Systematic and exploratory access to new Ce(IV)- and mixed-Metal Ce/Zr-MOFs

系统性和探索性地获取新型 Ce(IV) 和混合金属 Ce/Zr-MOF

• 批准号: 508229808
• 负责人: Professor Dr. Norbert Stock
• 金额: --
• 依托单位: Dipartimento di Chimica, Biologia e Biotecnologie
• 依托单位国家: 德国
• 项目类别: Research Grants
• 资助国家: 德国
• 项目状态: 未结题
• 来源: https://gepris.dfg.de/gepris/projekt/508229808?language=en
• 关键词: Systematic; exploratory; access; new; Ce

Metal-organic frameworks (MOFs) contain inorganic and organic building units that assemble to form 2D or 3D networks. The modular structures allow tuning the pore size and pore functionality in these materials. MOFs containing tri- and tetravalent metal ions and especially Zr-MOFs have been in the focus of many studies due to their thermal and chemical stability. The structural chemistry of Zr-MOFs is mainly characterized by the presence of hexanuclear Zr-O-clusters that are connected through organic molecules, usually carboxylate ions, to build up frameworks of various topologies. The structural chemistry of Zr-MOFs has been extended during the last few years and our group was able to discover new inorganic building units. In addition, we have developed a readily applicable synthesis route to Ce(IV)- and Ce(IV)/Zr-MOFs, which led to more than 25 new MOFs. The inorganic building unit in these crystal structures are exclusively the hexanuclear Ce(IV) and Ce(IV)/Zr-O-cluster respectively. Only lately, in 2020, Ce(IV)-MOFs containing a new inorganic building unit was reported when solvothermal reaction conditions were employed.The proposed project aims at the advancement of the synthetic and structural chemistry of Ce(IV)- and Ce(IV)/Zr-MOFs. We target the synthesis of MOFs with new inorganic building units, which will lead to the formation of new framework structures, as well as the formation of known framework structures containing inorganic building units with new Ce(IV)/Zr-compositions.To achieve these objectives two synthesis approaches will be followed. Route 1 is a more exploratory approach that relies on the use of high-throughput methods that allow the concurrent synthesis of 24 or 48 products in parallel. The solvents water and acetonitrile as well as di-, tri- and tetracarboxylic acids of different molecular geometry and flexibility will be employed. New MOFs with up to now unknown inorganic building units should be accessible through variation of the reaction parameters, such as molar ratios of stating materials, reaction temperature, overall concentration or the use of a modulator. Route 2 focuses on the synthesis and characterization of new hexanuclear Ce(IV)-O- and Ce(IV)/Zr-O-cluster. In addition to structural aspects, the local distribution of the Ce and Zr ions as well as the redox properties of the clusters will be studied. The cluster composition is expected to have a strong influence of the redox properties, which could be tuned for catalytic applications. The Ce-O- and Ce/Zr-O-clusters will be used as molecular precursors in ligand exchange reactions leading to the formation of MOFs. Mild reaction conditions will be investigated that will also allow us to study the crystallisation process by in-situ powder X-ray diffraction. Redox properties for selected Ce-O and Ce/Zr-O MOFs will also be determined. Thus, photocatalytic studies on the decomposition of dyes will be carried out.

金属有机框架（MOFs）包含无机和有机建筑单元，它们组装形成二维或三维网络。模块化结构允许调整这些材料的孔隙大小和孔隙功能。含有三价和四价金属离子的mof，特别是zr - mof由于其热稳定性和化学稳定性而成为许多研究的焦点。zr - mof的结构化学主要特征是六核zr - o簇的存在，这些簇通过有机分子（通常是羧酸盐离子）连接，以建立各种拓扑结构的框架。zr - mof的结构化学在过去几年中得到了扩展，我们的团队能够发现新的无机建筑单元。此外，我们还开发了一种易于应用的Ce(IV)-和Ce(IV)/ zr - mof的合成路线，从而产生了超过25种新的mof。这些晶体结构中的无机结构单元分别是六核Ce（IV）和Ce(IV)/ zr - o簇。直到最近，在2020年，当采用溶剂热反应条件时，才报道了含有新型无机建筑单元的Ce(IV)-MOFs。本项目旨在推进Ce(IV)-和Ce(IV)/Zr-MOFs的合成和结构化学研究。我们的目标是合成含有新的无机建筑单元的mof，这将导致新的框架结构的形成，以及含有新的Ce(IV)/ zr成分的无机建筑单元的已知框架结构的形成。为实现这些目标，将采取两种综合办法。路线1是一种更具探索性的方法，它依赖于使用高通量方法，允许同时合成24或48种产品。溶剂水和乙腈以及二羧酸、三羧酸和四羧酸具有不同的分子几何形状和柔韧性。通过改变反应参数，如状态材料的摩尔比、反应温度、总浓度或调制器的使用，应该可以获得具有迄今未知无机结构单元的新型mof。途径2主要研究了新型六核Ce(IV)- o -和Ce(IV)/ zr - o簇的合成与表征。除了结构方面，还将研究Ce和Zr离子的局部分布以及团簇的氧化还原性质。预计团簇组成对氧化还原性能有很强的影响，可以调整为催化应用。Ce- o -和Ce/ zr - o -簇将在配体交换反应中用作分子前体，从而形成mof。将研究温和的反应条件，这也将使我们能够通过原位粉末x射线衍射研究结晶过程。选定的Ce- o和Ce/Zr-O mof的氧化还原性能也将被确定。因此，对染料分解的光催化研究将会展开。