Herein,a nickel-catalyzed arylcyanation of unactivated alkenes via cyano group translocation with aryl boronic acids has been developed.These transformations provided a robust approach to constructing structurally div...Herein,a nickel-catalyzed arylcyanation of unactivated alkenes via cyano group translocation with aryl boronic acids has been developed.These transformations provided a robust approach to constructing structurally diverse 1,n-dinitriles or 4-amino nitriles from easily prepared and commercially available starting materials.The cyano group translocation was achieved,involving the addition into the intramolecular C–N triple bond followed by the retro-Thorpe reaction.Mechanistic studies revealed that high temperature and CsHCO_(3) as the base were crucial for the cyano group translocation.展开更多
Graphite carbon nitride has many excellent properties as a two-dimensional semiconductor material so that it has a wide application prospect in the field of photocatalysis.However,the traditional problems such as high...Graphite carbon nitride has many excellent properties as a two-dimensional semiconductor material so that it has a wide application prospect in the field of photocatalysis.However,the traditional problems such as high recombination rate of photogenerated carriers limit its application.In this work,we introduce nitrogen deficiency into g-C_(3)N_(4)to solve this problem a simple and safe in-situ reduction method.g-C_(3)N_(4)/CaCO_(3)was obtained by a simple and safe one-step calcination method with industrial-grade micron particles CaCO_(3).Cyano group modification was in-situ reduced during the thermal polymerization process,which would change the internal electronic structure of g-C_(3)N_(4).The successful combination of g-C_(3)N_(4)and CaCO_(3)and the introduction of cyanide have been proved by Fourier transform infrared spectroscopy and X-ray photoelectron spectrometer.The formation of the cyano group,an electron-absorbing group,promotes the effective separation of photogenic electron hole pairs and inhibits the recombination of photogenic carriers.These advantages result in the generation of more·O_(2)-and1O_(2)in the catalytic system,which increases the photocatalytic efficiency of nicotine degradation by ten times.Furthermore,the degradation process of nicotine has been studied in this work to provide a basis for the degradation of nicotine organic pollutants in the air.展开更多
The dual incorporation of two important functional groups—trifluoromethyl and cyano moieties into one heterocyclic core in a single-step reaction represents an appealing but largely unaddressed synthetic challenge.He...The dual incorporation of two important functional groups—trifluoromethyl and cyano moieties into one heterocyclic core in a single-step reaction represents an appealing but largely unaddressed synthetic challenge.Here we demonstrate that a silver-catalyzed[3+2]cycloaddition reaction of dicyanoalkenes with trifluorodiazoethane(CF_(3)CHN2)could render a facile construction of a unique category of pyrazoles that are simultaneously adorned by trifluoromethyl and cyano groups.Changing the location pattern of the cyano group in starting dicyanoalkene material allows regiodivergent access to two series of previously elusive trifluoromethyl cyanopyrazoles with an exquisite level of regiocontrol.Thus,this method could be applied in the preparation of cyano-analogues of CF_(3)-containing drugs(Celecoxib)and agrochemicals(Penthiopyrad and Fluazolate).Notably,several cyano-analogues of Celecoxib demonstrate enhanced inhibitory activity towards cyclooxygenase-2(COX-2),thereby laying a good foundation for developing new lead-based antiinflammatory agents.展开更多
The active site amount of photocatalysts,being the key factors in photocatalytic reactions,directly affects the photocatalytic performance of the photocatalyst.Pristine graphitic carbon nitride(g‐C_(3)N_(4))exhibits ...The active site amount of photocatalysts,being the key factors in photocatalytic reactions,directly affects the photocatalytic performance of the photocatalyst.Pristine graphitic carbon nitride(g‐C_(3)N_(4))exhibits moderate photocatalytic activity due to insufficient active sites.In this study,cyano‐modified porous g‐C_(3)N_(4)nanosheets(MCN‐0.5)were synthesized through molecular self‐assembly and alkali‐assisted strategies.The cyano group acted as the active site of the photocatalytic reaction,because the good electron‐withdrawing property of the cyano group promoted carrier separation.Benefiting from the effect of the active sites,MCN‐0.5 exhibited significantly enhanced photocatalytic activity for CO2 reduction under visible light irradiation.Notably,the photocatalytic activity of MCN‐0.5 was significantly reduced when the cyano groups were removed by hydrochloric acid(HCl)treatment,further verifying the role of cyano groups as active sites.The photoreduction of Pt nanoparticles provided an intuitive indication that the introduction of cyano groups provided more active sites for the photocatalytic reaction.Furthermore,the controlled experiments showed that g‐C_(3)N_(4)grafted with cyano groups using melamine as the precursor exhibited enhanced photocatalytic activity,which proved the versatility of the strategy for enhancing the activity of g‐C_(3)N_(4)via cyano group modification.In situ diffuse reflectance infrared Fourier transform spectroscopy and theoretical calculations were used to investigate the mechanism of enhanced photocatalytic activity for CO2 reduction by cyano‐modified g‐C_(3)N_(4).This work provides a promising route for promoting efficient solar energy conversion by designing active sites in photocatalysts.展开更多
The existence of defects in perovskite films is a major obstacle that prevents perovskite solar cells (PSCs) from high efficiency and long-term stability. A variety of additives have been introduced into perovskite fi...The existence of defects in perovskite films is a major obstacle that prevents perovskite solar cells (PSCs) from high efficiency and long-term stability. A variety of additives have been introduced into perovskite films for reducing the number of defects. Lewis base-based additive engineering has been considered as an effective way to eliminate defects, especially the defects caused by the uncoordinated Pb^(2+). In this work, for the first time, a bilateral cyano molecule (succinonitrile, SN) which is a commonly used plasticizer in solid electrolyte of solid-state lithium batteries was selected as an additive to modify organic–inorganic hybrid perovskite films in PSCs. SN is featured with two cyano groups (–C≡N) distributing at both terminals of the carbon chain, providing two cross-linking points to interact with perovskites crystals via coordinating with uncoordinated Pb2+ and forming hydrogen bonds with –NH2 groups in perovskite. It was found that the addition of SN into perovskite precursor solution could effectively reduce defects, particularly inhibit the appearance of Pb0 and thus suppress trap-assisted nonradiative charge carrier recombination. As a result, the efficiency of CH_(3)NH_(3)PbI_(3)(Cl) (MAPbI_(3)(Cl))-based PSCs was improved from 18.4% to 20._(3)% with enhanced long-term stability at N2 and humid air atmosphere. This work provides a facile and effective strategy to enhance the PCE and stability of PSCs simultaneously, facilitating the commercialization of PSCs.展开更多
Organic redox compounds are attractive cathode materials in aqueous zinc-ion batteries owing to their low cost,environmental friendliness,multiple-electron-transfer reactions,and resource sustainability.However,the re...Organic redox compounds are attractive cathode materials in aqueous zinc-ion batteries owing to their low cost,environmental friendliness,multiple-electron-transfer reactions,and resource sustainability.However,the realized energy density is constrained by the limited capacity and low voltage.Herein,copper-tetracyanoquinodimethane(CuTCNQ),an organic charge-transfer complex is evaluated as a zinc-ion battery cathode owing to the good electron acceptation ability in the cyano groups that improves the voltage output.Through electrochemical activation,electrolyte optimization,and adoption of graphene-based separator,CuTCNQ-based aqueous zinc-ion batteries deliver much improved rate performance and cycling stability with anti-self-discharge properties.The structural evolution of CuTCNQ during discharge/charge are investigated by ex situ Fourier transform infra-red(FT-IR)spectra,ex situ X-ray photoelectron spectroscopy(XPS),and in situ ultraviolet visible spectroscopy(UV-vis),revealing reversible redox reactions in both cuprous cations(Cu^(+))and organic anions(TCNQ^(x-1)),thus delivering a high voltage output of 1.0 V and excellent discharge capacity of 158 mAh g^(-1).The remarkable electrochemical performance in Zn//CuTCNQ is ascribed to the strong inductive effect of cyano groups in CuTCNQ that elevated the voltage output and the graphene-modified separator that inhibited CuTCNQ dissolution and shuttle effect in aqueous electrolytes.展开更多
基金supported by the National Natural Science Foundation of China(21971074,22001076)the Natural Science Foundation of Guangdong Province(2022A1515010660,2021A1515220024)the Natural Science Foundation of Guangzhou(202102020982)。
文摘Herein,a nickel-catalyzed arylcyanation of unactivated alkenes via cyano group translocation with aryl boronic acids has been developed.These transformations provided a robust approach to constructing structurally diverse 1,n-dinitriles or 4-amino nitriles from easily prepared and commercially available starting materials.The cyano group translocation was achieved,involving the addition into the intramolecular C–N triple bond followed by the retro-Thorpe reaction.Mechanistic studies revealed that high temperature and CsHCO_(3) as the base were crucial for the cyano group translocation.
基金supported by the National Natural Science Foundation of China (No.51703201)。
文摘Graphite carbon nitride has many excellent properties as a two-dimensional semiconductor material so that it has a wide application prospect in the field of photocatalysis.However,the traditional problems such as high recombination rate of photogenerated carriers limit its application.In this work,we introduce nitrogen deficiency into g-C_(3)N_(4)to solve this problem a simple and safe in-situ reduction method.g-C_(3)N_(4)/CaCO_(3)was obtained by a simple and safe one-step calcination method with industrial-grade micron particles CaCO_(3).Cyano group modification was in-situ reduced during the thermal polymerization process,which would change the internal electronic structure of g-C_(3)N_(4).The successful combination of g-C_(3)N_(4)and CaCO_(3)and the introduction of cyanide have been proved by Fourier transform infrared spectroscopy and X-ray photoelectron spectrometer.The formation of the cyano group,an electron-absorbing group,promotes the effective separation of photogenic electron hole pairs and inhibits the recombination of photogenic carriers.These advantages result in the generation of more·O_(2)-and1O_(2)in the catalytic system,which increases the photocatalytic efficiency of nicotine degradation by ten times.Furthermore,the degradation process of nicotine has been studied in this work to provide a basis for the degradation of nicotine organic pollutants in the air.
基金This work is supported by the National Natural Science Foundation of China(grant nos.92156025,21901181,and 21961142015)the National Key Research and Development Program of China(grant nos.2019YFA0905100 and 2021YFF0701700)Tianjin Municipal Science and Technology Commission(grant no.19JCQNJC04700).
文摘The dual incorporation of two important functional groups—trifluoromethyl and cyano moieties into one heterocyclic core in a single-step reaction represents an appealing but largely unaddressed synthetic challenge.Here we demonstrate that a silver-catalyzed[3+2]cycloaddition reaction of dicyanoalkenes with trifluorodiazoethane(CF_(3)CHN2)could render a facile construction of a unique category of pyrazoles that are simultaneously adorned by trifluoromethyl and cyano groups.Changing the location pattern of the cyano group in starting dicyanoalkene material allows regiodivergent access to two series of previously elusive trifluoromethyl cyanopyrazoles with an exquisite level of regiocontrol.Thus,this method could be applied in the preparation of cyano-analogues of CF_(3)-containing drugs(Celecoxib)and agrochemicals(Penthiopyrad and Fluazolate).Notably,several cyano-analogues of Celecoxib demonstrate enhanced inhibitory activity towards cyclooxygenase-2(COX-2),thereby laying a good foundation for developing new lead-based antiinflammatory agents.
文摘The active site amount of photocatalysts,being the key factors in photocatalytic reactions,directly affects the photocatalytic performance of the photocatalyst.Pristine graphitic carbon nitride(g‐C_(3)N_(4))exhibits moderate photocatalytic activity due to insufficient active sites.In this study,cyano‐modified porous g‐C_(3)N_(4)nanosheets(MCN‐0.5)were synthesized through molecular self‐assembly and alkali‐assisted strategies.The cyano group acted as the active site of the photocatalytic reaction,because the good electron‐withdrawing property of the cyano group promoted carrier separation.Benefiting from the effect of the active sites,MCN‐0.5 exhibited significantly enhanced photocatalytic activity for CO2 reduction under visible light irradiation.Notably,the photocatalytic activity of MCN‐0.5 was significantly reduced when the cyano groups were removed by hydrochloric acid(HCl)treatment,further verifying the role of cyano groups as active sites.The photoreduction of Pt nanoparticles provided an intuitive indication that the introduction of cyano groups provided more active sites for the photocatalytic reaction.Furthermore,the controlled experiments showed that g‐C_(3)N_(4)grafted with cyano groups using melamine as the precursor exhibited enhanced photocatalytic activity,which proved the versatility of the strategy for enhancing the activity of g‐C_(3)N_(4)via cyano group modification.In situ diffuse reflectance infrared Fourier transform spectroscopy and theoretical calculations were used to investigate the mechanism of enhanced photocatalytic activity for CO2 reduction by cyano‐modified g‐C_(3)N_(4).This work provides a promising route for promoting efficient solar energy conversion by designing active sites in photocatalysts.
基金This work was supported by the Australian Research Council Discovery Projects(DPI 50104365 and DPI 60104835)the National Natural Science Foundation of China(No.21908106 and 21878158)+2 种基金the Jiangsu Natural Science Foundation(No.BK20190682)the Program forjiangsu Specially-Appointed Professors,the Funding from State Key Laboratory of Materials-Oriented Chemical Engineering(No.ZK201808)a Project Funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD).
文摘The existence of defects in perovskite films is a major obstacle that prevents perovskite solar cells (PSCs) from high efficiency and long-term stability. A variety of additives have been introduced into perovskite films for reducing the number of defects. Lewis base-based additive engineering has been considered as an effective way to eliminate defects, especially the defects caused by the uncoordinated Pb^(2+). In this work, for the first time, a bilateral cyano molecule (succinonitrile, SN) which is a commonly used plasticizer in solid electrolyte of solid-state lithium batteries was selected as an additive to modify organic–inorganic hybrid perovskite films in PSCs. SN is featured with two cyano groups (–C≡N) distributing at both terminals of the carbon chain, providing two cross-linking points to interact with perovskites crystals via coordinating with uncoordinated Pb2+ and forming hydrogen bonds with –NH2 groups in perovskite. It was found that the addition of SN into perovskite precursor solution could effectively reduce defects, particularly inhibit the appearance of Pb0 and thus suppress trap-assisted nonradiative charge carrier recombination. As a result, the efficiency of CH_(3)NH_(3)PbI_(3)(Cl) (MAPbI_(3)(Cl))-based PSCs was improved from 18.4% to 20._(3)% with enhanced long-term stability at N2 and humid air atmosphere. This work provides a facile and effective strategy to enhance the PCE and stability of PSCs simultaneously, facilitating the commercialization of PSCs.
基金financially supported by the National Natural Science Foundation of China(Nos.52102117,51173170,and 21773216)the joint project from the Henan-Provincial and the China-National Natural Science Foundations(No.U2004208)Key Science and Technology Program of Henan Province(No.202102310212)
文摘Organic redox compounds are attractive cathode materials in aqueous zinc-ion batteries owing to their low cost,environmental friendliness,multiple-electron-transfer reactions,and resource sustainability.However,the realized energy density is constrained by the limited capacity and low voltage.Herein,copper-tetracyanoquinodimethane(CuTCNQ),an organic charge-transfer complex is evaluated as a zinc-ion battery cathode owing to the good electron acceptation ability in the cyano groups that improves the voltage output.Through electrochemical activation,electrolyte optimization,and adoption of graphene-based separator,CuTCNQ-based aqueous zinc-ion batteries deliver much improved rate performance and cycling stability with anti-self-discharge properties.The structural evolution of CuTCNQ during discharge/charge are investigated by ex situ Fourier transform infra-red(FT-IR)spectra,ex situ X-ray photoelectron spectroscopy(XPS),and in situ ultraviolet visible spectroscopy(UV-vis),revealing reversible redox reactions in both cuprous cations(Cu^(+))and organic anions(TCNQ^(x-1)),thus delivering a high voltage output of 1.0 V and excellent discharge capacity of 158 mAh g^(-1).The remarkable electrochemical performance in Zn//CuTCNQ is ascribed to the strong inductive effect of cyano groups in CuTCNQ that elevated the voltage output and the graphene-modified separator that inhibited CuTCNQ dissolution and shuttle effect in aqueous electrolytes.
