A H_(4)SiW_(12)O_(40)-catalyzed three-component tandem reaction for the synthesis of 3,3-disubstituted isoindolinones

A H_(4)SiW_(12)O_(40)-catalyzed three-component tandem reaction of 2-acylbenzoic acids,primary amines and phosphine oxides to form 3,3-disubstituted isoindolinones was developed.By employing A H_(4)SiW_(12)O_(40)as the catalyst and dimethyl carbonate(DMC)as the solvent,a diverse range of 2-acylbenzoic acid derivatives and primary amines worked well to give the C3-phosphinoyl-functionalized 3,3-disubstituted isoindolinones with the yield range of 61%-87%.Advantages of this transformation include green catalyst and solvent,available starting materials,broad substrate scope,high efficiency and operational simplicity with water as the sole by-product.The strategy achieved an efficient and green molecular fragment assembly to access isoindolinones,which would provide opportunities for the synthesis of potential biologically active molecules in a green manner.

Recent advances on catalysts for preferential oxidation of CO

The trace amount of CO in H2-rich gas poisons Pt electrode when it is adopted as feedstock for proton-exchange-membrane fuel cells.Preferential oxidation of CO(PROX)is a promising approach to selectively oxidize the trace amount of CO while keeping H2 unoxidized.Catalyst plays important roles in PROX.To date,enormous catalysts have been developed for PROX.Summarizing the catalysts developed for PROX and unveiling the reaction mechanism could definitely advance this research field.Herein,in this review,according to the nature of the active sites on the catalysts,we classify the catalysts into group VIII metal-based catalyst,group IB metal-based catalysts,group VIII-group IB bimetallic catalysts,transitional metal oxide catalysts as well as others,describe the progress of the catalysts in PROX in the latest five years,and extract the underlying reaction mechanism,with the aim to provide guidance for the rational design of efficient catalysts in the future.

Polyoxometalates based compounds for green synthesis of aldehydes and ketones

Molecular oxygen within Polyoxometalates(POMs)based compounds are ideal oxidants with high atom economy and its use results in the production of water as the only byproduct.Significant progress has been made in the development of catalytic methods for aerobic alcohol oxidation to have aldehydes and ketones with POMs based compounds.They are alternative to the use of traditional hypervalent iodine catalyst systems which are with molecular oxygen as a terminal oxidant.Further,POMs based catalysts can be applied to catalytic reactions with different modes of energization such as thermocatalysis,photocatalysis and electrocatalysis.This review summarizes the frontier advances in polyoxometalates for catalytic alcohol selective oxidation in thermocatalytic,electrocatalytic,and photocatalytic applications.The three advantages of POM catalysts in terms of performance,economy,and environmental protection are highlighted.These include the use of sol-gel and electrostatic assembly methods to increase the reaction surface area,reduce the use of precious metals,and improve the stability of POMs catalysts.The field of selective alcohol oxidation is advanced.Finally,the challenges of preparing more efficient and“green”catalysts are presented.

Confined interface engineering of self-supported Cu@N-doped graphene for electrocatalytic CO_(2) reduction with enhanced selectivity towards ethanol

Electroreduction of greenhouse gas CO_(2) into value-added fuels and chemicals provides a promising pathway to address the issues of energy crisis and environmental change.However,the regulations of the selectivity towards C2 product and the competing hydrogen evolution reaction(HER)are major challenges for CO_(2) reduction reaction(CO_(2)RR).Here,we develop an interface-enhanced strategy by depositing a thin layer of nitrogen-doped graphene(N-G)on a Cu foam surface(Cu-N-G)to selectively promote the ethanol pathway in CO_(2)RR.Compared to the undetectable ethanol selectivity of pure Cu and Cu@graphene(Cu-G),Cu-N-G has boosted the ethanol selectivity to 33.1%in total Faradic efficiency(FE)at−0.8 V vs.reversible hydrogen electrode(RHE).The experimental and density functional theory(DFT)results verify that the interconnected graphene coating can not only serve as the fast charge transport channel but also provide confined nanospace for mass transfer.The N doping can not only trigger the intrinsic interaction between N in N-G and CO_(2) molecule for enriching the local concentration of reactants but also promote the average valence state of Cu for C–C coupling pathways.The confinement effect at the interface of Cu-N-G can not only provide high adsorbed hydrogen(Had)coverage but also stabilize the key*HCCHOH intermediate towards ethanol pathway.The provided interface-enhanced strategy herein is expected to inspire the design of Cubased CO_(2)RR electrocatalysts towards multi-carbon products.

Additive-Mediated Selective Oxidation of Alcohols to Esters via Synergistic Effect Using Single Cation Cobalt Catalyst Stabilized with Inorganic Ligand

The direct catalytic oxidation of alcohols to esters is very appealing,but the economical-friendly catalysis systems are not yet well established.Herein,we show that a pure inorganic ligand-supported single-atomic cobalt compound,(NH_(4))_(3)[CoMo_(6)O_(18)(OH)_(6)](simplified as CoMo_(6)),could be used as a heterogeneous catalyst and effectively promote this type of reaction in the presence of 30%H_(2)O_(2)using KCl as an additive.The oxidative cross-esterification of various alcohols(aromatic and aliphatic)could be achieved under mild conditions in nearly all cases,affording the corresponding esters in high yields,including several drug molecules and natural products.Detailed studies have revealed that chloride ion is able to bind to the CoMo_(6)to form a supramolecular dimer 2(CoMo_(6)∙Cl),which can effectively catalyze the reaction via a synergistic effect from chloride ion and CoMo_(6).Mechanism studies and control reactions demonstrate that the esterification proceeds via the key oxidative immediate of aldehydes.

Preparation and spectral characteristics of anthracene/tetracene mixed crystals

A series of tetracene-doped anthracene crystals with different doping concentrations(the highest mo-lar ratio 100:1) are grown from solution.Crystal structures and optical characteristics of the above mixed crystals are investigated at room temperature.By changing the doping concentrations,the fluorescence can be adjusted from blue-green to green and even to yellow-green.The emission spectra of anthracene/tetracene(An/Te) mixed crystals reveal the sensitized fluorescence of tetracene and the partial quenching of anthracene emission.The data of transient photoluminescence(PL) decays illus-trate that in An/Te mixed crystals,the decay of anthracene becomes faster,while the PL lifetime of tet-racene is longer than that of the tetracene single crystals.All above experimental results suggest that there is excitation energy transfer from anthracene to tetracene in the mixed crystals.

A novel family of diarylethene-phthalocyanine dyad systems for nondestructive data processing

A novel family of diarylethene (DTE)-phthalocyanine (Pc) dyad systems were designed and synthesized. It was found that the significant change in the extension of the linear π-conjugation of DTE when irradiated by 254 nm UV light directly made the absorption of the Q-band of phthalocyanine decrease. Detecting the absorption changes of the Q-band would not induce the reversible photochromic reaction. Therefore, non-destructive readout was feasible based on the spectral changes of the Q-band when such materials were used as storage media.

Reducing obesity and inflammation in mice with organically-derivatized polyoxovanadate clusters

Obesity,characterized by the dysregulation of energy balance in adipose tissue and other metabolic organs,is frequently accompanied by chronic low-grade inflammation.As long-acting insulin sensitizers,the organically-derivatized polyoxovanadates(POVs),can extend the dosing interval of antidiabetic drugs from hourly to almost daily.In this work,the protective activity of POVs is investigated by an eight-week in vivo experiment,in which a small amount of POVs was administrated orally to a mouse model of dietinduced obesity every day.The present study shows that administration of POVs significantly decreases the body weight of mice,reduces adipose tissue accumulation,and simultaneously reduces adipose tissue inflammation.In addition,the anti-obesogenic population of i NKT cells is protected potentially by POVs,which subsequently alleviates visceral adipose tissue inflammation in high-fat-diet(HFD)-fed mice against diet-induced obesity.By contrast,the change in body weight after POV treatment is the result of a substantial reduction in fat mass,with no obvious effects on lean body mass.These findings demonstrate that supplementary of POVs would be an effective way to combat obesity and metabolic disorders while lowering metabolic inflammation.