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Developing polyoxometalate‐cyclodextrin cluster‐organic supramolecular framework (POM‐CD‐COSF) still remains challenging due to an extremely difficult task in rationally interconnecting two dissimilar building blocks. Here we report an unprecedented POM‐CD‐COSF crystalline structure produced through the self‐assembly process of a Krebs‐type POM, [Zn2(WO2)2(SbW9O33)2]10−, and two β‐CD units. The as‐prepared POM‐CD‐COSF‐based battery separator can be applied as a lightweight barrier (approximately 0.3 mg cm−2) to mitigate the polysulfide shuttle effect in lithium‐sulfur batteries. The designed Li−S batteries equipped with the POM‐CD‐COSF modified separator exhibit remarkable electrochemical performance, attributed to fast Li+ diffusion through the supramolecular channel of β‐CD, efficient polysulfide‐capture ability by the dynamic host–guest interaction of β‐CD, and improved sulfur redox kinetics by the bidirectional catalysis of POM cluster. This research provides a broad perspective for the development of multifunctional supramolecular POM frameworks and their applications in Li−S batteries. [ABSTRACT FROM AUTHOR]

The advancement of a naturally rich and effective bifunctional substance for hydrogen and oxygen evolution reaction is crucial to enhance hydrogen fuel production efficiency via the electrolysis process. Herein, facile and scalable hydrothermal synthesis of bifunctional electrocatalyst of polyoxometalate anchored zinc cobalt sulfide nanowire on Ni‐foam (NF) for overall water splitting is reported for the first time. The electrochemical analysis of POM@ZnCoS/NF displays significantly low HER and OER overpotentials of 170/337 and 200/300 mV to attain a current density of 10/40 and 20/50 mA cm−2, respectively, demonstrating the notable performance of POM@ZnCoS/NF toward H2 and O2 evolution reaction in alkaline medium. Additionally, the electrolyzer consisting of the POM@ZnCoS/NF anode and cathode shows an appealing potential of 1.56 V to deliver 10 mA cm−2 current density for overall water splitting. The high electrocatalytic activity of the POM@ZnCoS/NF is attributed to modulation of the electronic and chemical properties, increment of the electroactive sites and electrochemically active surface area of the zinc cobalt sulfide nanowires due to the anchorage of polyoxometalate nanoparticles. These results demonstrate the advantage of the polyoxometalate incorporation strategy for the design of cost‐effective and highly competent bifunctional catalysts for complete water splitting. [ABSTRACT FROM AUTHOR]

Direct Hydroxylation of benzene to phenol with high yield and selectivity has been the goal of phenol industrial production. Photocatalysis can serve as a competitive method to realize the hydroxylation of benzene to phenol owing to its cost‐effective and environmental friendliness, however it is still a forbidding challenge to obtain good yield, high selectivity and high atom availability meanwhile. Here we show a series of supramolecular catalysts based on alkoxohexavanadate anions and quinolinium ions for the photocatalytic hydroxylation of benzene to phenol under UV irradiation. We demonstrate that polyoxoalkoxovanadates can serve as efficient catalysts which can not only stabilize quinolinium radicals but also reuse H2O2 produced by quinolinium ions under light irradiation to obtain excellent synergistic effect, including competitive good yield (50.1 %), high selectivity (>99 %) and high atom availability. [ABSTRACT FROM AUTHOR]

Aromatic azo compounds, which play an important role in pharmaceutical and industrial applications, still face great challenges in synthesis. Herein, we report a molybdenum oxide compound, [N(C4H9)4]2[Mo6O19] (1), catalyzed selective oxidation of anilines with hydrogen peroxide as green oxidant. The oxidation of anilines can be realized in a fully selectively fashion to afford various symmetric/asymmetric azobenzene and azoxybenzene compounds, respectively, by changing additive and solvent, avoiding the use of stoichiometric metal oxidants. Preliminary mechanistic investigations suggest the intermediacy of highly active reactive and elusive Mo imido complexes. [ABSTRACT FROM AUTHOR]

Sub‐nanoscaled polyalkoxyvanadates (PAOVs) functionalized with various aliphatic acids are evaluated for their insulin‐sensitizing activity in lowering the blood glucose levels of diabetic mice in typical glucose tolerance tests. All the PAOVs can restore the blood glucose to normal levels after a single oral administration of PAOVs. Among them, the myristic acid‐modified PAOVs enable the response of insulin to the repeated glucose challenges, lasting for up to 13 h. The combined administration of PAOVs exerts better glucose control over insulin alone, while the capric acid‐ and myristic acid‐modified ones can enhance the responsiveness of insulin to glucose challenge and is comparable to a clinical‐used derivative of insulin. Interestingly, continuous glucose monitoring shows that myristic acid‐modified PAOV derivatives sensitize the responsiveness of insulin, almost matching with that of a healthy pancreas. These discoveries open up new opportunities for the application of PAOVs to promote glucose‐responsive and long‐lasting activity of insulin, which are expected to aid the accurate blood glucose control in insulin therapy while reducing the number of insulin administrations. [ABSTRACT FROM AUTHOR]

One halide ion (X−) can bind on the surface of nanoscale Anderson‐type polyoxometalate (POMs) clusters [(n‐C4H9)4N]3{AlMo6O18(OH)3[(OCH2)3CCH3]}, and form stable complexes in solution with binding constant K=1.53×103. Single‐crystal structural analysis showed that this binding behavior occurs through multiple hydrogen bonding between X− and three hydroxy groups on the uncapped side of the cluster. This supramolecular interaction in the cluster systems means that their catalytic activities, evaluated from the oxidation of alcohols to aldehydes, can be switched upon the introduction of halide ions and water molecules. The halide ions work as inhibitors by blocking the active sites of the clusters while they can be re‐activated by the addition of water. [ABSTRACT FROM AUTHOR]

Engineering photoredox‐triggered chemical transformation via visible light has been an emerging area in organic synthesis. However, most of the well‐established photocatalysts are based upon either transition metal complexes involved with noble metals and organic ligands or photosensitive organic dyes, the development of pure inorganic molecular photocatalysts that could provide better stability and durability is greatly retarded. Herein we discover that the Anderson polyoxometalate (POM) Na4[NiMo6O18(OH)6] (1), which consists of pure inorganic framework built from a central NiII core supported by six MoVIO6 inorganic scaffold/ligands, can be used as a powerful photocatalyst. Upon irradiation with visible light (>400 nm), the compound can catalyze, in high efficiency, a wide range of reactions, including the oxidative cross‐coupling reaction of chlorides with amines, as well as oxidation of chlorides using molecular oxygen, affording various imines, aldehydes, and ketones, respectively in high selectivity and good yields. Owing to the robust inorganic framework, this catalyst exhibits excellent stability during the catalysis and reusability with little loss of the catalytic activity, thus providing an alternative without use of complicated organic ligands and expensive noble metal‐based photosensitizers. Best supporting role: A practical and efficient environmentally benign catalytic protocol of oxidation of cross‐coupling reaction of chlorides with amines, as well as oxidation of halides was developed with inorganic‐ligand supported Ni‐photocatalyst Na4[NiMo6O18(OH)6] using molecular oxygen and visible light. This method utilizes mainly an inorganic polymolybdate ligand to support the Ni2+ ion and 1 atm O2 gas as the sole oxidant, which can smoothly proceed to afford various imines and aldehydes or ketones with high yields and selectivity, avoiding the use of complicated organic ligands and expensive noble metal‐based photosensitizers. [ABSTRACT FROM AUTHOR]

Abstract: An efficient, durable, and low‐cost hydrogen evolution reaction (HER) catalyst is an essential requirement for practical hydrogen production. Herein, an effective approach to facilitate the HER kinetics of molybdenum carbide (Mo2C) electrocatalysts is presented by tuning its electronic structure through atomic engineering of nitrogen implantation. Starting from the organoimido‐derivatized polyoxometalate nanoclusters with inherent MoN bonds, the formation of N‐implanted Mo2C (N@Mo2C) nanocrystals with perfectly adjustable amounts of N atoms is demonstrated. The optimized N@Mo2C electrocatalyst exhibits remarkable HER performance and good stability over 20 h in both acid and basic electrolytes. Further density functional theory calculations show that engineering suitable nitrogen atoms into Mo2C can regulate its electronic structure well and decrease MoH strength, leading to a great enhancement of the HER activity. It could be believed that this ligand‐controlled atomic engineering strategy might influence the overall catalyst design strategy for engineering the activation sites of nonprecious metal catalysts for energy conversions. [ABSTRACT FROM AUTHOR]

Abstract: A series of rod‐shaped polyoxometalates (POMs) [Bu4N]7[Mo6O18NC(CH2O)3MnMo6O18(OCH2)3CNMo6O18] and [Bu4N]7[ArNMo6O17NC(CH2O)3MnMo6O18(OCH2)3CNMo6O17NAr] (Ar=2,6‐dimethylphenyl, naphthyl and 1‐methylnaphthyl) were chosen to study the effects of cation–π interaction on macroionic self‐assembly. Diffusion ordered spectroscopy (DOSY) and isothermal titration calorimetry (ITC) techniques show that the binding affinity between the POMs and Zn2+ ions is enhanced significantly after grafting aromatic groups onto the clusters, leading to the effective replacement of tetrabutylammonium counterions (TBAs) upon the addition of ZnCl2. The incorporation of aromatic groups results in the significant contribution of cation–π interaction to the self‐assembly, as confirmed by the opposite trend of assembly size vs. ionic strength when compared with those without aromatic groups. The small difference between two aromatic groups toward the Zn2+ ions is amplified after combining with the clusters, which consequently triggers the self‐recognition behavior between two highly similar macroanions. [ABSTRACT FROM AUTHOR]

Abstract: A method for the aerobic oxidation of aldehydes to carboxylic acids in water by using an inorganic‐ligand‐supported copper catalyst was developed. This method was performed with the use of atmospheric oxygen as the sole oxidant under extremely mild aqueous conditions, and furthermore, a wide range of aldehydes with various functional groups were tolerated. The copper catalyst could be recycled and used in successive reactions at least six times without any appreciable degradation in performance. This method is operationally simple and avoids the use of high‐costing, toxic, air/moisture‐sensitive, and commercially unavailable organic ligands. The generality of this method gives it potential to be used on the industrial scale. [ABSTRACT FROM AUTHOR]

Abstract: The efficient evolution of hydrogen through electrocatalysis is considered a promising approach to the production of clean hydrogen fuel. Platinum (Pt)‐based materials are regarded as the most active hydrogen evolution reaction (HER) catalysts. However, the low abundance and high cost of Pt hinders the large‐scale application of these catalysts. Active, inexpensive, and earth‐abundant electrocatalysts to replace Pt‐based materials would be highly beneficial to the production of cost‐effective hydrogen energy. Herein, a novel organoimido‐derivatized heteropolyoxometalate, Mo4‐CNP, is designed as a precursor for electrocatalysts of the HER. It is demonstrated that the carbon, nitrogen, and phosphorus sources derived from the Mo4‐CNP molecules lead to in situ confined carburization, phosphorization, and chemical doping on an atomic scale, thus forming nitrogen‐doped porous molybdenum carbide and phosphide hybrids, which exhibit remarkable electrocatalytic activity for the HER. Such an organically functionalized polyoxometalate‐assisted strategy described here provides a new perspective for the development of highly active non‐noble metal electrocatalysts for hydrogen evolution. [ABSTRACT FROM AUTHOR]

A redox-responsive hybrid of polyoxometalate and conducting oligomer including its self-assemblies with controllable morphologies are reported. To this end, a hybrid molecule, containing a Lindqvist hexamolybdate as the polar head group and N,N′-bis(4′-amino-2,6-dimethylphenyl)-1,4-quinonediimine as the redox-responsive and aggregating group, is prepared. This hybrid exhibits redox-responsive behavior with controllable assembling morphological transition from spherical vesicles to short cylindrical vesicles. Besides, the hybrid-based self-assemblies are transferred to the surface, thus the surface wettability can be well-tuned owing to the morphological transitions of the self-assemblies. By marrying conducting materials with polyoxometalate chemistry, this research opens a new horizon of polyoxometalate-based self-assembled systems with potential applications in functional materials. [ABSTRACT FROM AUTHOR]

Most state-of-art transition-metal catalysts usually require organic ligands, which are essential for controlling the reactivity and selectivity of reactions catalyzed by transition metals. However, organic ligands often suffer from severe problems including cost, toxicity, air/moisture sensitivity, and being commercially unavailable. Herein, we show a simple, mild, and efficient aerobic oxidation procedure of amines using inorganic ligand-supported non-precious metal catalysts 1, (NH4) n[MMo6O18(OH)6] (M=Cu2+; Fe3+; Co3+; Ni2+; Zn2+, n=3 or 4), synthesized by a simple one-step method in water at 100 °C, demonstrating that the catalytic activity and selectivity can be significantly improved by changing the central metal atom. In the presence of these catalysts, the catalytic oxidation of primary and secondary amines, as well as the coupling of alcohols and amines, can smoothly proceed to afford various imines with O2 (1 atm) as the sole oxidant. In particular, the catalysts 1 have transition-metal ion core, and the planar arrangement of the six MoVI centers at their highest oxidation states around the central heterometal can greatly enhance the Lewis acidity of catalytically active sites, and also enable the electrons in the center to delocalize onto the six edge-sharing MO6 units, in the same way as ligands in traditional organometallic complexes. The versatility of this methodology maybe opens a path to catalytic oxidation through inorganic ligand-coordinated metal catalysis. [ABSTRACT FROM AUTHOR]

The first example of a heterogeneous iron(III)-catalyzed aerobic oxidation of aldehydes in water was developed. This method utilizes 1 atmosphere of oxygen as the sole oxidant, proceeds under extremely mild aqueous conditions, and covers a wide range of various functionalized aldehydes. Chromatography is generally not necessary for product purification. Its operational simplicity, gram-scale oxidation, and the ability to successively reuse the catalyst, make this new methodology environmentally benign and cost effective. The generality of this methodology gives it the potential to be used on an industrial scale. [ABSTRACT FROM AUTHOR]

The first example of a heterogeneous iron(III)-catalyzed aerobic oxidation of aldehydes in water was developed. This method utilizes 1 atmosphere of oxygen as the sole oxidant, proceeds under extremely mild aqueous conditions, and covers a wide range of various functionalized aldehydes. Chromatography is generally not necessary for product purification. Its operational simplicity, gram-scale oxidation, and the ability to successively reuse the catalyst, make this new methodology environmentally benign and cost effective. The generality of this methodology gives it the potential to be used on an industrial scale. [ABSTRACT FROM AUTHOR]

Herein we report a step-by-step strategy for the organic modification of polyoxovanadates, which is based on a suitable polyoxovanadate platform, and a series of novel functionalized polyoxovanadates can be synthesized conveniently by sequential esterification and amidation reactions. [ABSTRACT FROM AUTHOR]

A series of aliphatic organoimido derivatives of hexamolybdate based on amantadine, namely (nBu4N)2-[Mo6O18(≡NC10H15)] (1), (nBu4N)2 {cis-[Mo6O17(≡NC10H15)2]} (2), (nBu4N)2{trans-[Mo6O17(≡NC10H15)2]} (3), and (nBu4N)2[Mo6O16- (≡NC10H15)3] (4), was synthesized in reasonable yield by dehydration with N,N'-dicyclohexylcarbodiimide (DCC). They were characterized by IR and UV/Vis spectroscopy, elemental analysis, ESI mass spectrometry, and single-crystal X-ray structure analysis. The spectral and structural similarities and differences between monosubstituted, cis-disubstituted, and transdisubstituted organoimido derivatives were elucidated and may provide guidance for related work on organoimido-functionalized Lindqvist-type polyoxometalates. In addition, trans-disubstituted and polysubstituted derivatives containing aliphatic organoimido ligands have not yet been reported, and the crystal structure of the trans isomer may lead us to a deeper understanding of disubstituted derivatives. Furthermore, proliferation and morphology of MCF-7 cells were studied with compound 1. The present results show that the DCC-dehydrating protocol could be an efficient approach to covalently graft bioactive ligands such as amantadine onto POMs and enhance their application in clinical cancer treatment. [ABSTRACT FROM AUTHOR]

Trifluoromethylation of tetraphenlyborate counterions was successfully used to improve the electrochemical stabilities and device performance of cationic iridium(III) complexes. Melioration of the thermal, photoluminescent, electrochemical, and electrophosphorescent characteristics was achieved. Interionic hydrogen bonds were first found between the aromatic hydrogen atoms in the ancillary ligands of cations and the fluorine atoms in the trifluoromethyl groups of the anions. The strong impact of the counterions on the charge transport in the devices was investigated. A compound with two trifluoromethyl groups in the tetraphenlyborate ion shows the highest photoluminescent efficiency, the best electrochemical stability, and the greatest performance in green-blue-emitting devices, with a high current efficiency of 12.4 cd A−1 and an emission peak at λ=480 nm. The efficiencies achieved are the highest reported for OLEDs with ionic complexes emitting in the blue-green region. [ABSTRACT FROM AUTHOR]

Keywords: hydroxylation of benzene; polyoxovanadates; quinolinium; supramolecular photocatalysis; synergistic catalysis EN hydroxylation of benzene polyoxovanadates quinolinium supramolecular photocatalysis synergistic catalysis 14218 14219 2 06/18/21 20210621 NES 210621 A reader of this Research Article raised concerns regarding the isolated yield of phenol, the mass conservation of the catalytic system, the calculation of selectivity and the overoxidation of phenol, and the change of phenol yield with reaction time. As can be seen in Figure 2 of this Corrigendum, up to 12 h of reaction time, the conversion of benzene and the yield of phenol match well, and thus the phenol selectivity can be determined by analysis of the liquid phase. For the third repeated experiment, the GC-MS trace (Figure S3) showed that the residual benzene was 50.9 %, indicating a benzene conversion of 49.1 %, which was exactly identical to the yield of phenol of 49.1 %, implying again that the mass balance was fulfilled in our catalytic system. [Extracted from the article]

Keywords: hydroxylation of benzene; polyoxovanadates; quinolinium; supramolecular photocatalysis; synergistic catalysis EN hydroxylation of benzene polyoxovanadates quinolinium supramolecular photocatalysis synergistic catalysis 14338 14339 2 06/16/21 20210621 NES 210621 A reader of this Research Article raised concerns regarding the isolated yield of phenol, the mass conservation of the catalytic system, the calculation of selectivity and the overoxidation of phenol, and the change of phenol yield with reaction time. For the third repeated experiment, the GC-MS trace (Figure S3) showed that the residual benzene was 50.9 %, indicating a benzene conversion of 49.1 %, which was exactly identical to the yield of phenol of 49.1 %, implying again that the mass balance was fulfilled in our catalytic system. As can be seen in Figure 2 of this Corrigendum, up to 12 h of reaction time, the conversion of benzene and the yield of phenol match well, and thus the phenol selectivity can be determined by analysis of the liquid phase;. [Extracted from the article]

An inorganic-organic hybrid surfactant with a hexavanadate cluster as the polar head group was designed and observed to assemble into micelle structures, which further spontaneously coagulate into a 1D anisotropic structure in aqueous solutions. Such a hierarchical self-assembly process is driven by the cooperation of varied noncovalent interactions, including hydrophobic, electrostatic, and hydrogen-bonding interactions. The hydrophobic interaction drives the quick formation of the micelle structure; electrostatic interactions involving counterions leads to the further coagulation of the micelles into larger assemblies. This process is similar to the crystallization process, but the specific counterions and the directional hydrogen bonding lead to the 1D growth of the final assemblies. Since most of the hexavanadates are exposed to the surface, the 1D assembly with nanoscale thickness is a highly efficient heterogeneous catalyst for the oxidation of organic sulfides with appreciable recyclability. [ABSTRACT FROM AUTHOR]

On the basis of the well-developed N, N′-dicyclohexylcarbodiimide (DCC) imidoylization strategy, the novel trans-dinitrosyl-substituted polyoxometalate (POM) (NBu4)4[Mo6O17(≡NO)2] was synthesized in moderate yield with high purity through a highly selective reaction route under mild reaction conditions. Its structure was elucidated by IR and UV/Vis spectroscopy, ESI-MS, and single-crystal X-ray diffraction studies. Furthermore, its ability to undergo controlled NO release was confirmed by ESI-MS, and a curve of the amount of NO released as a function of time within a simulated body fluid system was obtained by UV spectroscopy. The rate of NO release is controlled by changing the pH of the system. This is the first time that the decomposition of a POM has been used to produce therapeutic NO species. This study provides a new route to controlled-release technology for NO storage and targeted delivery. [ABSTRACT FROM AUTHOR]

Doubly modified: Polyoxometalates can incorporate a large number of differENt functionalities in a way that mixes the ligands in a one ‐ pot reaction. A class of mixed organoimido bifunctionalized hexamolybdates is presENted that involves two differENt moieties L1 and L2, namely, differing aromatic, aromatic and aliphatic, and aliphatic moieties. [ABSTRACT FROM AUTHOR]

The functionalization of polyoxometalates (POMs), especially with an amino group to yield organonitrogenous derivatives of POMs, is an efficient approach to the enrichment of their structures and the diversification of their properties for various applications. The mechanism for the formation of organonitrogenous-derivatized hexamolybdates was explored by investigating the monofunctionalization of the [Mo6O19]2− ion with methylamine using the density functional theory (DFT) method. The calculations show that the direct imidoylization of hexamolybdate with methylamine is both kinetically and thermodynamically unfavorable. However, this imidoylization was found to take place readily in the presence of dimethylcarbodiimide (DMC), for which the free-energy barrier was calculated to be +32.5 kcal mol−1 in acetonitrile. Moreover, various factors controlling the efficiency of the imidoylization were examined. The calculations show that [W5MoO19]2− has a relatively lower reactivity than [Mo6O19]2−, and that the imidoylization of [W6O19]2− is an unfavorable process. With respect to the effect of carbodiimides, it is found that the catalytic activity is directly proportional to the electron-withdrawing effects of the substituents. As to the reactivity of RNH2, the computation results indicate that the free-energy barriers of the substitution reactions are linearly correlated with the basicity constants (p Kb) of the amino groups. It is noteworthy that the introduction of the proton dramatically decreases the free-energy barrier of the imidoylization of [Mo6O19]2− catalyzed by DMC to 24.3 kcal mol−1 in acetonitrile. [ABSTRACT FROM AUTHOR]

Cover Feature: Unprecedented Halide-Ion Binding and Catalytic Activity of Nanoscale Anionic Metal Oxide Clusters (ChemPlusChem 11/2019) B The cover feature b shows that halide ions can bind on the surface of nanoscale, anionic metal oxide clusters and form stable complexes in solution. Anion binding, heterogeneous catalysis, clusters, hydrogen bonding, polyoxometalates. [Extracted from the article]

An inorganic–organic hybrid surfactant with a hexavanadate cluster as the polar head group underwent stepwise assembly into micelles and finally, a 1D nanobelt structure with the cooperation of hydrophobic, electrostatic, and hydrogen‐bonding interactions; these last interactions are directional and lead to the anisotropic assemblies. The nanobelts are highly efficient heterogeneous catalysts for the oxidation of organic sulfides because most of the hexavanadates are exposed to the surface, showing its potential application in the petroleum industry and in environmentally benign chemistry. For more details see the Full Paper by T. Li, Y. Wei, T. Liu et al. on page 9589 ff. [ABSTRACT FROM AUTHOR]

The title compound, [Co(C(12)H(6)N(2)O(4))(H(2)O)(2)](n), has been hydrothermally synthesized and structurally characterized. It consists of polymeric chains of [Co(mu-(2,2'-bipyridyl-3,3'-dicarboxylato-kappa(4)N,N':O,O'))(H(2)O)(2)] units, in which each Co(II) cation is octahedrally coordinated by two chelating pyridyl N atoms, two chelating carboxyl O atoms from different carboxylate groups of another bipyridyl ligand, and two water molecules as terminal ligands. A crystallographic twofold axis parallel to the chain axis, passes through the Co atom.