Introduction Recently substituted-type of heteropolyanions has received much attention from the point of view of their catalysis. Hill, Finke, Neumann reported respectively that transition metal mono-substituted heter...Introduction Recently substituted-type of heteropolyanions has received much attention from the point of view of their catalysis. Hill, Finke, Neumann reported respectively that transition metal mono-substituted heteropolyanions PW;M, P;W;M and SiW;Ru have an ability to catalyze the epoxidation of olefin. We discovered that trisubstituted Keggin heteropolyanions have this property too. This paper describes the synthesis, properties of α- and β-[SiW;O;Co;（H;O）;];and its catalysis for the epoxidation of olefin by PhIO.展开更多
Six new compounds, alpha,beta-KaHb[GeW(9)M(3)(H2O)(3)O-37]. xH(2)O(M = Al, Ga, In; a + b = 7) and alpha-K9H5[Ge2W18Ga6(H2O)(3)O-74]. 20H(2)O, were synthesized from the lacunary precursors a and beta-GeW9O3410- and cha...Six new compounds, alpha,beta-KaHb[GeW(9)M(3)(H2O)(3)O-37]. xH(2)O(M = Al, Ga, In; a + b = 7) and alpha-K9H5[Ge2W18Ga6(H2O)(3)O-74]. 20H(2)O, were synthesized from the lacunary precursors a and beta-GeW9O3410- and characterized by elemental analysis, spectroscopy and electrochemistry. Tungsten-183 NMR spectra of the title complexes consist of two lines with intensity ratio 2:1 as expected for trisubstituted heteropoly anions. The intensity ratio of alpha-Ga compound is 1:2, which is different from others(a:1). With the help of FAB mass spectrum, we concluded that it is a dimer with D-3h structure in aqueous, and the others exist by monomers with C-3v structures.展开更多
基金Supported by the National Natural Science Foundation of China
文摘Introduction Recently substituted-type of heteropolyanions has received much attention from the point of view of their catalysis. Hill, Finke, Neumann reported respectively that transition metal mono-substituted heteropolyanions PW;M, P;W;M and SiW;Ru have an ability to catalyze the epoxidation of olefin. We discovered that trisubstituted Keggin heteropolyanions have this property too. This paper describes the synthesis, properties of α- and β-[SiW;O;Co;（H;O）;];and its catalysis for the epoxidation of olefin by PhIO.
文摘Six new compounds, alpha,beta-KaHb[GeW(9)M(3)(H2O)(3)O-37]. xH(2)O(M = Al, Ga, In; a + b = 7) and alpha-K9H5[Ge2W18Ga6(H2O)(3)O-74]. 20H(2)O, were synthesized from the lacunary precursors a and beta-GeW9O3410- and characterized by elemental analysis, spectroscopy and electrochemistry. Tungsten-183 NMR spectra of the title complexes consist of two lines with intensity ratio 2:1 as expected for trisubstituted heteropoly anions. The intensity ratio of alpha-Ga compound is 1:2, which is different from others(a:1). With the help of FAB mass spectrum, we concluded that it is a dimer with D-3h structure in aqueous, and the others exist by monomers with C-3v structures.
