【作者】 张达崴；

【导师】 单永奎；

【作者基本信息】 华东师范大学 ， 物理化学， 2005， 硕士

【摘要】 立方笼型倍半硅氧烷是一种新兴的无机纳米粒子基础材料,它以Si-O-Si键构成的硅氧六面体为核心,通过键联各种活性基团,可以形成多种无机有机纳米杂化材料。倍半硅氧烷衍生的杂化材料具有较高的硬度和热稳定性,引起人们的广泛关注。含钛催化剂对有机化合物氧化反应具有很好的催化活性和选择性,特别是钛硅分子筛材料近年来成为催化化学研究的热点。人们预测通过钛掺杂,倍半硅氧烷将具有一些特异的物理化学性质。本文以一种易得的倍半硅氧烷前驱体--笼形八聚硅酸盐为原料,合成了一种结构特殊的新型钛硅固体材料。并对其分别用羧酸活性染料和邻苯二酚进行了改性,拓展了该材料对可见光的吸收范围。本文的第二章以正硅酸乙酯为硅源,在较高浓度季铵碱的催化作用下,在甲醇溶液中水解,近似定量地生成了笼形八聚硅酸四甲基铵倍半硅氧烷。并以之为母体,用二甲基氯硅烷进行了硅烷基化反应。本文对文献报道的实验室合成工艺进行了一些改进,避免了有毒溶剂的使用并降低了合成成本,减少了硅烷基化试剂的用量并提高了产品收率和纯度。对反应产物用FT-IR、TG-DTA和29Si-NMR等手段进行了结构表征,证明本文所述的合成过程形成了规整性很高的倍半硅氧烷纳米粒子。本文的第三章以笼形八聚硅酸四甲基铵倍半硅氧烷为原料,以合成了一种新型的钛硅固体材料。并对所得产物分别用FT-IR、29Si-NMR、粉末XRD、UV-Vis、高分辨TEM、ICP和元素分析等手段进行了结构表征。该钛硅固体材料与众不同的结构特点是:它以完整的氧基倍半硅氧烷为结构基元,以钛氧四面体为桥联基团,两者在二维平面上缔合并重复排列形成规整性较高的层状结构,进而形成钛硅固体材料。本文的第四章分别使用罗丹明-B和甲基红对钛杂化倍半硅氧烷进行了改性,得到了两种经染料改性的倍半硅氧烷材料。并对其用FT-IR和UV-Vis进行了初步的结构表征和光化学性质分析。改性钛杂化倍半硅氧烷中生色基团的吸收光谱有一个明显的红移现象,本文对这一现象给出了一个合理的解释。更多还原

【Abstract】 The polyhedral oligosilsesquioxane (POSS) has an integral structure with high symmetry and has an average diameter of only 1.5 nm. POSS represents a rather versatile class of potential three-dimensional building blocks for the synthesis of nanostructured materials. In recent years, silsesquioxane-derived materials have received great attention due to their special structure and excellent physico-chemical, thermal and mechanical properties. In this dissertation, some kinds of silsesquioxane-derived materials have been synthesized.The metallasiloxanes have attracted considerable interest nowadays, because the presence of a metal in the siloxane framework often results in high thermal stability and improved catalytic and conducting properties. Titanium is often used as heteroatom due to its excellent photocatalytic activity. According to the literatures, incompletely condensed polyhedral silsesquioxanes is often used as precursor to synthesize titanium-hybrid silsesquioxanes.In this dissertation, a new king of titana-silica material was synthesized using cubic cage-like octasilicate as precursor. Then the material was modified by Methyl Red, Rhodamine-B and pyrocatechol separately. The modification expands the absorption ability of UV-Visible light of the material.In Chapter 2, cubic cage-like tetramethylammonium octasilicate was synthesized using ethyl silicate and tetramethylammonium hydroxide as precursors. And then Octa(dimethylsiloxy)silsesquioxane was synthesized by the reaction between octasilicate and chlorodimethylsilane. The products were characterized by FT-IR, TG-DTA and 29Si-NMR, which suggested that the cubic silicate cages were created in this way.In Chapter 3, a new kind of titanium hybrid silsesquioxane was synthesized using cubic cage-like tetramethylammonium octasilicate and dichlorodiethoxytitanium as precursors. The product was characterized byFT-IR, 29Si-NMR, UV-Vis, and XRD, which suggested that different from other titanium-silicon materials, the titanium hybrid silsesquioxane was formed with cubic cage-like POSS as building blocks and titanium as bridge atoms, and had a layer-structure.In Chapter 4, two kinds of dye-doped titanasilsesquioxanes were synthesized using titanium hybrid silsesquioxane, methyl red and rhodamine-B as precursors. The products were characterized by FT-IR and UV-Vis. A bathochromic shift was found after dye doping, and an explanation was given in this dissertation.In Chapter 5, a new kind of derivative of silsesquioxane was synthesized using titanium hybrid silsesquioxane and pyrocatechol as precursors. The product was characterized by FT-IR and UV-Vis. The product is stable and has a grand absorbance. A remarkable bathochromic shift was found after the reaction with pyrocatechol. This great change of the photochemistry property was explained with Molecular Orbital Theory in this dissertation.更多还原