Preparation of Novel Organic-Inorganic Hybrid Materials for Catalysts from Metal-Containing Silsesquioxanes

从含过渡金属的硅质多相催化剂的离散的、定义明确的可溶性模型化合物的角度来看，具有硅醇基团的不完全缩合的低聚倍半硅氧烷和含金属的倍半硅氧烷引起了人们的广泛关注。本文从制备有机-无机杂化材料催化剂前驱体的角度出发，合成了一系列具有甲硅烷基或甲锗烷基官能团的四族含茂烯的倍半硅氧烷。还研究了利用这些含金属的倍半硅氧烷制备多孔氧化物催化剂。（1）由含多种金属的倍半硅氧烷制备微孔固体氧化物：在约823 K下控制煅烧新合成的含第13族元素的倍半硅氧烷产生具有330-520 m2/g的高BET表面积<-1>和5.1 μ m直径的均匀控制的微孔的布朗斯台德酸性氧化物。它们的酸性支柱 ...更多信息 ERTIES很大程度上受倍半硅氧烷前体结构的影响，并且部分地受13族元素和抗衡阳离子的选择的控制。特别地，发现来自铝桥接的倍半硅氧烷的氧化物具有高BET表面积和大量的酸性位点。第13族元素氧化物在氧化硅基体中分散性的差异与前驱体的结构密切相关，这被认为是它们酸性差异的原因之一。通过对异丙苯等模型烃裂解反应的初步研究，发现这些氧化物尽管具有非晶态性质，但仍表现出极高的活性。（2）新型含第4族过渡金属官能团的倍半硅氧烷的合成：探索了一系列含烯基硅烷基和三甲基硅烷基的含二烯基的倍半硅氧烷的几种制备方法。其中，配合物Cp_2M[（c-C_5 H_9）_7Si_7O_<11>]（OSiMe_2CH_2CH=CH_2）[M = Zr或Hf]的结构通过单晶X射线衍射分析确定。初步考察了这些含茂二烯的倍半硅氧烷对叔丁基过氧化氢环氧化环己烯的催化活性，发现含茂钛的倍半硅氧烷表现出适度的催化活性。少

Incompletely condensed oligosilsesquioxanes with silanol groups and metal-containing silsesquioxanes have attracted much attention from the viewpoint of discrete, well-defined soluble model compounds of the transition metal-containing siliceous heterogeneous catalysts. In the present work, synthesis synthesis of a series of group 4 metallocene-containing silsesquioxanes with functional silyl or germyl groups have been performed from the viewpoint of the preparation of precursors of organic-inorganic hybrid materials for catalysts. Preparation of porous oxide catalysts utilizing these metal-containing silsesquioxanes was also examined.(1)Preparation_of Microporous Solid Oxides from Various-Metal Containing Silsesquioxane:The controlled calcination of newly-synthesized group 13 elements-containing silsesquioxanes at around 823 K produces Bronsted acidic oxides with high BET surface areas of 330-520 m^2g^<-1> and uniformly-controlled micropores of 5.1Å diameter diameter. Their acidic prop … More erties are greatly affected by the structure of silsesquioxane precursors, and partly controlled by the selection of group 13 elements and counter cations. In particular, oxides from aluminum-bridged silsesquioxanes were found to have high BET surface areas and a large amount of acidic sites. Differences in the dispersion of oxides of group 13 elements in silica matrixes, which are closely related to the structure of precursors, are considered to be one of the reasons of differences in their acidic characters. According to the preliminary study on the cracking of model hydrocarbons such as cumene, these oxides show exceptionally high activity in spite of their **orphous nature.(2)Synthesis of Novel Group 4 Transition Metal-Containing Silsesquioxanes with Functional Groups:Several preparation methods of a series of metallocene-containing silsesquioxanes with alkenylsilyl and trimethylsilyl groups have been explored. Among them, the structures of the complexes Cp_2M[(c-C_5H_9)_7Si_7O_<11>](OSiMe_2CH_2CH=CH_2) [M = Zr or Hf] are unambiguously established by the single-crystal X-ray diffraction analysis. The preliminary examination of the catalytic activity of these metallocene-containing silsesquioxanes towards the epoxidation of cyclohexene by tert-butyl hydroperoxide revealed that titanocene-containing silsesquioxanes show modest catalytic activity. Less