An efficient copper-catalyzed decarboxylative hydroboration of phenylpropiolic acids with bis（pinacolato）diboron was developed, affording b-vinylboronates as the only products in high yields. Extra hydrogen sources ...An efficient copper-catalyzed decarboxylative hydroboration of phenylpropiolic acids with bis（pinacolato）diboron was developed, affording b-vinylboronates as the only products in high yields. Extra hydrogen sources such as methanol are not needed in this catalytic system. This reaction could be performed successfully under ligand- and base-free conditions. It demonstrated that phenylpropiolic acids can be employed as alkyne synthons in the hydroboration reaction and exhibited good reactivity and higher selectivity than terminal alkynes.展开更多
The low-efficiency CO_(2) uptake capacity and insufficient photogenerated exciton dissociation of current metal halide perovskite(MHP)nanocrystals with end-capping ligands extremely restrict their application in the f...The low-efficiency CO_(2) uptake capacity and insufficient photogenerated exciton dissociation of current metal halide perovskite(MHP)nanocrystals with end-capping ligands extremely restrict their application in the field of artificial photosynthesis.Herein,we demonstrate that ligand-free CsPbBr_(3) with calliandralike nanostructure(LF-CPB CL)can be synthesized easily through a ligand-free seed-assisted dissolutionrecrystallization growth process,exhibiting significantly enhanced CO_(2) uptake capacity.More specifically,the abundant surface bromine(Br)vacancies in ligand-free MHP materials are demonstrated to be beneficial to photogenerated carrier separation.The electron consumption rate of LF-CPB CL for photocatalytic CO_(2) reduction increases 7 and 20 times over those of traditional ligand-capping CsPbBr_(3)nanocrystal(L-CPB NC)and bulk CsPbBr_(3),respectively.Moreover,the absence of ligand hindrance can facilitate the interfacial electronic coupling between LF-CPB CL and tetra(4-carboxyphenyl)porphyrin iron(Ⅲ)chloride(Fe-TCPP)cocatalyst,bringing forth significantly accelerated interfacial charge separation.The LF-CPB CL/Fe-TCPP exhibits a total electron consumption rate of 145.6μmol g^(-1) h^(-1) for CO_(2)photoreduction coupled with water oxidation which is over 14 times higher than that of L-CPB NC/FeTCPP.展开更多
A ligand-free nickel-catalyzed Kumada cross-coupling of aryl bromides and tert-butyl Grignard reagents led to the formation of a series of tert-butyl aryls in moderate to good yields, excellent tBu/iBu ratios, and goo...A ligand-free nickel-catalyzed Kumada cross-coupling of aryl bromides and tert-butyl Grignard reagents led to the formation of a series of tert-butyl aryls in moderate to good yields, excellent tBu/iBu ratios, and good functional group compatibility. A radical coupling process is indicated and a mechanism with a Ni(Ⅰ)-Ni(Ⅲ) catalytic cycle is proposed.展开更多
Aerobic oxidation of electron-rich benzylic and phenyl allylic alcohols was achieved with high yields with only 0.1 mol.% of Pd(OAc)2 catalyst in the absence of any ligand. This procedure was expected to be valuable f...Aerobic oxidation of electron-rich benzylic and phenyl allylic alcohols was achieved with high yields with only 0.1 mol.% of Pd(OAc)2 catalyst in the absence of any ligand. This procedure was expected to be valuable for realistic industrial-scale applications from both economic as well as environmental points of view.展开更多
We developed a simple and efficient Cu（II）-catalyzed ligand-free oxidation of diarylmethanes and secondary alcohols using 70% ten-butyl hydroperoxide （TBHP） in water. A series of diarylmethanes were directly oxidi...We developed a simple and efficient Cu（II）-catalyzed ligand-free oxidation of diarylmethanes and secondary alcohols using 70% ten-butyl hydroperoxide （TBHP） in water. A series of diarylmethanes were directly oxidized into diaryl ketones in 67%--98% yields. Additionally, various secondary alcohols were also transformed into the desired products in 48%--98% yields. Importantly, the catalytic system in the absence of any organic solvent, surfactant, or phase transfer agent, had a wide substrate scope and a high tolerance for various functional groups.展开更多
Symmetrical diynes were synthesized by ligand-free copper-catalyzed homocoupling reaction of 1,1-dibromo-1- alkenes using a DBU/DMSO system at room temperature in good to excellent yields.
A simple and efficient protocol for Fe/Cu cocatalyzed oxidative homocoupling reaction of terminal alkynes to symmetrical 1,4-disubstituted-l,3-diynes was presented. The results showed that both CuBr and FeC13 played e...A simple and efficient protocol for Fe/Cu cocatalyzed oxidative homocoupling reaction of terminal alkynes to symmetrical 1,4-disubstituted-l,3-diynes was presented. The results showed that both CuBr and FeC13 played erucial roles in the reaction. It is noteworthy that this protocol employs mild, efficient, aerobic and ligand free conditions. The alkynes, including aromatic, heteroaromatic and aliphatic alkynes, were transformed into the corresponding 1,3-diynes in good to excellent yields.展开更多
The synthesis of N-cyclohexyl carbamate-attached fluorene-alt-phenylene copolymer(PFPNCC)and the use of PFPNCC as a“ligand-free”fluorescent chemosensor for Cu(Ⅱ)are described.Addition of Cu(Ⅱ)can efficiently quenc...The synthesis of N-cyclohexyl carbamate-attached fluorene-alt-phenylene copolymer(PFPNCC)and the use of PFPNCC as a“ligand-free”fluorescent chemosensor for Cu(Ⅱ)are described.Addition of Cu(Ⅱ)can efficiently quench the fluorescence of PFPNCC in nucleophilic solvents such as DMF and DMSO,but not in low nucleophilic solvents such as 1,4-dioxane and THF.Ultraviolet-visible spectra of the mixture of the conjugated polymer and Cu(Ⅱ)indicate the presence of a reduced Cu(Ⅰ)ion in the solution.Furthermore,fluorescence recovery of PFPNCC observed at low temperature suggests that the quenching and reducing mechanism is most probably due to a photo-induced electron transfer from excited PFPNCC to Cu(Ⅱ).Our findings provide a novel strategy for highly selective conjugated polymer-based chemosensors for various target analytes,albeit“ligand-free”.展开更多
The boron trifluoride induced Suzuki-Miyaura cross-coupling of aryltriazenes with arylboronic acids catalyzed by Pd（OAc）2 without added ligands has been achieved for the first time. The reactions performed at room t...The boron trifluoride induced Suzuki-Miyaura cross-coupling of aryltriazenes with arylboronic acids catalyzed by Pd（OAc）2 without added ligands has been achieved for the first time. The reactions performed at room temperature under an argon atmosphere give biaryls in good to excellent yields. It is noteworthy that the reactions were conducted under mild and ligand-free conditions.展开更多
In the absence of any ligand, a recoverable palladium（O） on poly（vinylpyrrolidone） （PVP） catalyzed Suzuki reaction of aryl iodide and bromide with potassium aryltrifluoroborate was developed. The reaction condit...In the absence of any ligand, a recoverable palladium（O） on poly（vinylpyrrolidone） （PVP） catalyzed Suzuki reaction of aryl iodide and bromide with potassium aryltrifluoroborate was developed. The reaction conditions involved the use of water as the solvent, potassium carbonate as the base, and PVP supported palladium metal colloids as the catalyst. The palladium metal could be recovered and recycled for eight consecutive trials without significant loss of its activity.展开更多
A general synthesis of 1-aryl-l-H-indazoles from o-halogenated aryl aldehydes or ketones and aryl hydrazines was described. This protocol included an intermolecular condensation and a ligand-free copper-catalyzed intr...A general synthesis of 1-aryl-l-H-indazoles from o-halogenated aryl aldehydes or ketones and aryl hydrazines was described. This protocol included an intermolecular condensation and a ligand-free copper-catalyzed intramolecular Ullmann-type coupling reaction. This method was applied to a wide range of substrates to produce the indazole products in good yields.展开更多
基金Financial support from the National Science Foundation of China (No. 21202049)the Recruitment Program of Global Experts (1000 Talents Plan)+2 种基金Fujian Hundred Talents PlanProgram of Innovative Research Team of Huaqiao UniversityInstrumental Analysis Center of Huaqiao University for analysis support
文摘An efficient copper-catalyzed decarboxylative hydroboration of phenylpropiolic acids with bis（pinacolato）diboron was developed, affording b-vinylboronates as the only products in high yields. Extra hydrogen sources such as methanol are not needed in this catalytic system. This reaction could be performed successfully under ligand- and base-free conditions. It demonstrated that phenylpropiolic acids can be employed as alkyne synthons in the hydroboration reaction and exhibited good reactivity and higher selectivity than terminal alkynes.
基金financially supported by the Natural Science Foundation of Tianjin City(17JCJQJC43800)the National Key R&D Program of China(2017YFA0700104)+1 种基金the National Science Foundation of China(21931007,U21A20286)Jiangsu Funding Program for Excellent Postdoctoral Talent and the 111 Project of China(D17003)。
文摘The low-efficiency CO_(2) uptake capacity and insufficient photogenerated exciton dissociation of current metal halide perovskite(MHP)nanocrystals with end-capping ligands extremely restrict their application in the field of artificial photosynthesis.Herein,we demonstrate that ligand-free CsPbBr_(3) with calliandralike nanostructure(LF-CPB CL)can be synthesized easily through a ligand-free seed-assisted dissolutionrecrystallization growth process,exhibiting significantly enhanced CO_(2) uptake capacity.More specifically,the abundant surface bromine(Br)vacancies in ligand-free MHP materials are demonstrated to be beneficial to photogenerated carrier separation.The electron consumption rate of LF-CPB CL for photocatalytic CO_(2) reduction increases 7 and 20 times over those of traditional ligand-capping CsPbBr_(3)nanocrystal(L-CPB NC)and bulk CsPbBr_(3),respectively.Moreover,the absence of ligand hindrance can facilitate the interfacial electronic coupling between LF-CPB CL and tetra(4-carboxyphenyl)porphyrin iron(Ⅲ)chloride(Fe-TCPP)cocatalyst,bringing forth significantly accelerated interfacial charge separation.The LF-CPB CL/Fe-TCPP exhibits a total electron consumption rate of 145.6μmol g^(-1) h^(-1) for CO_(2)photoreduction coupled with water oxidation which is over 14 times higher than that of L-CPB NC/FeTCPP.
基金the Strategic Priority Research Program of the Chinese Academy of Sciences(No. XDB20000000)CAS (No. QYZDY-SSW-SLH029)+2 种基金National Natural Science Foundation of China (Nos. 21725205, 21432007, 21572246)STCSM18520712200K.C. Wong Education Foundation
文摘A ligand-free nickel-catalyzed Kumada cross-coupling of aryl bromides and tert-butyl Grignard reagents led to the formation of a series of tert-butyl aryls in moderate to good yields, excellent tBu/iBu ratios, and good functional group compatibility. A radical coupling process is indicated and a mechanism with a Ni(Ⅰ)-Ni(Ⅲ) catalytic cycle is proposed.
文摘Aerobic oxidation of electron-rich benzylic and phenyl allylic alcohols was achieved with high yields with only 0.1 mol.% of Pd(OAc)2 catalyst in the absence of any ligand. This procedure was expected to be valuable for realistic industrial-scale applications from both economic as well as environmental points of view.
基金We gratefully acknowledge financial support of this work by the National Natural Science Foundation of China （No. 21563025）, Shihezi University Training Programme for Distinguished Youth Scholars （No. 2014ZRKXJQ05）, and Start-Up Foundation for Young Scientists of Shihezi University （RCZX201408）.
文摘We developed a simple and efficient Cu（II）-catalyzed ligand-free oxidation of diarylmethanes and secondary alcohols using 70% ten-butyl hydroperoxide （TBHP） in water. A series of diarylmethanes were directly oxidized into diaryl ketones in 67%--98% yields. Additionally, various secondary alcohols were also transformed into the desired products in 48%--98% yields. Importantly, the catalytic system in the absence of any organic solvent, surfactant, or phase transfer agent, had a wide substrate scope and a high tolerance for various functional groups.
基金Project supported by the National Natural Science Foundation of China （No. 30873153）, and the Key Projects of Shanghai in Biomedical （No. 08431902700）.
文摘Symmetrical diynes were synthesized by ligand-free copper-catalyzed homocoupling reaction of 1,1-dibromo-1- alkenes using a DBU/DMSO system at room temperature in good to excellent yields.
基金We are grateful for financial support from the National Natural Science Foundation of China，the Priority Academic Program Development of Jiangsu Higher Education Institutions
文摘A simple and efficient protocol for Fe/Cu cocatalyzed oxidative homocoupling reaction of terminal alkynes to symmetrical 1,4-disubstituted-l,3-diynes was presented. The results showed that both CuBr and FeC13 played erucial roles in the reaction. It is noteworthy that this protocol employs mild, efficient, aerobic and ligand free conditions. The alkynes, including aromatic, heteroaromatic and aliphatic alkynes, were transformed into the corresponding 1,3-diynes in good to excellent yields.
基金supported by the National Basic Research Program of China(Grant No.2015CB932200)the National Natural Science Foundation of China(Grant Nos.21604042,61378081,21574064,and 21674048)+2 种基金Synergetic Innovation Center for Organic Electronics and Information Displays,Jiangsu National Synergetic Innovation Center for Advanced Materials,the Natural Science Foundation of Jiangsu Province of China(No.BK20150843)NUPTSF(Nos.NY215017,NY211003,and NY215080)the Innovation Program for Postgraduates Research of Colleges and Universities of Jiangsu Province(No.CXZZ12-0459).
文摘The synthesis of N-cyclohexyl carbamate-attached fluorene-alt-phenylene copolymer(PFPNCC)and the use of PFPNCC as a“ligand-free”fluorescent chemosensor for Cu(Ⅱ)are described.Addition of Cu(Ⅱ)can efficiently quench the fluorescence of PFPNCC in nucleophilic solvents such as DMF and DMSO,but not in low nucleophilic solvents such as 1,4-dioxane and THF.Ultraviolet-visible spectra of the mixture of the conjugated polymer and Cu(Ⅱ)indicate the presence of a reduced Cu(Ⅰ)ion in the solution.Furthermore,fluorescence recovery of PFPNCC observed at low temperature suggests that the quenching and reducing mechanism is most probably due to a photo-induced electron transfer from excited PFPNCC to Cu(Ⅱ).Our findings provide a novel strategy for highly selective conjugated polymer-based chemosensors for various target analytes,albeit“ligand-free”.
文摘The boron trifluoride induced Suzuki-Miyaura cross-coupling of aryltriazenes with arylboronic acids catalyzed by Pd（OAc）2 without added ligands has been achieved for the first time. The reactions performed at room temperature under an argon atmosphere give biaryls in good to excellent yields. It is noteworthy that the reactions were conducted under mild and ligand-free conditions.
基金Project supported by the National Natural Science Foundation of China （No. 20372024）, the Excellent Scientist Foundation of Anhui Province, China （No. 04046080）, the Scientific Research Foundation for the Returned 0verseas Chinese Scholars, the Ministry of Education of China （No. 2002247）, the Excellent Young Teacher Program of the Ministry of Education of China （No. 2024） and the Key Project of Science and Technology of the Ministry of Education of China （No. 0204069）.
文摘In the absence of any ligand, a recoverable palladium（O） on poly（vinylpyrrolidone） （PVP） catalyzed Suzuki reaction of aryl iodide and bromide with potassium aryltrifluoroborate was developed. The reaction conditions involved the use of water as the solvent, potassium carbonate as the base, and PVP supported palladium metal colloids as the catalyst. The palladium metal could be recovered and recycled for eight consecutive trials without significant loss of its activity.
基金Project supported by the National Natural Science Foundation of China＇（Nol 21002102）, and State Key Laboratory of Bioorganic and Natural Products Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences （No. 10184）.
文摘A general synthesis of 1-aryl-l-H-indazoles from o-halogenated aryl aldehydes or ketones and aryl hydrazines was described. This protocol included an intermolecular condensation and a ligand-free copper-catalyzed intramolecular Ullmann-type coupling reaction. This method was applied to a wide range of substrates to produce the indazole products in good yields.
