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
Eight new organo polyoxoinetalate charge transfer complexes (DH)\-6X\-2W\-\{18\}O\-\{62\}·(solv)\-n(D=Oxin(8 hydroxyquinoline), Py(Pyridine), Tol(toluene), A(aniline), DMA (N,N dimethyaniline), DEA(N,N diethylani...Eight new organo polyoxoinetalate charge transfer complexes (DH)\-6X\-2W\-\{18\}O\-\{62\}·(solv)\-n(D=Oxin(8 hydroxyquinoline), Py(Pyridine), Tol(toluene), A(aniline), DMA (N,N dimethyaniline), DEA(N,N diethylaniline), X=P, As; solv=DMF, H\-2O) was synthesized and characterized by using elemental analysis, IR, ESR. Polarographly, CV. Conductivity measurement, and X ray circle diffraction. The results showed that the crystal of (H\-2quinH)\-6P\-2W\-\{18\}O\-\{62\}·20H\-2O is Triclinic Crystal System, Space group \%P\{1-\}\%, with \%a=1.4659(5), b=2.045(8), c =2.1153(4) nm, α=90.01(3), β=87.95(2), γ=89.05(3)°, V =6.3393(35) nm\+3. This shows that under the irradiated title compound charge transfer between the organic donor and polyoxometalate anion has taken place.\;Polargraphy and cyclic Voltammetry show that the (H\-2quinH)\-6P\-2W\-\{18\}O\-\{62\}·20H\-2O undergoes three one electron reversible reduction steps in aqueous solution and four one electron quasi reversible reduction in DMF. Room temperature Conductivities of eight the title compounds ranging from 1.2×10\+\{-8\} to 3.6×10\+\{-9\} S·cm\+\{-1\} showed weak semiconducting behaviors.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Eight new organo polyoxoinetalate charge transfer complexes (DH)\-6X\-2W\-\{18\}O\-\{62\}·(solv)\-n(D=Oxin(8 hydroxyquinoline), Py(Pyridine), Tol(toluene), A(aniline), DMA (N,N dimethyaniline), DEA(N,N diethylaniline), X=P, As; solv=DMF, H\-2O) was synthesized and characterized by using elemental analysis, IR, ESR. Polarographly, CV. Conductivity measurement, and X ray circle diffraction. The results showed that the crystal of (H\-2quinH)\-6P\-2W\-\{18\}O\-\{62\}·20H\-2O is Triclinic Crystal System, Space group \%P\{1-\}\%, with \%a=1.4659(5), b=2.045(8), c =2.1153(4) nm, α=90.01(3), β=87.95(2), γ=89.05(3)°, V =6.3393(35) nm\+3. This shows that under the irradiated title compound charge transfer between the organic donor and polyoxometalate anion has taken place.\;Polargraphy and cyclic Voltammetry show that the (H\-2quinH)\-6P\-2W\-\{18\}O\-\{62\}·20H\-2O undergoes three one electron reversible reduction steps in aqueous solution and four one electron quasi reversible reduction in DMF. Room temperature Conductivities of eight the title compounds ranging from 1.2×10\+\{-8\} to 3.6×10\+\{-9\} S·cm\+\{-1\} showed weak semiconducting behaviors.
