查看更多>>摘要：It is urgent to recycle polyethylene terephthalate(PET)effectively,since it is the most consumed synthetic polyester and its improper disposal has caused significant environmental pollution.The existing chemical recycling methods highly rely on the nucleophilic sub-stitutions and hydrogenative depolymerizations,which typically require the use of excess of nucleophiles,excess strong acids or bases,expensive metal catalysts,and explosive gas atmosphere.Here,we demonstrate a mild and efficient protocol for oxidative depolymer-ization of PET to terephthalic acid using only an O2 balloon.Terephthalic acid can be recycled from PET-containing materials including a series of plastic products in daily life.The employing of relatively low loading of iron complex,the most earth-abundant transition metal,as the catalyst and the preliminary results on the large-scale reaction using 38 g of PET waste demonstrate the practical feasi-bility of this degradation method.This method can be also applicable for selective degradation of PET from mixed plastics.This work represents a rare example of a selective oxidative depolymerization and demonstrates the great potentials of such a concept in poly-ester recycling.
查看更多>>摘要：The precise syntheses of transition-rare-earth metal clusters with desired structures remain a great challenge.Herein,by utilizing SO42-anion released by in-situ decomposition of sodium dodecyl sulfate(SDS)as a template,a series of novel high-nuclearity 3d-4f clusters,formulated as[Ni24Pr22(μ3-OH)31(pida)24(SO4)4(NO3)9(CH3COO)3]·Br4·(NO3)11·16H2O·25CH3OH(1,H2pida=N-phenyliminodi-acetic acid),[Ni24Nd22(μ3-OH)31(pida)24(SO4)4(NO3)g(CH3COO)3]·Br4·(NO3)11·14H2O·24CH3OH(2)and[Ni24Gd22(μ3-OH)36(bida)24(SO4)7-(NO3)3(CH3COO)3]·(SO4)·Br4·(NO3)4·31H2O·32CH3OH(3,H2bida=N-benzyliminodiacetic acid),have been successfully isolated.X-ray crystal structure analyses reveal that all the cationic {Ni24RE22} cores in 1-3 possess a ball-like structure with C3v symmetry,and can be viewed as consisting of an inner {RE22} core and an outer {Ni24} shell.From 1 and 2 to 3,due to the lanthanide contraction effect,the coordination numbers for rare-earth metal centers in {RE22} are different,resulting in different number of SO42-and NO3-anions to support and stabilize the skeleton structures.Meanwhile,the magnetic properties of complexes 1-3 were also studied.The result revealed that complexes 1-3 show antiferromagnetic/ferrimagnetic interactions,and 3 exhibits magneto-caloric effect at ultralow temperatures with a maximum-ΔSm(magnetic entropy change)value of 33.03 J·kg-1·K-1 at 3.0 K and 7 T.
查看更多>>摘要：Electrocatalysis technology can effectively promote the hydrodechlorination of chloramphenicol(CAP)to reduce the bio-toxicity.However,there are still some challenges such as low degradation rate and poor stability.Here,we prepared porous N,O co-doped carbon supported Pd nanoparticles composites(Pd NPs/NO-C)for electrocatalytic degradation of CAP.The doping of N and O not only effectively enhanced the interaction between substrate and CAP,promoting the mass transfer process,but also enhanced the anchor-ing effect on Pd nanoparticles,avoiding the occurrence of aggregation.The prepared composites achieved removal efficiency of CAP over 99％within 1 h,and the rate constant was as high as 6.72 h-1,outperforming previous reported electrocatalysts.Additionally,Pd NPs/NO-C composites showed a wide range of pH tolerance,excellent ion interference resistance and long-term stability.Our work unravels the importance of mass transfer processes in solution to electrocatalytic hydrodechlorination and provides new research ideas for catalysts design.
查看更多>>摘要：Unsymmetric sulfides and selenides have great applications in the pharmaceutical field.Herein,we describe the reductive coupling reaction of xanthate esters with sulfur-containing and selenium-containing compounds(thio(seleno)sulfonates and disul-fides(selenides))under the nickel-catalyzed condition.It provides a mild and effective method for the synthesis of unsymmetric sul-fides and selenides which has the advantages of mild reaction conditions,high yields and a wide range of substrates.
查看更多>>摘要：An efficiently catalytic method toward the synthesis of indolin-2-ones featuring an allylic derived C3-quaternary stereocenter via an intramolecular Heck cyclization/Suzuki coupling of N-substituted-N-(2-bromophenyl)acrylamides and organoboron reagents was suc-cessfully developed by using a 1,3-bis(2,6-diisopropylphenyl)acenaphthoimidazol-2-ylidene(AnlPr)-ligated oxazoline palladacycle.It enabled a very broad substrate scope tolerating different functional groups,electronic properties and steric bulkiness.Notably,it re-vealed a great potential to build diverse heterocycle-fused indoline alkaloids via the same intermediate 3-allyl-1,3-dimethylindolin-2-one.
查看更多>>摘要：A highly enantioselective palladium-catalyzed intramolecular Heck reaction of unactivated alkenes is developed,which provides a powerful route to access a broad range of chiral 3,3-disubstituted-2,3-dihydrobenzofurans bearing all-carbon quaternary stereocenter of interest in pharmaceutical research.Its salient features include high yield,excellent chemo-and enantioselectivity,mild conditions,a broad substrate scope as well as versatile transformations of the product.
查看更多>>摘要：The cyanide anion(CN-)is known to be one of the most toxic anions.Therefore,there is an urgent need to develop a reliable,sensi-tive,selective,rapid and effective method for the detection of CN-.Here,a self-assembly strategy based on pillar[5]arene P5 and az-ine derivative AZ was used to construct supramolecular sensors,and it was found that the detection effect of CN-was significantly improved by the assembly strategy.The sensitivity of the assembled sensor P5-AZ to CN-is more than 10 times higher than that of AZ.The detect mechanism was further investigated by theoretical calculations and 1H NMR.The results showed that AZ detects CN-by a deprotonation process with fluorescence enhancement,while P5-AZ improves the sensitivity of CN-recognition through hydro-gen bonding,anion-n and anion-dipole interactions,as well as the strong bonding ability of the assembly.Supramolecular assembly P5-AZ has the advantages of low toxicity,high sensitivity,and more importantly,it provides a method to detect CN-sensitivity in the aqueous phase and organisms by host-guest assembly.
查看更多>>摘要：Traditional reduction coupling reactions of two bromides typically rely on transition metal catalysis.Here,we introduce the development of a visible-light catalytic direct reduction coupling reaction between α-CF3-alkyl bromides and alkynyl bromides to access valuable organic frameworks.Our research confirms the excellent compatibility of this reaction with various functional groups,which could be used to modify the substrate with biologically active molecular fragments.Mechanistic investigations,including control experiments,fluorescence quenching studies,and light-switching experiments,have provided insights into the reaction mechanism.This study paves the way for the application of visible-light catalysis in diverse synthetic transformations,offering a sustainable and efficient approach to organic synthesis.
查看更多>>摘要：The construction of acyclic quaternary carbon stereocenters,which are ubiquitous in many bioactive compounds,pharmaceuticals and natural products,has been a long persuit in synthetic organic chemistry.Among numerous methods,enantioselective nickel-catalysis has attracted incremental attention in recent years.This review summarizes the recent development in the asymmetric strategies,research progress,mechanistic investigations for the generation of acyclic quaternary carbon stereocenters via enantiose-lective nickel catalysis.
查看更多>>摘要：Room-temperature phosphorescence(RTP)materials have experienced rapid development due to their potential in organic light-emitting diode,information security,bioimaging,etc.However,the design of chiral organic phosphors with circularly polarized RTP(CPP)property remains a formidable challenge.Here,we introduce a chiral perturbation approach using a combination of chiral binaphthol and phenoselenazine derivative to achieve CPP.The photoactivated CPP in polystyrene(PS)film demonstrates a lumines-cence dissymmetry factor(glum),emission efficiency,and RTP lifetime up to 9.32 x 10-3,27.0％,and 40.0 ms,respectively.The remark-able sensitivity of PS film to oxygen and temperature enables the adjustable emission colors,ranging from green to offwhite and blue under varying conditions.The doping systems,utilizing hosts of triphenylphosphine and 9-phenylcarbazole,demonstrate an extended CPP lifetime of 85.9 ms and exhibit a persistent mechanoluminescence property with low pressure response threshold as low as 0.15 N.The information security provided by this CPP material was attained via the using of diverse emission colors and afterglow gener-ated by distinct UV irradiation times and host materials.Alternately,it can also be achieved by observing different emission patterns using R-and L-polarizer.The research has presented a reliable approach for producing CPP materials with high emission efficiency and glum.
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