Monodisperse Ni/Pd core/shell nanoparticles （NPs） have been synthesized by sequential reduction of nickel（II） acetate and palladium（II） bromide in oleylamine （OAm） and trioctylphosphine （TOP）. The Ni/Pd NPs ...Monodisperse Ni/Pd core/shell nanoparticles （NPs） have been synthesized by sequential reduction of nickel（II） acetate and palladium（II） bromide in oleylamine （OAm） and trioctylphosphine （TOP）. The Ni/Pd NPs have a narrow size distribution with a mean particle size of 10 nm and a standard deviation of 5% with respect to the particle diameter. Mechanistic studies showed that the presence of TOP was essential to control the reductive decomposition of Ni-TOP and Pd-TOP, and the formation of Ni/Pd core/shell NPs. Using the current synthetic protocol, the composition of the Ni/Pd within the core/shell structure can be readily tuned by simply controlling the initial molar ratio of the Ni and Pd salts. The as-synthesized Ni/Pd core/shell NPs were supported on graphene （G） and used as catalyst in Suzuki-Miyaura cross-coupling reactions. Among three different kinds of Ni/Pd NPs tested, the Ni/Pd （Ni/Pd = 3/2） NPs were found to be the most active catalyst for the Suzuki-Miyaura cross-coupling of arylboronic acids with aryl iodides, bromides and even chlorides in a dimethylformamide/water mixture by using K2CO3 as a base at 110 ℃. The G-Ni/Pd was also stable and reusable, providing 98% conversion after the 5th catalytic run without showing any noticeable Ni/Pd composition change. The G-Ni/Pd structure reported in this paper combines both the efficiency of a homogeneous catalyst and the durability of a heterogeneous catalyst, and is promising catalyst candidate for various Pd-based catalytic applications.展开更多
The challenge for single-atom catalysts in various C-C cross coupling reaction exists in the development of solid supporting materials.It has been desired tofind a supporting material designed in molecular level to an...The challenge for single-atom catalysts in various C-C cross coupling reaction exists in the development of solid supporting materials.It has been desired tofind a supporting material designed in molecular level to anchor a single-atom catalyst and provide high degree of dispersion and substrate access in aqueous media.Here,we prepared discrete cages of metal-organic polyhedra anchoring single Pd atom(MOP-BPY(Pd))and successfully performed a Suzuki-Miyaura cross coupling reaction with various substrates in aqueous media.It was revealed that each tetrahedral cage of MOP-BPY(Pd)has 4.5 Pd atoms on average and retained its high degree of dispersion up to 3 months in water.The coupling efficiencies of the Suzuki-Miyaura cross coupling reaction exhibited more than 90.0%for various substrates we have tested in the aqueous media,which is superior to those of the molecular Pd complex and metal-organic framework(MOF)anchoring Pd atoms.Moreover,MOP-BPY(Pd)was successfully recovered and recycled without performance degradation.展开更多
Valsartan 1, one of the most important agents used in antihypertensive therapy today, was synthesized starting from L-valin methyl ester hydrochloride 2 through four steps in an overall yield of 60%. The key step invo...Valsartan 1, one of the most important agents used in antihypertensive therapy today, was synthesized starting from L-valin methyl ester hydrochloride 2 through four steps in an overall yield of 60%. The key step involves the palladium-catalyzed Suzuki coupling. This method overcomes many of the drawbacks associated with the previously reported syntheses and is more suitable for industrial production.展开更多
Nickel（II） complexes Ni（L1）2 （1） and Ni（L2）2·CH3CN·H2O （2） （L1Cl = 2-（3-benzyl- 2,3-dihydroimidazlo-1-yl）-N-（pyridin-2-yl）acetamide, chloride salt, L2Cl = 2-（3-naphthalene-2- ylmethyl）-2,3-d...Nickel（II） complexes Ni（L1）2 （1） and Ni（L2）2·CH3CN·H2O （2） （L1Cl = 2-（3-benzyl- 2,3-dihydroimidazlo-1-yl）-N-（pyridin-2-yl）acetamide, chloride salt, L2Cl = 2-（3-naphthalene-2- ylmethyl）-2,3-dihydro-imidazlo-1-yl）-N-phenylacetamide, chloride salt） with amide-functionalized imidazolium NHC ligand were synthesized and determined by single-crystal X-ray diffraction. Complex 1 crystallizes in the monoclinic system, space group P21/cwith a = 9.2561（19）, b = 15.138（3）, c = 20.750（4） A, β = 90.216（3）°, V = 2907.3（10） A^3 and Z = 4. Complex 2 crystallizes in the orthorhombic system, space group Pbca with a = 15.5469（16）, b = 15.3521（15）, c = 31.177（3） A, V = 7441.2（13） ？3 and Z = 8. They are stable in the air and formed via intermolecular weak interactions, including C-H···π contacts and C–H···O hydrogen bonds. Complex 1 was applied in Suzuki coupling reaction through the investigation of reaction conditions under the optimal choice conditions： 80 ℃, K3PO4, 3% mol catalysts, 6% mol PPh3 and toluene as solvent system could afford 96% yield in 5 h.展开更多
文摘Monodisperse Ni/Pd core/shell nanoparticles （NPs） have been synthesized by sequential reduction of nickel（II） acetate and palladium（II） bromide in oleylamine （OAm） and trioctylphosphine （TOP）. The Ni/Pd NPs have a narrow size distribution with a mean particle size of 10 nm and a standard deviation of 5% with respect to the particle diameter. Mechanistic studies showed that the presence of TOP was essential to control the reductive decomposition of Ni-TOP and Pd-TOP, and the formation of Ni/Pd core/shell NPs. Using the current synthetic protocol, the composition of the Ni/Pd within the core/shell structure can be readily tuned by simply controlling the initial molar ratio of the Ni and Pd salts. The as-synthesized Ni/Pd core/shell NPs were supported on graphene （G） and used as catalyst in Suzuki-Miyaura cross-coupling reactions. Among three different kinds of Ni/Pd NPs tested, the Ni/Pd （Ni/Pd = 3/2） NPs were found to be the most active catalyst for the Suzuki-Miyaura cross-coupling of arylboronic acids with aryl iodides, bromides and even chlorides in a dimethylformamide/water mixture by using K2CO3 as a base at 110 ℃. The G-Ni/Pd was also stable and reusable, providing 98% conversion after the 5th catalytic run without showing any noticeable Ni/Pd composition change. The G-Ni/Pd structure reported in this paper combines both the efficiency of a homogeneous catalyst and the durability of a heterogeneous catalyst, and is promising catalyst candidate for various Pd-based catalytic applications.
基金the Basic Science Research Program(No.NRF-2019R1A2C4069764)by Convergent Technology R&D Program for Hum an Augm entation(No.2019M3C1B8077549)through the National Research Foundation of Korea(NRF)funded by Ministry of Science and ICT.
文摘The challenge for single-atom catalysts in various C-C cross coupling reaction exists in the development of solid supporting materials.It has been desired tofind a supporting material designed in molecular level to anchor a single-atom catalyst and provide high degree of dispersion and substrate access in aqueous media.Here,we prepared discrete cages of metal-organic polyhedra anchoring single Pd atom(MOP-BPY(Pd))and successfully performed a Suzuki-Miyaura cross coupling reaction with various substrates in aqueous media.It was revealed that each tetrahedral cage of MOP-BPY(Pd)has 4.5 Pd atoms on average and retained its high degree of dispersion up to 3 months in water.The coupling efficiencies of the Suzuki-Miyaura cross coupling reaction exhibited more than 90.0%for various substrates we have tested in the aqueous media,which is superior to those of the molecular Pd complex and metal-organic framework(MOF)anchoring Pd atoms.Moreover,MOP-BPY(Pd)was successfully recovered and recycled without performance degradation.
基金the National Natural Science Foundation of China (No.20272012)the Special Research Grant for Doctoral Sites in Chinese Universities (No.20010730001).
文摘Valsartan 1, one of the most important agents used in antihypertensive therapy today, was synthesized starting from L-valin methyl ester hydrochloride 2 through four steps in an overall yield of 60%. The key step involves the palladium-catalyzed Suzuki coupling. This method overcomes many of the drawbacks associated with the previously reported syntheses and is more suitable for industrial production.
基金supported by the National Natural Science Foundation of China(21102117)the Education Department of Sichuan Province(09ZX010)the College Student Science and Technology Innovation Key Foundation of China West Normal University
文摘Nickel（II） complexes Ni（L1）2 （1） and Ni（L2）2·CH3CN·H2O （2） （L1Cl = 2-（3-benzyl- 2,3-dihydroimidazlo-1-yl）-N-（pyridin-2-yl）acetamide, chloride salt, L2Cl = 2-（3-naphthalene-2- ylmethyl）-2,3-dihydro-imidazlo-1-yl）-N-phenylacetamide, chloride salt） with amide-functionalized imidazolium NHC ligand were synthesized and determined by single-crystal X-ray diffraction. Complex 1 crystallizes in the monoclinic system, space group P21/cwith a = 9.2561（19）, b = 15.138（3）, c = 20.750（4） A, β = 90.216（3）°, V = 2907.3（10） A^3 and Z = 4. Complex 2 crystallizes in the orthorhombic system, space group Pbca with a = 15.5469（16）, b = 15.3521（15）, c = 31.177（3） A, V = 7441.2（13） ？3 and Z = 8. They are stable in the air and formed via intermolecular weak interactions, including C-H···π contacts and C–H···O hydrogen bonds. Complex 1 was applied in Suzuki coupling reaction through the investigation of reaction conditions under the optimal choice conditions： 80 ℃, K3PO4, 3% mol catalysts, 6% mol PPh3 and toluene as solvent system could afford 96% yield in 5 h.
