Interlayer expansion of layer silicates with reactive metal centers, a new synthesis approach for nanoporous materials with silicate frameworks having distinct metals sites: Synthesis and crystal structure.

具有活性金属中心的层状硅酸盐的层间膨胀，一种具有不同金属位点的硅酸盐骨架纳米多孔材料的新合成方法：合成和晶体结构。

• 批准号: 285735268
• 负责人: Professor Dr. Hermann Gies
• 金额: --
• 依托单位: Department of Organic Chemistry
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2015
• 资助国家: 德国
• 起止时间: 2014-12-31 至 2018-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/285735268?language=en
• 关键词: Interlayer; expansion; layer; silicates; reactive

Nanoporous, crystalline solids are important materials for applications in separation processes, adsorption, form selective catalysis and also as depot materials. In addition, nanoporous materials are also used in solar heat storage devices. The classical zeolites are an important sub-group of nanoporous materials, however, coordination polymers such as metal organic frameworks or organic porous polymer networks are in the focus of interest currently. However, new synthesis routes for silicate zeolites have attracted new interest. On the one hand, template free synthesis has allowed to produce zeolites more efficiently, on the other hand, new zeolite framework types were synthesized using 'precursor chemistry', leading to very interesting, thermally resistant and catalytically active materials. As precursors, layered silicates were used which have been transformed in a topotactic condensation reaction into nanoporous framework structures. The general validity of the concept has been shown for a number of precursor materials.An extension of the approach was achieved by using silicate monomers as linkers bridging the layered precursors. The silicate linker connected surface silanols of neighbouring layers with each other in a registered arrangement. This lead to crystalline, nanoporous 3-dimensional silicates frameworks with extended porosity and functional groups at the linker site. Again, the general applicability of the concept has been shown for different linker groups and also for different precursor silicates. As technical term for the reaction "interlayer expansion" has been introduced.The current proposal is aimed at an extension of the interlayer expansion by using other elements as linker materials such as oxygen coordinated metal centers. In a first experiment, Fe has been introduced in interlayer expanded RUB-36 as silicate precursor. The new nanoporous material is thermally stable up to 500 °C, the Fe-center shows catalytic activity and does not leach out of the silicate during reaction. Preliminary results from crystal structure analysis proofed that Fe occupies ca. 50% of the linker sites and, thus, the introduction of metal centers on well defined framework sites. Other metal interlayer expansion reaction show promising results and Sn, Zn, Ti, V, and Eu on linker sites have already been obtained. In order to reproduce and optimize the synthesis, to improve crystallinity of the products, and to proof the substitution of Si by metal centers on the linker site, crystal structure analyses are required which shall be in the focus of the project. The powder materials shall be studied by Rietveld analysis of powder X-ray diffraction data to show the bulk crystallinity, and by single crystal techniques such as electron crystallography in order to obtain a most detailed view on the geometrical details of the new materials.

纳米方面的晶体固体是在分离过程中应用，添加吸收，形成选择性催化剂以及作为仓库材料的重要材料。另外，纳米多孔材料也用于太阳能储藏装置。经典的沸石是纳米多孔材料的重要亚组，但是，当前关注的是诸如金属有机框架或有机多孔聚合物网络等协调聚合物或有机多孔聚合物网络。但是，硅胶沸石的新合成途径引起了新的兴趣。一方面，无模板的合成允许更有效地生产沸石，另一方面，使用“前体化学”合成了新的沸石框架类型，从而导致非常有趣，具有热耐热性和催化活性材料。作为前体，使用了分层的硅酮，这些硅酮已在拓扑凝结反应中转化为纳米多孔框架结构。该概念的一般有效性已显示出许多前体材料。该方法的扩展是通过使用硅酮单体作为桥接层次前体的接头来实现的。有机硅连接器以注册的排列相互连接的相邻层的表面硅醇。这导致在接头位点具有较长的孔隙率和官能团的结晶，纳米多孔的3维有机硅框架。同样，该概念的一般适用性已显示针对不同的接头组以及不同的前体硅酮。由于已经引入了反应“层间膨胀”的技术术语。当前的建议是通过使用其他元素作为接头材料（例如氧气协调的金属中心）来扩展层间膨胀。在第一个实验中，已在层间中引入了FE，将RUB-36作为硅酮前体进行了扩展。新的纳米多孔材料的热稳定最高为500°C，Fe-Center显示出催化活性，并且在反应过程中不会离开硅酮。晶体结构分析的初步结果证明了FE占据Ca。 50％的接头站点，因此，在定义明确的框架站点引入了金属中心。其他金属层间膨胀反应显示了校对结果，并且已经获得了接头位点上的SN，Zn，Ti，V和EU。为了重现和优化合成，改善产品的结晶度，并证明由金属中心在接头位点上替换Si，需要进行晶体结构分析，这应是项目的重点。粉末材料应通过对粉末X射线衍射数据的Rietveld分析进行研究，以显示散装结晶度，并通过单晶技术（例如电子晶体学）进行研究，以便获得有关新材料几何细节的最详细视图。