Formation and Functionalization of Inorganic-Organic Nanostructured Materials Prepared by Self-Organization of Organoalkoxysilanes.

有机烷氧基硅烷衍生的硅基杂化物的结构控制是一个非常重要的课题。我们开发了一种新的方法，利用新设计的硅氧烷低聚物（C_nH_<2n+1>Si(OSi(OMe)_3)_3, n=8-18）作为单一前驱体来制备介结构硅基杂化体。根据前驱体中烷基链长度的不同，得到了有序的层状相或略扭曲的二维六边形相。具有六边形结构的杂化物经煅烧后可转化为中孔或微孔二氧化硅，去除有机基团，这是首次不使用表面活性剂作为模板合成六边形有序多孔二氧化硅。我们还报道了以烷氧三氯硅烷（n- c_nh_ <2n+1>OSiCl_3, n=12-20）为原料，合成由长链醇双分子层和薄硅层组成的新型层状有机硅纳米结构材料。其形成依赖于前驱体中Si-Cl基团优先水解产生的烷氧基硅三醇（n-C_nH_<2n+1>OSi(OH)_3）的自组装。在固体状态下，烷氧基硅三醇的缩聚反应可以形成二氧化硅网络，同时伴随着烷氧基的裂解。

Structural control of silica-based hybrids derived from organoalkoxysilanes is a subject of great importance. We developed a new approach to create mesostructured silica-based hybrids by using newly designed siloxane oligomers (C_nH_<2n+1>Si(OSi(OMe)_3)_3, n=8-18) as single precursors. Either well-ordered lamellar phase or slightly distorted 2D hexagonal phase was obtained depending on the alkyl chain lengths in the precursor. The hybrids with a hexagonal structure can be converted to meso-or micro-porous silica upon calcination to remove organic groups, which is the first example of the synthesis of hexagonally ordered porous silica without the use of surfactants as template.We also reported the synthesis of novel layered silica-organic nanostructured materials, consisting of bimolecular layers of long-chain alcohols and thin silica layers, from alkoxytrichlorosilanes (n-C_nH_<2n+1>OSiCl_3, n=12-20). The formation relies on the self-assembly of alkoxysilanetriols (n-C_nH_<2n+1>OSi(OH)_3) generated by the preferential hydrolysis of Si-Cl groups in the precursors. Polycondensation of alkoxysilanetriols was found to proceed in the solid state to form silica networks, being accompanied by the cleavage of the alkoxy groups.