A novel method for synthesis of substituted u-oxo-bis[tetraphenyl porphyrinatoiron] compotmds ([TRPPFe]20) based on the reaction among free base porphyrins (TRPPH2), FeSO4·7H2O and H2O in one pot was proposed...A novel method for synthesis of substituted u-oxo-bis[tetraphenyl porphyrinatoiron] compotmds ([TRPPFe]20) based on the reaction among free base porphyrins (TRPPH2), FeSO4·7H2O and H2O in one pot was proposed and investigated. Four kinds of [TRPPFe]2O were synthesized by this novel synthetic method, and their structures were characterized by elemental analysis, infrared spectra and UV-vis spectroscopy. The reaction conditions, including the effect of different iron salts on the formation of [TRPPFe]2O, the reaction time between FeSO4-7H2O and TRPPH2, the molar ratio of FeSO4-7H2O/TRPPH2 as well as the volume ratio of H2O/DMF, were investigated. The [TRPPFe]2O yield of 93% 98% could be obtained under the following optimal conditions: the reaction time of FeSOn-7H2O with TRPPH2 was about 10 h, the molar ratio of FeSOn-7H2O/TRPPH2 about 5 : 1, and the volume ratio of H2O/DMF exceeded 2 : 1. Further research indicated that only TRPPFeCI were formed once FeSOn-7H2O was replaced by FeCl2-4H2O, the reason of which might be that halogen ions in iron salts interfered the formation of [TRPPFe]2O, suggesting that halogen ions should be avoided in this novel synthetic method.展开更多
A Convenient method for the synthesis of fused phosphorusheterocycle 1,3,2-oxazaphosphorin-[3.2-a]-8-oxo-10-thio(or seleno)-[1,3,2]-benzodiazaphosphorines was carried out in one pot by the reaction of Tris(diethylamin...A Convenient method for the synthesis of fused phosphorusheterocycle 1,3,2-oxazaphosphorin-[3.2-a]-8-oxo-10-thio(or seleno)-[1,3,2]-benzodiazaphosphorines was carried out in one pot by the reaction of Tris(diethylamino)phosphine with multifunctional compounds 2-(N-(beta or gamma-hydroxyl) alkylene) amino-benzamides 1. When PCL3 was used, only chlorinated product was obtained.展开更多
The adsorption of CO_(2) on MgAl layered double hydroxides(MgAl-LDHs) based adsorbents has been an effective way to capture CO_(2),however the adsorption capacity was hampered due to the pore structure and the dispers...The adsorption of CO_(2) on MgAl layered double hydroxides(MgAl-LDHs) based adsorbents has been an effective way to capture CO_(2),however the adsorption capacity was hampered due to the pore structure and the dispersibility of adsorption active sites.To address the problem,we investigate the effect of intercalated anion and alkaline etching time on the structure,morphology and CO_(2) uptake performances of MgAl-LDHs.MgAl-LDHs are synthesized by the onepot hydrothermal method,followed by alkaline etching of NaOH,and characterized by x-ray diffraction,N_(2) adsorption,scanning electron microscopy and Fourier transform infrared spectroscopy.The CO_(2) adsorption tests of the samples are performed on a thermogravimetric analyzer,and the adsorption data are fitted by the first-order,pseudo-second-order and Elovich models,respectively.The results demonstrate that among the three intercalated samples,MgAl(Cl) using chloride salts as precursors possesses the highest adsorption capacity of CO_(2),owing to high crystallinity and porous structure,while MgAl(Ac) employing acetate salts as precursors displays the lowest CO_(2) uptake because of poor crystallinity,disorderly stacked structure and unsatisfactory pore structure.With regard to alkaline etching,the surface of the treated MgAl(Cl) is partly corroded,thus the specific surface area and pore volume increase,which is conducive to the exposure of adsorption active sites.Correspondingly,the adsorption performance of the alkaline-etched adsorbents is significantly improved,and MgAl(Cl)-6 has the highest CO_(2) uptake.With the alkaline etching time further increasing,the CO_(2) adsorption capacity of MgAl(Cl)-9 sharply decreases,mainly due to the collapse of pore structure and the fragmentized sheet-structure.Hence,the CO_(2) adsorption performance is greatly influenced by alkaline etching time,and appropriate alkaline etching time can facilitate the contact between CO_(2) molecules and the adsorbent.展开更多
The construction of heterojunction photocatalysts for efficiently utilizing solar energy has attracted considerable attention to solve the energy crisis and reduce environmental pollution.In this study,we use the ener...The construction of heterojunction photocatalysts for efficiently utilizing solar energy has attracted considerable attention to solve the energy crisis and reduce environmental pollution.In this study,we use the energy released from an easily-occurred exothermic chemical reaction to serve as the drive force to trigger the formation of Cd S and C_(3)N_(4) nanocomposites which are successfully fabricated with cadmium nitrate and thiourea without addition of any solvents and protection of inert gas at initial temperature,a little higher than the melting point of thiourea.The as-prepared Cd S/C_(3)N_(4) materials exhibit high efficiency for photocatalytic hydrogen evolution reaction(HER)with the HER rate as high as 15,866μmol/(g·hr)under visible light irradiation(λ>420 nm),which is 89 and 9 times those of pristine C_(3)N_(4) and Cd S,respectively.Also,the apparent quantum efficiency(AQE)of Cd S/C_(3)N_(4)–1:2–200–2(Cd S/C_(3)N_(4)–1:2–200–2 means the ratio of Cd to S is 1:2 and the reaction temperature is set at 200℃ for two hours)reaches 3.25%atλ=420±15 nm.After irradiated for more than 24 hr,the HER efficiencies of Cd S/C_(3)N_(4) do not exhibit any attenuation.The DFT calculation suggests that the charge difference causes an internal electric field from C_(3)N_(4) pointing to Cd S,which can more effectively promote the transfer of photogenerated electrons from Cd S to C_(3)N_(4).Therefore,most HER should occur on C_(3)N_(4) surface where photogenerated electrons accumulate,which largely protects Cd S from photo-corrosion.展开更多
A convenient synthesis of 1-alkyl-2-chloro-1H-indole-3-carbaldehyde oximes(5a―5d) and 1-alkyl-2-phenoxy-1H-indole-3-carbaldehyde oximes(6a―6d) from 2-indolone was completed via the Vilsmeier-Haack reac-tion,with...A convenient synthesis of 1-alkyl-2-chloro-1H-indole-3-carbaldehyde oximes(5a―5d) and 1-alkyl-2-phenoxy-1H-indole-3-carbaldehyde oximes(6a―6d) from 2-indolone was completed via the Vilsmeier-Haack reac-tion,with N-alkylation and oximation as the key steps.An improved one-pot method for the synthesis of 1-alkyl-2-alkoxy-1H-indole-3-carbaldehyde oximes(7a―7h) from 1-alkyl-2-chloro-1H-indole-3-carbaldehydes(3a―3d) was described.The Williamson reactions and esterification reactions were performed and the oxime-ethers and oxime-esters were synthesized,respectively.The new synthesized compounds(3a―11d) were characterized by 1H NMR,IR,MS,and elemental analysis.展开更多
Since the utilization of abundant biomass to develop advanced materials has become an utmost priority in recent years,we developed two sustainable routes(i.e.,the impregnation method and the one-pot synthesis)to prepa...Since the utilization of abundant biomass to develop advanced materials has become an utmost priority in recent years,we developed two sustainable routes(i.e.,the impregnation method and the one-pot synthesis)to prepare the hydrochar-supported catalysts and tested its catalytic performance on the reductive amination.Several techniques,such as TEM,XRD and XPS,were adopted to characterize the structural and catalytic features of samples.Results indicated that the impregnation method favors the formation of outer-sphere surface complexes with porous structure as well as well-distributed metallic nanoparticles,while the one-pot synthesis tends to form the inner-sphere surface complexes with relatively smooth appearance and amorphous metals.This difference explains the better activity of catalysts prepared by the impregnation method which can selectively convert benzaldehyde to benzylamine with an excellent yield of 93.7%under the optimal reaction conditions;in contrast,the catalyst prepared by the one-pot synthesis only exhibits a low selectivity near to zero.Furthermore,the gram-scale test catalyzed by the same catalysts exhibits a similar yield of benzylamine in comparison to its smaller scale,which is comparable to the previously reported heterogeneous noble-based catalysts.More surprisingly,the prepared catalysts can be expediently recycled by a magnetic bar and remain the satisfying catalytic activity after reusing up to five times.In conclusion,these developed catalysts enable the synthesis of functional amines with excellent selectivity and carbon balance,proving cost-effective and sustainable access to the wide application of reductive amination.展开更多
A simple one-pot non-isocyanate route for synthesizing thermoplastic polyureas is presented. In situ urethanization was conducted from the ring-opening reaction of ethylene carbonate with poly(propylene glycol) bis(2-...A simple one-pot non-isocyanate route for synthesizing thermoplastic polyureas is presented. In situ urethanization was conducted from the ring-opening reaction of ethylene carbonate with poly(propylene glycol) bis(2-aminopropyl ether) and hexanediamine,m-xylylenediamine, or diethylene glycol bis(3-aminopropyl) ether at 100 °C for 6 h under normal pressure. Melt transurethane polycondensation was successively conducted at 170 °C under a reduced pressure of 399 Pa for different time periods. A series of nonisocyanate thermoplastic polyureas(NI-TPUreas) were prepared. The NI-TPUreas were characterized by gel permeation chromatography,FTIR, 1 H-NMR, differential scanning calorimetry, thermogravimetric analysis, wide-angle X-ray diffraction, atomic force microscopy,and tensile test. NI-TPUreas exhibited Mn of up to 1.67 × 104 g/mol, initial decomposition temperature over 290 °C, and tensile strength of up to 32 MPa. Several crystallizable NI-TPUreas exhibited Tm exceeding 98 °C. NI-TPUreas with good thermal and mechanical properties were prepared through a green and simple one-pot non-isocyanate route.展开更多
Collective syntheses of A.baumannii CPS K43,K47 and K88 repeating units have been accomplished via a newα-glycosylation method with GlcN_(3) as donors,which features:1)mild reaction conditions,2)good to high yields,3...Collective syntheses of A.baumannii CPS K43,K47 and K88 repeating units have been accomplished via a newα-glycosylation method with GlcN_(3) as donors,which features:1)mild reaction conditions,2)good to high yields,3)excellent stereoselectivities.The synthetic route also highlights an orthogonal one-pot coupling strategy on the basis of glycosyl ortho-(1-phenylvinyl)benzoates for stereoselective constructions of both 1,2-trans and 1,2-cis glycosidic bonds,precluding the issues of aglycone transfer.展开更多
Main observation and conclusion Selenoesters are useful substitutes for traditional thioesters in protein ligation chemistry due to their high reactivity in the trans-thio/selenoesterification reaction.However,existin...Main observation and conclusion Selenoesters are useful substitutes for traditional thioesters in protein ligation chemistry due to their high reactivity in the trans-thio/selenoesterification reaction.However,existing synthetic routes to access peptide selenoester require a selenoesterification reaction between a selenide and a protected peptide with a free carboxylate at the C-terminus.展开更多
An efficient and simple procedure was developed for the green synthesis of various 2-aryl-l-ben- zylated-1H-benzimidazoles in high yields by condensation of o-phenylenediamine with aldehydes with P2O5/SiO2 as catalyst...An efficient and simple procedure was developed for the green synthesis of various 2-aryl-l-ben- zylated-1H-benzimidazoles in high yields by condensation of o-phenylenediamine with aldehydes with P2O5/SiO2 as catalyst under solvent-free and ambient conditions.展开更多
Constructing“nanoglue”between inorganic electroactive species and conductive carbon scaffolds is an effective strategy to improve their compatibility and binding interaction,holding a great promise for fabricating h...Constructing“nanoglue”between inorganic electroactive species and conductive carbon scaffolds is an effective strategy to improve their compatibility and binding interaction,holding a great promise for fabricating high-performance hybrid electrodes for supercapacitors.However,multistep reactions are usually required to obtain these multicomponent systems,thus giving rise to the complicated and time-consuming issues.Herein,we for the first time,demonstrate a green one-pot method to anchor coaxial double-layer MnO_(2)/Ni(OH)_(2)nanosheets on electrospun carbon nanofibers(CNFs)(denoted as MNC),where the intermediate MnO_(2)layer serves as the“nanoglue”to couple the vertically aligned Ni(OH)_(2)nanosheets and conductive CNFs.Benefiting from the unique chemical composition and hierarchical architecture,the resultant electrode delivers outstanding electrochemical performance,including an excellent specific capacitance(1133.3 F g^(-1)at 1 A g^(-1))and an ultrahigh rate capability(844.4 F g^(-1)at 20 A g^(-1)).Moreover,the asymmetric supercapacitor assembled by using the MNC as positive electrode and the CNF as negative electrode can achieve an optimal energy density of 35.1 Wh kg^(-1)and a maximum power density of 8000 W kg^(-1).The one-pot strategy that stabilizes electroactive metal hydroxides on conductive carbons using a MnO_(2)“nanoglue”to design advanced hybrid electrodes is expected to be broadly applicable not only to the supercapacitor technology but also to other electrochemical applications.展开更多
We report a synthetic design and the experimental exploration of preparation of disubstituted polyacetylenes (PAs, P3) through 1,3-dipolar cycloaddition of azides with precursor PA bearing alkyne pendants. The precu...We report a synthetic design and the experimental exploration of preparation of disubstituted polyacetylenes (PAs, P3) through 1,3-dipolar cycloaddition of azides with precursor PA bearing alkyne pendants. The precursor PA (P2) was derived by desilylation of the pristine PA with trimethylethynylsilane side chains (P1). P1 was obtained by polymerization of a dual-alkyne containing monomer with one of the alkynes end-capping by trimethylsilane (M) under the promotion of WC16-Ph4Sn catalyst. Two synthetic routes, i.e. two-steps (from P1 to P3 via precursor P2) and one-pot (from P1 to P3 without separation and purification of P2) were tried and the results indicated that one-pot strategy is more facile and resultant P3-1 showed higher purity and higher molecular weight than the resultant of P3-2. By using the techniques such as GPC, FTIR and 1H NMR spectroscopy the polymerization behavior and the structures of the polymers were well characterized.展开更多
A sequential one-pot synthesis of N-sulfonylcyclothioureas from N-monosulfonyl diamines, CS2 and chloroace- tic acid at room temperature in water is described. In the absence of highly toxic thiophosgene and organic s...A sequential one-pot synthesis of N-sulfonylcyclothioureas from N-monosulfonyl diamines, CS2 and chloroace- tic acid at room temperature in water is described. In the absence of highly toxic thiophosgene and organic solvents, this method is environmentally benign. Simple reaction conditions, easy purification of the products, good yields and thioglycolic acid as the useful byproduct are also important attributes of this methodology. The plausible mechanism including tandem reactions is proposed.展开更多
基金Supported by the National Natural Science Foundation of China (20776003, 20576005) and the Key Project of Natural Science Foundation of Beijing (2061001).
文摘A novel method for synthesis of substituted u-oxo-bis[tetraphenyl porphyrinatoiron] compotmds ([TRPPFe]20) based on the reaction among free base porphyrins (TRPPH2), FeSO4·7H2O and H2O in one pot was proposed and investigated. Four kinds of [TRPPFe]2O were synthesized by this novel synthetic method, and their structures were characterized by elemental analysis, infrared spectra and UV-vis spectroscopy. The reaction conditions, including the effect of different iron salts on the formation of [TRPPFe]2O, the reaction time between FeSO4-7H2O and TRPPH2, the molar ratio of FeSO4-7H2O/TRPPH2 as well as the volume ratio of H2O/DMF, were investigated. The [TRPPFe]2O yield of 93% 98% could be obtained under the following optimal conditions: the reaction time of FeSOn-7H2O with TRPPH2 was about 10 h, the molar ratio of FeSOn-7H2O/TRPPH2 about 5 : 1, and the volume ratio of H2O/DMF exceeded 2 : 1. Further research indicated that only TRPPFeCI were formed once FeSOn-7H2O was replaced by FeCl2-4H2O, the reason of which might be that halogen ions in iron salts interfered the formation of [TRPPFe]2O, suggesting that halogen ions should be avoided in this novel synthetic method.
文摘A Convenient method for the synthesis of fused phosphorusheterocycle 1,3,2-oxazaphosphorin-[3.2-a]-8-oxo-10-thio(or seleno)-[1,3,2]-benzodiazaphosphorines was carried out in one pot by the reaction of Tris(diethylamino)phosphine with multifunctional compounds 2-(N-(beta or gamma-hydroxyl) alkylene) amino-benzamides 1. When PCL3 was used, only chlorinated product was obtained.
基金Project supported by the National Natural Science Foundation of China(Grant No.21606058)the Natural Science Foundation of Guangxi,China(Grant Nos.2017GXNSFBA198193 and 2017GXNSFBA198124)the Startup Foundation for Doctors of Guilin University of Technology(Grant No.GLUTQD2015008)。
文摘The adsorption of CO_(2) on MgAl layered double hydroxides(MgAl-LDHs) based adsorbents has been an effective way to capture CO_(2),however the adsorption capacity was hampered due to the pore structure and the dispersibility of adsorption active sites.To address the problem,we investigate the effect of intercalated anion and alkaline etching time on the structure,morphology and CO_(2) uptake performances of MgAl-LDHs.MgAl-LDHs are synthesized by the onepot hydrothermal method,followed by alkaline etching of NaOH,and characterized by x-ray diffraction,N_(2) adsorption,scanning electron microscopy and Fourier transform infrared spectroscopy.The CO_(2) adsorption tests of the samples are performed on a thermogravimetric analyzer,and the adsorption data are fitted by the first-order,pseudo-second-order and Elovich models,respectively.The results demonstrate that among the three intercalated samples,MgAl(Cl) using chloride salts as precursors possesses the highest adsorption capacity of CO_(2),owing to high crystallinity and porous structure,while MgAl(Ac) employing acetate salts as precursors displays the lowest CO_(2) uptake because of poor crystallinity,disorderly stacked structure and unsatisfactory pore structure.With regard to alkaline etching,the surface of the treated MgAl(Cl) is partly corroded,thus the specific surface area and pore volume increase,which is conducive to the exposure of adsorption active sites.Correspondingly,the adsorption performance of the alkaline-etched adsorbents is significantly improved,and MgAl(Cl)-6 has the highest CO_(2) uptake.With the alkaline etching time further increasing,the CO_(2) adsorption capacity of MgAl(Cl)-9 sharply decreases,mainly due to the collapse of pore structure and the fragmentized sheet-structure.Hence,the CO_(2) adsorption performance is greatly influenced by alkaline etching time,and appropriate alkaline etching time can facilitate the contact between CO_(2) molecules and the adsorbent.
基金supported by National Key Research and Development Program of China(No.2016YFA0203100)the National Natural Science Foundation of China(Nos.21537004,21777169,and 21621064)the Beijing Municipal Natural Science Foundation(No.8202046)。
文摘The construction of heterojunction photocatalysts for efficiently utilizing solar energy has attracted considerable attention to solve the energy crisis and reduce environmental pollution.In this study,we use the energy released from an easily-occurred exothermic chemical reaction to serve as the drive force to trigger the formation of Cd S and C_(3)N_(4) nanocomposites which are successfully fabricated with cadmium nitrate and thiourea without addition of any solvents and protection of inert gas at initial temperature,a little higher than the melting point of thiourea.The as-prepared Cd S/C_(3)N_(4) materials exhibit high efficiency for photocatalytic hydrogen evolution reaction(HER)with the HER rate as high as 15,866μmol/(g·hr)under visible light irradiation(λ>420 nm),which is 89 and 9 times those of pristine C_(3)N_(4) and Cd S,respectively.Also,the apparent quantum efficiency(AQE)of Cd S/C_(3)N_(4)–1:2–200–2(Cd S/C_(3)N_(4)–1:2–200–2 means the ratio of Cd to S is 1:2 and the reaction temperature is set at 200℃ for two hours)reaches 3.25%atλ=420±15 nm.After irradiated for more than 24 hr,the HER efficiencies of Cd S/C_(3)N_(4) do not exhibit any attenuation.The DFT calculation suggests that the charge difference causes an internal electric field from C_(3)N_(4) pointing to Cd S,which can more effectively promote the transfer of photogenerated electrons from Cd S to C_(3)N_(4).Therefore,most HER should occur on C_(3)N_(4) surface where photogenerated electrons accumulate,which largely protects Cd S from photo-corrosion.
基金Supported by the Natural Science Foundation of Liaoning Province,China(No.202142037)
文摘A convenient synthesis of 1-alkyl-2-chloro-1H-indole-3-carbaldehyde oximes(5a―5d) and 1-alkyl-2-phenoxy-1H-indole-3-carbaldehyde oximes(6a―6d) from 2-indolone was completed via the Vilsmeier-Haack reac-tion,with N-alkylation and oximation as the key steps.An improved one-pot method for the synthesis of 1-alkyl-2-alkoxy-1H-indole-3-carbaldehyde oximes(7a―7h) from 1-alkyl-2-chloro-1H-indole-3-carbaldehydes(3a―3d) was described.The Williamson reactions and esterification reactions were performed and the oxime-ethers and oxime-esters were synthesized,respectively.The new synthesized compounds(3a―11d) were characterized by 1H NMR,IR,MS,and elemental analysis.
基金This work was supported financially by the National Key R&D Program of China(2018YFB1501500)National Natural Science Foundation of China(51976225).
文摘Since the utilization of abundant biomass to develop advanced materials has become an utmost priority in recent years,we developed two sustainable routes(i.e.,the impregnation method and the one-pot synthesis)to prepare the hydrochar-supported catalysts and tested its catalytic performance on the reductive amination.Several techniques,such as TEM,XRD and XPS,were adopted to characterize the structural and catalytic features of samples.Results indicated that the impregnation method favors the formation of outer-sphere surface complexes with porous structure as well as well-distributed metallic nanoparticles,while the one-pot synthesis tends to form the inner-sphere surface complexes with relatively smooth appearance and amorphous metals.This difference explains the better activity of catalysts prepared by the impregnation method which can selectively convert benzaldehyde to benzylamine with an excellent yield of 93.7%under the optimal reaction conditions;in contrast,the catalyst prepared by the one-pot synthesis only exhibits a low selectivity near to zero.Furthermore,the gram-scale test catalyzed by the same catalysts exhibits a similar yield of benzylamine in comparison to its smaller scale,which is comparable to the previously reported heterogeneous noble-based catalysts.More surprisingly,the prepared catalysts can be expediently recycled by a magnetic bar and remain the satisfying catalytic activity after reusing up to five times.In conclusion,these developed catalysts enable the synthesis of functional amines with excellent selectivity and carbon balance,proving cost-effective and sustainable access to the wide application of reductive amination.
基金financially supported by the National Natural Science Foundation of China (No. 21244006)Beijing Natural Science Foundation (No. 2182056)
文摘A simple one-pot non-isocyanate route for synthesizing thermoplastic polyureas is presented. In situ urethanization was conducted from the ring-opening reaction of ethylene carbonate with poly(propylene glycol) bis(2-aminopropyl ether) and hexanediamine,m-xylylenediamine, or diethylene glycol bis(3-aminopropyl) ether at 100 °C for 6 h under normal pressure. Melt transurethane polycondensation was successively conducted at 170 °C under a reduced pressure of 399 Pa for different time periods. A series of nonisocyanate thermoplastic polyureas(NI-TPUreas) were prepared. The NI-TPUreas were characterized by gel permeation chromatography,FTIR, 1 H-NMR, differential scanning calorimetry, thermogravimetric analysis, wide-angle X-ray diffraction, atomic force microscopy,and tensile test. NI-TPUreas exhibited Mn of up to 1.67 × 104 g/mol, initial decomposition temperature over 290 °C, and tensile strength of up to 32 MPa. Several crystallizable NI-TPUreas exhibited Tm exceeding 98 °C. NI-TPUreas with good thermal and mechanical properties were prepared through a green and simple one-pot non-isocyanate route.
基金supports from National Natural Science Foundation of China(22322110)the CAS Pioneer Hundred Talents Program(No.2017-128)+1 种基金Yunnan Province Science and Technology Department(202305AH340005)the Young Talents Project of High-level Talent Introduction Program of Yunnan Province are greatly acknowledged。
文摘Collective syntheses of A.baumannii CPS K43,K47 and K88 repeating units have been accomplished via a newα-glycosylation method with GlcN_(3) as donors,which features:1)mild reaction conditions,2)good to high yields,3)excellent stereoselectivities.The synthetic route also highlights an orthogonal one-pot coupling strategy on the basis of glycosyl ortho-(1-phenylvinyl)benzoates for stereoselective constructions of both 1,2-trans and 1,2-cis glycosidic bonds,precluding the issues of aglycone transfer.
基金Financial support for this work was gratefully received from the National Natural Science Foundation of China(Nos.22077080,21907064 and 91753102)the Interdisciplinary Program of Shanghai Jiao Tong University(No.YG2020YQ14).
文摘Main observation and conclusion Selenoesters are useful substitutes for traditional thioesters in protein ligation chemistry due to their high reactivity in the trans-thio/selenoesterification reaction.However,existing synthetic routes to access peptide selenoester require a selenoesterification reaction between a selenide and a protected peptide with a free carboxylate at the C-terminus.
文摘An efficient and simple procedure was developed for the green synthesis of various 2-aryl-l-ben- zylated-1H-benzimidazoles in high yields by condensation of o-phenylenediamine with aldehydes with P2O5/SiO2 as catalyst under solvent-free and ambient conditions.
基金supported by the research grants from National Natural Science Foundation of China(52103057)Natural Science Foundation of Shandong Province,China(ZR2019BEM001)China Postdoctoral Science Foundation(2018M630745).
文摘Constructing“nanoglue”between inorganic electroactive species and conductive carbon scaffolds is an effective strategy to improve their compatibility and binding interaction,holding a great promise for fabricating high-performance hybrid electrodes for supercapacitors.However,multistep reactions are usually required to obtain these multicomponent systems,thus giving rise to the complicated and time-consuming issues.Herein,we for the first time,demonstrate a green one-pot method to anchor coaxial double-layer MnO_(2)/Ni(OH)_(2)nanosheets on electrospun carbon nanofibers(CNFs)(denoted as MNC),where the intermediate MnO_(2)layer serves as the“nanoglue”to couple the vertically aligned Ni(OH)_(2)nanosheets and conductive CNFs.Benefiting from the unique chemical composition and hierarchical architecture,the resultant electrode delivers outstanding electrochemical performance,including an excellent specific capacitance(1133.3 F g^(-1)at 1 A g^(-1))and an ultrahigh rate capability(844.4 F g^(-1)at 20 A g^(-1)).Moreover,the asymmetric supercapacitor assembled by using the MNC as positive electrode and the CNF as negative electrode can achieve an optimal energy density of 35.1 Wh kg^(-1)and a maximum power density of 8000 W kg^(-1).The one-pot strategy that stabilizes electroactive metal hydroxides on conductive carbons using a MnO_(2)“nanoglue”to design advanced hybrid electrodes is expected to be broadly applicable not only to the supercapacitor technology but also to other electrochemical applications.
基金partially supported by the National Natural Science Foundation of China (21074113,20634020 & 20974028)the National Basic Research Program of China (973 Program,2009CB623605)+1 种基金the Research Grants Council of Hong Kong (603509 & HKUST2/CRF/10)the University Grants Committee of Hong Kong (AoE/P-03/08)
文摘We report a synthetic design and the experimental exploration of preparation of disubstituted polyacetylenes (PAs, P3) through 1,3-dipolar cycloaddition of azides with precursor PA bearing alkyne pendants. The precursor PA (P2) was derived by desilylation of the pristine PA with trimethylethynylsilane side chains (P1). P1 was obtained by polymerization of a dual-alkyne containing monomer with one of the alkynes end-capping by trimethylsilane (M) under the promotion of WC16-Ph4Sn catalyst. Two synthetic routes, i.e. two-steps (from P1 to P3 via precursor P2) and one-pot (from P1 to P3 without separation and purification of P2) were tried and the results indicated that one-pot strategy is more facile and resultant P3-1 showed higher purity and higher molecular weight than the resultant of P3-2. By using the techniques such as GPC, FTIR and 1H NMR spectroscopy the polymerization behavior and the structures of the polymers were well characterized.
基金Project supported by the National Natural Science Foundation of China (No. 20802049).
文摘A sequential one-pot synthesis of N-sulfonylcyclothioureas from N-monosulfonyl diamines, CS2 and chloroace- tic acid at room temperature in water is described. In the absence of highly toxic thiophosgene and organic solvents, this method is environmentally benign. Simple reaction conditions, easy purification of the products, good yields and thioglycolic acid as the useful byproduct are also important attributes of this methodology. The plausible mechanism including tandem reactions is proposed.