Double salts with a multifunctional character made from Zintl phases and oxo- as well as halogeno-metalates

本研究项目旨在通过两种无机组分在分子离子水平上的结合，采用合成固态化学的方法，开发用于新型功能材料的基础化合物。重点是由9个原子组成的三角面体、聚阴离子锗和锡簇，它们与第二种阴离子（如金属氧酸盐和金属卤化物阴离子）结合，形成新的杂化半导体固态材料（双盐）。由于它们的相互结构可调性，碱金属Zintl相和碱金属金属氧化物或金属卤化物的结合为新的多组分杂化材料的产生和设计提供了许多可能性。由于双盐可以以可变的组成出现，这种化合物类具有可调带隙的潜力。这种新材料在光电子学方面具有应用潜力，原则上也可以作为水分解催化剂。在第一步中，基于少数已知的代表，系统地开发了双盐的合成方案，并应用于各种其他组合。用x射线衍射和拉曼光谱对新化合物进行了结构表征。基本的电子性质，如带隙或磁性，构成元素的氧化态，表明单元之间可能的电荷转移，是通过实验确定的。利用量子化学计算，一方面计算了电子结构和带隙；另一方面，在结构关系的基础上，确定了具有混合特性的稳定的、新的、未知的候选物质，并利用理论方法进行了热力学稳定性测试。在进一步的步骤中，使用开发的合成协议特异性地合成选定的候选物。具体来说，在本项目申请中，杂化化合物的生产是以[Ge9]4 -、[Sn9]4 -和[M@Sn9] x-为组分1和[MO4]x - （M =过渡金属）或四面体配位卤化物（如[SnBr4]2 -、[PbBr4]2 -、[MX4]x-； x =卤素）或[MX6]x- (M = Sn, Pb)类型卤化物的金属氧化物或金属卤化物阴离子为组分2。这两种成分的结构单元被称为碱金属化合物，但它们的组合是第一次在这里系统地发展。如今，第二种成分已经用于金属青铜和太阳能电池。这种组合使元件的构建单元之间的电荷转移过程和更好的可调带隙成为可能。

This research project aims for the development of fundamental compounds for new functional materials by means of synthetic solid-state chemistry through the combination of two inorganic components at the molecular ionic level. The focus is on deltahedral, polyanionic germanium and tin clusters comprising nine atoms, that are in combination with a second type of anion such as oxometalates and metal-halide anions form new, hybrid semiconducting solid state materials (double salts). Due to their mutual structural tunability, the combination of both alkali-metal Zintl phases and alkali-metal metal-oxides or metal-halides offers numerous possibilities for the generation and design of new multi-component hybrid materials. Since double salts can appear with variable composition, this compound class has the potential for tunable band gaps. The new material class has application potential in optoelectronics and, in principle, also as a water splitting catalyst.In a first step, synthesis protocols for double salts are systematically developed based on the few known representatives and are applied to various other combinations. The new compounds are structurally characterized by means of X-ray diffraction methods and Raman spectroscopy. Basic electronic properties such as band gaps or magnetic properties, oxidation states of the constituting elements that suggest a possible charge transfer between the units, are determined experimentally. Using quantum chemical calculations, on the one hand, the electronic structures and band gaps are calculated. On the other hand, stable, new, unknown candidates with hybrid character are identified on the basis of structural relationships and tested with regard to thermodynamic stability using theoretical methods. In a further step, selected candidates are specifically synthesized using the synthesis protocols developed. Specifically, in the project applied for here, hybrid compounds are produced which contain the polyanions [Ge9]4–, [Sn9]4– and [M@Sn9] x– as component 1 and metal-oxide or metal-halide anions of the [MO4]x– (M = transition metal) or tetrahedrally coordinated halides (e.g. [SnBr4]2–, [PbBr4]2–, [MX4]x-; X = halogen) or halides of the type [MX6]x- (M = Sn, Pb) as component 2. The structural units of both components are known as alkali-metal compounds, however in combination they are systematically developed here for the first time. Component 2 is already used today in metallic bronzes and in solar cells. The combination enables charge-transfer processes between the building units of the components and better tunable band gaps.