查看更多>>摘要：Realizing the hydrogen economy by water electrolysis is an attractive approach for hydrogen production,while the efficient and stable bifunctional catalysts under high current densities are the bottleneck that limits the half-cell reactions of water splitting.Here,we propose an approach of hydrothermal and thermal annealing methods for robust MoO2/MoNi4@Ru/RuO2 heterogeneous cuboid ar-ray electrocatalyst with multiplying surface-active sites by depositing a monolayer amount of Ru.Benefiting from abundant MoO2/MoNi4@Ru/RuO2 heterointerfaces,MoO2/MoNi4@Ru/RuO2 heterogeneous cuboid array electrocatalysts effectively drive the alkaline water splitting with superior hydrogen evolution reaction(HER)and oxygen evolution reaction(OER)performances.The syn-thesized MoO2/MoNi4@Ru/RuO2 has high HER activity,which realizes the working overpotentials of 48 mV at 50 mA·cm-2,further achieving overpotentials of 230 mV for industry-level 1000 mA·cm-2 in alkaline water electrolysis.Moreover,it also showed an en-hanced OER activity than commercial RuO2 with a small overpotential of 280 mV at 200 mA·cm-2 in alkaline media.When building an electrolyzer with electrodes of(-)MoO2/MoNi4@Ru/RuO2lIMoO2/MoNi4@Ru/RuO2(+),a cell voltage of 1.63 V and 1.75 V is just re-quired to support the current density of 200 mA·cm-2 and 500 mA·cm-2 in alkaline water electrolysis,much lower than that of the electrolyzer of(-)Pt/CIIRuO2(+).This work demonstrates that MoO2/MoNi4@Ru/RuO2 heterogeneous nanosheet arrays are promising candidates for industrial water electrolysis applications,providing a possibility for the exploration of water electrolysis with a large current density.
查看更多>>摘要：This work describes a general method for the synthesis of a series of sulfenylated and selenylated carboranes at room temperature using readily available iodocarboranes as starting materials via boron-centered carboranyl radicals.Such hypervalent boron radicals are generated by a visible-light-promoted Pd(O)/Pd(I)pathway.They are useful intermediates and can be trapped by disulfides and phenylselenyl chloride for the convenient construction of B-S/Se bonds.
查看更多>>摘要：Chiral supramolecular assembly of n-conjugated luminophores provides a promising avenue for enhancing circularly polarized lumi-nescence.In this study,we shed light on the impact of π-conjugation length on circularly polarized luminescent performance of the resulting supramolecular assemblies,by designing a tetra-cyanostilbene monomeric compound alongside two dicyanostilbene con-trol compounds.These cyanostilbene-based compounds possess the ability to form chiral supramolecular polymers in toluene,driv-en by a synergistic combination of intermolecular hydrogen bonding and π-π stacking interactions.The extended π-aromatic skele-ton brings bathochromic-shifted fluorescence and enhanced intermolecular stacking capability for the tetra-cyanostilbene com-pound.Consequently,chiral supramolecular assemblies formed by the tetra-cyanostilbene compound demonstrate a remarkable two-fold increase in glum values relative to the assemblies formed by the dicyanostilbene compounds.Overall,this study provides valuable insights into the relationship between n-conjugation length and the circularly polarized luminescent performance ofπ-conjugated supramolecular assemblies.
查看更多>>摘要：Different novel fused multicyclic iminosugars were synthesized from D-ribose tosylate,aniline and vinyl ethyl ether by one-pot three-component stereoselective[4+2]reaction at different temperatures.The iminium-ion is the key intermediate for the reaction.As a result,several complex fused iminosugars 3a were obtained by aza-Diels-Alder mechanism at 60 ℃,while a series of aza-C-glycosides 5a were prepared by Mannich reaction at room temperature accompanied by another tetrahydroquinoline-fused iminosugars 4a(tricyclic derivatives)through aza-Diels-Alder cycloaddition.This strategy will help to construct structurally diverse and bioactive iminosugar analogues.
查看更多>>摘要：A photocatalytic[3+2]annulation of alkenes with vinyl azides was developed under irradiation by visible light in the presence of or-ganic dye photocatalysts.Broad substrate scope and high functional group tolerance were demonstrated by more than 50 examples.The reaction provides a novel and efficient method for the synthesis of polyfunctionalized pyrroles under very mild metal-free condi-tions without other additives.
查看更多>>摘要：Tetralin-1-carboxamides are frequently incorporated in myriad medicinally important molecules.However,their existing synthetic routes not only suffer from some drawbacks such as tedious procedures,harsh reaction conditions,narrow substrate scope,low yields,and environmental problems,but are also based upon the elaboration of uneasily available non-linear tetralin derivatives.Herein,we describe a metal-and additive-free visible light-induced[4+2]annulation of two simple linear starting materials,namely acrylamides and 2-benzyl-2-bromocarbonyls,through a cascade C(sp3)-Br/C(sp2)-H bond cleavage,double C-C bond formation,and aromatization sequence.The developed protocol provides a convenient,efficient,and green approach to a variety of tetra-lin-1-carboxamide derivatives with good functional group compatibility.Importantly,the resulting products could also undergo the LiCI-mediated mono-decarboxylative cyclization process to further furnish the architecturally novel bridged polycyclic imides with excellent cis-diastereoselectivities.
查看更多>>摘要：In this study,a novel approach is proposed to achieve the uniformly dispersed Ru nanoparticles with N coordination loaded on three-dimensionally ordered macro/mesoporous carbon(3DOMMC)through simultaneous pyrolysis of Ru3+and cyanamide on 3DOMMC.In an alkaline medium,the synthesized catalysts exhibit exceptional hydrogen evolution reaction(HER)performance.Spe-cifically,Ru-N/3DOMMC demonstrates a significantly low overpotential of 13.8 mV to achieve a current density of 10 mA·cm-2,and it exhibits a mass activity 17.5 times higher than that of commercial Pt/C.The outstanding performance could be attributed to the ultra-high Ru dispersion and more efficient contact between active sites and reactant,which derived from the large specific surface area and interconnective three-dimensionally macro/mesopores of 3DOMMC.
查看更多>>摘要：The development of accurate,rapid and practical electrochemical sensing technology for antibiotic detection has an important ap-plication prospect in many fields such as food safety,environmental monitoring,medical and health care.In this research,kanamycin specific DNA aptamer and its partially complementary short chain were self-assembled onto the surface of an integrated portable plastic gold electrode(PGE)by Au-S bond,and a simple kanamycin electrochemical biosensor interface was constructed.At the same time,the epoxy resin channel layer was designed,and the auxiliary instrument was set up independently in the laboratory,which could help to measure and analyze eight groups of samples automatically in turn.The quantitative analysis results showed that in 20 min,the sensor had a good linear relationship between the peak current change of square wave voltammetry and the negative logarithm of kanamycin concentration when kanamycin concentration was in the range of 1-1000 μmol/L,and the detec-tion limit could reach 0.40 μmol/L.In addition,the discrimination could be achieved within 5 min in the real-time analysis mode.The sensor had a simple construction method,good selectivity and stability,and could be used for rapid or real-time detection of kana-mycin residues in actual water samples,which provided a new direction for the practical detection of kanamycin in environmental water samples.
查看更多>>摘要：Carbonyl compounds have attracted considerable attention due to their extensive applications in drug discovery.Furthermore,they are important synthetic intermediates for the construction of carbon-carbon and carbon-heteroatom bonds.Transition-metal-cata-lyzed carbonylation via the insertion of CO is one of the most efficient and straightforward strategies to access carbonyl compounds.However,most of the transition-metal-catalyzed carbonylative reactions require expensive and toxic noble-metal catalysts.There-fore,there is a growing demand for the exploration of nickel-catalyzed carbonylative reactions via the insertion of CO due to the earth abundance and low cost of nickel.Compared with the well-established palladium-catalyzed carbonylative reactions,nick-el-catalyzed analogous transformations have been relatively underdeveloped.This is primarily because CO strongly binds to nickel,often resulting in catalyst poisoning.In recent years,some research groups have focused on using CO surrogates or NN2 pincer nickel catalyst to circumvent the formation of Ni(CO)4.Nickel-catalyzed carbonylation has been applied in the construction of carbon-yl-containing compounds,such as ketones,carboxylic acids,thioesters,acyl chloride and carboxamides.
查看更多>>摘要：All-solution-processed organic solar cells(OSCs)(from the bottom electrode to the top electrode)are highly attractive thanks to their low cost,lightweight and high-throughput production.However,achieving highly efficient all-solution-processed OSCs remains a sig-nificant challenge.One of the key issues is the lack of high-quality solution-processed electrode systems that can replace indium tin oxide(ITO)and vacuum-deposited metal electrodes.In this paper,we comprehensively review recent advances in all-solution-processed OSCs,and classified the devices as the top electrode materials,including silver nanowires(AgNWs),conducting polymers and composite conducting materials.The correlation between electrode materials,properties of electrodes,and device performance in all-solution-processed OSCs is elucidated.In addition,the critical roles of the active layer and interface layer are also discussed.Finally,the prospects and challenges of all-solution-processed OSCs are presented.
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