查看更多>>摘要：A disulfide-based poly(ether-b-amide)copolymer with rapid self-healing capability under moderate conditions was synthesized from 4,4'-dithiodibutyric acid(DTDBA),isophorondiamine(IPDA)and poly(tetramethylene oxide)(PTMO)based on a two-step method.The incorporation of IPDA with asymmetric structure and substantial steric hindrance not only effectively decreased the number of regular H-bonds,but also inhibited the crystallization of polyamide segments,imparting the synthesized poly(ether-b-amide)copolymer with an amorphous structural feature.Based on the coordination of segmental diffusion and recombination of disulfide bonds and hydro-gen bonds,the scratches and damaged mechanical properties of PEBADS-I611 could be completely self-healed after healing at 40 ℃ for only 11 min and 3 h,respectively.
查看更多>>摘要：A label-free deoxyribozyme(DNAzyme)biosensor for m6A demethylase activity detection is developed.When demethylase FTO(Fat mass and obesity-associated protein),an important m6A demethylase of ALKBH demethylase family is present,the m6A group is spe-cifically demethylated,and the cleavage activity of DNAzyme is restored.This allows the cleavage product that contains G-quadruplex sequence to bind to thioflavin T(ThT)and generate fluorescence signals.The biosensor shows high specificity and sensitivity,and fast reaction speed.Our study demonstrates a new design of allosteric DNAzyme for sensing.This method represents the first label-free nucleic acid biosensor for FTO assay,providing a feasible route towards inhibitors screening.
查看更多>>摘要：Multicomponent alkene 1,2-dicarbofunctionalizations(DCFs)have emerged as a powerful strategy to rapidly incorporate both two carbon subunits across one C—C double bond in one step for enhancing molecular complexity and diversity.To the best of our knowledge,there is only one report on photoredox-catalyzed three-component DCFs with malonates through the radical-radical cross-coupling,while photoredox-catalyzed radical-polar crossover(RPC)-type DCFs with malonates were still rare.Herein,we describe a redox-neutral RPC-type 1,2-dialkylation of styrenes with malonates and aldehydes through the synergistic Brønsted base/photore-dox catalysis system.This transition-metal-free strategy provides an efficient and clean approach to a broad variety of 6-hydroxy esters and also features exceptionally mild conditions,wide compatibility of substrate scope and functional groups,and high atomic econo-my.Moreover,three-component 1,2-alkylacylation from the same starting materials was achieved in one-pot manner through such RPC-type coupling and subsequent two-electron oxidation process,providing a set of δ-keto esters of interest in pharmaceutical re-search.
查看更多>>摘要：Poly(3-hydroxybutyrate),a crucial member of the large biodegradable polyhydroxyalkanoate family,suffers from its brittleness.To enhance its performance,we employed a straightforward approach involving the ring-opening copolymerization of racemic-β-bu-tyrolactone(rac-β-BL)and β-propiolactone(β-PL)using the syndio-selective amino-alkoxy-bis(phenolate)-yttrium complex as a cata-lyst,thanks to the excellent ductility of poly(3-hydroxypropionate).Control over the rac-β-BL/β-PL feeding ratios and polymerization time yielded random or block copolymers with tunable thermal and mechanical properties comparable to traditional fossil-based plastics.Furthermore,we achieved one-pot synthesis of hard-soft-hard triblock copolymers by exploiting monomers'different co-polymerization rates and a bifunctional initiator,thus transforming polyhydroxyalkanoates from hard and tough plastics to soft and ductile thermoplastic elastomers.
查看更多>>摘要：Energy transformation is imminent,and hydrogen energy is one of the important new energy sources.One of the keys to increasing the rate of hydrogen evolution during electrolysis is the use of high-performance catalysts for oxygen evolution reactions(OER).Sin-gle-atom alloys(SAAs)have garnered significant attention because they partially reduce costs and combine the advantages of both single-atom catalysts(SACs)and alloy catalysts.Herein,an efficient pyrolysis strategy based on a mixing and drying process is designed to anchor ultra-small Co cluster particles,combined with Ru single atoms dispersed on nitrogen-doped ultra-thin carbon nanosheets(Ru1Co SAA/NC).The prepared electrocatalyst exhibits superior OER activity and superb stability,demonstrating an overpotential of 238 mV for OER with a current density of 10 mA·cm-2 in 0.5 mol/L H2SO4.And we also utilized in-situ XAS to detect the oxidation state of Ru sites during OER.All in all,this method achieves cost reductions and efficiency improvements through the design of SAAs,offer-ing new prospects for the structural transformation of clean energy.
查看更多>>摘要：The development of efficient and sustainable methods to obtain spirocyclic compounds is of significance as these structures are wide-ly found in pharmaceuticals and agrochemicals.Herein,we disclose an electrochemical dearomative spirocyclization of N-acyl sulfon-amides in a continuous-flow cell.The reaction is simple and efficient without external catalysts or supporting electrolytes and could be applied in a decagram-scale synthesis.
查看更多>>摘要：A Ru(Ⅱ)-catalyzed ortho allylation reaction of N-aryl-7-azaindole with readily available 2-methylidene cyclic carbonate has been developed.This reaction is an effective pathway for synthesizing 7-azaindole derivatives with a wide scope of substrates and high yields.In addition,the method can be extended to the allylation of other heterocyclic compounds and several cyclic carbonates,highlighting the practicality of this strategy for synthesis.
查看更多>>摘要：Catalytic four-component radical carbonylation of unactivated alkenes has recently been recognized as a robust protocol for rapid construction of various structurally diverse carbonyl compounds.Given the significance of fluorine-containing groups,this reaction class has been extensively applied to assembly of a variety of perfluoroalkyl carboxylic acid derivatives by transition metal catalysis.Herein,we report a visible-light-driven radical relay 1,2-perfluoroalkylation aminocarbonylation of unactivated alkenes using CO gas as carbonyl source and 4CzIPN as organic photocatalyst.A wide range of alkenes and amines were well tolerated,providing the valu-able β-perfluoroalkylated amides with generally good yields and high chemoselectivity.
查看更多>>摘要：The investigation of n-type doping holds a significant interest for the application of thermoelectrics.Herein,the doping of an indandi-one-terminated compound Q-4F with a singlet open-shell ground state was studied using two n-dopants N-DMBI and LCV.Both of these two dopants can effectively dope Q-4F due to the large offset between the singly occupied molecular orbital(SOMO)of dopants and the lowest unoccupied molecular orbital(LUMO)of Q-4F.N-DMBI has a higher doping ability than LCV as demonstrated by the UV-vis-NIR and EPR measurements.However,in comparison to N-DMBI doped Q-4F,LCV doped system exhibits much higher electrical conductivity and power factor due to its unperturbed molecular packing and favorable morphology after doping.The optimal conduc-tivity of LCV doped Q-4F is 7.16 x 10-2±0.16 S·cm-1 and the highest power factor reaches 12.3±0.85 μW·m-1·K-2.These results demonstrate that the modulation of n-dopants is a powerful strategy to balance the doping efficiency and microstructure toward a maximum thermoelectric performance.
查看更多>>摘要：The phenomenon of strong metal-support interaction(SMSI)observed in supported metal catalysts,usually accompanied by the formation of the encapsulation layer on metal nanoparticles,has attracted extensive research attention due to its significance in heterogeneous catalysis.Notably,great progress has been made in recent years in investigating SMSI by in situ transmission electron microscopy(TEM),along with an enhanced comprehension of the underlying mechanisms governing SMSI formation.This emerging topic summarizes recent progress utilizing in situ TEM to study the interaction between metal and support and the relationship be-tween the structure and performance of the supported catalyst under reaction conditions.A brief perspective about the use of in situ TEM for further study of SMSI is also presented,showing prospects in this field that will stimulate further upsurging research in promoting the catalytic efficiency of supported catalysts.
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