Cyclopropenones have been extensively utilized in catalytic ring-opening and ring-expansion reactions for the synthesis of unsaturated carbonyl compounds.The first rhodium-catalyzed ring-opening reaction of aryl-/alky...Cyclopropenones have been extensively utilized in catalytic ring-opening and ring-expansion reactions for the synthesis of unsaturated carbonyl compounds.The first rhodium-catalyzed ring-opening reaction of aryl-/alkyl-substituted cyclopropenones is accomplished,successfully affording acyloin derivatives.This transformation represents a novel reaction pattern involving cyclopropenones.The resulting acyloin products constitute important building blocks in organic synthesis and serve as fundamental structural frameworks in numerous natural products.展开更多
The Rh(III)-catalyzed C—H functionalization of sulfoxonium ylides and successively annulation with two classes of cyclic diazo compounds has been realized,affording structurally diverse fused-ring or spirocyclic comp...The Rh(III)-catalyzed C—H functionalization of sulfoxonium ylides and successively annulation with two classes of cyclic diazo compounds has been realized,affording structurally diverse fused-ring or spirocyclic compounds under redoxneutral conditions.The reaction proceeds via successive chelation-assisted C—H activation,carbene insertion,and intramolecular[3+3]/[4+1]annulation processes.展开更多
In the search for new drugs with more efficient active ingredients, various transition metals are being explored as potential metallopharmaceuticals. These compounds, which combine drugs with metals, have shown promis...In the search for new drugs with more efficient active ingredients, various transition metals are being explored as potential metallopharmaceuticals. These compounds, which combine drugs with metals, have shown promise as chemotherapeutic agents, akin to the accidental discovery of cisplatin and its organic derivatives in the late 20th century. This discovery transformed the sciences, particularly in the fields of organic and inorganic chemistry, by offering new insights into the compositions and molecular geometries of inorganic complexes through coordination chemistry, while also intersecting with other scientific domains such as pharmacology and medicine. To contribute to the development of new chemotherapeutic compounds through simple and reproducible synthetic processes, this study utilized rhodium(III) chloride hydrate (RhCl3.nH2O) to synthesize a series of compounds with the following organic N-heterocyclic ligands: 4,4'-dimethyl-2,2'-bipyridine, isonicotinamide, and N-(3-pyridyl)-isonicotinamide (3-pina). Two analytical techniques were employed to characterize the resulting materials: spectroscopic analysis in the infrared region, which suggested interactions and substitutions at the metal center by the organic compounds, and thermoanalytical analyses, which led to the proposal of minimum formulas for the compounds as follows: C1 [RhCl2(4,4'-Met-2,2'-bipy)2]Cl∙5/2H2O and C2 [Rh(4,4'-Met-2,2'-bipy)2(Iso)2] Cl3∙1/2H2O. However, the complexation of the third compound could not be confirmed due to the physicochemical characteristics of the resulting complex being very similar to those of the starting material, thereby validating the effectiveness of these techniques in differentiating and characterizing the synthesized salts. Due to their solubility in water and/or alcohol and thermal stability, the complexes were tested in biological media to assess cell viability in peripheral blood mononuclear cells. The solutions of these salts demonstrated favorable cell viability under the tested conditions, according to statistical analysis, obtaining average viability in the range of 95 ≤ x ≤ 100, with standard deviations between 3.29 ≤ x ≤ 4.44 for living cells.展开更多
The hydrosilylation of alkenes with triethoxysilane has been achieved at 120 C in the presence of 0.01 mol%of thioetherfunctionalized MCM-41 anchored rhodium complex,affording the corresponding addition products in 68...The hydrosilylation of alkenes with triethoxysilane has been achieved at 120 C in the presence of 0.01 mol%of thioetherfunctionalized MCM-41 anchored rhodium complex,affording the corresponding addition products in 68-91%yields.This supported rhodium complex can be reused several times without noticeable loss of activity.Our system not only solves the basic problems of catalyst separation and recovery,but also avoids the use of phosphine ligands.展开更多
A new process recycling rhodium from organic waste containing rhodium in acetic acid industry is developed. Use the special affinity of base metal sulfides (FeS, Ni2S3 , CuS, etc.) on platinum group metals, adopting h...A new process recycling rhodium from organic waste containing rhodium in acetic acid industry is developed. Use the special affinity of base metal sulfides (FeS, Ni2S3 , CuS, etc.) on platinum group metals, adopting high nickel matte trapping-aluminothermic activation method to recovery rhodium from incinerator residue of organic rhodium waste. The method is shorter process, lower equipment requirement, and the higher activity of rhodium black. In pyrometallurgy enrichment process,the recovery rate of rhodium reached 94.65%, the full flow of rhodium recovery rate was 92.04%.展开更多
A highly efficient and selective[2+2+2]cyclization of diynes and monoalkynes was catalyzed by rhodium under room temperature in water/THF mixed solvent,affording isoindolines and isobenzofurans in good to excellent yi...A highly efficient and selective[2+2+2]cyclization of diynes and monoalkynes was catalyzed by rhodium under room temperature in water/THF mixed solvent,affording isoindolines and isobenzofurans in good to excellent yields.The center atoms (N,O) in the diynes showed a significant effect for the cyclization.展开更多
Organic cation and halide anion defects are omnipresent in the perovskite films,which will destroy perovskite electronic structure and downgrade the properties of devices.Defect passivation in halide perovskites is cr...Organic cation and halide anion defects are omnipresent in the perovskite films,which will destroy perovskite electronic structure and downgrade the properties of devices.Defect passivation in halide perovskites is crucial to the application of solar cells.Herein,tiny amounts of trivalent rhodium ion incorporation can help the nucleation of perovskite grain and passivate the defects in the grain boundaries,which can improve efficiency and stability of perovskite solar cells.Through first-principle calculations,rhodium ion incorporation into the perovskite structure can induce ordered arrangement and tune bandgap.In experiment,rhodium ion incorporation with perovskite can contribute to preparing larger crystalline and uniform film,reducing trap-state density and enlarging charge carrier lifetime.After optimizing the content of 1% rhodium,the devices achieved an efficiency up to 20.71% without obvious hysteresis,from 19.09% of that pristine perovskite.In addition,the unencapsulated solar cells maintain 92% of its initial efficiency after 500 h in dry air.This work highlights the advantages of trivalent rhodium ion incorporation in the characteristics of perovskite solar cells,which will promote the future industrial application.展开更多
Herein,we report for the first time the synthesis of preformed bimetallic Pd-Rh nanoparticles with different Pd:Rh ratios(nominal molar ratio:80-20,60-40,40-60,20-80) and the corresponding Pd and Rh monometallic ones ...Herein,we report for the first time the synthesis of preformed bimetallic Pd-Rh nanoparticles with different Pd:Rh ratios(nominal molar ratio:80-20,60-40,40-60,20-80) and the corresponding Pd and Rh monometallic ones by sol immobilization using polyvinyl alcohol(PVA) as protecting agent and NaBH4 as reducing agent,using carbon nanofibers with high graphitization degree(HHT) as the desired support.The synthesized catalysts were characterized by means of Transmission Electron Microscopy(TEM) and inductively coupled plasma optical emission spectroscopy(ICP-OES).TEM shows that the average particle size of the Pd-Rh nanoparticles is the range of 3-4 nm,with the presence of few large agglomerated nanoparticles.For bimetallic catalysts,EDX-STEM analysis of individual nanoparticles demonstrated the presence of random-alloyed nanoparticles even in all cases Rh content is lower than the nominal one(calculated Pd:Rh molar ratio:90-10,69-31,49-51,40-60).The catalytic performance of the Pd-Rh catalysts was evaluated in the liquid phase dehydrogenation of formic acid to H2.It was found that Pd-Rh molar ratio strongly influences the catalytic performance.Pd-rich catalysts were more active than Rh-rich ones,with the highest activity observed for Pd90:Rh10(1792 h^(-1)),whereas Pd69:Rh31(921 h^(-1)) resulted the most stable during recycling tests.Finally,Pd90:Rh10 was chosen as a representative sample for the liquid-phase hydrogenation of muconic acid using formic acid as hydrogen donor,showing good yield to adipic acid.展开更多
A porous silica-polymer-based adsorbent,isoBuBTP/Si O2-P,was prepared by a vacuum impregnation method and used for the recovery of ruthenium,rhodium,and palladium from nitric acid solution.The experimental results rev...A porous silica-polymer-based adsorbent,isoBuBTP/Si O2-P,was prepared by a vacuum impregnation method and used for the recovery of ruthenium,rhodium,and palladium from nitric acid solution.The experimental results revealed that iso Bu-BTP/SiO2-P exhibited unique adsorption properties such as high saturation adsorption capacity(Ru:0.35 mmol g^-1,Rh:0.32 mmol g^-1,Pd:1.05 mmol g^-1)and excellent selectivity over other metal ions,such as lanthanides(SF(PGM/M)>40)in 1 M HNO3 solution.The adsorption process conformed to the pseudosecond-order model and Langmuir model.From the UV,FTIR,and XPS analyses,it can be concluded that the strong affinity between functional groups(C–N=C)and metal ions as well as NO3-played a role in coordination during the adsorption process.Furthermore,the desorption behavior was studied,and it was found that the adsorbed Pd,Rh,and Ru could be eluted with a 0.01 M nitric acid–0.1M thiocarbamide solution,5M hydrochloric acid,and sodium hypochlorite(CP)solution,respectively.Finally,based on those findings,a simple process for the separation and recovery of Pd,Rh,and Ru from high-level liquid waste using iso Bu-BTP/SiO2-P was designed and proposed.展开更多
Rhodium(Ⅲ)-catalyzed synthesis of indole derivatives has been realized via cascade reaction of C -H alkylation/nucleophilic cyclization starting from readily available N-phenylpyridin-2-amines and sulfoxonium ylides....Rhodium(Ⅲ)-catalyzed synthesis of indole derivatives has been realized via cascade reaction of C -H alkylation/nucleophilic cyclization starting from readily available N-phenylpyridin-2-amines and sulfoxonium ylides. Notably, this transformation could smoothly proceed with high yields, good regioselectivity, and feature broad group tolerance and under redox-neutral condition to avoid external oxidant. The titled products are potentially important building blocks in the organic synthesis through various chemical transformations.展开更多
This study attempted to develop an appropriate catalyst used for the steam reforming of gasified spent solvents. Rh2O3/ CeOE-Al2O3 catalysts with various CeO2 loadings were prepared and heated at different temperature...This study attempted to develop an appropriate catalyst used for the steam reforming of gasified spent solvents. Rh2O3/ CeOE-Al2O3 catalysts with various CeO2 loadings were prepared and heated at different temperatures of 500 and 800 ℃, and their surface properties were studied using X-ray diffraction （XRD）, X-ray photoelectron spectroscopy （XPS）, transmission electron microscopy （TEM）, temperature programmed reduction （TPR） and Bmmauer-Emmett-Teller （BET） analyses. Rhodium existed in the form of Rh2O3, regardless of the sample composition as well as the heating temperature. In the tested range of cerium addition （up to 12 times the rhodium mass）, no significant changes in BET surface areas and binding energy corresponding to Rh 3d5/2 were observed. Instead, the addition of cerium led to a greatly enhanced dispersion of rhodium nanoparticles, and no agglomeration of rhodium was observed for samples heated even at 800 ℃. Honeycomb monolith rhodium catalysts promoted with cerium were fabricated and tested for the steam reforming of a gasified spent solvent, mainly consisting of butylene （C4H8）. The test results suggested that a cerium-promoted rhodium catalyst could be used as an appropriate reforming catalyst for treating low-quality non-methane hydrocarbons without the formation of coke at high temperatures of up to 900 ℃.展开更多
By using the famous Wilkinson＇s catalyst, N-alkylation of sulfonamides can be easily realized under mild aerobic conditions by using alcohols as the alkylating reagent, giving monoalkylated sulfonamides in high yield...By using the famous Wilkinson＇s catalyst, N-alkylation of sulfonamides can be easily realized under mild aerobic conditions by using alcohols as the alkylating reagent, giving monoalkylated sulfonamides in high yields and selectivities with water produced as the only byproduct. This advantageous aerobic method is potentially general in substrate scope that it can also be applied to other amides, amines and alcohols.展开更多
Gas phase carbonylation of methane is studied in the presence of molecular oxygen over pure carbon carriers and carbon supported rhodium chalcogen halides. Activated carbons and fullerene blacks have been used as carb...Gas phase carbonylation of methane is studied in the presence of molecular oxygen over pure carbon carriers and carbon supported rhodium chalcogen halides. Activated carbons and fullerene blacks have been used as carbon supports. XPS and IR-spectroscopy data show the formation of rhodium chalcogen halides in solids prepared by different methods. We have found that the productivity of acetic acid by carbon supported rhodium chalcogen halides depends strongly on the carbon carrier and the method of the catalyst preparation. Namely, the catalyst with highest productivity for the acetic acid is prepared by synthesizing the rhodium chalcogen halide over the carbon support followed by thermal destruction. We have also found that rhodium chalcogen halides over activated carbons are more active compared with fullerene supported catalysts.展开更多
Three diphosphinites were synthesized for preparing rhodium-diphosphinite complexes. The complexes were used for asymmetric catalytic hydrogenation of amino acid precursor alpha-acetamidocinnamic acid and its methyl e...Three diphosphinites were synthesized for preparing rhodium-diphosphinite complexes. The complexes were used for asymmetric catalytic hydrogenation of amino acid precursor alpha-acetamidocinnamic acid and its methyl ester. With all complexes, D-amino acid is the most abundant product.展开更多
A new rhodium catalyzed ring opening reaction of oxabenzonorbornadienes and its derivatives was described. This reaction forms a new carbon-nitrogen bond via an intermolecular allylic displacement of the bridgehead o...A new rhodium catalyzed ring opening reaction of oxabenzonorbornadienes and its derivatives was described. This reaction forms a new carbon-nitrogen bond via an intermolecular allylic displacement of the bridgehead oxygen with a piperazine's derivatives, which proceeds with very high regioselectivity.展开更多
The synthesis of bo rylated orga nofluorines is of great interest due to their potential values as synthons in modular construction of fluorine-containing molecules.Reported herein is a rhodium-catalyzed hydrobo ratio...The synthesis of bo rylated orga nofluorines is of great interest due to their potential values as synthons in modular construction of fluorine-containing molecules.Reported herein is a rhodium-catalyzed hydrobo ration of arylgem-difluoroalkenes leading to a series of α-difluoromethylated benzylborons.The use of cationic rhodium catalyst and a biphosphine ligand with large bite angle was crucial for reactivity by offering good regioselectivity and diminishing the undesired β-F elimination.Preliminary derivatizations of the products were conducted to showcase the utility of this protocol.展开更多
Sulfoxonium ylides as carbene precursors couple smoothly with thioureas in the presence of 5 mol% of rhodium(Ⅱ) acetate dimmer via carbenoid insertion to afford the corresponding 2-aminothiazoles with high chemoselec...Sulfoxonium ylides as carbene precursors couple smoothly with thioureas in the presence of 5 mol% of rhodium(Ⅱ) acetate dimmer via carbenoid insertion to afford the corresponding 2-aminothiazoles with high chemoselectivity,providing a facile and efficient approach to access a variety of 2-aminothiazole derivatives with good functional groups tolerance.展开更多
The first theoretical study on the mechanism of [RhCl（CO）2]2-catalyzed [5 ＋ 1] cycloadditions of 3- acyloxy-1,4-enyne （ACE） and CO has been performed using density functional theory （DFT） calculations. The effe...The first theoretical study on the mechanism of [RhCl（CO）2]2-catalyzed [5 ＋ 1] cycloadditions of 3- acyloxy-1,4-enyne （ACE） and CO has been performed using density functional theory （DFT） calculations. The effect of ester on reactivity of this reaction has been investigated. The computational results have revealed that the preferred catalytic cycle involves the sequential steps of 1,2-acyloxy migration, CO insertion, reductive elimination to form ketene intermediate, 6π-electroncyclization, and aromatization to afford the resorcinol product. The 1,2-acyloxy migration is found to be the rate-determining step of the catalytic cycle. The electron-rich p-dimethylaminobenzoate substrate promotes 1,2-acyloxy migration and significantly increases the reactivity by stabilizing the positive charge building up in the oxocyclic transition state.展开更多
Vibrational and H-NMR spectroscopic studies on di-μ-chlorobis(1,5-cyclooctadiene) of iridium(I) and rhodium (I) complexes have been carried out. In addition, the two D2h and D2 structures for both complexes have been...Vibrational and H-NMR spectroscopic studies on di-μ-chlorobis(1,5-cyclooctadiene) of iridium(I) and rhodium (I) complexes have been carried out. In addition, the two D2h and D2 structures for both complexes have been fully optimized. It was expected from the single-molecule vapor-phase density functional theory (DFT) calculation that the D2 structure is more stable by 5 - 6 kcal/mol. While spectroscopic analysis study confirms that in the solid phase, the two complexes retain the higher D2h symmetry. The vibrational wavenumbers of certain modes associated to free 1,5-cyc- looctadiene were observed to be shifted to lower values upon coordination with rhodium or iridium metals. It was also found theoretically that the metal-olefin interaction is slightly more pronounced for iridium metal.展开更多
Rhodium-catalyzed cycloaddition reaction was calculated by density functional theory M06-2X method to directly synthesize benzoxepine and coumarin derivatives.In this work,we conducted a computational study of two com...Rhodium-catalyzed cycloaddition reaction was calculated by density functional theory M06-2X method to directly synthesize benzoxepine and coumarin derivatives.In this work,we conducted a computational study of two competitive mechanisms in which the carbon atom of acetylene or carbon monoxide attacked and inserted from two different directions of the six-membered ring reactant to clarify the principle characteristics of this transformation.The calculation results reveal that:(i)the insertion process of alkyne or carbon monoxide is the key step of the reaction;(ii)for the(5+2)cycloaddition reaction of acetylene,higher energy is required to break the Rh−O bond of the reactant,and the reaction tends to complete the insertion from the side of the Rh−C bond;(iii)for the(5+1)cycloaddition of carbon monoxide,both reaction paths have lower activation free energy,and the two will generate a competition mechanism.展开更多
基金Project supported by the National Natural Science Foundation of China(Nos.22071242,21871260)。
文摘Cyclopropenones have been extensively utilized in catalytic ring-opening and ring-expansion reactions for the synthesis of unsaturated carbonyl compounds.The first rhodium-catalyzed ring-opening reaction of aryl-/alkyl-substituted cyclopropenones is accomplished,successfully affording acyloin derivatives.This transformation represents a novel reaction pattern involving cyclopropenones.The resulting acyloin products constitute important building blocks in organic synthesis and serve as fundamental structural frameworks in numerous natural products.
文摘The Rh(III)-catalyzed C—H functionalization of sulfoxonium ylides and successively annulation with two classes of cyclic diazo compounds has been realized,affording structurally diverse fused-ring or spirocyclic compounds under redoxneutral conditions.The reaction proceeds via successive chelation-assisted C—H activation,carbene insertion,and intramolecular[3+3]/[4+1]annulation processes.
文摘In the search for new drugs with more efficient active ingredients, various transition metals are being explored as potential metallopharmaceuticals. These compounds, which combine drugs with metals, have shown promise as chemotherapeutic agents, akin to the accidental discovery of cisplatin and its organic derivatives in the late 20th century. This discovery transformed the sciences, particularly in the fields of organic and inorganic chemistry, by offering new insights into the compositions and molecular geometries of inorganic complexes through coordination chemistry, while also intersecting with other scientific domains such as pharmacology and medicine. To contribute to the development of new chemotherapeutic compounds through simple and reproducible synthetic processes, this study utilized rhodium(III) chloride hydrate (RhCl3.nH2O) to synthesize a series of compounds with the following organic N-heterocyclic ligands: 4,4'-dimethyl-2,2'-bipyridine, isonicotinamide, and N-(3-pyridyl)-isonicotinamide (3-pina). Two analytical techniques were employed to characterize the resulting materials: spectroscopic analysis in the infrared region, which suggested interactions and substitutions at the metal center by the organic compounds, and thermoanalytical analyses, which led to the proposal of minimum formulas for the compounds as follows: C1 [RhCl2(4,4'-Met-2,2'-bipy)2]Cl∙5/2H2O and C2 [Rh(4,4'-Met-2,2'-bipy)2(Iso)2] Cl3∙1/2H2O. However, the complexation of the third compound could not be confirmed due to the physicochemical characteristics of the resulting complex being very similar to those of the starting material, thereby validating the effectiveness of these techniques in differentiating and characterizing the synthesized salts. Due to their solubility in water and/or alcohol and thermal stability, the complexes were tested in biological media to assess cell viability in peripheral blood mononuclear cells. The solutions of these salts demonstrated favorable cell viability under the tested conditions, according to statistical analysis, obtaining average viability in the range of 95 ≤ x ≤ 100, with standard deviations between 3.29 ≤ x ≤ 4.44 for living cells.
基金National Natural Science Foundation of China(No.20862008)Natural Science Foundation of Jiangxi Province(No.2008GQH0034)for financial support
文摘The hydrosilylation of alkenes with triethoxysilane has been achieved at 120 C in the presence of 0.01 mol%of thioetherfunctionalized MCM-41 anchored rhodium complex,affording the corresponding addition products in 68-91%yields.This supported rhodium complex can be reused several times without noticeable loss of activity.Our system not only solves the basic problems of catalyst separation and recovery,but also avoids the use of phosphine ligands.
基金the National High Technology Research and Development Program of China(863 Program): (2012AA063203, 2012AA063204, 2012AA063207)
文摘A new process recycling rhodium from organic waste containing rhodium in acetic acid industry is developed. Use the special affinity of base metal sulfides (FeS, Ni2S3 , CuS, etc.) on platinum group metals, adopting high nickel matte trapping-aluminothermic activation method to recovery rhodium from incinerator residue of organic rhodium waste. The method is shorter process, lower equipment requirement, and the higher activity of rhodium black. In pyrometallurgy enrichment process,the recovery rate of rhodium reached 94.65%, the full flow of rhodium recovery rate was 92.04%.
文摘A highly efficient and selective[2+2+2]cyclization of diynes and monoalkynes was catalyzed by rhodium under room temperature in water/THF mixed solvent,affording isoindolines and isobenzofurans in good to excellent yields.The center atoms (N,O) in the diynes showed a significant effect for the cyclization.
基金supported by the Ministry of Education of China(IRT1148)the National Natural Science Foundation of China(U1732126,11804166,51602161,51372119)+3 种基金China Postdoctoral Science Foundation(2018M630587)the Priority Academic Program Development of Jiangsu Higher Education Institutions(YX03001)Guangdong Science and Technology Program(2017B030314002)Graduate Research Innovation Fund of Jiangsu Province(KYCX18_0863,KYCX18_0847,KYCX18_0869)。
文摘Organic cation and halide anion defects are omnipresent in the perovskite films,which will destroy perovskite electronic structure and downgrade the properties of devices.Defect passivation in halide perovskites is crucial to the application of solar cells.Herein,tiny amounts of trivalent rhodium ion incorporation can help the nucleation of perovskite grain and passivate the defects in the grain boundaries,which can improve efficiency and stability of perovskite solar cells.Through first-principle calculations,rhodium ion incorporation into the perovskite structure can induce ordered arrangement and tune bandgap.In experiment,rhodium ion incorporation with perovskite can contribute to preparing larger crystalline and uniform film,reducing trap-state density and enlarging charge carrier lifetime.After optimizing the content of 1% rhodium,the devices achieved an efficiency up to 20.71% without obvious hysteresis,from 19.09% of that pristine perovskite.In addition,the unencapsulated solar cells maintain 92% of its initial efficiency after 500 h in dry air.This work highlights the advantages of trivalent rhodium ion incorporation in the characteristics of perovskite solar cells,which will promote the future industrial application.
文摘Herein,we report for the first time the synthesis of preformed bimetallic Pd-Rh nanoparticles with different Pd:Rh ratios(nominal molar ratio:80-20,60-40,40-60,20-80) and the corresponding Pd and Rh monometallic ones by sol immobilization using polyvinyl alcohol(PVA) as protecting agent and NaBH4 as reducing agent,using carbon nanofibers with high graphitization degree(HHT) as the desired support.The synthesized catalysts were characterized by means of Transmission Electron Microscopy(TEM) and inductively coupled plasma optical emission spectroscopy(ICP-OES).TEM shows that the average particle size of the Pd-Rh nanoparticles is the range of 3-4 nm,with the presence of few large agglomerated nanoparticles.For bimetallic catalysts,EDX-STEM analysis of individual nanoparticles demonstrated the presence of random-alloyed nanoparticles even in all cases Rh content is lower than the nominal one(calculated Pd:Rh molar ratio:90-10,69-31,49-51,40-60).The catalytic performance of the Pd-Rh catalysts was evaluated in the liquid phase dehydrogenation of formic acid to H2.It was found that Pd-Rh molar ratio strongly influences the catalytic performance.Pd-rich catalysts were more active than Rh-rich ones,with the highest activity observed for Pd90:Rh10(1792 h^(-1)),whereas Pd69:Rh31(921 h^(-1)) resulted the most stable during recycling tests.Finally,Pd90:Rh10 was chosen as a representative sample for the liquid-phase hydrogenation of muconic acid using formic acid as hydrogen donor,showing good yield to adipic acid.
基金This work was supported by the National Natural Science Foundation of China(Nos.11705032,11675102,and 11975082)the Natural Science Foundation of Guangxi Province(No.2017GXNSFBA198175)the Science and Technology Major Project of Guangxi Province(No.AA17204100).
文摘A porous silica-polymer-based adsorbent,isoBuBTP/Si O2-P,was prepared by a vacuum impregnation method and used for the recovery of ruthenium,rhodium,and palladium from nitric acid solution.The experimental results revealed that iso Bu-BTP/SiO2-P exhibited unique adsorption properties such as high saturation adsorption capacity(Ru:0.35 mmol g^-1,Rh:0.32 mmol g^-1,Pd:1.05 mmol g^-1)and excellent selectivity over other metal ions,such as lanthanides(SF(PGM/M)>40)in 1 M HNO3 solution.The adsorption process conformed to the pseudosecond-order model and Langmuir model.From the UV,FTIR,and XPS analyses,it can be concluded that the strong affinity between functional groups(C–N=C)and metal ions as well as NO3-played a role in coordination during the adsorption process.Furthermore,the desorption behavior was studied,and it was found that the adsorbed Pd,Rh,and Ru could be eluted with a 0.01 M nitric acid–0.1M thiocarbamide solution,5M hydrochloric acid,and sodium hypochlorite(CP)solution,respectively.Finally,based on those findings,a simple process for the separation and recovery of Pd,Rh,and Ru from high-level liquid waste using iso Bu-BTP/SiO2-P was designed and proposed.
基金partial financial support from the Ministry of Science and Technology of China (No. 2016YFE0132600)Zhengzhou University
文摘Rhodium(Ⅲ)-catalyzed synthesis of indole derivatives has been realized via cascade reaction of C -H alkylation/nucleophilic cyclization starting from readily available N-phenylpyridin-2-amines and sulfoxonium ylides. Notably, this transformation could smoothly proceed with high yields, good regioselectivity, and feature broad group tolerance and under redox-neutral condition to avoid external oxidant. The titled products are potentially important building blocks in the organic synthesis through various chemical transformations.
基金Project supported by the National Research Foundation of Korea(NRF)by the Korea government(MSIP)(NRF-2012M2A8A5025658)
文摘This study attempted to develop an appropriate catalyst used for the steam reforming of gasified spent solvents. Rh2O3/ CeOE-Al2O3 catalysts with various CeO2 loadings were prepared and heated at different temperatures of 500 and 800 ℃, and their surface properties were studied using X-ray diffraction （XRD）, X-ray photoelectron spectroscopy （XPS）, transmission electron microscopy （TEM）, temperature programmed reduction （TPR） and Bmmauer-Emmett-Teller （BET） analyses. Rhodium existed in the form of Rh2O3, regardless of the sample composition as well as the heating temperature. In the tested range of cerium addition （up to 12 times the rhodium mass）, no significant changes in BET surface areas and binding energy corresponding to Rh 3d5/2 were observed. Instead, the addition of cerium led to a greatly enhanced dispersion of rhodium nanoparticles, and no agglomeration of rhodium was observed for samples heated even at 800 ℃. Honeycomb monolith rhodium catalysts promoted with cerium were fabricated and tested for the steam reforming of a gasified spent solvent, mainly consisting of butylene （C4H8）. The test results suggested that a cerium-promoted rhodium catalyst could be used as an appropriate reforming catalyst for treating low-quality non-methane hydrocarbons without the formation of coke at high temperatures of up to 900 ℃.
基金the National Natural Science Foundation of China(No.20902070)Natural Science Foundation of Zhejiang Province(No.Y4100579)Qianjiang Talents Program(No.QJD0902004) of Zhejiang Province for financial supports
文摘By using the famous Wilkinson＇s catalyst, N-alkylation of sulfonamides can be easily realized under mild aerobic conditions by using alcohols as the alkylating reagent, giving monoalkylated sulfonamides in high yields and selectivities with water produced as the only byproduct. This advantageous aerobic method is potentially general in substrate scope that it can also be applied to other amides, amines and alcohols.
文摘Gas phase carbonylation of methane is studied in the presence of molecular oxygen over pure carbon carriers and carbon supported rhodium chalcogen halides. Activated carbons and fullerene blacks have been used as carbon supports. XPS and IR-spectroscopy data show the formation of rhodium chalcogen halides in solids prepared by different methods. We have found that the productivity of acetic acid by carbon supported rhodium chalcogen halides depends strongly on the carbon carrier and the method of the catalyst preparation. Namely, the catalyst with highest productivity for the acetic acid is prepared by synthesizing the rhodium chalcogen halide over the carbon support followed by thermal destruction. We have also found that rhodium chalcogen halides over activated carbons are more active compared with fullerene supported catalysts.
文摘Three diphosphinites were synthesized for preparing rhodium-diphosphinite complexes. The complexes were used for asymmetric catalytic hydrogenation of amino acid precursor alpha-acetamidocinnamic acid and its methyl ester. With all complexes, D-amino acid is the most abundant product.
文摘A new rhodium catalyzed ring opening reaction of oxabenzonorbornadienes and its derivatives was described. This reaction forms a new carbon-nitrogen bond via an intermolecular allylic displacement of the bridgehead oxygen with a piperazine's derivatives, which proceeds with very high regioselectivity.
基金financial support from the National Natural Science Foundation of China(No.21971261)Guangdong Provincial Key Laboratory of Chiral Molecule and Drug Discovery(No.2019B030301005)+1 种基金Key Project of Chinese National Programs for Fundamental Research and Development(No.2016YFA0602900)the Local Innovative and Research Teams Project of Guangdong Pearl River Talents Program(No.2017BT01Y093)is gratefully acknowledged。
文摘The synthesis of bo rylated orga nofluorines is of great interest due to their potential values as synthons in modular construction of fluorine-containing molecules.Reported herein is a rhodium-catalyzed hydrobo ration of arylgem-difluoroalkenes leading to a series of α-difluoromethylated benzylborons.The use of cationic rhodium catalyst and a biphosphine ligand with large bite angle was crucial for reactivity by offering good regioselectivity and diminishing the undesired β-F elimination.Preliminary derivatizations of the products were conducted to showcase the utility of this protocol.
基金support from the National Natural Science Foundation of China (Nos.81373259 and 81573286)Sichuan Science and Technology Program (Nos.2020YJ0221 and 2018JY0537)。
文摘Sulfoxonium ylides as carbene precursors couple smoothly with thioureas in the presence of 5 mol% of rhodium(Ⅱ) acetate dimmer via carbenoid insertion to afford the corresponding 2-aminothiazoles with high chemoselectivity,providing a facile and efficient approach to access a variety of 2-aminothiazole derivatives with good functional groups tolerance.
基金Tianjin Natural Science Foundation (No.14JCYBJC20100 X.X.)MOE Innovation Teams (Nos.IRT-13R30 and IRT13022) of ChinaNIH (No.R01GM088285 W.T.) for financial support
文摘The first theoretical study on the mechanism of [RhCl（CO）2]2-catalyzed [5 ＋ 1] cycloadditions of 3- acyloxy-1,4-enyne （ACE） and CO has been performed using density functional theory （DFT） calculations. The effect of ester on reactivity of this reaction has been investigated. The computational results have revealed that the preferred catalytic cycle involves the sequential steps of 1,2-acyloxy migration, CO insertion, reductive elimination to form ketene intermediate, 6π-electroncyclization, and aromatization to afford the resorcinol product. The 1,2-acyloxy migration is found to be the rate-determining step of the catalytic cycle. The electron-rich p-dimethylaminobenzoate substrate promotes 1,2-acyloxy migration and significantly increases the reactivity by stabilizing the positive charge building up in the oxocyclic transition state.
文摘Vibrational and H-NMR spectroscopic studies on di-μ-chlorobis(1,5-cyclooctadiene) of iridium(I) and rhodium (I) complexes have been carried out. In addition, the two D2h and D2 structures for both complexes have been fully optimized. It was expected from the single-molecule vapor-phase density functional theory (DFT) calculation that the D2 structure is more stable by 5 - 6 kcal/mol. While spectroscopic analysis study confirms that in the solid phase, the two complexes retain the higher D2h symmetry. The vibrational wavenumbers of certain modes associated to free 1,5-cyc- looctadiene were observed to be shifted to lower values upon coordination with rhodium or iridium metals. It was also found theoretically that the metal-olefin interaction is slightly more pronounced for iridium metal.
基金This work was supported by the Natural Science Foundation of Gansu Province(20JR5RA479)the Outstanding Youth Research Program of Lanzhou University of Arts and Sciences(2018JCQN008).
文摘Rhodium-catalyzed cycloaddition reaction was calculated by density functional theory M06-2X method to directly synthesize benzoxepine and coumarin derivatives.In this work,we conducted a computational study of two competitive mechanisms in which the carbon atom of acetylene or carbon monoxide attacked and inserted from two different directions of the six-membered ring reactant to clarify the principle characteristics of this transformation.The calculation results reveal that:(i)the insertion process of alkyne or carbon monoxide is the key step of the reaction;(ii)for the(5+2)cycloaddition reaction of acetylene,higher energy is required to break the Rh−O bond of the reactant,and the reaction tends to complete the insertion from the side of the Rh−C bond;(iii)for the(5+1)cycloaddition of carbon monoxide,both reaction paths have lower activation free energy,and the two will generate a competition mechanism.
