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Rechargeable aqueous zinc-ion batteries (AZIBs) have garnered widespread attention due to their low cost, non-flammability, eco-friendliness, and abundant anode element content, with the potential to supplant lithium-ion batteries. Nevertheless, their development is hindered by zinc dendrite growth, corrosion passivation, the hydrogen evolution reaction (HER), and active material decomposition, severely impairing the cycling lifespan and coulombic efficiency of AZIBs. As a cathode material, sulfur offers superior theoretical capacity, non-toxicity, and lower cost compared to traditional aqueous zinc-ion battery active materials, thus compensating for the shortcomings of low discharge capacity and insufficient overall energy density in AZIBs. Although research on aqueous zinc-sulfur batteries (AZSBs) is relatively scarce, their exceptional performance has yielded outstanding results. This paper first reviews the cathode materials and reaction mechanisms of aqueous zinc–sulfur batteries, and then systematically analyzes the pertinent electrochemical performance data following the latest research on electrolyte modification and additive engineering. Subsequently, we discuss and analyze potential solutions to the existing impediments in zinc–sulfur batteries. Finally, based on an analysis of current research findings, we propose future research directions with the aim of providing inspiration to overcome the latent challenges facing aqueous zinc-sulfur batteries. [ABSTRACT FROM AUTHOR]

Both polyoxometalates (POMs) and organic small molecular catalysts show excellent performance in chemical synthesis. The incorporation of nanoscale POMs and organocatalysts allows the full expression of their respective merits and enables elusive reactions to be achieved in one catalytic system. However, the covalent combination of such two components has been rarely explored. Here, we have successfully designed and synthesized a bifunctional nanomolecular catalyst L -Pro-Mn-Anderson by grafting L -proline onto an Mn-Anderson POM for the first time, and catalytic experiments show that L -Pro-Mn-Anderson can realize the one-pot alcohol oxidation/three-component reaction to synthesize two types of heterocyclic compounds (5-aryl-pyrimido[4,5-b]quinoline-dione derivatives and pyrazolo[3,4-b] pyridine derivatives) in high yields up to 97%. The detailed characterization of the catalyst and the catalytic mechanism has shown that L -Pro-Mn-Anderson exhibits synergistic effects that combine both organic and inorganic catalytic functions, and the covalent linkage improves the overall redox activity of the molecular catalyst. This study opens up a new way for the design and application of covalently combined organic–inorganic molecular catalysts toward de novo organic synthesis. [ABSTRACT FROM AUTHOR]

A novel supramolecular complex Li3Cl[(HPW12O40)(H24C12O6)3(CH3CN)2] {CR-PW12} was confirmed first to apply as a sulfur host in lithium–sulfur batteries. The {CR-PW12}@S cathode exhibits a reversible capacity of 1120 mA h g−1 at 1.0 C and excellent cycle stability. [ABSTRACT FROM AUTHOR]

A Keggin-type polyoxometalate-based crystalline complex, [(SiMo12O40)Cu6(2,2′-bipy)6(Mo6O22)] (complex 1), has been prepared by using a Waugh-type polyoxometalate building block [MnMo9O32]6−, and for the first time, Waugh-type polyoxometalate was converted to a Keggin-type structure under hydrothermal conditions by using a Teflon-lined reactor with glass vials. The synthesized complex was characterized by single-crystal and powder X-ray diffraction, thermogravimetric analysis, Fourier transform infrared spectroscopy, Raman spectroscopy, ultraviolet-visible spectroscopy, X-ray photoelectron spectroscopy, and elemental analysis. Structural characterization results show that complex 1 comprises Keggin-type [SiMo12O40]4− anions and [Cu6(2,2′-bipy)6(Mo6O22)]4+ cation moieties composed of isopolymolybdates with 2,2′-bipy-coordinated copper ions, leading to a three-dimensional (3D) supramolecular network. This polyoxometalate assembly exhibits excellent photocatalytic properties and good cyclic stability for the photodegradation of methylene blue (MB) dye. In addition, the experimental results demonstrate that complex 1 also possesses outstanding electrocatalytic activity for nitrite reduction. [ABSTRACT FROM AUTHOR]

The direct catalytic oxidation of alcohols to carboxylic acids is very appealing, however, economic and environmentally friendly catalytic systems should be further explored from the aspect of less waste production and a convenient procedure. Herein, we display a structurally defined inorganic ligand-supported iron compound, (TBA)3[FeMo6O18(OH)6] (simplified as FeMo6), which could be used as a heterogeneous molecular catalyst in water for this conversion, with oxygen as the terminal oxidant and KCl as an additive. The oxidation of various alcohols (aromatic and aliphatic) could be achieved in almost all cases under mild conditions and provided the corresponding carboxylic acids in high yields, including some active molecular entities and natural molecules with carboxyl structures. Detailed studies showed that chloride ions could combine with the molecular catalyst FeMo6 to form a supramolecular aggregate FeMo6·Cl, which could effectively catalyze the reaction, relying on the synergistic effect of chloride ions and FeMo6. Control experiments, 1H NMR studies and density functional theory (DFT) calculations showed that the oxidation reaction might involve a free radical pathway. [ABSTRACT FROM AUTHOR]

The carbon–carbon bond cleavage of 1,2-diols is an important chemical transformation. Although traditional stoichiometric and catalytic oxidation methods have been widely used for this transformation, an efficient and valuable method should be further explored from the views of reusable catalysts, less waste, and convenient procedures. Herein an inorganic-ligand supported iron catalyst (NH4)3[FeMo6O18(OH)6]·7H2O was described as a heterogeneous molecular catalyst in acetic acid for this transformation in which hydrogen peroxide was used as the terminal oxidant. Under the optimized reaction conditions, carbon–carbon bond cleavage of 1,2-diols could be achieved in almost all cases and carboxylic acids or ketones could be afforded with a high conversion rate and high selectivity. Furthermore, the catalytic system was used efficiently to degrade renewable biomass oleic acid. Mechanistic insights based on the observation of the possible intermediates and control experiments are presented. [ABSTRACT FROM AUTHOR]

A highly efficient method to oxidize methylarenes to their corresponding acids with a reusable Cr catalyst was developed. The reaction can be carried out in water with 1 atm oxygen and K2S2O8 as cooxidants, proceeds under green and mild conditions, and is suitable for the oxidation of both electron-deficient and electron-rich methylarenes, including heteroaryl methylarenes, even at the gram level. The excellent result, together with its simplicity of operation and the ability to continuously reuse the catalyst, makes this new methodology environmentally benign and cost-effective. The generality of this methodology gives it the potential for use on an industrial scale. Differing from the accepted oxidation mechanism of toluene, GC-MS studies and DFT calculations have revealed that the key benzyl alcohol intermediate is formed under the synergetic effect of the chromium and molybdenum in the Cr catalyst, which can be further oxidized to afford benzaldehyde and finally benzoic acid. [ABSTRACT FROM AUTHOR]

Organo disulfides represent an abundant class of compounds in chemical biology, pharmaceutical fields, and industry. They are traditionally synthesized by the oxidation of mercaptan in the presence of an organic ligand supported metal catalyst or toxic oxidants under harsh conditions. Here, we disclose a highly-efficient pathway in which disulfide is synthesized by organic boric acid and Na2S2O3 using the catalyst (NH4)3[CrMo6O18(OH)6], demonstrating a high activity and excellent selectivity. Various boric acid derivatives have been successfully transformed into the corresponding disulfides. Mechanistic insights have been furnished based on the observation of intermediate and control experiments. [ABSTRACT FROM AUTHOR]

We report an efficient method for the oxidative dehydrogenation of hydrazines and diarylamines in aqueous ethanol using Anderson-type polyoxomolybdate-based iron(III) as a catalyst and hydrogen peroxide as an oxidant. A series of azo compounds and tetraarylhydrazines were obtained in moderate to excellent yields. The reaction conditions and substrate scopes are complementary or superior to those of more established protocols. In addition, the catalyst shows good stability and reusability in water. The preliminary mechanistic studies suggest that a radical process is involved in the reaction. [ABSTRACT FROM AUTHOR]

Novel Anderson-type polyoxomanganotungstate clusters with the β-isomer structure, [{R1R2C(CH2O)2}MnIVW6O22]6−, were synthesized and monofunctionalized with derivatives of 1,3-propanediol via a one-pot strategy, and show unprecedented coordination activity as non-lacunary polyoxotungstate clusters and could have potential in the future construction of POM-frameworks. [ABSTRACT FROM AUTHOR]

The direct esterification of alcohols with non-noble metal-based catalytic systems faces great challenges. Here, we report a new chrome-based catalyst stabilized by a single pentaerythritol decorated Anderson-type polyoxometalate, [N(C4H9)4]3[CrMo6O18(OH)3C{(OCH2)3CH2OH}], which can realize the efficient transformation from alcohols to esters by H2O2 oxidation in good yields and high selectivity without extra organic ligands. A variety of alcohols with different functionalities including some natural products and pharmaceutical intermediates are tolerated in this system. The chrome-based catalyst can be recycled several times and still keep the original configuration and catalytic activity. We also propose a reasonable catalytic mechanism and prove the potential for industrial applications. [ABSTRACT FROM AUTHOR]

A simple and efficient protocol for the formylation of amines with formic acid, catalyzed by a polyoxometalate-based chromium catalyst, is described. Notably, this method shows excellent activity and chemoselectivity for the formylation of primary amines; diamines have also been successfully employed. Importantly, the chromium catalyst is potentially non-toxic, environmentally benign and safer than the widely used high valence chromium catalysts such as CrO3 and K2Cr2O7. The catalyst can be recycled several times with a negligible impact on activity. Finally, a plausible mechanism is provided based on the observation of intermediate and control experiments. [ABSTRACT FROM AUTHOR]

Direct catalytic oxidation of alcohols to carboxylic acids is very attractive, but economical catalysis systems have not yet been well established. Here, we show that a pure inorganic ligand-supported chromium compound, (NH4)3[CrMo6O18(OH)6] (simplified as CrMo6), could be used to effectively promote this type of reaction in the presence of CO2. In almost all cases, oxidation of various alcohols (aromatic and aliphatic) could be achieved under mild conditions, and the corresponding carboxylic acids can be achieved in high yield. The chromium catalyst 1 can be reused several times with little loss of activity. Mechanism study and control reactions demonstrate that the acidification proceeds via the key oxidative immediate of aldehydes. [ABSTRACT FROM AUTHOR]

Two novel polyoxovanadate-iodoBodipy supramolecular assemblies, named as (2I-BDP-C6)2V6 and (2I-BDP-C6)3V10, were first synthesized by the self-assembly of anionic hexavanadate and decavanadate with cationic iodoBodipy for photochemotherapy, respectively. The mechanisms for synergistic photochemotherapy of the anion–cation pairs were determined. In particular, (2I-BDP-C6)3V10 can effectively kill lung cancer cells (HepG2) by synergetic chemotherapy as well as photodynamic therapy. [ABSTRACT FROM AUTHOR]

The first example of an inorganic-ligand supported iron(III) catalysed coupling of formic acid and amines to form formamides is reported. The pure inorganic catalyst (NH4)3[FeMo6O18(OH)6] (1), which consists of a central FeIII single-atomic core supported within a cycle-shaped inorganic ligand consisting of six MoVIO6 octahedra, shows excellent activity and selectivity, and avoids the use of complicated/commercially unavailable organic ligands. Various primary amines and secondary amines have been successfully transformed into the corresponding formamides under mild conditions, and the formylation of primary diamines has also been achieved for the first time. The Fe catalyst 1 can be reused several times without appreciable loss of activity. [ABSTRACT FROM AUTHOR]

Over the past two decades, there have been major developments in the transition iron-catalyzed selective oxidation of alkenes to epoxides; a common structure found in drug, isolated natural products, and fine chemicals. Many of these approaches have enabled highly efficient and selective epoxidation of alkenes via the design of specialized ligands, which facilitates to control the activity and selectivity of the reactions catalyzed by iron atom. Herein, we report the development of the olefin epoxidation with inorganic-ligand supported iron-catalysts using 30% H2O2 as an oxidant, and the mechanism is similar to iron-porphyrin type. With the catalyst 1, (NH4)3[FeMo6O18(OH)6], various aromatic and aliphatic alkenes were successfully transformed into the corresponding epoxides with excellent yields as well as chemo- and stereo-selectivity. This catalytic system possesses the advantages of being able to avoid the use of expensive, toxic, air/moisture sensitive and commercially unavailable organic ligands. The generality of this methodology is simple to operate and exhibits high catalytic activity as well as excellent stability, which gives it the potential to be used on an industrial scale, and maybe opens a way for the catalytic oxidation reaction via inorganic-ligand coordinated iron catalysis. [ABSTRACT FROM AUTHOR]

The oxidative esterification of various aldehydes with alcohols could be achieved by a heterogeneous iron(III) catalyst supported on a ring-like POM inorganic ligand under mild conditions, affording the corresponding esters, including several drug molecules and natural products, in high yields. ESI-MS and control experiments demonstrated that POM-FeV(＝O) was the active catalytic species and the plausible mechanism was presented. More importantly, the 6th run of the iron catalyst recycles shows only a slight decrease in the yield. [ABSTRACT FROM AUTHOR]

The oxidation of alcohols to aldehydes or ketones is a highly relevant conversion for the pharmaceutical and fine-chemical industries, and for biomass conversion, and is commonly performed using stoichiometric amounts of highly hazardous oxidants. The aerobic oxidation of alcohols with transition metal complex catalysts previously required complicated organic ligands and/or nitroxyl radicals as co-catalysts. Herein, we report an efficient and eco-friendly method to promote the aerobic oxidation of alcohols using an inorganic-ligand supported copper catalyst 1, (NH4)4[CuMo6O18(OH)6], with O2 (1 atm) as the sole oxidant. Catalyst 1 is synthesized directly from cheap and commonly available (NH4)6Mo7O24·4H2O and CuSO4, which consists of a pure inorganic framework built from a central CuII core supported by six MoVIO6 inorganic scaffolds. The copper catalyst 1 exhibits excellent selectivity and activity towards a wide range of substrates in the catalytic oxidation of alcohols, and can avoid the use of toxic oxidants, nitroxyl radicals, and potentially air/moisture sensitive and complicated organic ligands that are not commercially available. Owing to its robust inorganic framework, catalyst 1 shows good stability and reusability, and the catalytic oxidation of alcohols with catalyst 1 could be readily scaled up to gram scale with little loss of catalytic activity, demonstrating great potential of the inorganic-ligand supported Cu catalysts in catalytic chemical transformations. [ABSTRACT FROM AUTHOR]

An efficient oxidation and functionalization of C–H bonds with an inorganic-ligand supported iron catalyst and hydrogen peroxide to prepare the corresponding ketones was achieved using the bromide ion as a promoter. Preliminary mechanistic investigations indicated that the bromide ion can bind to FeMo6 to form a supramolecular species (FeMo6·2Br), which can effectively catalyze the reaction. [ABSTRACT FROM AUTHOR]

Herein, we divulge an efficient protocol for aerobic oxidation of alcohols with an inorganic-ligand supported iodine catalyst, (NH4)5[IMo6O24]. The catalyst system is compatible with a wide range of groups and exhibits high selectivity, and shows excellent stability and reusability, thus serving as a potentially greener alternative to the classical transformations. [ABSTRACT FROM AUTHOR]

By controlling the terminal organic ligands, various fascinating supramolecular assemblies originating from hydrogen bonding interactions in different dimensions in a series of hexavanadate hybrids were synthesized via step-by-step organic modification. These hybrids were characterized, and their structures were determined by single-crystal X-ray diffraction. Moreover, the introduction of a rigid bridging ligand has a positive influence on the assembly of supramolecular architectures, providing a new vision for the design and synthesis of advanced inorganic–organic materials. [ABSTRACT FROM AUTHOR]

Several novel triol-ligands functionalized Anderson–Evans type polyoxotungstates, K3Na3[{HOCH2C(CH2O)3}AlO3W6O18], K3Na3[{HOCH2C(CH2O)3}CrO3W6O18], K3Na3[{HOCH2C(CH2O)3}CoO3W6O18], and K3Na3[{H3CC(CH2O)3}CoO3W6O18], were successfully synthesized and characterized, in which some of the central metal ions have never been found in the Anderson-type polyoxotungstates. The single crystal X-ray diffraction analysis indicated that the clusters were on a status, in which only one-side μ3-O was protonated. This indicates that the three-protonated cluster is a common type of Anderson cluster aside zero-protonated (A-type) and six-protonated (B-type), which could be named as the T-type. [ABSTRACT FROM AUTHOR]

In this work, we confirmed that the copper-catalysed azide–alkyne cycloaddition (CuAAC) reaction is an effective method for the organic-functionalization of polyoxometalates (POMs). Herein, for the first time, four novel 1,2,3-triazole functionalized polyoxovanadate (POV) organic–inorganic hybrids, (Bu4N)2[V6O13{(OCH2)3C5H6N3O}2]·1.5CH3CN 2, (Bu4N)2[V6O13{(OCH2)3C7H8N3O2}2]·2CH3CN 3, (Bu4N)2[V6O13{(OCH2)3C11H10N3}2] 4 and (Bu4N)2[V6O13{(OCH2)3C10H7N3Cl}2] 5 were prepared through the CuAAC reaction using the azide functionalized hexavanadate, (Bu4N)2[V6O13{(OCH2)3CCH2N3}2]·2.5CH3CN 1, as the precursor, where CuI was used as the catalyst and N,N-diisopropylethylamine (DIPEA) as a stabilizer for CuI. All the four compounds were structurally and compositionally characterized by single-crystal X-ray diffraction, elemental analyses, powder X-ray diffraction (XRD), Fourier transform infrared (FT-IR), 1H NMR, ESI-MS, UV-Vis and thermogravimetric analysis (TGA). [ABSTRACT FROM AUTHOR]

A high resolution X-ray diffraction study has been carried out on [(C4H9)4N]2 [V6O13{(OCH2)3CCH2OCCH2CH3}2] (V6–C3) at 100 K. The V6 core possesses a negative charge, leading to a strong polarization of the anion. A nucleophilic region localized near the organic moiety and an electrophilic region in the vicinity of the V6 core provide an overall description of charge-transfer behavior. [ABSTRACT FROM AUTHOR]

A new synthetic approach to tri-substituted trisalkoxy-hexavanadate clusters containing different organic groups was developed in this work. Four mixed-valence or fully reduced POV hybrids were synthesized and structurally characterized, including an amino-containing derivative of hexavanadate, Na2[VIV3VV3O10{NH2C(CH2O)3}3] (1). Furthermore, a novel mixed-valence POV hybrid was prepared via the amidation of 1, indicating that 1 can be used as an excellent building block for the design and synthesis of mixed-valence POV functional materials. [ABSTRACT FROM AUTHOR]

Three novel bis(Triol)-functionalized Anderson cluster derivatives (POM–L–POM, POM–L, L–POM–L) were efficiently synthesized, which manifest interesting self-assembly and synergistic effects. They provided strong support in synthons, applications in syntheses and properties for designing organic–inorganic hybrid chains. [ABSTRACT FROM AUTHOR]

A reaction strategy for the post-functionalization of hexavanadate derivatives is presented herein. In this study, five polyoxovanadate-based organic–inorganic hybrids TBA2[V6O13{(OCH2)3CCOO(CH2)15CH3}2] (2), TBA2[V6O13{(OCH2)3CCOO(CH2)8CH=CH2}2] (3), TBA2[V6O13{(OCH2)3CCOOCH2CF3}2] (4), TBA2[V6O13{(OCH2)3CCOO(CH2CH2O)3CH3}2] (5), and TBA2[V6O13{(OCH2)3CCOO(CH2)12OH}2]·2CH3CH2OH (6) were successfully synthesized via esterification of carboxylic acid groups-containing TBA2[V6O13{(OCH2)3CCOOH}2] (1) with five alcohols possessing different functional groups. These hybrids were characterized by single crystal X-ray diffraction, IR, ESI-MS, 1H and 13C-NMR spectroscopies, and elemental analysis. Moreover, the formation of large vesicles was observed in a mixed solution of compound 2 due to its surfactant-like structure. [ABSTRACT FROM AUTHOR]

The first molybdovanadate cluster with a polyarylimido trimetal fragment, [V4Mo3O14(NAr)3(μ2-NAr)3]2−, was in situ synthesized by using (TBA)3[H3V10O28] as proton and vanadium sources. Additional aniline hydrochlorides will give rise to the formation of phenyl guanidines, which will serve as cations and proton donors to form chain-like and dimeric supermolecules via H-bonding. [ABSTRACT FROM AUTHOR]

An effective synthetic strategy for the amino-containing organic derivative of hexavanadate, TBA2[V6O13{(OCH2)3CNH2}2], is presented. By using this method, the yield is increased extremely and crystals of the intermediate and cation-exchanged products are both obtained and structurally characterized via single-crystal X-ray diffraction, IR and 1H-NMR. [ABSTRACT FROM AUTHOR]

By addition of excess acid into the reaction mixture, a series of organically-derived Anderson-type polyoxometalates, {[R1CR2(CH2O)2]CrMo6O18(OH)4}3−, with diols as the ligands are reported herein. Such a diol functionalization mode not only works for some specific triol ligands but also can readily be extended to the diol ligands, which will greatly enrich the species of alkoxo-derivatized Anderson POM clusters. [ABSTRACT FROM AUTHOR]

A hexamolybdate-based organic–inorganic hybrid molecule containing a chloralkane fragment is synthesized and its Cl atom can be substituted by iodine and nitrate through nucleophilic substitution reactions in high yields, which provide a post-functionalization protocol to bring in various additional functional groups into polyoxometalate-based hybrid materials under mild conditions. [ABSTRACT FROM AUTHOR]

A class of monoorganoimido-substituted hexamolybdates containing a pyridine group have been firstly synthesized. Furthermore, a reaction protocol of alkylation based on the resulting pyridine-functionalized hexamolybdates has been developed, with which a type of zwitterionic clusters has been successfully obtained. [ABSTRACT FROM AUTHOR]

The μ2-O atom in Anderson polyoxometalates was regioselectively activated by the introduction of protons, which, upon functionalization with triol ligands, could afford a series of unique χ isomers of the organically-derived Anderson cluster {[RCC(CH2O)3]MMo6O18(OH)3}3−. Herein proton-controlled isomer transformation between the δ and χ isomer was observed by using the fingerprint region in the IR spectra and 13C NMR spectra. [ABSTRACT FROM AUTHOR]

Monofunctionalized alkylimido derivatives of hexamolybdate, (Bu4N)2[Mo6O18(≡N–R)] (R = methyl, Me; ethyl, Et; n-propyl, n-Pr; i-propyl, i-Pr; n-butyl, n-Bu; t-butyl, t-Bu; cyclohexyl, Cy; n-hexyl, Hex; and n-octadecyl, Ode), have been prepared in high purity and good yield by the reaction of [Bu4N]4[α-Mo8O26] with appropriate aliphatic amine hydrochlorides in anhydrous acetonitrile, using N,N′-dicyclohexylcarbodiimide (DCC) as the dehydrating agent. Eight compounds have been determined by single crystal X-ray diffraction analysis and all compounds have been studied with 1H-NMR, IR, UV-vis, ESI mass spectrometry and cyclic voltammetry. A structural and 1H-NMR study show β hydrogen atoms of those alkylimido derivatives of hexamolybdate have strong Brønsted acidity compared to the hydrogen atoms in other positions. [ABSTRACT FROM AUTHOR]

Phosphorescent quantum yields have been increased by 12 times by choosing bulky boracic anions as counterions for blue-emitting cationic iridium(iii) complexes. [ABSTRACT FROM AUTHOR]

Correction for ‘Diversified polyoxovanadate derivatives obtained by copper(i)-catalysed azide–alkyne cycloaddition reaction: their synthesis and structural characterization’ by Hongli Jia et al., Dalton Trans., 2018, 47, 577–584. [ABSTRACT FROM AUTHOR]

An effective synthetic strategy for the amino-containing organic derivative of hexavanadate, TBA2[V6O13{(OCH2)3CNH2}2], is presented. By using this method, the yield is increased extremely and crystals of the intermediate and cation-exchanged products are both obtained and structurally characterized via single-crystal X-ray diffraction, IR and 1H-NMR. [ABSTRACT FROM AUTHOR]

Direct catalytic oxidation of alcohols to carboxylic acids is very attractive, but economical catalysis systems have not yet been well established. Here, we show that a pure inorganic ligand-supported chromium compound, (NH4)3[CrMo6O18(OH)6] (simplified as CrMo6), could be used to effectively promote this type of reaction in the presence of CO2. In almost all cases, oxidation of various alcohols (aromatic and aliphatic) could be achieved under mild conditions, and the corresponding carboxylic acids can be achieved in high yield. The chromium catalyst 1 can be reused several times with little loss of activity. Mechanism study and control reactions demonstrate that the acidification proceeds via the key oxidative immediate of aldehydes. [ABSTRACT FROM AUTHOR]

A highly efficient method to oxidize methylarenes to their corresponding acids with a reusable Cr catalyst was developed. The reaction can be carried out in water with 1 atm oxygen and K 2 S 2 O 8 as cooxidants, proceeds under green and mild conditions, and is suitable for the oxidation of both electron-deficient and electron-rich methylarenes, including heteroaryl methylarenes, even at the gram level. The excellent result, together with its simplicity of operation and the ability to continuously reuse the catalyst, makes this new methodology environmentally benign and cost-effective. The generality of this methodology gives it the potential for use on an industrial scale. Differing from the accepted oxidation mechanism of toluene, GC-MS studies and DFT calculations have revealed that the key benzyl alcohol intermediate is formed under the synergetic effect of the chromium and molybdenum in the Cr catalyst, which can be further oxidized to afford benzaldehyde and finally benzoic acid.

Novel Anderson-type polyoxomanganotungstate clusters with the β-isomer structure, [{R 1 R 2 C(CH 2 O) 2 }Mn IV W 6 O 22 ] 6- , were synthesized and monofunctionalized with derivatives of 1,3-propanediol via a one-pot strategy, and show unprecedented coordination activity as non-lacunary polyoxotungstate clusters and could have potential in the future construction of POM-frameworks.

A simple and efficient protocol for the formylation of amines with formic acid, catalyzed by a polyoxometalate-based chromium catalyst, is described. Notably, this method shows excellent activity and chemoselectivity for the formylation of primary amines; diamines have also been successfully employed. Importantly, the chromium catalyst is potentially non-toxic, environmentally benign and safer than the widely used high valence chromium catalysts such as CrO 3 and K 2 Cr 2 O 7 . The catalyst can be recycled several times with a negligible impact on activity. Finally, a plausible mechanism is provided based on the observation of intermediate and control experiments.

Over the past two decades, there have been major developments in the transition iron-catalyzed selective oxidation of alkenes to epoxides; a common structure found in drug, isolated natural products, and fine chemicals. Many of these approaches have enabled highly efficient and selective epoxidation of alkenes via the design of specialized ligands, which facilitates to control the activity and selectivity of the reactions catalyzed by iron atom. Herein, we report the development of the olefin epoxidation with inorganic-ligand supported iron-catalysts using 30% H 2 O 2 as an oxidant, and the mechanism is similar to iron-porphyrin type. With the catalyst 1, (NH 4 ) 3 [FeMo 6 O 18 (OH) 6 ], various aromatic and aliphatic alkenes were successfully transformed into the corresponding epoxides with excellent yields as well as chemo- and stereo-selectivity. This catalytic system possesses the advantages of being able to avoid the use of expensive, toxic, air/moisture sensitive and commercially unavailable organic ligands. The generality of this methodology is simple to operate and exhibits high catalytic activity as well as excellent stability, which gives it the potential to be used on an industrial scale, and maybe opens a way for the catalytic oxidation reaction via inorganic-ligand coordinated iron catalysis.

An efficient oxidation and functionalization of C-H bonds with an inorganic-ligand supported iron catalyst and hydrogen peroxide to prepare the corresponding ketones was achieved using the bromide ion as a promoter. Preliminary mechanistic investigations indicated that the bromide ion can bind to FeMo 6 to form a supramolecular species (FeMo 6 ·2Br), which can effectively catalyze the reaction.

A practical, efficient and environmentally benign catalytic protocol for the oxidative cross-coupling reaction of halides with amines, oxidative self-coupling of amines and oxidation of halides was developed with inorganic-ligand supported ZnPOM (NH4)4[ZnMo6O18(OH)6] using molecular oxygen. This method mainly utilizes an inorganic polymolybdate ligand to support the Zn2+ ion, avoiding the use of complicated organic ligands.

Correction for 'Diversified polyoxovanadate derivatives obtained by copper(i)-catalysed azide-alkyne cycloaddition reaction: their synthesis and structural characterization' by Hongli Jia et al., Dalton Trans., 2018, 47, 577-584.