Frustrated Lewis-Pairs with Silicon, Germanium and Tin as Lewis-acidic Functions

阻挫刘易斯酸碱对（FLP）的概念是基于刘易斯酸和碱之间的相互作用，其被阻止形成经典加合物。所得到的未淬灭的反应电势可用于结合小分子，裂解或活化它们，例如用于氢的异裂裂解或用于二氧化碳和其他温室气体的活化。通过这种方式，新的反应和催化过程成为可能。大多数已知的FLP化学是基于元素硼和磷，即硼烷和膦作为酸和碱。其他元素[酸：Al，Zn，P（V），Si+，碱：N，O]的探索要少得多。随着第一个不带电荷的分子内硅磷FLP，（C2 F5）3SiCH 2 P（t-Bu）2的出现，我们最近能够将我们在双生供体-受体化合物领域的长期专业知识成功地应用于FLP化学的现代发展。硅的分子化学很容易理解，因为它具有巨大的工业重要性，我们现在想利用这一优势进行FLP化学。为此，本项目旨在产生新型的分子内FLP体系（RF）3SiCH 2 P（R）2，RF代表电负性（e. G.氟化的）烷基或芳基（Z. B。C6 F5、C5 NF 4等）R代表烷基或胺官能团（t-Bu、CH（SiMe 3）2、NR ′ 2等）。Si和P原子之间的链的长度和类型将变化。除了硅之外，锗和锡将用于提供更软的结合伴侣，就HSAB概念而言，用于活化小分子，因此结合更弱，因此在催化过程中更容易去除。开发中性Si-FLP系统的概念将在一个平行的子项目中转移到具有单独的酸和碱分子的分子间系统。酸是化合物如（RF）4Si，碱也包括超碱性体系如磷杂三环。将测试所得FLP系统的结合、活化小分子的活性及其催化能力（例如不饱和底物的氢化）。仲氢的实验将有助于机理的理解。先进的结构研究包括气相电子衍射测量自由分子的几何形状和实验电荷密度的研究，以更详细地阐明键合情况。

The concept of frustrated Lewis acid base pairs (FLP) is based on the interaction between Lewis acids and bases, which are prevented from the formation of a classical adduct. The resulting unquenched reaction potential can be used to bind small molecules, cleave or activate them, e.g. for the heterolytic cleavage of hydrogen or for the activation of carbon dioxide and other greenhouse gases. In this way novel reactions and catalytic processes have become possible. Most of the known FLP chemistry is based on the elements boron and phosphorus, i.e. boranes and phosphanes as acids and bases. Other elements [acids: Al, Zn, P (V), Si+, bases: N, O] are much less explored. With the presentation of a first uncharged intramolecular silicon-phosphorus FLP, (C2F5)3SiCH2P(t-Bu)2, we were recently able to apply our long-standing expertise in the field of geminal donor-acceptor compounds successfully to the modern developments of FLP chemistry. The molecular chemistry of silicon is easily accessible because of its immense industrial importance; we now want to make use of this advantage for FLP chemistry.For this purpose, this project aims at generating novel intramolecular FLP systems of the type (RF)3SiCH2P(R)2, with RF representing electronegative (e. g. fluorinated) alkyl or aryl groups (z. B. C6F5, C5NF4, etc.) and R representing alkyl or amine functions (t-Bu, CH(SiMe3)2, NR'2, etc.). The length and type of the chain between the Si and P atoms will be varied. In addition to silicon germanium and tin will be used to offer softer binding partners in terms of the HSAB concept for the activation of small molecules that are thus bound more weakly and hence in terms of catalytic processes more easily removable. The concept to develop neutral Si-FLP systems will be transferred in a parallel subproject to intermolecular systems with separate acid and base molecules. The acids are compounds such as (RF)4Si, and the bases also include super basic systems such as phosphatranes. The resulting FLP systems will be tested for their activity of binding, activating small molecules and for their catalytic ability (e.g. hydrogenation of unsaturated substrates). Experiments with para-hydrogen will contribute the mechanistic insights. Advanced structural investigations include gas phase electron diffraction measurements for free molecule geometries and experimental charge density studies to shed more light on the bonding situation in more detail.