Oxidative hydrogenation of polyanions with gallium, silicon, germanium and tin - functional materials by subtle redox chemistry

通过微妙的氧化还原化学作用，聚阴离子与镓、硅、锗和锡的氧化氢化 - 功能材料

• 批准号: 277832266
• 负责人: Professor Dr. Holger Kohlmann
• 金额: --
• 依托单位: Institut für Anorganische Chemie
• 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/277832266?language=en
• 关键词: Oxidative; hydrogenation; polyanions; gallium; silicon

Zintl phases are compounds between an alkaline or alkaline earth metal M with an element E of group 13-16 and usually contain polyanions [Ex-]n with covalent E-E bonds. Hydrogen may react either by oxidizing these polyanions thus increasing their connectivity or by insertion or addition of hydrogen to the polyanions. In a previous project, preliminary rules for the formation of main group element-element and element-hydrogen bonds were established. The hydrogenation of Zintl phases with silicon and germanium zigzag chains (ME with M = Ca, Sr, Ba; E = Si, Ge) by in situ X-ray and neutron powder diffraction, electron microscopy, thermal analysis, solid-state nuclear magnetic resonance spectroscopy, total neutron scattering, quantum-mechanical modelling and Raman spectroscopy revealed new Zintl phase hydrides (MEH4/3, MEH5/3 and MEH6/3) with condensed hydrogen-containing polyanions and intermediates with lower hydrogen content. In the series M(I)-M(II)-M(III), i. e. alkali-alkaline earth-rare earth, the chemical bonding of H atoms shifts from covalent to ionic and metallic. In this project, we will refine this rule-of-thumb for hydrogenation reactions of Zintl phases, enabling us to rationalize existence, thermodynamic stability, chemical bonding, crystal and electronic structure, and hydrogen capacity of hydrogenated Zintl phases. Initially about 45 compounds MxEy with E = Ga, Si, Ge, Sn and M = alkali-alkaline earth-rare earth or a mixture of two of them, featuring various polyanions (zigzag chains, helices, five- and six-membered rings, dumb-bells, 1D ribbons and 3D nets) will be studied by the above mentioned methods. The detailed knowledge of the rules governing the formation of E-E and E-H bonds will enable us to predict further hydrogenation reactions of Zintl phases, i. e. allow for a connectivity tuning in polyanions of Zintl phase hydrides by oxidation with hydrogen. The potential in the preparation of materials for hydrogen storage and low-dimensional materials shall be explored. On one hand, practical aspects of Zintl phases as hydrogen stores will be tested. By volumetric and gravimetric method, thermodynamics, kinetics, reversibility and cycleability for hydrogen storage will be studied for CaSi and further candidates identified in the first part of the project. On the other hand, Zintl phase hydrides will be used as precursors for 1D and 2D materials. Hydrolysis, ammonolysis and methylation reactions may lead to 1D and 2D polymers, which could be interesting intermediates to silicane, germanane, and stannanane or related materials. The controlled oxidation of polyanions by hydrogen, to be developed in this project, has got a great potential for the fine tuning of structural, electronic and magnetic properties of solids. The results of this project are expected to stimulate materials related research with compounds containing polyanions of triels and tetrels, especially gallium, silicon, germanium, tin.

ZINTL相是具有13-16组元素E的碱性或碱土金属M之间的化合物，通常包含具有共价E-E键的聚体[ex-]。氢可以通过氧化这些多支接来反应，从而提高它们的连通性，或通过向多支晶体插入或添加氢。在先前的项目中，建立了主要组元素元素和元素 - 氢键的初步规则。通过原位X射线和中子粉末衍射，电子显微镜，热分析，固态核磁磁性共振光谱，总中子散射，量子力学建模和拉曼光谱法揭示了具有含氢的多疗中心的新Zintl期氢化物（MEH4/3，MEH5/3和MEH6/3），具有较低的氢含量。在系列中，m（i）-m（ii）-m（iii），i。 e。碱性碱性土壤，H原子的化学键从共价转移到离子和金属。在这个项目中，我们将改进ZINTL相的氢化反应规则，使我们能够合理化存在，热力学稳定性，化学键合，晶体和电子结构以及氢化ZINTL相的氢能力。最初，大约45种具有E = GA，SI，GE，SN和M =碱性碱性土壤地球或其中两个混合物的Mxey，具有各种Polyanions（Zigzag链，螺旋，五和六元的环），上述方法将研究哑铃，1D丝带和3D网）。对管理E-E和E-H键形成规则的详细知识将使我们能够预测Zintl阶段的进一步氢化反应，即。 e。通过用氢氧化，可以在Zintl期氢化物的聚体中进行连通性调节。应探索用于制备氢存储材料和低维材料的潜力。一方面，将测试ZINTL阶段的实际方面。通过体积和重量法，将研究CASI的热力学，动力学，动力学，可逆性和环循环性，用于CASI和项目第一部分中的其他候选者。另一方面，ZINTL期氢化物将用作1D和2D材料的前体。水解，氨解和甲基化反应可能导致1D和2D聚合物，这可能是硅，德国烷和Stannanane或相关材料的有趣中间体。在该项目中要开发的氢对聚鸡的控制氧化具有很大的潜力，可以对固体的结构，电子和磁性特性进行微调。预计该项目的结果将刺激材料相关的研究，其中含有三层和四元的多层化合物，尤其是甘露，硅，锗，锡。