In the presence of Dawson-type polyoxotungstate, α 2-[(n-C 4H 9) 4] (11-n)P 2W 17O 61(M n+·Br)[abbreviated as P 2W 17M·Br, M=Co(Ⅱ), Mn(Ⅲ), Cu(Ⅱ)] and saturated [(n-C 4H 9) 4N] 6P 2W 18O 62(abbreviated as...In the presence of Dawson-type polyoxotungstate, α 2-[(n-C 4H 9) 4] (11-n)P 2W 17O 61(M n+·Br)[abbreviated as P 2W 17M·Br, M=Co(Ⅱ), Mn(Ⅲ), Cu(Ⅱ)] and saturated [(n-C 4H 9) 4N] 6P 2W 18O 62(abbreviated as P 2W 18), cycloaddition reaction of carbon dioxide to propylene oxide were studied under moderate reaction conditions without any additional organic solvents. The experimental results indicated that the synthesis of propylene carbonate was completed in 98% yield and 100% selectivity by using {P 2W 17Co·Br} as the catalyst, while the P 2W 18 complex showed the lowest catalytic activity with less than 1% yield of propylene carbonate. The dependency of the catalytic activity on transition metal of mono-substituted polyoxometalate, P 2W 17M·Br, as well as the nucleophilicity of the bromide ion was concluded from the process analysis.展开更多
SmPO4 nanorods were synthesized by a microemulsion system containing water, cetyltrimethylammonium bromide（CTAB）, cyclohexane, and n-pentanol. Transmission electron microscopy（TEM） was used to characterize the sha...SmPO4 nanorods were synthesized by a microemulsion system containing water, cetyltrimethylammonium bromide（CTAB）, cyclohexane, and n-pentanol. Transmission electron microscopy（TEM） was used to characterize the shape and size of the as-synthesized sample. It was found that ω（molar ratio of water to surfactant） and reactant concentration play an important role in the formation of SmPO4 nanostructures.展开更多
A new 3D rare-earth coordination polymer[Ce 2(H 2btc)(btc)(H 2O) 2] n (1) was hydrothermally synthesized and its structure was characterized by the single crystal X-ray diffraction. Compound 1 crystallizes in a tricli...A new 3D rare-earth coordination polymer[Ce 2(H 2btc)(btc)(H 2O) 2] n (1) was hydrothermally synthesized and its structure was characterized by the single crystal X-ray diffraction. Compound 1 crystallizes in a triclinic crystal system,space group P 1 with a =0.641 17(13) nm, b = 0.939 41(19) nm , c =0.957 97(19) nm, α =103.888(17)°, β =74.57(3)°, γ =76.71(3)°, V = 0.540 98(19) nm 3 , Z=1,\{R=\}0.026 4,wR 2 =0.077 9. The three-dimensional compound 1 is built by linking one crystallographically independent nine-coordination Ce(Ⅲ) subunit through the btc and the H 2btc ligands. Each nine-coordinate Ce(Ⅲ) unit is a distorted tricapped trigonal prism,of which eight oxygen atoms belong to six different carboxylate groups of btc or H 2btc and a water molecule,with the Ce(Ⅲ)—O bond lengths ranging from 0.240 3(3) nm to 0.263 6(3) nm.展开更多
文摘In the presence of Dawson-type polyoxotungstate, α 2-[(n-C 4H 9) 4] (11-n)P 2W 17O 61(M n+·Br)[abbreviated as P 2W 17M·Br, M=Co(Ⅱ), Mn(Ⅲ), Cu(Ⅱ)] and saturated [(n-C 4H 9) 4N] 6P 2W 18O 62(abbreviated as P 2W 18), cycloaddition reaction of carbon dioxide to propylene oxide were studied under moderate reaction conditions without any additional organic solvents. The experimental results indicated that the synthesis of propylene carbonate was completed in 98% yield and 100% selectivity by using {P 2W 17Co·Br} as the catalyst, while the P 2W 18 complex showed the lowest catalytic activity with less than 1% yield of propylene carbonate. The dependency of the catalytic activity on transition metal of mono-substituted polyoxometalate, P 2W 17M·Br, as well as the nucleophilicity of the bromide ion was concluded from the process analysis.
文摘SmPO4 nanorods were synthesized by a microemulsion system containing water, cetyltrimethylammonium bromide（CTAB）, cyclohexane, and n-pentanol. Transmission electron microscopy（TEM） was used to characterize the shape and size of the as-synthesized sample. It was found that ω（molar ratio of water to surfactant） and reactant concentration play an important role in the formation of SmPO4 nanostructures.
文摘A new 3D rare-earth coordination polymer[Ce 2(H 2btc)(btc)(H 2O) 2] n (1) was hydrothermally synthesized and its structure was characterized by the single crystal X-ray diffraction. Compound 1 crystallizes in a triclinic crystal system,space group P 1 with a =0.641 17(13) nm, b = 0.939 41(19) nm , c =0.957 97(19) nm, α =103.888(17)°, β =74.57(3)°, γ =76.71(3)°, V = 0.540 98(19) nm 3 , Z=1,\{R=\}0.026 4,wR 2 =0.077 9. The three-dimensional compound 1 is built by linking one crystallographically independent nine-coordination Ce(Ⅲ) subunit through the btc and the H 2btc ligands. Each nine-coordinate Ce(Ⅲ) unit is a distorted tricapped trigonal prism,of which eight oxygen atoms belong to six different carboxylate groups of btc or H 2btc and a water molecule,with the Ce(Ⅲ)—O bond lengths ranging from 0.240 3(3) nm to 0.263 6(3) nm.
