Sulphur-containing aromatic amines were prepared efficiently in good to excellent yields by reduction of the corresponding sulphur-containing aromatic nitro compounds with hydrazine hydrate in the presence of iron（Ⅲ...Sulphur-containing aromatic amines were prepared efficiently in good to excellent yields by reduction of the corresponding sulphur-containing aromatic nitro compounds with hydrazine hydrate in the presence of iron（Ⅲ） oxide-MgO catalyst. The catalyst exhibited high activity and stability for the reduction of sulphur-containing aromatic nitro compounds. The yields of sulphur-containing aromatic amines were up to 91-99 % at 355 K after reduction for 1-4 h over this catalyst.展开更多
Sulphur-containing aromatic nitro compounds were rapidly reduced to the corresponding amines in high yields by employing hydrazine hydrate as a hydrogen donor in the presence of iron oxide hydroxide catalyst. It was w...Sulphur-containing aromatic nitro compounds were rapidly reduced to the corresponding amines in high yields by employing hydrazine hydrate as a hydrogen donor in the presence of iron oxide hydroxide catalyst. It was worth noting that the catalyst exhibited extremely high activity. The reduction could be completed within 20-50 min and the yields were up to 97-99 %.展开更多
Aromatic nitro compounds were reduced to the corresponding anilines by refluxing with potassium selenated borohydride (KBH2Se3) prepared from potassium borohydride and selenium in refluxed formamide.
Hydrogenation reactions play crucial roles on chemical synthesis and pollutant elimination.The improvement of the ability to activate reactants and increase of the contact probability between the catalysts and reactan...Hydrogenation reactions play crucial roles on chemical synthesis and pollutant elimination.The improvement of the ability to activate reactants and increase of the contact probability between the catalysts and reactants are positive to improve the catalytic performance.Herein,we have reported the design of two-dimensional porous Ni-Ni_(3)N-Ni Mo N heterojunction sheets(2D Mo-Ni based nanosheets)for efficient catalytic hydrogenation of the aromatic nitro-compounds.The heterojunction interfaces provide plentiful active sites to improve the activating ability of the catalyst on the reactants.Additionally,the 2D porous structure facilitates not only the contact of catalytic sites with reactants but also mass transfer and diffusion,both of which are favorable to accelerating the hydrogenation process.As a result,the optimized sample of 2D Mo-Ni sheet exhibits good activity for the hydrogenation of aromatic nitro-compounds by converting 0.2 mmol/L(30 mL)of p-nitrophenol to p-aminophenol within 45 s with good recyclability.The activation energy and the reaction rate at 25℃ is 31.11 k J/mol and 0.0796 s^(-1),respectively,both of which surpass most of reported non-noble metal catalysts and rivals with most noble metal-based catalysts.The combination of late and early transition metals provides an innovative way to obtain outstanding catalysts for the hydrogenation.展开更多
N-Alkylhydroxylamines have been shown to undergo a stereospecific cis addition to 1-phenyl-2 -nitropropene compounds, whereas the corresponding O-alkylhydroxylamines give no diastereoselectivity. The concerted additio...N-Alkylhydroxylamines have been shown to undergo a stereospecific cis addition to 1-phenyl-2 -nitropropene compounds, whereas the corresponding O-alkylhydroxylamines give no diastereoselectivity. The concerted addition mechanism was provided to explain the difference.展开更多
By using the density functional theory （B3LYP） and four highly accurate complete basis set （CBS-Q, CBS-QB3, CBS-Lq, and CBS-4M）ab initio methods, the X（C, N, O）-NO2 bond dissociation energies （BDEs） for CH3NO2...By using the density functional theory （B3LYP） and four highly accurate complete basis set （CBS-Q, CBS-QB3, CBS-Lq, and CBS-4M）ab initio methods, the X（C, N, O）-NO2 bond dissociation energies （BDEs） for CH3NO2, C2H3NO2, C2H5NO2, HONO2, CH3ONO2, C2H5ONO2, NH2NO2 （CH3）2NNO2 are computed. By comparing the computed BDEs and experimental results, it is found that the B3LYP method is unable to predict satisfactorily the results of bond dissociation energy （BDE）; however, all four CBS models are generally able to give reliable predication of the X（C, N, O）-NO2 BDEs for these nitro compounds. Moreover, the CBS-4M calculation is the least computationally demanding among the four CBS methods considered, Therefore, we recommend CBS-4M method as a reliable method of computing the BDEs for this nitro compound system.展开更多
Arylamines constitute a fundamental class of organic compounds critical to pharmaceuticals,dyes,and advanced materials.The direct synthesis of arylamines from nitro compounds demonstrates significant advantages in ste...Arylamines constitute a fundamental class of organic compounds critical to pharmaceuticals,dyes,and advanced materials.The direct synthesis of arylamines from nitro compounds demonstrates significant advantages in step economy,cost efficiency,and functional group compatibility.However,conventional methodologies frequently necessitate transition metal catalysts or excessive reducing agents,limiting their practical applicability.Herein,we introduce a highly efficient photochemical protocol for the synthesis of arylamines from readily accessible nitro compounds and Grignard reagents under purple light(390—395 nm)irradiation,eliminating the requirement for transition metal catalysts or external reducing agents.This protocol exhibits exceptional tolerance to sterically hindered substrates and sensitive functional groups.Preliminary mechanistic investigations suggest the involvement of nitrosoarenes and diarylamine nitrogen radicals as key intermediates in the reaction pathway.展开更多
Aromatic nitro compounds present substantial health and environmental concerns due to their toxic nature and potential explosive properties.Consequently,the development of host–vip molecular recognition systems for...Aromatic nitro compounds present substantial health and environmental concerns due to their toxic nature and potential explosive properties.Consequently,the development of host–vip molecular recognition systems for these compounds serves a dual-purpose:enabling the fabrication of high-performance sensors for detection and guiding the design of efficient adsorbents for environmental remediation.This study investigated the host–vip recognition behavior of perethylated pillar[n]arenes toward two aromatic nitro molecules,1-chloro-2,4-dinitrobenzene and picric acid.Various techniques including^(1)H NMR,2D NOESY NMR,and UV-vis spectroscopy were employed to explore the binding behavior between pillararenes and aromatic nitro vips in solution.Moreover,valuable single crystal structures were obtained to elucidate the distinct solid-state assembly behaviors of these vips with different pillararenes.The assembled solid-state supramolecular structures observed encompassed a 1:1 host–vip inclusion complex,an external binding complex,and an exo-wall tessellation complex.Furthermore,based on the findings from these systems,a pillararene-based test paper was developed for efficient picric acid detection,and the removal of picric acid from solution was also achieved using pillararenes powder.This research provides novel insights into the development of diverse host–vip systems toward hazardous compounds,offering potential applications in environmental protection and explosive detection domains.展开更多
bState Key Laboratory of Organometallic Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, Shanghai 200032, China The differently substituted aromatic nitro compounds were chemoselect...bState Key Laboratory of Organometallic Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, Shanghai 200032, China The differently substituted aromatic nitro compounds were chemoselectively reduced by Sm/HOAc system in an ionic liquid medium to afford aromatic amines. Under these conditions the other substituents, such as -X, -CHO, -COOH, -CN, -NHTos and -alkyl, remained intact. The notable advantages of this reaction are its mild conditions, simple operation, short reaction time, high yields and easy recycling of ionic liquid.展开更多
The Michael addition reactions of fluorinated nitro compounds with electron deficient olefins to give γ-fiuoro-γ-nitro-esters, nitriles and ketones which bear a fluorinated quaternary carbon center were reported. Th...The Michael addition reactions of fluorinated nitro compounds with electron deficient olefins to give γ-fiuoro-γ-nitro-esters, nitriles and ketones which bear a fluorinated quaternary carbon center were reported. The reactions were promoted by TMG, affording the desired adducts in acceptable to good yields.展开更多
Development of the economic, environmentally friendly synthesis of amines from nitro compounds remains important and challenging. In this work, the graphene shell encapsulated none noble Ni-based catalysts were succes...Development of the economic, environmentally friendly synthesis of amines from nitro compounds remains important and challenging. In this work, the graphene shell encapsulated none noble Ni-based catalysts were successfully designed and synthesized via an environmentally friendly method using H2O or Et OH as solvent. These fresh and recycling catalysts were characterized by X-ray diffraction and X-ray photoelectron spectroscopy. For the nitro compounds hydrogenation, Ni@C-600-H2O exhibits the best catalytic activity to achieve 100 mol/mol conversions of nitrobenzene and 99% selectivity of aniline under mild reaction conditions of 1.0 MPa H2and 60°C.Many halogen-substituted, olefin substituted nitro compounds and aliphatic nitro compounds were investigated and desired products were obtained in excellent selectivity. What is more, the catalyst had excellent stability and could be recycled 13 times without any significant loss in selectivity and activity. Furthermore, we also reported the methodology for tertiary amines synthesis using Ni-based catalyst via one-pot, cost-effective tandem combination reaction with nitrobenzene hydrogenation and amines N-methylation.展开更多
The intermolecular reductive cyclization of o-nitrobenzene-sulfonamides with aliphatic ketones induced by TiCl4/Sm system was studied and a series of 3, 3-disubstituted-3,4-dihydro(2H)-1,2, 4-benzothiadiazine-1,1-diox...The intermolecular reductive cyclization of o-nitrobenzene-sulfonamides with aliphatic ketones induced by TiCl4/Sm system was studied and a series of 3, 3-disubstituted-3,4-dihydro(2H)-1,2, 4-benzothiadiazine-1,1-dioxides were synthesized in moderate to high yields under mild and neutral conditions.展开更多
Nanoparticles have properties that can be fine-tuned by their size as well as shape.Hence,there is significant current interest in preparing nano-materials of small size dispersity and to arrange them in close-packed ...Nanoparticles have properties that can be fine-tuned by their size as well as shape.Hence,there is significant current interest in preparing nano-materials of small size dispersity and to arrange them in close-packed aggregates.This letter describes a way of synthesising silver nanoparticles and their protection to aggregate by silica gel.The combination of catalytic quantities of immobilized silver nanoparticles with reductive ability of NaBH_4 efficiently reduces aromatic nitroarenes to the corresponding amines in aqueous medium.Noteworthy is that highly chemoselective reactions were achieved in the presence of other functional groups such as halogen and carboxylic acid groups.The silver particles immobilized on silica gel are stable in the presence of oxygen for several months.展开更多
Henry reaction is one of the most classical reactions to construct synthetically useful product nitro alcohol, which as a privileged skeleton is widely distributed in various pharmaceuticals. This review summarizes th...Henry reaction is one of the most classical reactions to construct synthetically useful product nitro alcohol, which as a privileged skeleton is widely distributed in various pharmaceuticals. This review summarizes the recent progress of copper-catalyzed asymmetric Henry reaction from 2011 to 2016. The significant progress that has been made in this area will be highlighted and some of challenges that the author believes may be hindering further progress will be revealed.展开更多
Graphene （GR）-CdS nanocomposites with different weight addition ratios of GR have been assembled by a facile solvothermal treatment. The GR-CdS nanocomposite photocatalyst with an appropriate ratio of GR exhibits en...Graphene （GR）-CdS nanocomposites with different weight addition ratios of GR have been assembled by a facile solvothermal treatment. The GR-CdS nanocomposite photocatalyst with an appropriate ratio of GR exhibits enhanced photoactivity for selective reduction of aromatic nitro compounds to the corresponding aromatic amines in water under visible light irradiation as compared with blank-CdS. The characterization of GR-CdS nanocomposite photocatalysts by a collection of techniques discloses that： i） GR can tune the microscopic morphology of CdS nanoparticles and improve light absorption intensity in the visible light region; ii） GR scaffolds act as an electron reservoir to trap and shuttle the electrons photogenerated from CdS semiconductor under the visible light illumination; iii） the introduction of GR enhances the adsorption capacity of GR-CdS nanocomposites toward the substrates, aromatic nitro compounds. The synergistic effect of these factors should account for the photoactivity advancement of GR-CdS nanocomposites toward the probe reactions. Furthermore, because the photogenerated holes in the system are trapped by the quenching agent ammonium oxalate, the as-obtained GR-CdS photocataiyst is stable during the photocatalytic reduction reactions. A reasonable model has also been proposed to illustrate the reaction mechanism.展开更多
A new approach for preparation ol various substituted phenylethylamines from the corresponding nitro compounds with iron powder and NH4Cl in 75% aqueous ethanol solution was developed.
The catalytic hydrogenation of nitroaromatics is an environmentally friendly technology for aniline production,and it is crucial to develop noble-metal-free catalysts that can achieve chemoselective hydrogenation of n...The catalytic hydrogenation of nitroaromatics is an environmentally friendly technology for aniline production,and it is crucial to develop noble-metal-free catalysts that can achieve chemoselective hydrogenation of nitroaromatics under mild reaction conditions.In this work,zinc-modified Ni-Ti catalysts(Ni_(x)Zn_(y)Ti_(1))were fabricated and applied for the hydrogenation of nitroaromatics hydrogenation.It was found that the introduction of zinc effectively increases the surface Ni density,enhances the electronic effect,and improves the interaction between Ni and TiO_(2),resulting in smaller Ni particle size,more oxygen vacancies,higher dispersion and greater concentration of Ni on the catalyst surface.Furthermore,the electron-rich Ni^(δ-) obtained by electron transfer from Zn and Ti to Ni effectively adsorbs and dissociates hydrogen.The results reveal that Ni_(x)Zn_(y)Ti_(1)(Ni_(0.5)Zn_(0.5)Ti_(1))shows excellent catalytic performance under mild conditions(70℃and 6 bar).These findings provide a rational strategy for the development of highly active non-noble-metal hydrogenation catalysts.展开更多
Designing and synthesizing high-efficiency non-precious metal-based catalysts having uniform active sites increases the reactivity and selectivity of materials and provides a platform for an in-depth understanding of ...Designing and synthesizing high-efficiency non-precious metal-based catalysts having uniform active sites increases the reactivity and selectivity of materials and provides a platform for an in-depth understanding of their catalytic reaction mechanism.In this study,we provided an approach for fabricating isolated nickel single-atom sites(Ni SAs)with high loading(4.9 wt.%)stabilized on nitrogen-doped hollow carbon spheres(NHCS)using a core–shell structured Zn/Ni bimetallic zeolitic imidazolate framework(ZIF)composite as the sacrificial template.The as-fabricated Ni SAs/NHCS catalyst shows superior activity,selectivity,and recycling durability for the catalytic transfer hydrogenation of nitrobenzene to aniline,thus achieving 100%yield of aniline with a turn-over frequency(TOF)value as high as 29.9 h^(−1) under mild conditions.This TOF value is considerably superior to the supported Ni nanoparticle catalysts.The experiments designed show that the hollow structure feature of NHCS facilitates accessible active sites and mass transfer,which thus contributes to the enhancement of the catalytic performance of Ni SAs/NHCS.Density functional theory calculations show the high chemo-selectivity and activity of the Ni SAs catalyst,arising from the unique role of the single Ni-N3 site on simultaneously activating the H donor(N_(2)H_(4))and substrate,as well as the hydrogenation of the–NOH group as the rate-determining step.展开更多
Cu-based catalysts are widely used in various heterogeneous catalytic reaction systems,the precise control of their electronic structure is an intrinsic require-ment for the rational design of metal catalysts,and it i...Cu-based catalysts are widely used in various heterogeneous catalytic reaction systems,the precise control of their electronic structure is an intrinsic require-ment for the rational design of metal catalysts,and it is also an important basis for clarifying their structure-activity relationships.Changing the electronic structure of Cu-based catalysts is an important way to improve the catalytic hydrogenation performance of Cu-based catalysts by controlling the adsorption intensity be-tween the reaction adsorbate and the active center.In this paper,the application of selective hydrogenation of Cu-based catalysts is reviewed,with a special emphasis on the selective catalytic hydrogenation reduction of p-nitrostyrene and CO_(2).This review particularly emphasizes the application of Cu-based catalysts in the field of selective hydrogenation and discusses the influence of their different properties on selective hydrogenation performance.展开更多
文摘Sulphur-containing aromatic amines were prepared efficiently in good to excellent yields by reduction of the corresponding sulphur-containing aromatic nitro compounds with hydrazine hydrate in the presence of iron（Ⅲ） oxide-MgO catalyst. The catalyst exhibited high activity and stability for the reduction of sulphur-containing aromatic nitro compounds. The yields of sulphur-containing aromatic amines were up to 91-99 % at 355 K after reduction for 1-4 h over this catalyst.
文摘Sulphur-containing aromatic nitro compounds were rapidly reduced to the corresponding amines in high yields by employing hydrazine hydrate as a hydrogen donor in the presence of iron oxide hydroxide catalyst. It was worth noting that the catalyst exhibited extremely high activity. The reduction could be completed within 20-50 min and the yields were up to 97-99 %.
文摘Aromatic nitro compounds were reduced to the corresponding anilines by refluxing with potassium selenated borohydride (KBH2Se3) prepared from potassium borohydride and selenium in refluxed formamide.
基金the support of this research by the National Natural Science Foundation of China(No.91961111)the Natural Science Foundation of Heilongjiang Province(No.ZD2021B003)Fundamental Research Funds for the Central Universities(No.2572022BU05)。
文摘Hydrogenation reactions play crucial roles on chemical synthesis and pollutant elimination.The improvement of the ability to activate reactants and increase of the contact probability between the catalysts and reactants are positive to improve the catalytic performance.Herein,we have reported the design of two-dimensional porous Ni-Ni_(3)N-Ni Mo N heterojunction sheets(2D Mo-Ni based nanosheets)for efficient catalytic hydrogenation of the aromatic nitro-compounds.The heterojunction interfaces provide plentiful active sites to improve the activating ability of the catalyst on the reactants.Additionally,the 2D porous structure facilitates not only the contact of catalytic sites with reactants but also mass transfer and diffusion,both of which are favorable to accelerating the hydrogenation process.As a result,the optimized sample of 2D Mo-Ni sheet exhibits good activity for the hydrogenation of aromatic nitro-compounds by converting 0.2 mmol/L(30 mL)of p-nitrophenol to p-aminophenol within 45 s with good recyclability.The activation energy and the reaction rate at 25℃ is 31.11 k J/mol and 0.0796 s^(-1),respectively,both of which surpass most of reported non-noble metal catalysts and rivals with most noble metal-based catalysts.The combination of late and early transition metals provides an innovative way to obtain outstanding catalysts for the hydrogenation.
文摘N-Alkylhydroxylamines have been shown to undergo a stereospecific cis addition to 1-phenyl-2 -nitropropene compounds, whereas the corresponding O-alkylhydroxylamines give no diastereoselectivity. The concerted addition mechanism was provided to explain the difference.
基金Project supported by the National Natural Science Foundation of China and China Academy of Engineering Physics （Grant Nos 10376021, 10274055）.
文摘By using the density functional theory （B3LYP） and four highly accurate complete basis set （CBS-Q, CBS-QB3, CBS-Lq, and CBS-4M）ab initio methods, the X（C, N, O）-NO2 bond dissociation energies （BDEs） for CH3NO2, C2H3NO2, C2H5NO2, HONO2, CH3ONO2, C2H5ONO2, NH2NO2 （CH3）2NNO2 are computed. By comparing the computed BDEs and experimental results, it is found that the B3LYP method is unable to predict satisfactorily the results of bond dissociation energy （BDE）; however, all four CBS models are generally able to give reliable predication of the X（C, N, O）-NO2 BDEs for these nitro compounds. Moreover, the CBS-4M calculation is the least computationally demanding among the four CBS methods considered, Therefore, we recommend CBS-4M method as a reliable method of computing the BDEs for this nitro compound system.
基金supported by the National Natural Science Foundation of China(22171174)the Fundamental Research Funds for the Central Universities(GK202304033,GK202406026)+2 种基金the Innovation Capability Support Program of Shaanxi(2023-CX-TD-28)the Shaanxi Fundamental Science Research Project for Chemistry&Biology(22JHZ002)the Natural Science Foundation of Shaanxi Province(2023-JC-YB-100).
文摘Arylamines constitute a fundamental class of organic compounds critical to pharmaceuticals,dyes,and advanced materials.The direct synthesis of arylamines from nitro compounds demonstrates significant advantages in step economy,cost efficiency,and functional group compatibility.However,conventional methodologies frequently necessitate transition metal catalysts or excessive reducing agents,limiting their practical applicability.Herein,we introduce a highly efficient photochemical protocol for the synthesis of arylamines from readily accessible nitro compounds and Grignard reagents under purple light(390—395 nm)irradiation,eliminating the requirement for transition metal catalysts or external reducing agents.This protocol exhibits exceptional tolerance to sterically hindered substrates and sensitive functional groups.Preliminary mechanistic investigations suggest the involvement of nitrosoarenes and diarylamine nitrogen radicals as key intermediates in the reaction pathway.
基金supported by the fundamental research funds of Zhejiang Sci-Tech University(No.22212286-Y)the Natural Science Foundation of Zhejiang Province(No.LQ24B040003)。
文摘Aromatic nitro compounds present substantial health and environmental concerns due to their toxic nature and potential explosive properties.Consequently,the development of host–vip molecular recognition systems for these compounds serves a dual-purpose:enabling the fabrication of high-performance sensors for detection and guiding the design of efficient adsorbents for environmental remediation.This study investigated the host–vip recognition behavior of perethylated pillar[n]arenes toward two aromatic nitro molecules,1-chloro-2,4-dinitrobenzene and picric acid.Various techniques including^(1)H NMR,2D NOESY NMR,and UV-vis spectroscopy were employed to explore the binding behavior between pillararenes and aromatic nitro vips in solution.Moreover,valuable single crystal structures were obtained to elucidate the distinct solid-state assembly behaviors of these vips with different pillararenes.The assembled solid-state supramolecular structures observed encompassed a 1:1 host–vip inclusion complex,an external binding complex,and an exo-wall tessellation complex.Furthermore,based on the findings from these systems,a pillararene-based test paper was developed for efficient picric acid detection,and the removal of picric acid from solution was also achieved using pillararenes powder.This research provides novel insights into the development of diverse host–vip systems toward hazardous compounds,offering potential applications in environmental protection and explosive detection domains.
基金theNationalNaturalScienceFoundationofChina (No .2 9872 0 10 )theNaturalScienceFoundationofZhejiangProvinceChina (No .2 0 0 72 0 33)
文摘bState Key Laboratory of Organometallic Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, Shanghai 200032, China The differently substituted aromatic nitro compounds were chemoselectively reduced by Sm/HOAc system in an ionic liquid medium to afford aromatic amines. Under these conditions the other substituents, such as -X, -CHO, -COOH, -CN, -NHTos and -alkyl, remained intact. The notable advantages of this reaction are its mild conditions, simple operation, short reaction time, high yields and easy recycling of ionic liquid.
文摘The Michael addition reactions of fluorinated nitro compounds with electron deficient olefins to give γ-fiuoro-γ-nitro-esters, nitriles and ketones which bear a fluorinated quaternary carbon center were reported. The reactions were promoted by TMG, affording the desired adducts in acceptable to good yields.
基金National Key R&D Program of China(2019YFD1100601)National Natural Science Foundation of China(Project 51976225)Dalian National Laboratory Cooperation Foundation,Chinese Academy of Sciences(Project DNL201916)for financial support。
文摘Development of the economic, environmentally friendly synthesis of amines from nitro compounds remains important and challenging. In this work, the graphene shell encapsulated none noble Ni-based catalysts were successfully designed and synthesized via an environmentally friendly method using H2O or Et OH as solvent. These fresh and recycling catalysts were characterized by X-ray diffraction and X-ray photoelectron spectroscopy. For the nitro compounds hydrogenation, Ni@C-600-H2O exhibits the best catalytic activity to achieve 100 mol/mol conversions of nitrobenzene and 99% selectivity of aniline under mild reaction conditions of 1.0 MPa H2and 60°C.Many halogen-substituted, olefin substituted nitro compounds and aliphatic nitro compounds were investigated and desired products were obtained in excellent selectivity. What is more, the catalyst had excellent stability and could be recycled 13 times without any significant loss in selectivity and activity. Furthermore, we also reported the methodology for tertiary amines synthesis using Ni-based catalyst via one-pot, cost-effective tandem combination reaction with nitrobenzene hydrogenation and amines N-methylation.
基金Project supported by the National Natural Science Foundation of China (No. 29872010)Natural Science Foundation of Zhejiang Province, China
文摘The intermolecular reductive cyclization of o-nitrobenzene-sulfonamides with aliphatic ketones induced by TiCl4/Sm system was studied and a series of 3, 3-disubstituted-3,4-dihydro(2H)-1,2, 4-benzothiadiazine-1,1-dioxides were synthesized in moderate to high yields under mild and neutral conditions.
基金supports for this work by Shahid Chamran University Research Council
文摘Nanoparticles have properties that can be fine-tuned by their size as well as shape.Hence,there is significant current interest in preparing nano-materials of small size dispersity and to arrange them in close-packed aggregates.This letter describes a way of synthesising silver nanoparticles and their protection to aggregate by silica gel.The combination of catalytic quantities of immobilized silver nanoparticles with reductive ability of NaBH_4 efficiently reduces aromatic nitroarenes to the corresponding amines in aqueous medium.Noteworthy is that highly chemoselective reactions were achieved in the presence of other functional groups such as halogen and carboxylic acid groups.The silver particles immobilized on silica gel are stable in the presence of oxygen for several months.
基金the National Natural Science Foundation of China (Nos. 2127222, 21432009, 21472177, J1310010)Chinese Academy of Sciences(No. XDB20000000)
文摘Henry reaction is one of the most classical reactions to construct synthetically useful product nitro alcohol, which as a privileged skeleton is widely distributed in various pharmaceuticals. This review summarizes the recent progress of copper-catalyzed asymmetric Henry reaction from 2011 to 2016. The significant progress that has been made in this area will be highlighted and some of challenges that the author believes may be hindering further progress will be revealed.
基金supported by the National Natural Science Foundation of China(NSFC)(21173045,20903023)the Award Program for Minjiang Scholar Professorship+3 种基金the Natural Science Foundation(NSF)of Fujian Province for Distinguished Young Investigator(Grant No.2012J06003)the Program for Changjiang Scholars and Innovative Research Team in Universities(PCSIRT0818)the Program for Returned High-Level Overseas Chinese Scholars of Fujian provincethe Project Sponsored by the Scientific Research Foundation for the Returned Overseas Chinese Scholars,State Education Ministry
文摘Graphene （GR）-CdS nanocomposites with different weight addition ratios of GR have been assembled by a facile solvothermal treatment. The GR-CdS nanocomposite photocatalyst with an appropriate ratio of GR exhibits enhanced photoactivity for selective reduction of aromatic nitro compounds to the corresponding aromatic amines in water under visible light irradiation as compared with blank-CdS. The characterization of GR-CdS nanocomposite photocatalysts by a collection of techniques discloses that： i） GR can tune the microscopic morphology of CdS nanoparticles and improve light absorption intensity in the visible light region; ii） GR scaffolds act as an electron reservoir to trap and shuttle the electrons photogenerated from CdS semiconductor under the visible light illumination; iii） the introduction of GR enhances the adsorption capacity of GR-CdS nanocomposites toward the substrates, aromatic nitro compounds. The synergistic effect of these factors should account for the photoactivity advancement of GR-CdS nanocomposites toward the probe reactions. Furthermore, because the photogenerated holes in the system are trapped by the quenching agent ammonium oxalate, the as-obtained GR-CdS photocataiyst is stable during the photocatalytic reduction reactions. A reasonable model has also been proposed to illustrate the reaction mechanism.
文摘A new approach for preparation ol various substituted phenylethylamines from the corresponding nitro compounds with iron powder and NH4Cl in 75% aqueous ethanol solution was developed.
基金supported by the National Natural Science Foundation of China(Grant Nos.22078277,21908185)Project of Hunan Provincial Education Department(Grant Nos.19B572,20B547)the Collaborative Innovation Center of New Chemical Technolo gies Technolo gies for Environmental Benignity and Efficient Resource Utilization,and the National Department of Education Engineering Research Centre for Chemical Process Simulation and Optimization。
文摘The catalytic hydrogenation of nitroaromatics is an environmentally friendly technology for aniline production,and it is crucial to develop noble-metal-free catalysts that can achieve chemoselective hydrogenation of nitroaromatics under mild reaction conditions.In this work,zinc-modified Ni-Ti catalysts(Ni_(x)Zn_(y)Ti_(1))were fabricated and applied for the hydrogenation of nitroaromatics hydrogenation.It was found that the introduction of zinc effectively increases the surface Ni density,enhances the electronic effect,and improves the interaction between Ni and TiO_(2),resulting in smaller Ni particle size,more oxygen vacancies,higher dispersion and greater concentration of Ni on the catalyst surface.Furthermore,the electron-rich Ni^(δ-) obtained by electron transfer from Zn and Ti to Ni effectively adsorbs and dissociates hydrogen.The results reveal that Ni_(x)Zn_(y)Ti_(1)(Ni_(0.5)Zn_(0.5)Ti_(1))shows excellent catalytic performance under mild conditions(70℃and 6 bar).These findings provide a rational strategy for the development of highly active non-noble-metal hydrogenation catalysts.
基金the National Natural Science Foundation of China(Nos.21576243 and 21701168)Natural Science Foundation of Zhejiang Province(Nos.LY18B060006,LY17B060001,and LY21B030003)+2 种基金the National Key R&D Program of China(No.2020YFA0406101)Dalian high level talent innovation project(No.2019RQ063)Open project Foundation of State Key Laboratory of Structural Chemistry,Fujian Institute of Research on the Structure of Matter,Chinese Academy of Sciences(No.20200021).
文摘Designing and synthesizing high-efficiency non-precious metal-based catalysts having uniform active sites increases the reactivity and selectivity of materials and provides a platform for an in-depth understanding of their catalytic reaction mechanism.In this study,we provided an approach for fabricating isolated nickel single-atom sites(Ni SAs)with high loading(4.9 wt.%)stabilized on nitrogen-doped hollow carbon spheres(NHCS)using a core–shell structured Zn/Ni bimetallic zeolitic imidazolate framework(ZIF)composite as the sacrificial template.The as-fabricated Ni SAs/NHCS catalyst shows superior activity,selectivity,and recycling durability for the catalytic transfer hydrogenation of nitrobenzene to aniline,thus achieving 100%yield of aniline with a turn-over frequency(TOF)value as high as 29.9 h^(−1) under mild conditions.This TOF value is considerably superior to the supported Ni nanoparticle catalysts.The experiments designed show that the hollow structure feature of NHCS facilitates accessible active sites and mass transfer,which thus contributes to the enhancement of the catalytic performance of Ni SAs/NHCS.Density functional theory calculations show the high chemo-selectivity and activity of the Ni SAs catalyst,arising from the unique role of the single Ni-N3 site on simultaneously activating the H donor(N_(2)H_(4))and substrate,as well as the hydrogenation of the–NOH group as the rate-determining step.
基金supported by the National Natural Science Foundation of China(No.52271189).
文摘Cu-based catalysts are widely used in various heterogeneous catalytic reaction systems,the precise control of their electronic structure is an intrinsic require-ment for the rational design of metal catalysts,and it is also an important basis for clarifying their structure-activity relationships.Changing the electronic structure of Cu-based catalysts is an important way to improve the catalytic hydrogenation performance of Cu-based catalysts by controlling the adsorption intensity be-tween the reaction adsorbate and the active center.In this paper,the application of selective hydrogenation of Cu-based catalysts is reviewed,with a special emphasis on the selective catalytic hydrogenation reduction of p-nitrostyrene and CO_(2).This review particularly emphasizes the application of Cu-based catalysts in the field of selective hydrogenation and discusses the influence of their different properties on selective hydrogenation performance.
