Preparation of intermetallic phases in ionic liquids

离子液体中金属间相的制备

• 批准号: 253286982
• 负责人: Professor Juri Grin
• 金额: --
• 依托单位: Max-Planck-Institut für Chemische Physik fester Stoffe (MPI CPfS)
• 依托单位国家: 德国
• 项目类别: Priority Programmes
• 财政年份: 2014
• 资助国家: 德国
• 起止时间: 2013-12-31 至 2020-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/253286982?language=en
• 关键词: Preparation; intermetallic; phases; ionic; liquids

The preparation of intermetallic phases at low temperatures continues to be a challenging task. During the past years, redox reactions of reactive intermetallic precursors have been developed to a versatile method providing access particularly to metastable intermetallic phases. The reactions so far have been conducted mostly as heterogeneous gas-solid reactions. Additionally, low-temperature redox reactions on cluster species in ammonia or organic amine solutions of Zintl phases provide access to new metalloid species such as cluster polymers. But, in most cases, phases containing solvent molecules or complex cations have been obtained. In that respect, redox reactions in ionic liquids acting as a solvent for the intermetallic precursors might provide an alternative route to new purely intermetallic phases. However, such attempts so far have suffered from a too high reactivity of the applied ionic liquids towards highly reactive precursors such as Zintl phases, resulting in a fast and difficult to control mostly heterogeneous oxidation to amorphous products. This project, on the one hand, aims to develop inert ionic liquids capable of dissolving intermetallic phases containing Zintl clusters at low temperatures and to systematically study thus possible controlled homogeneous redox reactions to new metastable intermetallic phases by addition of suitable oxidizing agents. The applicability of such redox reactions in ionic liquids on salt-like carbides will be investigated as well, promising the preparation of new carbides or even elemental carbon modifications with polymeric structural motifs. Furthermore, topotactic redox reactions of respective intermetallic precursors will be investigated in purposefully synthesized ionic liquids of suitable reactivity and sufficient dissolution capability for product species to enable complete conversion of the precursor phase and to provide access to technically interesting yet otherwise hardly accessible product species such as graphene-analogous silicon sheets. For the studies within this project, so called TAAILs (Tunable Alkyl-Aryl Ionic Liquids) will be synthesized, the imidazolium cations of which carry functionalized phenyl substituents enabling electronic tuning and thus modification of the reactivity as proton source. The alkyl side chains will be functionalized by anionic or polyether groups enhancing solubility of salts or salt-like phases by complexation of cations. Furthermore, the protic activity of such ILs will be tuned by selective exchange of the hydrogens on carbon atoms of the imidazole core against inert aryl substituents.

在低温下制备金属间化合物相仍然是一项具有挑战性的任务。在过去的几年里，反应性金属间化合物前驱体的氧化还原反应已经发展成一种通用的方法，特别是提供了进入亚稳定金属间化合物相的途径。到目前为止，这些反应大多是以非均相气固反应进行的。此外，在锌相的氨或有机胺溶液中，簇合物上的低温氧化还原反应提供了获得新的类金属物种的途径，如簇合物。但是，在大多数情况下，已经获得了含有溶剂分子或络合阳离子的相。在这方面，离子液体中的氧化还原反应作为金属间化合物前体的溶剂，可能提供一种新的纯金属间化合物相的替代途径。然而，到目前为止，这种尝试的缺点是所应用的离子液体对高活性前体(如锌相)的反应性太高，导致快速且难以控制非晶态产物的主要非均相氧化。一方面，本项目旨在开发能够在低温下溶解含锌簇合物的金属间化合物相的惰性离子液体，并通过添加合适的氧化剂来系统地研究新的亚稳态金属间化合物相可能发生的受控均相氧化还原反应。这种氧化还原反应在离子液体中对类盐碳化物的适用性也将被研究，有望制备新的碳化物，甚至是具有聚合物结构基元的元素碳修饰。此外，将在特意合成的离子液体中研究各个金属间前体的拓扑定向氧化还原反应，这些离子液体具有适当的反应性和足够的溶解能力，使产品物种能够完全转化前驱物相，并提供技术上感兴趣但否则难以获得的产品物种，如类似石墨烯的硅片。在该项目的研究中，将合成所谓的TAAILs(可调烷基芳基离子液体)，其咪唑阳离子携带能够进行电子调节的官能化苯基取代基，从而改变作为质子源的反应性。烷基侧链将被阴离子或聚醚基团官能化，通过阳离子的络合作用增强盐或类盐相的溶解性。此外，这类离子液体的质子活性将通过咪唑核碳原子上的氢与惰性芳基取代基的选择性交换来调节。