MXenes are under the spotlight due to their versatile physicochemical characteristics. Since their discovery in 2011, significant advancements have been achieved in their synthesis and application sectors. However, th...MXenes are under the spotlight due to their versatile physicochemical characteristics. Since their discovery in 2011, significant advancements have been achieved in their synthesis and application sectors. However, the spontaneous oxidation of MXenes, which is critical to its processing and product lifespan, has gotten less attention due to its chemical complexity and poorly understood oxidation mechanism. This perspective focuses on the oxidation stability of MXenes and addresses the most recent advancements in understanding and the possible countermeasures to limit the spontaneous oxidation of MXenes. A section is dedicated to the presently accessible methods for monitoring oxidation, with a discussion on the debatable oxidation mechanism and coherently operating factors that contribute to the complexity of MXenes oxidation. The current potential solutions for mitigating MXenes oxidation and the existing challenges are also discussed with prospects to prolong MXene's shelf-life storage and expand their application scope.展开更多
The nitrile compounds are present in a variety of biologically active natural products and pharmaceuticals,and the nitrile groups are versatile synthetic intermediates to other functionalized compounds.Herein,the asym...The nitrile compounds are present in a variety of biologically active natural products and pharmaceuticals,and the nitrile groups are versatile synthetic intermediates to other functionalized compounds.Herein,the asymmetric reduction ofα,β-unsaturated nitriles with water as a hydrogen source is reported.The reaction is catalyzed by the complex of[Ir(COD)Cl]_(2)and(R_(a),S)-Ph-Bn-SiPhox,and allows the preparation of useful enantioenriched chiral 3,3-disubstituted propionitriles with high optical purities in mild conditions.展开更多
Poly(N-ethylaniline)(PNEA)composites with varying silicate content were fabricated on copper through a novel electropolymerized strategy in acidic solution.Thickness,compactness,conductivity and adhesive strength of t...Poly(N-ethylaniline)(PNEA)composites with varying silicate content were fabricated on copper through a novel electropolymerized strategy in acidic solution.Thickness,compactness,conductivity and adhesive strength of the composite(PNEA-10 Si)were optimized as silicate content reached 10 m M.Electrochemical,morphological and solution analyses were employed to evaluate the protective performance of PNEA and PNEA-10 Si coatings for copper in 3.5%Na Cl solution.Results of electrochemical analyses indicated that as-prepared coatings retarded the oxygen reduction process efficiently for copper in 3.5%Na Cl solution,drained corrosion current density and elevated interfacial charge transfer resistance.Due to favorable barrier effect,compact structure and low porosity index,PNEA-10 Si composite exhibited superior anti-corrosive performance,which was more tolerant than PNEA during long-time immersion.PNEA-10 Si coated sample exhibited a stable topography after 144 h immersion with the minimum concentration of released ions revealing the improved protection capacity.Electronic/atomic-multiscale calculations were conducted to clarify the deposition and protection mechanism of as-prepared coatings.Outcomes of density functional theory corroborated that silicate is stabilized in the PNEA layer via electrostatic force;and immobile silicate positively contributed to the charge transfer barrier of the composite.Molecular dynamics simulations evidenced that the favorable compatibility between PNEA and silicate facilitated polymer deposition and confined in-situ ions diffusion.展开更多
County forestry economy is a strong power for regional green economic development,and an important way to improve farmers' income and promote living environment in urban and rural areas. According to the investiga...County forestry economy is a strong power for regional green economic development,and an important way to improve farmers' income and promote living environment in urban and rural areas. According to the investigation of ten typical counties or cities with forestry industrial advantage,this paper sums up the elementary experiences of county forestry economy,analyzes its prominent problems. Countermeasures are brought forward to improve the development of county forestry economy.展开更多
A series of novel polyethylene glycol-dicationic imidazolium-based ionic liquids(mPEG-ILs)were synthesized by facile quaternization reaction from various elaborately designed di-imidazoles and PEG,which were then stud...A series of novel polyethylene glycol-dicationic imidazolium-based ionic liquids(mPEG-ILs)were synthesized by facile quaternization reaction from various elaborately designed di-imidazoles and PEG,which were then studied as green plasticizers for sustainable polylactide(PLA)material.展开更多
An efficient stereoselective cobalt-catalyzed hydrovinylative cyclization of 1,6-enynes with chalcones toobtain functionalized pyrrolidines has been developed. The products were furnished in good yields withup to 93% ...An efficient stereoselective cobalt-catalyzed hydrovinylative cyclization of 1,6-enynes with chalcones toobtain functionalized pyrrolidines has been developed. The products were furnished in good yields withup to 93% ee. A plausible mechanism through which the transformation was initiated by cyclization of1,6-enynes is proposed.展开更多
New blue-light promoted methods for the addition of iodoacetonitrile(ICH_(2)CN)to alkene/alkynes have been developed.The reaction led to the formation of cyanoalkylated products when conjugated alkene/styrene was used...New blue-light promoted methods for the addition of iodoacetonitrile(ICH_(2)CN)to alkene/alkynes have been developed.The reaction led to the formation of cyanoalkylated products when conjugated alkene/styrene was used.In the case of alkynes and non-conjugated alkenes,iodoalkylation takes place furnishing the corresponding alkenyl iodides and alkyl iodides,respectively.Notably,trans-alkenyl iodides were obtained as the major product.A plausible reaction mechanism is also proposed.展开更多
A tandem isomerization/hydroarylation reaction of oxabenzonorbomadienes and arylacetylenes was realized by using AgOTf as catalyst. 1,1-Diarylethylenes could be easily generated as products in moderate to good yields ...A tandem isomerization/hydroarylation reaction of oxabenzonorbomadienes and arylacetylenes was realized by using AgOTf as catalyst. 1,1-Diarylethylenes could be easily generated as products in moderate to good yields in this tandem reaction.展开更多
基金financial support by the National Natural Science Foundation of China (Grant No. U2004212 and 51802012)。
文摘MXenes are under the spotlight due to their versatile physicochemical characteristics. Since their discovery in 2011, significant advancements have been achieved in their synthesis and application sectors. However, the spontaneous oxidation of MXenes, which is critical to its processing and product lifespan, has gotten less attention due to its chemical complexity and poorly understood oxidation mechanism. This perspective focuses on the oxidation stability of MXenes and addresses the most recent advancements in understanding and the possible countermeasures to limit the spontaneous oxidation of MXenes. A section is dedicated to the presently accessible methods for monitoring oxidation, with a discussion on the debatable oxidation mechanism and coherently operating factors that contribute to the complexity of MXenes oxidation. The current potential solutions for mitigating MXenes oxidation and the existing challenges are also discussed with prospects to prolong MXene's shelf-life storage and expand their application scope.
基金grateful to the National Natural Science Foundation of China(Nos.21961045 and 22061048)the Basic Research Project of Chongqing Academy of Chinese Materia Medica(No.jbky20190028)+2 种基金the Fund Project of Yunnan Key Laboratory of Pharmacology for Natural Products(No.YKLPNP-K2303)Yunnan Provincial Key Laboratory Construction Plan Funding of UniversitiesYunnan Provincial Engineering Research Center Construction Plan Funding of Universities for their financial support.
文摘The nitrile compounds are present in a variety of biologically active natural products and pharmaceuticals,and the nitrile groups are versatile synthetic intermediates to other functionalized compounds.Herein,the asymmetric reduction ofα,β-unsaturated nitriles with water as a hydrogen source is reported.The reaction is catalyzed by the complex of[Ir(COD)Cl]_(2)and(R_(a),S)-Ph-Bn-SiPhox,and allows the preparation of useful enantioenriched chiral 3,3-disubstituted propionitriles with high optical purities in mild conditions.
基金financially supported by the Beijing Municipal Natural Science Foundation(No.2192016)the National Natural Science Foundation of China(No.21606005)the Support Project of High-level Teachers in Beijing Municipal Universities in the Period of 13th Five-year Plan(No.CIT&TCD201904042)。
文摘Poly(N-ethylaniline)(PNEA)composites with varying silicate content were fabricated on copper through a novel electropolymerized strategy in acidic solution.Thickness,compactness,conductivity and adhesive strength of the composite(PNEA-10 Si)were optimized as silicate content reached 10 m M.Electrochemical,morphological and solution analyses were employed to evaluate the protective performance of PNEA and PNEA-10 Si coatings for copper in 3.5%Na Cl solution.Results of electrochemical analyses indicated that as-prepared coatings retarded the oxygen reduction process efficiently for copper in 3.5%Na Cl solution,drained corrosion current density and elevated interfacial charge transfer resistance.Due to favorable barrier effect,compact structure and low porosity index,PNEA-10 Si composite exhibited superior anti-corrosive performance,which was more tolerant than PNEA during long-time immersion.PNEA-10 Si coated sample exhibited a stable topography after 144 h immersion with the minimum concentration of released ions revealing the improved protection capacity.Electronic/atomic-multiscale calculations were conducted to clarify the deposition and protection mechanism of as-prepared coatings.Outcomes of density functional theory corroborated that silicate is stabilized in the PNEA layer via electrostatic force;and immobile silicate positively contributed to the charge transfer barrier of the composite.Molecular dynamics simulations evidenced that the favorable compatibility between PNEA and silicate facilitated polymer deposition and confined in-situ ions diffusion.
文摘County forestry economy is a strong power for regional green economic development,and an important way to improve farmers' income and promote living environment in urban and rural areas. According to the investigation of ten typical counties or cities with forestry industrial advantage,this paper sums up the elementary experiences of county forestry economy,analyzes its prominent problems. Countermeasures are brought forward to improve the development of county forestry economy.
基金The authors are grateful for financial support from the National Natural Science Foundation of China(No.51573130)the Open Foundation of Beijing Key Laboratory of Quality Evaluation Tech no logy for Hygiene and Safety of Plastics.
文摘A series of novel polyethylene glycol-dicationic imidazolium-based ionic liquids(mPEG-ILs)were synthesized by facile quaternization reaction from various elaborately designed di-imidazoles and PEG,which were then studied as green plasticizers for sustainable polylactide(PLA)material.
基金supported by the National Natural Science Foundation of China(21961045 and 22061048)Yunnan Provincial Key Laboratory Construction Plan Funding of Universities,the Reserve Talents of Young and Middle-aged Academic Leaders of Yunnan Province(202005AC160016)Yunnan Provincial Engineering Research Center Construction Plan Funding of Universities.
文摘An efficient stereoselective cobalt-catalyzed hydrovinylative cyclization of 1,6-enynes with chalcones toobtain functionalized pyrrolidines has been developed. The products were furnished in good yields withup to 93% ee. A plausible mechanism through which the transformation was initiated by cyclization of1,6-enynes is proposed.
基金We are grateful to the National Natural Science Foundation of China(Nos.21961045,22061048)the Yunnan Provincial Key Laboratory Construction Plan Funding of Universities and Yunnan Provincial Engineering Research Center Construction Plan Funding of Universities for their financial support.
文摘New blue-light promoted methods for the addition of iodoacetonitrile(ICH_(2)CN)to alkene/alkynes have been developed.The reaction led to the formation of cyanoalkylated products when conjugated alkene/styrene was used.In the case of alkynes and non-conjugated alkenes,iodoalkylation takes place furnishing the corresponding alkenyl iodides and alkyl iodides,respectively.Notably,trans-alkenyl iodides were obtained as the major product.A plausible reaction mechanism is also proposed.
文摘A tandem isomerization/hydroarylation reaction of oxabenzonorbomadienes and arylacetylenes was realized by using AgOTf as catalyst. 1,1-Diarylethylenes could be easily generated as products in moderate to good yields in this tandem reaction.
