Graphene-based materials possess significant potential for the treatment of dye wastewater due to their exceptional adsorption properties toward stubborn pollutants.However,their utilization is hindered by high prepar...Graphene-based materials possess significant potential for the treatment of dye wastewater due to their exceptional adsorption properties toward stubborn pollutants.However,their utilization is hindered by high preparation costs,low yields,environmental pollution during synthesis,and challenges in regenerating the adsorbent.This study proposes a novel approach to address these limitations by developing nitrogen-doped three-dimensional(3D)polyvinyl alcohol(PVA)crosslinked graphene sponges(N-PGA)using a cross-linking method with ammonium carbonate.This method offers a relatively mild,environmentally friendly approach.Ammonium carbonate serves as both a reducing and modifying agent,facilitating the formation of the intrinsic structure of N-PGA and acting as a nitrogen source.Meanwhile,PVA is utilized as the cross-linking agent.The results demonstrate that N-PGA exhibits a favorable internal 3D hierarchical porous structure and possesses robust mechanical properties.The measured specific surface area(BET)of N-PGA was as high as406.538 m^(2)·g^(-1),which was favorable for its efficient adsorption of Congo red(CR)dye molecules.At an initial concentration of 50 mg·L^(-1),N-PGA achieved an impressive removal rate of 89.6%and an adsorption capacity of 112 mg·g^(-1)for CR dye.Furthermore,it retained 79%of its initial adsorption capacity after 10 cycles,demonstrating excellent regeneration performance.In summary,the synthesized N-PGA displays remarkable efficacy in the adsorption of CR dye in wastewater,opening up new possibilities for utilizing 3D porous graphene nanomaterials as efficient adsorbents in wastewater treatment.展开更多
Objective: Obstructive sleep apnea-hypopnea syndrome (OSA) is a disease of obstructive apnea or hypopnea caused by a repeated partial or complete collapse of the upper airway during sleep. The inspiratory part of the ...Objective: Obstructive sleep apnea-hypopnea syndrome (OSA) is a disease of obstructive apnea or hypopnea caused by a repeated partial or complete collapse of the upper airway during sleep. The inspiratory part of the flow-volume curve (F-V curve) can be used as an auxiliary means to evaluate upper airway obstruction in adults. This study is to evaluate the ability of the F-V curve to predict the OSA and explore inspiratory indicators related to airway obstruction during sleep. Methods: There were 332 patients included in this cross-sectional study, who were accompanied by snoring, daytime sleepiness and other symptoms, with suspicion of OSA. According to the nocturnal polysomnography, the subjects were distributed into mild to moderate OSA group, severe OSA group and non-OSA group. A pulmonary function test was used to collect the subjects’ spirometry and F-V curves. Results: There was no significant difference in a variety of indices derived from the F-V curve between OSA and normal subjects, including 25% inspiratory flow rate, middle inspiratory flow rate, 75% inspiratory flow rate, peak flow rate, and forced inspiratory flow rate in the first second. The pulmonary function parameters were significantly correlated with the weight, age and sex of the subjects. Conclusion: These findings suggest that the inspiratory curve of pulmonary function cannot evaluate the upper airway abnormalities in patients with obstructive apnea-hypopnea syndrome.展开更多
Polyhedral boranes are a class of well-known boron molecular clusters with unique physical and chemical properties,and great efforts have been made in the past decades to find more effective synthetic methods.However,...Polyhedral boranes are a class of well-known boron molecular clusters with unique physical and chemical properties,and great efforts have been made in the past decades to find more effective synthetic methods.However,the established synthetic methods suffer from low efficiency and low selectivity because the mechanism of the B-H bond condensation reaction,critical for the synthesis of the polyhedral boranes,is not well understood.Here we report highly selective and efficient synthetic methods of the salts of the tetradecahydridoundecaborate(1-)(B_(11)H^(-)_(14)) and dodecahydrido-dodecaborates(2-)(B_(12)H_(12)^(2-)) anions by employing commercially available and inexpensive starting materials.Both theoretical and experimental investigations are carried out to elucidate the reaction mechanisms.We have found that the nature of the B-H bond condensation is the dihydrogen bonding interaction in which the positively charged hydrogens(bridged hydrogens) play a crucial role.The current study has not only led to more effective and selective synthetic methods for B_(11)H^(-)_(14) and B_(12)H_(12)^(2-) but also unveiled the nature of the B-H bond condensation and the general formation mechanisms of polyhedral boranes.This finding will facilitate the development of more effective synthetic methods for polyhedral boranes and spur their wide application.展开更多
Rare earth(RE)silicate is one of the most promising environmental barrier coatings for silicon-based ceramics in gas turbine engines.However,calcium-magnesium-alumina-silicate(CMAS)corrosion becomes much more serious ...Rare earth(RE)silicate is one of the most promising environmental barrier coatings for silicon-based ceramics in gas turbine engines.However,calcium-magnesium-alumina-silicate(CMAS)corrosion becomes much more serious and is the critical challenge for RE silicate with the increasing operating temperature.Therefore,it is quite urgent to clarify the mechanism of high-temperature CMAS-induced degradation of RE silicate at relatively high temperatures.Herein,the interaction between RE_(2)SiO_(5) and CMAS up to 1500℃was investigated by a novel high temperature in-situ observation method.High temperature promotes the growth of the main reaction product(Ca_(2)RE_(8)(SiO_(4))6O_(2))fast along the[001]direction,and the precipitation of short and horizontally distributed Ca_(2)RE_(8)(SiO_(4))6O_(2) grains was accelerated during the cooling process.The increased temperature increases the solubility of RE elements,decreases the viscosity of CMAS,and thus elevates the corrosion reaction rate,making RE_(2)SiO_(5) fast interaction with CMAS and less affected by RE element species.展开更多
Lead-free halide double perovskites have gathered wide scientific interest since they are environmentally friendly and stable.However,compared to the lead perovskites,their optoelectronic properties are compromised.He...Lead-free halide double perovskites have gathered wide scientific interest since they are environmentally friendly and stable.However,compared to the lead perovskites,their optoelectronic properties are compromised.Herein we report a series of bulk lead-free mixed Bi-In halide double perovskites:Cs2AgBi1-xInxCl6(0<x<1).The Cs2AgBi0.125In0.875Cl6breaks the parity-forbidden transition and retains direct band gap structure,having warm-white light emission,with photoluminescence quantum efficiency(PLQE)of 70.3%,much higher than the PLQE of reported lead perovskite materials.Its exciton self-trapping dynamics is investigated.Meanwhile,the Cs2AgBi0.125In0.875Cl6nanocrystals and Cs2AgBi0.125In0.875Cl6microcrystals can be synthesized by modified hot injection and rapid cooling crystallization,respectively.The size effect of Cs2AgBi0.125In0.875Cl6is studied on the photoluminescence(PL)property.Additionally,the bulk material exhibits excellent stability on exposure to light,humidity and air for more than 3 months.It is a promising candidate as highly efficient warm white-light emitting material for road lighting.展开更多
Symmetric 1,3-diketones with fluorine or fluorinated substituents on the prochiral carbon remain to be established.Herein,we have developed a novel prochiral fluorinated oxindanyl 1,3-diketone and successfully applied...Symmetric 1,3-diketones with fluorine or fluorinated substituents on the prochiral carbon remain to be established.Herein,we have developed a novel prochiral fluorinated oxindanyl 1,3-diketone and successfully applied these substrates in carbene-catalyzed asymmetric desymmetrization.Accordingly,a versatile strategy for asymmetric generation of organofluorines with fluorine or fluorinated methyl groups has been developed.Multiple stereogenic centers were selectively constructed with satisfactory outcomes.Structurally diverse enantioenriched organofluorines were generated with excellent results in terms of yields,diastereoselectivities,and enantioselectivities.Notably,exchanging fluorinated methyl groups to fluorine for this prochiral 1,3-diketones leads to switchable stereoselectivity.Mechanistic aspects and origin of stereoselectivity were studied by DFT calculations.Notably,some of the prepared organofluorines demonstrated competitive antibacterial activities.展开更多
The solvent additive strategy has been widely utilized to boost the power conversion efficiency(PCE)of organic solar cells(OSCs).However,the residual solvent additive in the active layer tends to induce a gradual morp...The solvent additive strategy has been widely utilized to boost the power conversion efficiency(PCE)of organic solar cells(OSCs).However,the residual solvent additive in the active layer tends to induce a gradual morphology degradation and further influences the long-term stability of OSCs.Here,a solid additive,1,4-diiodobenzene(DIB),was introduced to fabricate efficient OSCs.We found that the treatment of DIB can lead to optimized morphology to form a bicontinuous network with intensified intermolecular packing in the donor and acceptor phases.Notably,DIB can be easily removed from the active layer via a simple alcohol washing process and no further post-thermal annealing is needed,which is desirable for large-scale manufacturing of OSCs.As a result,high efficiencies of 17.47%for PM6:Y6 and 18.13%(certified as 17.7%)for PM6:BTP-eC9 binary OSCs are achieved,which are among the highest efficiencies reported for binary OSCs thus far.Moreover,OSCs fabricated with DIB also exhibit superior stability compared with the as-cast and traditional solvent additive processed devices.Additionally,DIB was successfully applied in different active layers,manifesting its general applicability.This work provides a feasible approach to enhance both the efficiency and stability of OSCs.展开更多
Based on 4-bromo-1,8-naphthalic anhydride,one novel ratiometric fluorescence H_(2)S-probe(IDNA)was designed and synthesized.Further studies indicate that IDNA can sensitively recognize H_(2)S(detection limit of 7 μmo...Based on 4-bromo-1,8-naphthalic anhydride,one novel ratiometric fluorescence H_(2)S-probe(IDNA)was designed and synthesized.Further studies indicate that IDNA can sensitively recognize H_(2)S(detection limit of 7 μmol/L)with good selectivity and anti-interference ability.In addition,IDNA has satisfactory photostability in HeLa cells,ability of mitochondrial co-localization,and can be utilized in fluorescence imaging of H_(2)S.展开更多
The granular sludge of microbial fermentation systems includes various biomass-degrading enzymes and different microflora,which have significant impacts on the degradation of biomass and the stability of the system.An...The granular sludge of microbial fermentation systems includes various biomass-degrading enzymes and different microflora,which have significant impacts on the degradation of biomass and the stability of the system.An up-flow anaerobic sludge blanket(UASB)reactor was used to grow hydrogen-producing granular sludge.The results showed that the formation of the granular sludge underwent four stages,i.e.,flocculation of the sludge,formation of the flocculent sludge,swelling of the flocculent sludge,and formation of the granular sludge.The formed granular sludge mostly had regular spherical and ellipsoidal shapes with a fractal dimension of 2.08±0.4;the settling velocities were 0.84 cm/s to 1.96 cm/s in water,the porosity was 0.67-0.95.The shear sensitivity(Kss)of the granular sludge was 0.1152.The granular sludge had a culture cycle of approximately 70 d and a hydrogen yield of 1.09 mol H2/mol glucose.展开更多
Benzo[1,2-b:4,5-b′]dithiophene(BDT) has been widely used to construct donor-acceptor(D-A) copolymers in organic solar cells(OSCs). However, benzo[1,2-b:4,5-b′]difuran(BDF), an analogue of BDT, has received less atte...Benzo[1,2-b:4,5-b′]dithiophene(BDT) has been widely used to construct donor-acceptor(D-A) copolymers in organic solar cells(OSCs). However, benzo[1,2-b:4,5-b′]difuran(BDF), an analogue of BDT, has received less attention than BDT. The photovoltaic performance of BDF copolymers has lagged behind that of BDT copolymers. Here, we designed and synthesized two BDF copolymers, PBF1-C and PBF1-C-2Cl. PBF1-C-2Cl, which is composed of BDF and benzo[1,2-c:4,5-c′]dithiophene-4,8-dione connected by a chlorinated thiophene π-bridge, displays a low-lying highest occupied molecular orbital energy level,which helps in yielding a high open-circuit voltage(Voc) in OSCs. As a result, when blended with Y6, PBF1-C-2Cl-based devices showed a high Voc of 0.83 V and a power conversion efficiency(PCE) of 13.10%. To the best of our knowledge, the PCE of 13.10% is among the highest efficiency values for OSCs based on BDF copolymers.展开更多
Symmetric 1,3-diketones with fluorine or fluorinated substituents on the prochiral carbon remain to be established.Herein,we have developed a novel prochiral fluorinated oxindanyl 1,3-diketone and successfully applied...Symmetric 1,3-diketones with fluorine or fluorinated substituents on the prochiral carbon remain to be established.Herein,we have developed a novel prochiral fluorinated oxindanyl 1,3-diketone and successfully applied these substrates in carbene-catalyzed asymmetric desymmetrization.Accordingly,a versatile strategy for asymmetric generation of organofluorines with fluorine or fluorinated methyl groups has been developed.Multiple stereogenic centers were selectively constructed with satisfactory outcomes.Structurally diverse enantioenriched organofluorines were generated with excellent results in terms of yields,diastereoselectivities,and enantioselectivities.Notably,exchanging fluorinated methyl groups to fluorine for this prochiral 1,3-diketones leads to switchable stereoselectivity.Mechanistic aspects and origin of stereoselectivity were studied by DFT calculations.Notably,some of the prepared organofluorines demonstrated competitive antibacterial activities.展开更多
An NHC-catalyzed regiospecific allylation ofα-substituted allenoates with MBH carbonates derived from aryl aldehyde furnished highly functionalized 1,5-enynes bearing a quaternary carbon successfully.Combining with D...An NHC-catalyzed regiospecific allylation ofα-substituted allenoates with MBH carbonates derived from aryl aldehyde furnished highly functionalized 1,5-enynes bearing a quaternary carbon successfully.Combining with DFT calculations,the reaction mechanism of this conversion was proposed.This method has the advantages of high regioselectivity,good yields and mild reaction conditions.This transformation not only provided a new access to 1,5-enyne,but also enriched the chemistry of allenoates and NHC catalysis.展开更多
基金supported by the National Natural Science Foundation of China(51671052,51750110513,52250610222)the Fundamental Research Funds for the Central Universities(N182502042)the Liao Ning Revitilization Talents Program(XLYC1902105)。
文摘Graphene-based materials possess significant potential for the treatment of dye wastewater due to their exceptional adsorption properties toward stubborn pollutants.However,their utilization is hindered by high preparation costs,low yields,environmental pollution during synthesis,and challenges in regenerating the adsorbent.This study proposes a novel approach to address these limitations by developing nitrogen-doped three-dimensional(3D)polyvinyl alcohol(PVA)crosslinked graphene sponges(N-PGA)using a cross-linking method with ammonium carbonate.This method offers a relatively mild,environmentally friendly approach.Ammonium carbonate serves as both a reducing and modifying agent,facilitating the formation of the intrinsic structure of N-PGA and acting as a nitrogen source.Meanwhile,PVA is utilized as the cross-linking agent.The results demonstrate that N-PGA exhibits a favorable internal 3D hierarchical porous structure and possesses robust mechanical properties.The measured specific surface area(BET)of N-PGA was as high as406.538 m^(2)·g^(-1),which was favorable for its efficient adsorption of Congo red(CR)dye molecules.At an initial concentration of 50 mg·L^(-1),N-PGA achieved an impressive removal rate of 89.6%and an adsorption capacity of 112 mg·g^(-1)for CR dye.Furthermore,it retained 79%of its initial adsorption capacity after 10 cycles,demonstrating excellent regeneration performance.In summary,the synthesized N-PGA displays remarkable efficacy in the adsorption of CR dye in wastewater,opening up new possibilities for utilizing 3D porous graphene nanomaterials as efficient adsorbents in wastewater treatment.
文摘Objective: Obstructive sleep apnea-hypopnea syndrome (OSA) is a disease of obstructive apnea or hypopnea caused by a repeated partial or complete collapse of the upper airway during sleep. The inspiratory part of the flow-volume curve (F-V curve) can be used as an auxiliary means to evaluate upper airway obstruction in adults. This study is to evaluate the ability of the F-V curve to predict the OSA and explore inspiratory indicators related to airway obstruction during sleep. Methods: There were 332 patients included in this cross-sectional study, who were accompanied by snoring, daytime sleepiness and other symptoms, with suspicion of OSA. According to the nocturnal polysomnography, the subjects were distributed into mild to moderate OSA group, severe OSA group and non-OSA group. A pulmonary function test was used to collect the subjects’ spirometry and F-V curves. Results: There was no significant difference in a variety of indices derived from the F-V curve between OSA and normal subjects, including 25% inspiratory flow rate, middle inspiratory flow rate, 75% inspiratory flow rate, peak flow rate, and forced inspiratory flow rate in the first second. The pulmonary function parameters were significantly correlated with the weight, age and sex of the subjects. Conclusion: These findings suggest that the inspiratory curve of pulmonary function cannot evaluate the upper airway abnormalities in patients with obstructive apnea-hypopnea syndrome.
基金supported by the National Natural Science Foundation of China(22171246,U1804253 to X.C.and 21773214 to D.W.)the National Science Foundation(CHE-2053541 to L.-S.W.)。
文摘Polyhedral boranes are a class of well-known boron molecular clusters with unique physical and chemical properties,and great efforts have been made in the past decades to find more effective synthetic methods.However,the established synthetic methods suffer from low efficiency and low selectivity because the mechanism of the B-H bond condensation reaction,critical for the synthesis of the polyhedral boranes,is not well understood.Here we report highly selective and efficient synthetic methods of the salts of the tetradecahydridoundecaborate(1-)(B_(11)H^(-)_(14)) and dodecahydrido-dodecaborates(2-)(B_(12)H_(12)^(2-)) anions by employing commercially available and inexpensive starting materials.Both theoretical and experimental investigations are carried out to elucidate the reaction mechanisms.We have found that the nature of the B-H bond condensation is the dihydrogen bonding interaction in which the positively charged hydrogens(bridged hydrogens) play a crucial role.The current study has not only led to more effective and selective synthetic methods for B_(11)H^(-)_(14) and B_(12)H_(12)^(2-) but also unveiled the nature of the B-H bond condensation and the general formation mechanisms of polyhedral boranes.This finding will facilitate the development of more effective synthetic methods for polyhedral boranes and spur their wide application.
基金This work was financially supported by the National Natural Science Foundation of China(Grant Nos.52202078 and 52202126)Guangdong Basic and Applied Basic Research Foundation for Distinguished Young Scholars(Grant No.2021B1515020083)+1 种基金Guangdong Basic and Applied Basic Research Foundation(Grant Nos.2021A1515110293 and 2022A1515012201)Shenzhen Science and Technology Program(Grant Nos.202206193000001 and 20220818183014003).
文摘Rare earth(RE)silicate is one of the most promising environmental barrier coatings for silicon-based ceramics in gas turbine engines.However,calcium-magnesium-alumina-silicate(CMAS)corrosion becomes much more serious and is the critical challenge for RE silicate with the increasing operating temperature.Therefore,it is quite urgent to clarify the mechanism of high-temperature CMAS-induced degradation of RE silicate at relatively high temperatures.Herein,the interaction between RE_(2)SiO_(5) and CMAS up to 1500℃was investigated by a novel high temperature in-situ observation method.High temperature promotes the growth of the main reaction product(Ca_(2)RE_(8)(SiO_(4))6O_(2))fast along the[001]direction,and the precipitation of short and horizontally distributed Ca_(2)RE_(8)(SiO_(4))6O_(2) grains was accelerated during the cooling process.The increased temperature increases the solubility of RE elements,decreases the viscosity of CMAS,and thus elevates the corrosion reaction rate,making RE_(2)SiO_(5) fast interaction with CMAS and less affected by RE element species.
基金supported by the National Natural Science Foundation of China (21533010, 21525315)the National Key Research and Development Program of China (2017YFA0204800)+2 种基金DICP DMTO201601DICP ZZBS201703the Science Challenging Program (JCKY2016212A501)
文摘Lead-free halide double perovskites have gathered wide scientific interest since they are environmentally friendly and stable.However,compared to the lead perovskites,their optoelectronic properties are compromised.Herein we report a series of bulk lead-free mixed Bi-In halide double perovskites:Cs2AgBi1-xInxCl6(0<x<1).The Cs2AgBi0.125In0.875Cl6breaks the parity-forbidden transition and retains direct band gap structure,having warm-white light emission,with photoluminescence quantum efficiency(PLQE)of 70.3%,much higher than the PLQE of reported lead perovskite materials.Its exciton self-trapping dynamics is investigated.Meanwhile,the Cs2AgBi0.125In0.875Cl6nanocrystals and Cs2AgBi0.125In0.875Cl6microcrystals can be synthesized by modified hot injection and rapid cooling crystallization,respectively.The size effect of Cs2AgBi0.125In0.875Cl6is studied on the photoluminescence(PL)property.Additionally,the bulk material exhibits excellent stability on exposure to light,humidity and air for more than 3 months.It is a promising candidate as highly efficient warm white-light emitting material for road lighting.
基金supported by the National Key R&D Program of China(2017YFA0204704)National Natural Science Foundation of China(21602105)Natural Science Foundation of Jiangsu Province(BK20171460)。
文摘Symmetric 1,3-diketones with fluorine or fluorinated substituents on the prochiral carbon remain to be established.Herein,we have developed a novel prochiral fluorinated oxindanyl 1,3-diketone and successfully applied these substrates in carbene-catalyzed asymmetric desymmetrization.Accordingly,a versatile strategy for asymmetric generation of organofluorines with fluorine or fluorinated methyl groups has been developed.Multiple stereogenic centers were selectively constructed with satisfactory outcomes.Structurally diverse enantioenriched organofluorines were generated with excellent results in terms of yields,diastereoselectivities,and enantioselectivities.Notably,exchanging fluorinated methyl groups to fluorine for this prochiral 1,3-diketones leads to switchable stereoselectivity.Mechanistic aspects and origin of stereoselectivity were studied by DFT calculations.Notably,some of the prepared organofluorines demonstrated competitive antibacterial activities.
基金supported by the National Natural Science Foundation of China(52003013,21734001,51825301)China Postdoctoral Science Foundation(BX20190023)the financial support by the National Research Foundation(NRF)of Korea(2016M1A2A2940911,2019R1A6A1A11044070)。
文摘The solvent additive strategy has been widely utilized to boost the power conversion efficiency(PCE)of organic solar cells(OSCs).However,the residual solvent additive in the active layer tends to induce a gradual morphology degradation and further influences the long-term stability of OSCs.Here,a solid additive,1,4-diiodobenzene(DIB),was introduced to fabricate efficient OSCs.We found that the treatment of DIB can lead to optimized morphology to form a bicontinuous network with intensified intermolecular packing in the donor and acceptor phases.Notably,DIB can be easily removed from the active layer via a simple alcohol washing process and no further post-thermal annealing is needed,which is desirable for large-scale manufacturing of OSCs.As a result,high efficiencies of 17.47%for PM6:Y6 and 18.13%(certified as 17.7%)for PM6:BTP-eC9 binary OSCs are achieved,which are among the highest efficiencies reported for binary OSCs thus far.Moreover,OSCs fabricated with DIB also exhibit superior stability compared with the as-cast and traditional solvent additive processed devices.Additionally,DIB was successfully applied in different active layers,manifesting its general applicability.This work provides a feasible approach to enhance both the efficiency and stability of OSCs.
基金We are grateful for the financial supports from the National Natural Science Foundation of China(Nos.U1704161,U1504203,21601158)Zhengzhou University(No.32210431).
文摘Based on 4-bromo-1,8-naphthalic anhydride,one novel ratiometric fluorescence H_(2)S-probe(IDNA)was designed and synthesized.Further studies indicate that IDNA can sensitively recognize H_(2)S(detection limit of 7 μmol/L)with good selectivity and anti-interference ability.In addition,IDNA has satisfactory photostability in HeLa cells,ability of mitochondrial co-localization,and can be utilized in fluorescence imaging of H_(2)S.
基金The authors are grateful to the financial support by National Natural Science Foundation of China(Grant No.51506027)“Young Talents”Project of Northeast Agricultural University(Grant No.16QC18).
文摘The granular sludge of microbial fermentation systems includes various biomass-degrading enzymes and different microflora,which have significant impacts on the degradation of biomass and the stability of the system.An up-flow anaerobic sludge blanket(UASB)reactor was used to grow hydrogen-producing granular sludge.The results showed that the formation of the granular sludge underwent four stages,i.e.,flocculation of the sludge,formation of the flocculent sludge,swelling of the flocculent sludge,and formation of the granular sludge.The formed granular sludge mostly had regular spherical and ellipsoidal shapes with a fractal dimension of 2.08±0.4;the settling velocities were 0.84 cm/s to 1.96 cm/s in water,the porosity was 0.67-0.95.The shear sensitivity(Kss)of the granular sludge was 0.1152.The granular sludge had a culture cycle of approximately 70 d and a hydrogen yield of 1.09 mol H2/mol glucose.
基金supported by the National Natural Science Foundation of China (21674007, 51825301, 21975012, 21875204, 21875204, 21734001)the financial support from the National Research Foundation (NRF) of Korea (NRF-2019R1A2C2085290, 2019R1A6A1A11044070).
文摘Benzo[1,2-b:4,5-b′]dithiophene(BDT) has been widely used to construct donor-acceptor(D-A) copolymers in organic solar cells(OSCs). However, benzo[1,2-b:4,5-b′]difuran(BDF), an analogue of BDT, has received less attention than BDT. The photovoltaic performance of BDF copolymers has lagged behind that of BDT copolymers. Here, we designed and synthesized two BDF copolymers, PBF1-C and PBF1-C-2Cl. PBF1-C-2Cl, which is composed of BDF and benzo[1,2-c:4,5-c′]dithiophene-4,8-dione connected by a chlorinated thiophene π-bridge, displays a low-lying highest occupied molecular orbital energy level,which helps in yielding a high open-circuit voltage(Voc) in OSCs. As a result, when blended with Y6, PBF1-C-2Cl-based devices showed a high Voc of 0.83 V and a power conversion efficiency(PCE) of 13.10%. To the best of our knowledge, the PCE of 13.10% is among the highest efficiency values for OSCs based on BDF copolymers.
基金supported by the National Key R&D Program of China(2017YFA0204704)National Natural Science Foundation of China(21602105)Natural Science Foundation of Jiangsu Province(BK20171460).
文摘Symmetric 1,3-diketones with fluorine or fluorinated substituents on the prochiral carbon remain to be established.Herein,we have developed a novel prochiral fluorinated oxindanyl 1,3-diketone and successfully applied these substrates in carbene-catalyzed asymmetric desymmetrization.Accordingly,a versatile strategy for asymmetric generation of organofluorines with fluorine or fluorinated methyl groups has been developed.Multiple stereogenic centers were selectively constructed with satisfactory outcomes.Structurally diverse enantioenriched organofluorines were generated with excellent results in terms of yields,diastereoselectivities,and enantioselectivities.Notably,exchanging fluorinated methyl groups to fluorine for this prochiral 1,3-diketones leads to switchable stereoselectivity.Mechanistic aspects and origin of stereoselectivity were studied by DFT calculations.Notably,some of the prepared organofluorines demonstrated competitive antibacterial activities.
基金support by National Natural Science Foundation of China(No.21871113,21773214,21372101)a project Funded by the Priority Academic Program Development of Jiangsu Higher Education Institution and TAPP.
文摘An NHC-catalyzed regiospecific allylation ofα-substituted allenoates with MBH carbonates derived from aryl aldehyde furnished highly functionalized 1,5-enynes bearing a quaternary carbon successfully.Combining with DFT calculations,the reaction mechanism of this conversion was proposed.This method has the advantages of high regioselectivity,good yields and mild reaction conditions.This transformation not only provided a new access to 1,5-enyne,but also enriched the chemistry of allenoates and NHC catalysis.
