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

聚硅酸是带负电的分子离子，完全由化学元素硅原子构成。硅是半导体技术的核心元素，硅结构是在非常高的温度下由熔体产生的，或者同样是由气相的耗能沉积产生的。同原子硅结构块（如聚硅酸盐）的溶液化学仅初步存在。聚硅酸盐可以在碱金属反离子的化合物中固态合成。对于来自同一化学基团的较重元素锗、锡和铅，一种类似化合物的溶液化学已经建立了一段时间。利用这些元素的同原子构建块，可以有针对性地制备新的元素结构和含有过渡金属的新化合物。在很长一段时间里，人们认为类似的聚硅酸酯是不溶的。仅仅在十年前，人们才发现液态氨，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酸盐。对这些溶液的精确组成知之甚少，在这种情况下，最好的分析方法是核磁共振波谱法。申请人可以在2013年报告第一个聚硅化物的核磁共振信号。本课题拟系统研究在何种条件下液态氨中存在何种聚硅酸盐。与此相关的是对溶液的进一步核磁共振研究，以及对从溶液中结晶的氨化物的x射线研究。同样，人们对溶解的聚硅酸盐的化学反应知之甚少。在这个项目中，我们建议将这些元素与过渡金属化合物反应，过渡金属化合物已经与更重的同系物锗、锡和铅产生了有趣的新化合物。该项目的长期目标是建立聚硅酸盐的溶液化学。

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.