile/Eu-pbmc membrane (PEM) by an in-situ growth strategy. Benefiting from the appreciable loading of Eu-pbmc nanoparticles and high water permeation flux, PEM possesses effective detection for MnO with a limit of detection (LOD) of 17 nM.

Highly Stable Zinc-Based Metal-Organic Frameworks and Corresponding Flexible Composites for Removal and Detection of Antibiotics in Water.

Antibiotic contamination of water bodies is a major environmental concern. Exposure to superfluous antibiotics is an ecological stressor correlated to the development of antibiotic resistance. Thus, it is imperative that effective methods are developed to simultaneously detect and remove such antibiotics so as to avoid inadvertent release.

Chain length effect in the functionalization of polyoxometalates with α,ω-alkyldiphosphonates.

Altering the organic spacers in hybrid complexes of polyoxotungstates and long-chain α,ω-alkyldiphosphonates (Ln), by a single CH group (e.g.L6vs.

{Mo24Fe12} macrocycles: anion templation with large polyoxometalate guests.

POM and circumstance: Nanometer-sized polyoxometalates (POMs) bring a new direction to anion-templated supramolecular chemistry. The Keggin (left) and Dawson-type (right) polyoxoanions direct the assembly of giant metallomacrocycles through an array of weak hydrogen-bonding interactions. The concerted action of multiple hydrogen bonds keeps the templating guests embedded within the hosts, even in the solution state.

The self-assembly of a macroion with anisotropic surface charge density distribution.

A macroion, having anisotropic surface charge density distribution, shows unique self-assembly behaviour in polar solvents. Regular "blackberry"-like assemblies form in methanol-water mixtures due to counter-ion mediated attraction and the strong contribution of hydrogen bonding. However, rod-like assemblies form in acetone-water mixtures as the charge inhomogeneity effect overcomes the non-directional hydrogen bonding.

Revisiting the polyoxometalate-based late-transition-metal-oxo complexes: the "oxo wall" stands.

Terminal oxo complexes of the late transition metals Pt, Pd, and Au have been reported by us in Science and Journal of the American Chemical Society. Despite thoroughness in characterizing these complexes (multiple independent structural methods and up to 17 analytical methods in one case), we have continued to study these structures. Initial work on these systems was motivated by structural data from X-ray crystallography and neutron diffraction and (17)O and (31)P NMR signatures which all indicated differences from all previously published compounds.

A co-crystal of polyoxometalates exhibiting single-molecule magnet behavior: the structural origin of a large magnetic anisotropy.

A polyoxometalate-based {Mn(III)(3)Mn(IV)} single-molecule magnet exhibits a large axial anisotropy (D = -0.86 cm(-1)) resulting from a near-parallel alignment of Jahn-Teller axes. Its rigorous three-fold symmetry (i.

A polyoxometalate-based single-molecule magnet with an S = 21/2 ground state.

Ligand modification transforms a polyoxometalate-anchored cubane-type [Mn(III)(3)Mn(IV)O(4)] core into a centrosymmetric [Mn(III)(6)Mn(IV)O(8)] di-cubane cluster, and restores the slow magnetization relaxation characteristics typical for [Mn(4)O(4)] cubane-based single-molecule magnets.