一系列含有茂金属的倍半硅氧烷与alkenylsilyl和三甲基甲硅烷基,CP ' 2 M [(CC 5 ħ 9)7的Si 7 ø 11 ](OSiMe 2 R)(图2b - d,3B - d,4D,5D:CP' = Cp(环戊二烯基),Cp *(五甲基环戊二烯基); M = Ti,Zr,Hf,R =甲基,乙烯基,烯丙基)。配合物Cp 2 M [(cC 5 H 9)7 Si 7 O 11 ](OSiMe 2的结构CH 2 CH CH 2)(M = Zr(3d),Hf(5d))已通过单晶X射线衍射分析明确建立。含锆茂的倍半硅氧烷单硅醇Cp 2 Zr [(cC 5 H 9)7 Si 7 O 11 ](OH)(3a)或其ha衍生物Cp 2 Hf [(cC 5 H 9)7 Si 7 O 11 ](OH)(5a),可以通过倍半硅氧烷倍半硅氧烷三硅醇(cC 5 H 9)7 Si 7 O 9(OH)3(1
The catalytic activities of a series of porous oxides prepared from silsesquioxanes for the cracking of hydrocarbons have been examined. In addition to known group 13 element-containing silsesquioxanes, new aluminum-bridged silsesquioxanes bearing various countercations, [Y](+)[(c-C5H9)(7)Si7O12(SiMe3)}(2)Al](-) ([Y](+) = [H2NMe2](+) (2b), [HNMe2(C8H17)](+) (2c), [HNMe2(C18H37)](+) (2e), [HNC5H5](+)[(c-C5H9)(8)Si8O13}(2)Al](-) (3d), and [HNC5H5](+)[(i-C4H9)(8)Si8O13}(2)Al](-) (4d), have been synthesized. The controlled calcination of these silsesquioxanes at around 823 K produced amorphous porous acidic oxides with high BET surface areas of 360-520 m(2) g(-1) and uniformly controlled micropores of 5-6 Angstrom diameter. Among the oxides examined, those prepared from aluminum-bridged silsesquioxanes show excellent catalytic activities for the cracking of cumene even at low reaction temperatures of around 523 K. Under identical conditions commercially available silica-alumina catalysts do not show significant activities, indicating exceptionally high activities of the silsesquioxane-based oxides despite their amorphous nature. (C) 2004 Elsevier Inc. All rights reserved.