Electrochemical polymerization of 3-fluoroalkoxy and 3-fluoroether thiophenes gives polymers with relatively high molecular weights and good processibility. Investigation of these polymers by means of GPC indicates th...Electrochemical polymerization of 3-fluoroalkoxy and 3-fluoroether thiophenes gives polymers with relatively high molecular weights and good processibility. Investigation of these polymers by means of GPC indicates that an increase in the number of fluorine atoms in the fluorinated group results in a decrease in degree of polymerization of the polymers in the same polythiophene series. As shown by NMR and FTIR, the polyfluorinated group substituted polythiophenes have regular 2, 5-coupling in their main chains. The SEM micrographs of the polymer films exhibit that polymer (1)-poly [3-2, 2, 3, 3-tetrafluoro-propoxy) thiophene] possesses more regular structure than the other polymers do. Substitution of polythiophenes by fluorinated groups leads to the polymers with high electric, electrochemical and thermal stability.展开更多
Three series of polythiophenes containing fluoroalkoxy and fluoroether substituents were prepared by electrochemical polymerization. The effect of substituents with fluoroalkoxy or ether functional groups on the elect...Three series of polythiophenes containing fluoroalkoxy and fluoroether substituents were prepared by electrochemical polymerization. The effect of substituents with fluoroalkoxy or ether functional groups on the electrochemical polymerization of thiophene monomers and properties of the obtained polymers were analyzed. The introduction of a fluoroether functional group at the 3-position of the thiophene ring leads to an increase of the oxidation potential of the monomer and to a decrease of the conductivity of the resulting polymers, even with the use of a CH2 group as spacer. Conversely, the presence of an oxygen atom directly at the 3-position of the thiophene ring, which offsets the negative withdrawing effect of fluoroalkyl groups, facilitates the synthesis of highly conducting polythiophenes.展开更多
A new homocoupling methodology mediated by a novel combination of CuCl-2,2'-dipyridyl and its application to the synthesis of substituted polyfluorinated alka-2,4-dienes are described.
A series of poly(fluoroalkoxy thiophenes) have been prepared by electrochemical and chemical polymerization respectively. The substitution of thiophene by polyfluorinated alkoxy chains affords more favorable structure...A series of poly(fluoroalkoxy thiophenes) have been prepared by electrochemical and chemical polymerization respectively. The substitution of thiophene by polyfluorinated alkoxy chains affords more favorable structures in electronic effect and higher stabilities of their polymers than conventional alkoxy chain substituted polymers.展开更多
The direct iodination of polyfluorinated vinyl stannanes by tin-iodine exchange methodology was achieved giving （Z）-α-fluoro-β-trifluoromethyl vinyl iodides stereospecifically. Changing the substituent in R group ...The direct iodination of polyfluorinated vinyl stannanes by tin-iodine exchange methodology was achieved giving （Z）-α-fluoro-β-trifluoromethyl vinyl iodides stereospecifically. Changing the substituent in R group from the electron-withdrawing group to electron-donating group led to an increase in the yield from 78% to 90%, while it was moved from para to meta position the reaction did not afford a dramatic change in the yield （90% to 95%）. In addition, this reaction also can be applied to the vinyl stannane with heterocyclic group. The further coupling reaction of prepared vinyl iodide containing heterocyclic moiety with （Z）-α-fluoro-β-trifluoromethylstannanes gave polyfluorinated heterocyclic alkadienes with 2E,4E-selectivity.展开更多
Per-and polyfluorinated substances(PFASs)contaminates the arable soil through multiple paths,and poses a threat to both farmland ecosystems and human health.In this study,the potential sources and distribution charact...Per-and polyfluorinated substances(PFASs)contaminates the arable soil through multiple paths,and poses a threat to both farmland ecosystems and human health.In this study,the potential sources and distribution characteristics of 12 legacy PFASs in the soil and rivers for irrigation purposes were investigated in farmland systems,and the risks posed by PFASs to earthworm and aquatic organisms were also assessed.Based on field investigations in Yangtze River Basin,we found long-chain perfluoroalkyl carboxylic acids(PFCAs)were the major contaminants in arable soil and rivers for irrigation purposes,with PFOA(Perfluorooctanoic acid)being the most dominant monomer.Concentration levels of PFASs in arable soil were strongly related to land use types,the average concentration of PFASs(341.18±600.19 ng/g)in the paddy fields was 100-fold higher than that of dry fields(3.79±4.11 ng/g).Source apportionment revealed that PFASs detected in paddy fields were mainly associated with industrial effluents,domestic sewage,and irrigation water.In rivers for irrigation purposes,higher PFASs contamination were primarily distributed in industrial areas,such as plastic processing,paper,textile and electronics factories.The PFASs in the irrigation river water posed a low-medium risk to daphnia and fish,while the PFASs(PFOA and perfluorododecanoic acid(PFDoDA))in soil posed a medium-high risk to earthworms.These results provided insights that sewage irrigation caused serious pollution of PFASs in the agricultural environment,should be paid more attention.展开更多
Atmospheric particulate matter(PM)is a dominant source of air pollution,in particular,molecules less than 2.5μm in diameter,endangering human health.An estimated 2.1 million deaths from exposure to PM2.5 and 700,000 ...Atmospheric particulate matter(PM)is a dominant source of air pollution,in particular,molecules less than 2.5μm in diameter,endangering human health.An estimated 2.1 million deaths from exposure to PM2.5 and 700,000 cases of respiratory disease caused by atmospheric pollution were reported on an annual basis.The main components of PM2.5 include heavy metal elements,water-soluble ions,carbon aerosols,ozone,and organic compounds.Per-and polyfluoroalkyl substances(PFASs)are a large group of representative pollutants among the organic compounds absorbed in PM2.5.PFASs are widely used in industrial production and hardly degraded in the environment,resulting in their accumulation in water,food,and air,and abosorbed by humans via ingestion and inhalation.On the other hand,accumulation of PFAS in the human body is proving to be associated with some unfavorable health outcomes,whereas the mechanisms underlying the effects of PFAS exposure on human lung diseases remain unclear at present.The toxicological effects of organic components are a significant focus of research.This review will fix our attention on the changes in the distribution,composition,and content of PFAS in PM2.5 by location and year,and provide an overview on the influence of PM2.5 and PFAS on lung health,with indications of possible synergistic adverse effects of PM2.5 and PFAS on pulmonary homeostasis.展开更多
基金This work was supported by the National Natural Science Foundation of China.
文摘Electrochemical polymerization of 3-fluoroalkoxy and 3-fluoroether thiophenes gives polymers with relatively high molecular weights and good processibility. Investigation of these polymers by means of GPC indicates that an increase in the number of fluorine atoms in the fluorinated group results in a decrease in degree of polymerization of the polymers in the same polythiophene series. As shown by NMR and FTIR, the polyfluorinated group substituted polythiophenes have regular 2, 5-coupling in their main chains. The SEM micrographs of the polymer films exhibit that polymer (1)-poly [3-2, 2, 3, 3-tetrafluoro-propoxy) thiophene] possesses more regular structure than the other polymers do. Substitution of polythiophenes by fluorinated groups leads to the polymers with high electric, electrochemical and thermal stability.
基金This work was supported by the National Natural Science Foundation of China.
文摘Three series of polythiophenes containing fluoroalkoxy and fluoroether substituents were prepared by electrochemical polymerization. The effect of substituents with fluoroalkoxy or ether functional groups on the electrochemical polymerization of thiophene monomers and properties of the obtained polymers were analyzed. The introduction of a fluoroether functional group at the 3-position of the thiophene ring leads to an increase of the oxidation potential of the monomer and to a decrease of the conductivity of the resulting polymers, even with the use of a CH2 group as spacer. Conversely, the presence of an oxygen atom directly at the 3-position of the thiophene ring, which offsets the negative withdrawing effect of fluoroalkyl groups, facilitates the synthesis of highly conducting polythiophenes.
基金the National Natural Science Foundation of China (No. 29972046) and Chinese Academy of Sciences.
文摘A new homocoupling methodology mediated by a novel combination of CuCl-2,2'-dipyridyl and its application to the synthesis of substituted polyfluorinated alka-2,4-dienes are described.
基金supported by the National Natural Science Foundation of China.
文摘A series of poly(fluoroalkoxy thiophenes) have been prepared by electrochemical and chemical polymerization respectively. The substitution of thiophene by polyfluorinated alkoxy chains affords more favorable structures in electronic effect and higher stabilities of their polymers than conventional alkoxy chain substituted polymers.
文摘The direct iodination of polyfluorinated vinyl stannanes by tin-iodine exchange methodology was achieved giving （Z）-α-fluoro-β-trifluoromethyl vinyl iodides stereospecifically. Changing the substituent in R group from the electron-withdrawing group to electron-donating group led to an increase in the yield from 78% to 90%, while it was moved from para to meta position the reaction did not afford a dramatic change in the yield （90% to 95%）. In addition, this reaction also can be applied to the vinyl stannane with heterocyclic group. The further coupling reaction of prepared vinyl iodide containing heterocyclic moiety with （Z）-α-fluoro-β-trifluoromethylstannanes gave polyfluorinated heterocyclic alkadienes with 2E,4E-selectivity.
基金supported by the Fundamental Research Funds for The Central Universities(No.B230201058).
文摘Per-and polyfluorinated substances(PFASs)contaminates the arable soil through multiple paths,and poses a threat to both farmland ecosystems and human health.In this study,the potential sources and distribution characteristics of 12 legacy PFASs in the soil and rivers for irrigation purposes were investigated in farmland systems,and the risks posed by PFASs to earthworm and aquatic organisms were also assessed.Based on field investigations in Yangtze River Basin,we found long-chain perfluoroalkyl carboxylic acids(PFCAs)were the major contaminants in arable soil and rivers for irrigation purposes,with PFOA(Perfluorooctanoic acid)being the most dominant monomer.Concentration levels of PFASs in arable soil were strongly related to land use types,the average concentration of PFASs(341.18±600.19 ng/g)in the paddy fields was 100-fold higher than that of dry fields(3.79±4.11 ng/g).Source apportionment revealed that PFASs detected in paddy fields were mainly associated with industrial effluents,domestic sewage,and irrigation water.In rivers for irrigation purposes,higher PFASs contamination were primarily distributed in industrial areas,such as plastic processing,paper,textile and electronics factories.The PFASs in the irrigation river water posed a low-medium risk to daphnia and fish,while the PFASs(PFOA and perfluorododecanoic acid(PFDoDA))in soil posed a medium-high risk to earthworms.These results provided insights that sewage irrigation caused serious pollution of PFASs in the agricultural environment,should be paid more attention.
基金supported by the Major Research Plan-Integrated Program of National Natural Science Foundation of China(No.92143301)the National Natural Science Foundation of China(No.31971318)Chinese Academy of Medical Sciences(CAMS)Innovation Fund for Medical Science(No.CIFMS 2019-I2M-5-018).
文摘Atmospheric particulate matter(PM)is a dominant source of air pollution,in particular,molecules less than 2.5μm in diameter,endangering human health.An estimated 2.1 million deaths from exposure to PM2.5 and 700,000 cases of respiratory disease caused by atmospheric pollution were reported on an annual basis.The main components of PM2.5 include heavy metal elements,water-soluble ions,carbon aerosols,ozone,and organic compounds.Per-and polyfluoroalkyl substances(PFASs)are a large group of representative pollutants among the organic compounds absorbed in PM2.5.PFASs are widely used in industrial production and hardly degraded in the environment,resulting in their accumulation in water,food,and air,and abosorbed by humans via ingestion and inhalation.On the other hand,accumulation of PFAS in the human body is proving to be associated with some unfavorable health outcomes,whereas the mechanisms underlying the effects of PFAS exposure on human lung diseases remain unclear at present.The toxicological effects of organic components are a significant focus of research.This review will fix our attention on the changes in the distribution,composition,and content of PFAS in PM2.5 by location and year,and provide an overview on the influence of PM2.5 and PFAS on lung health,with indications of possible synergistic adverse effects of PM2.5 and PFAS on pulmonary homeostasis.
