The reaction of a ruthenium carbide complex RuCl2（C：）（PCy3）2 with [H（Et2O）x]＋[BF4]- at a molar ratio of 1：2 produced a two-core ruthenium carbene complex, {[RuCl（=CHPCy3）（PCy3）]2（μ-Cl）3}＋·[BF4]-,...The reaction of a ruthenium carbide complex RuCl2（C：）（PCy3）2 with [H（Et2O）x]＋[BF4]- at a molar ratio of 1：2 produced a two-core ruthenium carbene complex, {[RuCl（=CHPCy3）（PCy3）]2（μ-Cl）3}＋·[BF4]-, in the form of a yellow-green crystalline solid in a yield of 94%. This two-core ruthenium complex is a selective catalyst for ring closing metathesis of unsubstituted terminal dienes. More importantly, no isomerized byproduct was observed for N-substrates when the two-core ruthenium complex was used as the catalyst at an elevated temperature（137 °C）, indicating that the complex is a chemo-selective catalyst for ring closing metathesis reactions.展开更多
As a renewable biomass-based compound with wide applications in food additives,fine chemical synthesis and fuels,γ-valerolactone(GVL)has attached much attention.While,pyrrolidones are widely used in pharmaceutical,ag...As a renewable biomass-based compound with wide applications in food additives,fine chemical synthesis and fuels,γ-valerolactone(GVL)has attached much attention.While,pyrrolidones are widely used in pharmaceutical,agrochemical,material industrial and other chemical production.In this research,we demonstrated transformations of biomass-based ethyl levulinate(EL)into GVL and pyrrolidones by using heterogeneous catalysts(CNT-Ru-1)with N-heterocyclic carbene ruthenium(NHC-Ru)complex grafted on multi-walled carbon nanotube(CNT).The Ru catalyst showed high efficiency on EL hydrogenation to GVL with both EL conversion and GVL yield exceeding 99%.Moreover,the Ru catalyst readily promoted reductive amination of EL in the presence of various amines for pyrrolidone synthesis.Finally,the Ru catalyst was also applicable to hydrogenation of various carbonyl compounds for the synthesis of the corresponding alcohols with excellent catalytic performance.The research provides insight for heterogenizing the homogeneous noble metal-based catalysts with high catalytic active for biomass-based transformations.展开更多
Herein,we present a method for the homogeneous hydrogenation of nitroarenes to produce anilines using low catalyst loading(1 mo%)of copper N-heterocyclic carbene complexes as the catalyst and ammonia borane as the sou...Herein,we present a method for the homogeneous hydrogenation of nitroarenes to produce anilines using low catalyst loading(1 mo%)of copper N-heterocyclic carbene complexes as the catalyst and ammonia borane as the source of hydrogen.A wide range of nitroarenes,featuring diverse functional groups,were selectively transformed into their corresponding primary aromatic amines with high yields.This process can be readily scaled up and exhibits compatibility with various sensitive functional groups,including halogen,trifluoromethyl,aminomethyl,alkenyl,cyano,ester,amide,and hydroxyl.Notably,this catalytic methodology finds application in the synthesis of essential drug compounds.Mechanistic investigations suggest that the in-situ-generated Cu-H species may serve as active intermediates,with reduction pathways involving species such as azobenzene,1,2-diphenylhydrazine,nitrosobenzene,and N-phenylhydroxylamine.展开更多
A new class of luminescent mechanochromic cyclometalated Ir(Ⅲ)complexes with pyridyl acyclic carbene ligands have been developed.These complexes shown predominant MLCT phosphorescence mixed with^(3)LC character.In th...A new class of luminescent mechanochromic cyclometalated Ir(Ⅲ)complexes with pyridyl acyclic carbene ligands have been developed.These complexes shown predominant MLCT phosphorescence mixed with^(3)LC character.In the solid state and neat film,the emission of these complexes show significant red-shift upon mechanical grinding.展开更多
The reactivity of PCcarbeneP iron carbenes,[{PC(sp^(2))P}Fe(L)(N_(2))](1-L,L=NC^(t)Bu,PMe_(3)),was investigated toward imines,ketones,diazenes,2-vinylpyridine,and 8-methylquinoline,and revealed the directed activation...The reactivity of PCcarbeneP iron carbenes,[{PC(sp^(2))P}Fe(L)(N_(2))](1-L,L=NC^(t)Bu,PMe_(3)),was investigated toward imines,ketones,diazenes,2-vinylpyridine,and 8-methylquinoline,and revealed the directed activation of aryl,vinyl,or benzyl C–H bonds by 1,2-addition across the iron-carbene bond.Our results support a syn 1,2-addition of these bonds,suggesting a metal–ligand cooperative process for the activation of these substrates.These findings highlight the potential of iron-carbene complexes in C–H activation processes,and deviate from the traditional mechanisms employed for iron promoted C–H activations.展开更多
Chiral C2-symmetric N-heterocyclic carbene （NHC） palladium diaquo complex 5b prepared from （S）-BINAM was found to be a fairly effective catalyst for the enantioselective asymmetric fluorination of oxindoles to giv...Chiral C2-symmetric N-heterocyclic carbene （NHC） palladium diaquo complex 5b prepared from （S）-BINAM was found to be a fairly effective catalyst for the enantioselective asymmetric fluorination of oxindoles to give the corresponding products in moderate enantioselectivities along with good to excellent yields.展开更多
Homoleptic Ir_((III))based carbene complexes are known to be the most promising emitters of future blue OLED devices.To provide the proof-of-concept,we designed a series of functional di-CF_(3)-functionalized benzo[d]...Homoleptic Ir_((III))based carbene complexes are known to be the most promising emitters of future blue OLED devices.To provide the proof-of-concept,we designed a series of functional di-CF_(3)-functionalized benzo[d]imidazol-3-ium pro-chelates,which could afford single product emitters after proper modification.For benzoimidazol-2-ylidene with an N-methyl substituent,selective formation of the product can be achieved by introduction of t-butylphenyl for the phenyl group,as shown by shifting the product from mixed m-Ir(dfp)_(3)and f-Ir(dfp)_(3)to the single isomer f-Ir(dfpb)_(3).Alternatively,for di-N-aryl substituted carbene chelates,the steric encumbrance imposed between the ortho-CF_(3)group and the adjacent N-aryl substituent redirects the cyclometalation to the other N-aryl substituent,leading to the formation of one single product,e.g.,f-Ir(tBpp)_(3)and f-Ir(ptBp)_(3).Moreover,the doped OLED based on f-Ir(tBpp)_(3)delivered true-blue emission centered at 457 nm and a maximum EQE of 15.6%.Furthermore,upon addition of terminal emittersν-DABNA and t-DABNA,the respective hyper^(-)OLEDs exhibited narrowband blue emission with a maximum EQE of 18.9%at 474 nm and 18.1%at 462 nm,respectively.These highlighted the potential of these Ir_((III))emitters in the fabrication of blue OLEDs.展开更多
基金Supported by the National Natural Science Foundation of China(No.20872108)
文摘The reaction of a ruthenium carbide complex RuCl2（C：）（PCy3）2 with [H（Et2O）x]＋[BF4]- at a molar ratio of 1：2 produced a two-core ruthenium carbene complex, {[RuCl（=CHPCy3）（PCy3）]2（μ-Cl）3}＋·[BF4]-, in the form of a yellow-green crystalline solid in a yield of 94%. This two-core ruthenium complex is a selective catalyst for ring closing metathesis of unsubstituted terminal dienes. More importantly, no isomerized byproduct was observed for N-substrates when the two-core ruthenium complex was used as the catalyst at an elevated temperature（137 °C）, indicating that the complex is a chemo-selective catalyst for ring closing metathesis reactions.
基金the financial support from the National Natural Science Foundation of China(U1810111,51872124 and21676116)Natural Science Foundation of Guangdong Province,China(2018B030311010)+1 种基金the Fundamental Research Funds for the Central Universities(21617431)Key Laboratory of Biomass Chemical Engineering of Ministry of Education,Zhejiang University(2018BCE002)
文摘As a renewable biomass-based compound with wide applications in food additives,fine chemical synthesis and fuels,γ-valerolactone(GVL)has attached much attention.While,pyrrolidones are widely used in pharmaceutical,agrochemical,material industrial and other chemical production.In this research,we demonstrated transformations of biomass-based ethyl levulinate(EL)into GVL and pyrrolidones by using heterogeneous catalysts(CNT-Ru-1)with N-heterocyclic carbene ruthenium(NHC-Ru)complex grafted on multi-walled carbon nanotube(CNT).The Ru catalyst showed high efficiency on EL hydrogenation to GVL with both EL conversion and GVL yield exceeding 99%.Moreover,the Ru catalyst readily promoted reductive amination of EL in the presence of various amines for pyrrolidone synthesis.Finally,the Ru catalyst was also applicable to hydrogenation of various carbonyl compounds for the synthesis of the corresponding alcohols with excellent catalytic performance.The research provides insight for heterogenizing the homogeneous noble metal-based catalysts with high catalytic active for biomass-based transformations.
基金financial support from the National Natural Science Foundation of China(22061041)Key Project of Science&Technology of Shaanxi Province(2023-YBGY-430)+5 种基金Project of Science&Technology Bureau of Yulin City(CXY-2022-185)Doctoral Research Foundation of Yan'an University(YDBK2019-60)the Training Program of Innovation and Entrepreneurship for Undergraduates of Yan'an University(D2022077)Research Program of Yan'an University(YDY2020-61)the Youth Innovation Team Project of Shaanxi Provincial Education Department(No.23JP193)National Science Foundation of Shaanxi Province(S2023-JC-QN-0079).
文摘Herein,we present a method for the homogeneous hydrogenation of nitroarenes to produce anilines using low catalyst loading(1 mo%)of copper N-heterocyclic carbene complexes as the catalyst and ammonia borane as the source of hydrogen.A wide range of nitroarenes,featuring diverse functional groups,were selectively transformed into their corresponding primary aromatic amines with high yields.This process can be readily scaled up and exhibits compatibility with various sensitive functional groups,including halogen,trifluoromethyl,aminomethyl,alkenyl,cyano,ester,amide,and hydroxyl.Notably,this catalytic methodology finds application in the synthesis of essential drug compounds.Mechanistic investigations suggest that the in-situ-generated Cu-H species may serve as active intermediates,with reduction pathways involving species such as azobenzene,1,2-diphenylhydrazine,nitrosobenzene,and N-phenylhydroxylamine.
基金supported by the General Research Fund(Project No.CityU 11306217 and CityU 11303318).
文摘A new class of luminescent mechanochromic cyclometalated Ir(Ⅲ)complexes with pyridyl acyclic carbene ligands have been developed.These complexes shown predominant MLCT phosphorescence mixed with^(3)LC character.In the solid state and neat film,the emission of these complexes show significant red-shift upon mechanical grinding.
基金supported by the Natural Science Foundation(award number:2102517).
文摘The reactivity of PCcarbeneP iron carbenes,[{PC(sp^(2))P}Fe(L)(N_(2))](1-L,L=NC^(t)Bu,PMe_(3)),was investigated toward imines,ketones,diazenes,2-vinylpyridine,and 8-methylquinoline,and revealed the directed activation of aryl,vinyl,or benzyl C–H bonds by 1,2-addition across the iron-carbene bond.Our results support a syn 1,2-addition of these bonds,suggesting a metal–ligand cooperative process for the activation of these substrates.These findings highlight the potential of iron-carbene complexes in C–H activation processes,and deviate from the traditional mechanisms employed for iron promoted C–H activations.
文摘Chiral C2-symmetric N-heterocyclic carbene （NHC） palladium diaquo complex 5b prepared from （S）-BINAM was found to be a fairly effective catalyst for the enantioselective asymmetric fluorination of oxindoles to give the corresponding products in moderate enantioselectivities along with good to excellent yields.
基金supported by funding from the Research Grant Council(CityU 11304221 and CityU 11312722)the City University of Hong Kong,Hong Kong SAR。
文摘Homoleptic Ir_((III))based carbene complexes are known to be the most promising emitters of future blue OLED devices.To provide the proof-of-concept,we designed a series of functional di-CF_(3)-functionalized benzo[d]imidazol-3-ium pro-chelates,which could afford single product emitters after proper modification.For benzoimidazol-2-ylidene with an N-methyl substituent,selective formation of the product can be achieved by introduction of t-butylphenyl for the phenyl group,as shown by shifting the product from mixed m-Ir(dfp)_(3)and f-Ir(dfp)_(3)to the single isomer f-Ir(dfpb)_(3).Alternatively,for di-N-aryl substituted carbene chelates,the steric encumbrance imposed between the ortho-CF_(3)group and the adjacent N-aryl substituent redirects the cyclometalation to the other N-aryl substituent,leading to the formation of one single product,e.g.,f-Ir(tBpp)_(3)and f-Ir(ptBp)_(3).Moreover,the doped OLED based on f-Ir(tBpp)_(3)delivered true-blue emission centered at 457 nm and a maximum EQE of 15.6%.Furthermore,upon addition of terminal emittersν-DABNA and t-DABNA,the respective hyper^(-)OLEDs exhibited narrowband blue emission with a maximum EQE of 18.9%at 474 nm and 18.1%at 462 nm,respectively.These highlighted the potential of these Ir_((III))emitters in the fabrication of blue OLEDs.
