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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]

Anderson-type ([XM6O24]n−) polyoxometalates (POMs) are a class of polymetallic-oxygen cluster inorganic compounds with special structures and properties. They have been paid extensive attention by researchers now, due to their chemical modification and designability, which have been widely applied in the fields of materials, catalysis and medicine. In contemporary years, the application of Anderson-type POMs in catalytic organic oxidation reaction has gradually shown great significance for the research of green catalytic process. In this paper, we investigate the application of Anderson-type POMs in organic synthesis reaction, and these works are summarized according to the different structure of POMs. This will provide a new strategy for further investigation of the catalytic application of Anderson-type POMs and the study of green catalysis. [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]

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]

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]

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]

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]

An amendment to this paper has been published and can be accessed via a link at the top of the paper. [ABSTRACT FROM AUTHOR]

Abstract: We report the preparation and characterization of a Pt/γ-Fe2O3 nanocomposite catalyst and its novel catalytic properties for the selective hydrogenation of ortho-chloronitrobenzene (o-CNB). The catalytic hydrodechlorination of the hydrogenation product ortho-chloroaniline (o-CAN) over the catalyst was fully suppressed for the first time at complete conversion of o-CNB. The nanocomposite catalyst also exhibited excellent catalytic activity and stability for the reaction of interest, suggesting that it may be suitable for industrial application. The magnetic property of the Pt/γ-Fe2O3 nanocomposite provided a convenient route for separating the catalyst from the reaction system in an applied magnetic field. [Copyright &y& Elsevier]