Polysilicides and their Transition Metal Complexes: Synthesis and Structure Elucidation in Liquid Ammonia and in Solid Ammoniates

多晶硅化物是带负电荷的分子离子，它们完全由化学元素硅的原子构成。硅是半导体技术中的核心元素，硅结构是在非常高的温度下从熔体中产生的，或者是通过同样需要能量的气相沉积产生的。同原子硅结构单元如多晶硅化物的溶液化学仅初步存在。聚硅化物可以通过固态合成在具有碱金属抗衡离子的化合物中产生。对于来自同一化学族的较重元素锗、锡和铅，过去一段时间已经建立了类似物化合物的溶液化学。利用这些元素的同原子结构单元，可以通过定向方法制备新的元素结构和新的过渡金属化合物。可比较的聚硅化物被认为长时间不溶。仅在十年前，人们才发现液氨（一种在低温下冷凝的气体）能够在很小程度上溶解某种碱金属聚硅化物。关于这些溶液的精确组成知之甚少，在这种情况下最好的分析方法是NMR光谱法。申请人可以在2013年报告第一个多硅化物的NMR信号。在本项目中，我们提出系统地研究在液氨中存在哪些多硅化物在什么条件下。与此相关的是对溶液的进一步NMR研究，以及对从溶液结晶的氨化物的X射线研究。同样，对溶解的多晶硅化物的化学反应知之甚少。在该项目中，我们建议将这些元素构建块与过渡金属化合物反应，这些化合物已经产生了有趣的新化合物，具有较重的同系物锗，锡和铅。该项目的长期目标是建立一种多晶硅化物的溶液化学。

Polysilicides are negatively charged molecular ions that are built exclusively from atoms of the chemical element silicon. Silicon is the central element in semiconductor technology, silicon structures are generated from melts at very high temperatures or by likewise energy-demanding depositions from the gas phase. A solution chemistry for homoatomic silicon building blocks such as polysilicides exists only rudimentarily. Polysilicides can be generated by solid state syntheses in compounds with alkali metal counter-ions. For the heavier elements germanium, tin and lead from the same chemical group, a solution chemistry of analogues compounds has been established for some time past. With the homoatomic building blocks of these elements, new element structures and new chemical compounds with transition metals could be prepared by a directed approach. The comparable polysilicides were thought to be insoluble for a long time. Only ten years ago it could be shown that liquid ammonia, a gas condensed at low temperatures, is able to dissolve a certain type of alkali metal polysilicides to a small extent. On the precise composition of these solutions is little known, the best analytical method in this case is NMR spectroscopy. The applicants could report on the first NMR-Signal of a polysilicide in 2013. In the project we propose to study systematically which polysilicides exist in liquid ammonia under which conditions. Relevant for this are further NMR investigations of the solutions, but also X-ray investigations on the ammoniates which crystalize from the solutions. Again, little is known on chemical reactions with dissolved polysilicides. In the project, we propose to react these elemental building blocks with transition metal compounds which have already yielded interesting new compounds with the heavier homologs germanium, tin and lead. The long term goal of the proposed project is to establish a solution chemistry of polysilicides.