We have developed a new method to grow uniform graphene films directly on various substrates, such as insulators, semiconductors, and even metals, without using any catalyst. The growth was carried out using a remote ...We have developed a new method to grow uniform graphene films directly on various substrates, such as insulators, semiconductors, and even metals, without using any catalyst. The growth was carried out using a remote plasma enhancement chemical vapor deposition （r-PECVD） system at relatively low temperatures, enabling the deposition of graphene films up to 4-inch wafer scale. Scanning tunneling microscopy （STM） confirmed that the films are made up of nanocrystalline graphene particles of tens of nanometers in lateral size. The growth mechanism for the nanographene is analogous to that for diamond grown by PECVD methods, in spite of sp2 carbon atoms being formed in the case of graphene rather than sp3 carbon atoms as in diamond. This growth approach is simple, low-cost, and scalable, and might have potential applications in fields such as thin film resistors, gas sensors, electrode materials, and transparent conductive films.展开更多
The organic compound 2,5-furandicarboxylic acid（FDCA） has been identified by the US Department of Energy（DOE） as a valuable platform chemical for a wide range of industrial applications. Currently, the most popula...The organic compound 2,5-furandicarboxylic acid（FDCA） has been identified by the US Department of Energy（DOE） as a valuable platform chemical for a wide range of industrial applications. Currently, the most popular route for FDCA synthesis is reported to be the oxidation of 5-hydroxymethylfurfural（HMF）by O_2 over the catalysis of noble metals（e.g., Au, Pt, Ru, and Pd）. However, the high costs of noble metal catalysts remain a major barrier for producing FDCA at an industrial scale. Herein, we report a transition metal-free synthesis strategy for the oxidation of HMF to FDCA under O_2 or ambient air. A simple but unprecedented process for the aerobic oxidation of HMF was carried out in organic solvents using only bases as the promoters. According to the high performance liquid chromatography（HPLC） analysis, excellent product yield（91%） was obtained in the presence of NaOH in dimethylformamide（DMF） at room temperature（25 ℃）. A plausible mechanism for the NaOH-promoted aerobic oxidation of HMF in DMF is also outlined in this paper. After the reaction, the sodium salt of FDCA particles were dispersed in the reaction mixture, making it possible for product separation and solvent reuse. The new HMF oxidation approach is expected to be a practical alternative to current ones, which depend on the use of noble metal catalysts.展开更多
A series of AIN nanostructures were synthesized by an ultrahigh-temperature, catalyst-free, physical vapor transport（PVT） process. Energy dispersive X-ray spectroscopy（EDX）, X-ray diffraction（XRD）, X-Ray photoel...A series of AIN nanostructures were synthesized by an ultrahigh-temperature, catalyst-free, physical vapor transport（PVT） process. Energy dispersive X-ray spectroscopy（EDX）, X-ray diffraction（XRD）, X-Ray photoelectron spectroscopy（XPS）,high resolution transmission electron microscopy（HRTEM） detection show that high quality AIN nanowires were prepared. Nanostructures including nanorings, nanosprings, nanohelices, chainlike nanowires, six-fold symmetric nanostructure and rod-like structure were successfully obtained by controlling the growth duration and temperature. The morphology evolution was attributed to electrostatic polar charge model and the crystalline lattice structure of AIN.展开更多
The importance of CF3-containing molecules in pharmaceuticals, agrochemicals and materials intrigues the intense interest in synthetic methodology of these compounds. With a purpose to enrich trifluoromethylation meth...The importance of CF3-containing molecules in pharmaceuticals, agrochemicals and materials intrigues the intense interest in synthetic methodology of these compounds. With a purpose to enrich trifluoromethylation methodology, we carefully examined the substrate scope of hydroxytrifluoromethylation of alkenes using iodotrifluoromethane, and the reaction provided β-trifluoromethyl alcohols in good yields under extremely mild conditions without catalysts. We found that our reaction can be applied to not only styrenes but also various aliphatic alkenes with excellent selectivity;no ketone was detected in most of our cases. Another feature of our discovery is “simple”. The reaction was carried out in air, irradiated by visible light, at room temperature and most importantly no catalyst was needed. A solution of CF3I in DMSO was used as the facile trifluoromethylating reagent, which simplified the utilization of gaseous CF3I. Based on 19F NMR spectroscopy, we observed a halogen bond between CF3I and tertiary amine in this reaction. The interaction may promote single electron transfer by the visible light irradiation.展开更多
Herein,an electrochemically driven catalyst-free nucleophilic aromatic substitution(S_(N)Ar)of electron-rich fluoroarenes with carboxylic acids as weak nucleophiles under mild conditions was reported.A series of highl...Herein,an electrochemically driven catalyst-free nucleophilic aromatic substitution(S_(N)Ar)of electron-rich fluoroarenes with carboxylic acids as weak nucleophiles under mild conditions was reported.A series of highly valuable ester derivatives were obtained in a direct and rapid way.This transformation features commercially available reagents and an exceptionally broad substrate scope with good functional group tolerance,using cheap and abundant electrodes and completed within a short reaction time.Gram-scale synthesis and complex biorelevant compounds ligation further highlighted the potential utility of the methodology.The mechanistic investigations and density functional theory(DFT)calculations verified the feasibility of the proposed pathway of this transformation.展开更多
A catalyst-free and atom-economical[4+3]cycloaddition of azadienes with C,N-cyclic azomethine imines has been developed,providing an efficient and environmentally benign access to 1,2,4-triazepines with high diastereo...A catalyst-free and atom-economical[4+3]cycloaddition of azadienes with C,N-cyclic azomethine imines has been developed,providing an efficient and environmentally benign access to 1,2,4-triazepines with high diastereoselectivities and yields.This reaction can be performed in 2-methyltetrahydrofuran under mild conditions smoothly.展开更多
A selective protocol for the synthesis of either a-ketoamides or quinoxaline derivatives under the same reaction conditions has been achieved simply by varying substitution number of amino-groups. The method features ...A selective protocol for the synthesis of either a-ketoamides or quinoxaline derivatives under the same reaction conditions has been achieved simply by varying substitution number of amino-groups. The method features metal-free, room temperature and broad substrate scopes as well as no extra oxidant.This process applies to various substituent groups and gives products in moderate to good yield. Finally, a rational mechanism was proposed.展开更多
A facile procedure for the synthesis of 2,4,5-lriarylimidazoles is being reported starting from benzil, aromatic aldehyde and ammonium acetate. The reactions were carried out with catalyst-free, solvent-free and under...A facile procedure for the synthesis of 2,4,5-lriarylimidazoles is being reported starting from benzil, aromatic aldehyde and ammonium acetate. The reactions were carried out with catalyst-free, solvent-free and under microwave irradiation conditions in high yield （80-99%） with short time （3-5 min） and environmental benign, as well as convenient operation. The structures of the compounds have been confirmed on the basis of their IR, 1H NMR, and/or 13C NMR, MS, and elemental analyzer.展开更多
The copper-catalyzed and metal-free azide-alkyne click polymerizations have become efficient tools for polymer synthesis. However,the 1,3-dipolar polycycloadditions between internal alkynes and azides are rarely emplo...The copper-catalyzed and metal-free azide-alkyne click polymerizations have become efficient tools for polymer synthesis. However,the 1,3-dipolar polycycloadditions between internal alkynes and azides are rarely employed to construct functional polymers. Herein, the polycycloadditions of dibutynoate(1) and tetraphenylethene-containing diazides(2) were carried out at 100 °C for 12 h under solvent-and catalyst-free conditions, producing soluble poly(methyltriazolylcarboxylate)s(PMTCs) with high molecular weights in high yields. The resultant polymers were thermally stable with 5% weight loss temperatures up to 377 °C. The PMTCs showed aggregation-induced emission(AIE)properties. They could work as fluorescent sensors for detecting explosive with high sensitivity, and generate two-dimensional fluorescent photopatterns with high resolution. Furthermore, their triazolium salts could be utilized for cell-imaging applications.展开更多
Because imines could be used as convenient starting materials in various fields, the development of an easy synthetic method of imine was strongly desired. In response to this demand, we thought that it would be an ef...Because imines could be used as convenient starting materials in various fields, the development of an easy synthetic method of imine was strongly desired. In response to this demand, we thought that it would be an effective synthesis method if an aldehyde and an amine could be reacted to give an imine in good yield under solvent- and catalyst-free conditions. In fact, we tried the reaction of benzaldehyde with various amines under solvent- and catalyst-free conditions followed by removal of water that was produced in the reaction system by a vacuum pump, and desired imines could be obtained in good yields. Observation of this reaction using a nuclear magnetic resonance spectrometer revealed that the reaction rate was extremely fast at the initial stage but slowed over time. However, the reaction of benzaldehyde with aniline differed greatly, and the reaction rate dramatically improved in 47 - 48 minutes after the start of the reaction. At this time, we found that the reaction system underwent a phase transition from the liquid phase to the solid phase.展开更多
An efficient, atom-economic and green approach to synthesizing enamines was developed by intermolecular hydroamination of activated alkynes with high yields under catalyst- and solvent-free conditions. β-Dimethylamin...An efficient, atom-economic and green approach to synthesizing enamines was developed by intermolecular hydroamination of activated alkynes with high yields under catalyst- and solvent-free conditions. β-Dimethylamino-acrylate derivatives were also obtained with high yields. In the synthetic process of the derivatives, N,N-dimethylformamide（DMF） pretreated with metal Na, was used as reactant instead of dimethylamine gas. The proposed synthetic method can be used for the synthesis of （E）-ethyl-3-（dimethylamino）acrylate（3cl）, and provide a new possible way to the synthesis of Quinolones.展开更多
A simple and efficient method for the synthesis of 3-indolyl-3-hydroxy oxindoles and unsymmetrical 3,3-di(indolyl)indolin-2-ones using microwave irradiation without catalyst and solvent is described. A series of 3-ind...A simple and efficient method for the synthesis of 3-indolyl-3-hydroxy oxindoles and unsymmetrical 3,3-di(indolyl)indolin-2-ones using microwave irradiation without catalyst and solvent is described. A series of 3-indolyl-3-hydroxy oxindoles and unsymmetrical 3,3-di(indolyl)indolin-2-ones have been synthesized in very short reaction times of 5 and 10 minutes and in yields ranging from 31% to 98% and from 53% to 78% respectively. This method offers a significant advantage over the conventional methods in terms of simplicity and shorter reaction time. To the best of our knowledge compounds N-allyl-3-hydroxy-3-(1-methyl-indol-3-yl)indolin-2-one (6c), N-allyl-3-hydroxy-3-(5-methoxy-indol-3-yl)indolin-2-one (8c), N-benzyl-3-hydroxy-3-(1-methyl-indol-3-yl) indolin-2-one (10c), N-propargyl-3-hydroxy-3-(1-methyl-indol-3-yl)indolin-2-one (13c), N-propargyl-3-hydroxy-3-(5-methoxy-indol-3-yl)indolin-2-one (14c), 3-(5-methoxy-1H-indol-3-yl)-3-(1H-indol-3-yl)indolin-2-one (1e), 3-1-methyl(5-methoxy-1H-indol-3-yl)-3-(1H-indol-3-yl)indolin-2-one (2e), 3-1-allyl(5-methoxy-1H-indol-3-yl)-3-(1H-indol-3-yl)indolin-2-one (3e), 3-1-benzyl(5-methoxy-1H-in- dol-3-yl)-3-(1H-indol-3-yl)indolin-2-one (4e) and 3-1-(prop-2-ynyl)(5-methoxy-1H-indol-3-yl)-3(1H-indol-3-yl)indolin-2-one (5e) are reported here for the first time. All the compounds are characterized by IR, 1H, 13C NMR and HRMS.展开更多
基金This work was supported by the Institute of Physics Start-up Founding, 100 Talents Program of the Chinese Academy of Sciences （CAS）, the Science Foundation of CAS, the National Science Foundation of China （NSFC） （grant Nos. 10974226 and 11074288）, and the National 973 project of China （grant No. 2010CB934202）.
文摘We have developed a new method to grow uniform graphene films directly on various substrates, such as insulators, semiconductors, and even metals, without using any catalyst. The growth was carried out using a remote plasma enhancement chemical vapor deposition （r-PECVD） system at relatively low temperatures, enabling the deposition of graphene films up to 4-inch wafer scale. Scanning tunneling microscopy （STM） confirmed that the films are made up of nanocrystalline graphene particles of tens of nanometers in lateral size. The growth mechanism for the nanographene is analogous to that for diamond grown by PECVD methods, in spite of sp2 carbon atoms being formed in the case of graphene rather than sp3 carbon atoms as in diamond. This growth approach is simple, low-cost, and scalable, and might have potential applications in fields such as thin film resistors, gas sensors, electrode materials, and transparent conductive films.
基金This work was supported by the SEEDS grant from the Ohio Agricultural Research and Development Center(OARDC)of the Ohio State University,Ohio,USA[grant number 2016-105].
文摘The organic compound 2,5-furandicarboxylic acid（FDCA） has been identified by the US Department of Energy（DOE） as a valuable platform chemical for a wide range of industrial applications. Currently, the most popular route for FDCA synthesis is reported to be the oxidation of 5-hydroxymethylfurfural（HMF）by O_2 over the catalysis of noble metals（e.g., Au, Pt, Ru, and Pd）. However, the high costs of noble metal catalysts remain a major barrier for producing FDCA at an industrial scale. Herein, we report a transition metal-free synthesis strategy for the oxidation of HMF to FDCA under O_2 or ambient air. A simple but unprecedented process for the aerobic oxidation of HMF was carried out in organic solvents using only bases as the promoters. According to the high performance liquid chromatography（HPLC） analysis, excellent product yield（91%） was obtained in the presence of NaOH in dimethylformamide（DMF） at room temperature（25 ℃）. A plausible mechanism for the NaOH-promoted aerobic oxidation of HMF in DMF is also outlined in this paper. After the reaction, the sodium salt of FDCA particles were dispersed in the reaction mixture, making it possible for product separation and solvent reuse. The new HMF oxidation approach is expected to be a practical alternative to current ones, which depend on the use of noble metal catalysts.
基金Project supported by the Natural Science Foundation of Tianjin,China(No.15JCQNJC03700)the National Natural Science Foundation of China(Nos.51702297)
文摘A series of AIN nanostructures were synthesized by an ultrahigh-temperature, catalyst-free, physical vapor transport（PVT） process. Energy dispersive X-ray spectroscopy（EDX）, X-ray diffraction（XRD）, X-Ray photoelectron spectroscopy（XPS）,high resolution transmission electron microscopy（HRTEM） detection show that high quality AIN nanowires were prepared. Nanostructures including nanorings, nanosprings, nanohelices, chainlike nanowires, six-fold symmetric nanostructure and rod-like structure were successfully obtained by controlling the growth duration and temperature. The morphology evolution was attributed to electrostatic polar charge model and the crystalline lattice structure of AIN.
基金the National Natural Science Foundation of China (Nos.21672239,21737004 and 21421002)Key Laboratory of Photochemical Conversion and Optoelectr onic Materials,TIPC,CAS,the Sanming Institute of Fluorochemical Industry (Nos.FCIT201704GR,FCIT201705GR,FCIT201701BR)STS Program of Chinese Academy of Science (KF-STS-QYZX-068).
文摘The importance of CF3-containing molecules in pharmaceuticals, agrochemicals and materials intrigues the intense interest in synthetic methodology of these compounds. With a purpose to enrich trifluoromethylation methodology, we carefully examined the substrate scope of hydroxytrifluoromethylation of alkenes using iodotrifluoromethane, and the reaction provided β-trifluoromethyl alcohols in good yields under extremely mild conditions without catalysts. We found that our reaction can be applied to not only styrenes but also various aliphatic alkenes with excellent selectivity;no ketone was detected in most of our cases. Another feature of our discovery is “simple”. The reaction was carried out in air, irradiated by visible light, at room temperature and most importantly no catalyst was needed. A solution of CF3I in DMSO was used as the facile trifluoromethylating reagent, which simplified the utilization of gaseous CF3I. Based on 19F NMR spectroscopy, we observed a halogen bond between CF3I and tertiary amine in this reaction. The interaction may promote single electron transfer by the visible light irradiation.
基金Financial support from National Key R&D Program of China(2022YFA1503200)National Natural Science Foundation of China(Grant No.22371149,22188101)+2 种基金the Fundamental Research Funds for the Central Universities(No.63223015)Frontiers Science Center for New Organic Matter,Nankai University(Grant No.63181206)Nankai University are gratefully acknowledged.
文摘Herein,an electrochemically driven catalyst-free nucleophilic aromatic substitution(S_(N)Ar)of electron-rich fluoroarenes with carboxylic acids as weak nucleophiles under mild conditions was reported.A series of highly valuable ester derivatives were obtained in a direct and rapid way.This transformation features commercially available reagents and an exceptionally broad substrate scope with good functional group tolerance,using cheap and abundant electrodes and completed within a short reaction time.Gram-scale synthesis and complex biorelevant compounds ligation further highlighted the potential utility of the methodology.The mechanistic investigations and density functional theory(DFT)calculations verified the feasibility of the proposed pathway of this transformation.
基金We thank the Marine S&T Fund of Shandong Province for Pilot National Laboratory for Marine Science and Technology(QNLM)(No.2022QNLM030003-2)the Fundamental Research Funds for the Central Universities,Ocean University of China,Qingdao National Laboratory for Marine Science and Technology(Nos.LMDBCXRC201902 and LMDBCXRC201903)+2 种基金Taishan Scholar Program of Shandong Province(Nos.tsqn201909056 and tsqn202103152)National Natural Science Foundation of China(No.22171251)Natural Science Foundation of Shandong Province(No.ZR2021QB033)for financial support.
文摘A catalyst-free and atom-economical[4+3]cycloaddition of azadienes with C,N-cyclic azomethine imines has been developed,providing an efficient and environmentally benign access to 1,2,4-triazepines with high diastereoselectivities and yields.This reaction can be performed in 2-methyltetrahydrofuran under mild conditions smoothly.
文摘A selective protocol for the synthesis of either a-ketoamides or quinoxaline derivatives under the same reaction conditions has been achieved simply by varying substitution number of amino-groups. The method features metal-free, room temperature and broad substrate scopes as well as no extra oxidant.This process applies to various substituent groups and gives products in moderate to good yield. Finally, a rational mechanism was proposed.
基金the Jiangsu Key Laboratory for Chemistry of Low-Dimensional Materials for financial support(No. JSKC07041)
文摘A facile procedure for the synthesis of 2,4,5-lriarylimidazoles is being reported starting from benzil, aromatic aldehyde and ammonium acetate. The reactions were carried out with catalyst-free, solvent-free and under microwave irradiation conditions in high yield （80-99%） with short time （3-5 min） and environmental benign, as well as convenient operation. The structures of the compounds have been confirmed on the basis of their IR, 1H NMR, and/or 13C NMR, MS, and elemental analyzer.
基金partially supported by the National Natural Science Foundation of China (Nos. 21875152 and 21404077)the Natural Science Foundation of the Jiangsu Higher Education Institutions of China (No. 17KJB150034)+2 种基金the Priority Academic Program Development of Jiangsu High Education Institutions (PAPD)the financial supports from Jiangsu Planned Projects for Postdoctoral Research Funds (No. 1501023B)China Postdoctoral Science Foundation (No. 2016M591906)
文摘The copper-catalyzed and metal-free azide-alkyne click polymerizations have become efficient tools for polymer synthesis. However,the 1,3-dipolar polycycloadditions between internal alkynes and azides are rarely employed to construct functional polymers. Herein, the polycycloadditions of dibutynoate(1) and tetraphenylethene-containing diazides(2) were carried out at 100 °C for 12 h under solvent-and catalyst-free conditions, producing soluble poly(methyltriazolylcarboxylate)s(PMTCs) with high molecular weights in high yields. The resultant polymers were thermally stable with 5% weight loss temperatures up to 377 °C. The PMTCs showed aggregation-induced emission(AIE)properties. They could work as fluorescent sensors for detecting explosive with high sensitivity, and generate two-dimensional fluorescent photopatterns with high resolution. Furthermore, their triazolium salts could be utilized for cell-imaging applications.
文摘Because imines could be used as convenient starting materials in various fields, the development of an easy synthetic method of imine was strongly desired. In response to this demand, we thought that it would be an effective synthesis method if an aldehyde and an amine could be reacted to give an imine in good yield under solvent- and catalyst-free conditions. In fact, we tried the reaction of benzaldehyde with various amines under solvent- and catalyst-free conditions followed by removal of water that was produced in the reaction system by a vacuum pump, and desired imines could be obtained in good yields. Observation of this reaction using a nuclear magnetic resonance spectrometer revealed that the reaction rate was extremely fast at the initial stage but slowed over time. However, the reaction of benzaldehyde with aniline differed greatly, and the reaction rate dramatically improved in 47 - 48 minutes after the start of the reaction. At this time, we found that the reaction system underwent a phase transition from the liquid phase to the solid phase.
基金Supported by the National Natural Science Foundation of China（Nos.20902001, 21102001）, the Natural Science Foundation of the Educational Department of Anhui Province, China（No.KJ2014A013）, the ＂211＂ Project of Anhui University（China） and the Doctor Research Start-up Fund of Anhui University（China）.
文摘An efficient, atom-economic and green approach to synthesizing enamines was developed by intermolecular hydroamination of activated alkynes with high yields under catalyst- and solvent-free conditions. β-Dimethylamino-acrylate derivatives were also obtained with high yields. In the synthetic process of the derivatives, N,N-dimethylformamide（DMF） pretreated with metal Na, was used as reactant instead of dimethylamine gas. The proposed synthetic method can be used for the synthesis of （E）-ethyl-3-（dimethylamino）acrylate（3cl）, and provide a new possible way to the synthesis of Quinolones.
文摘A simple and efficient method for the synthesis of 3-indolyl-3-hydroxy oxindoles and unsymmetrical 3,3-di(indolyl)indolin-2-ones using microwave irradiation without catalyst and solvent is described. A series of 3-indolyl-3-hydroxy oxindoles and unsymmetrical 3,3-di(indolyl)indolin-2-ones have been synthesized in very short reaction times of 5 and 10 minutes and in yields ranging from 31% to 98% and from 53% to 78% respectively. This method offers a significant advantage over the conventional methods in terms of simplicity and shorter reaction time. To the best of our knowledge compounds N-allyl-3-hydroxy-3-(1-methyl-indol-3-yl)indolin-2-one (6c), N-allyl-3-hydroxy-3-(5-methoxy-indol-3-yl)indolin-2-one (8c), N-benzyl-3-hydroxy-3-(1-methyl-indol-3-yl) indolin-2-one (10c), N-propargyl-3-hydroxy-3-(1-methyl-indol-3-yl)indolin-2-one (13c), N-propargyl-3-hydroxy-3-(5-methoxy-indol-3-yl)indolin-2-one (14c), 3-(5-methoxy-1H-indol-3-yl)-3-(1H-indol-3-yl)indolin-2-one (1e), 3-1-methyl(5-methoxy-1H-indol-3-yl)-3-(1H-indol-3-yl)indolin-2-one (2e), 3-1-allyl(5-methoxy-1H-indol-3-yl)-3-(1H-indol-3-yl)indolin-2-one (3e), 3-1-benzyl(5-methoxy-1H-in- dol-3-yl)-3-(1H-indol-3-yl)indolin-2-one (4e) and 3-1-(prop-2-ynyl)(5-methoxy-1H-indol-3-yl)-3(1H-indol-3-yl)indolin-2-one (5e) are reported here for the first time. All the compounds are characterized by IR, 1H, 13C NMR and HRMS.
