Polydentate Lewis Acid Acceptor Bowls and Chalices

多齿路易斯酸受体碗和圣杯

• 批准号: 424957011
• 负责人: Professor Dr. Norbert W. Mitzel
• 金额: --
• 依托单位: Arbeitsgruppe Anorganische Chemie und Strukturchemie
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2019
• 资助国家: 德国
• 起止时间: 2018-12-31 至 2023-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/424957011?language=en
• 关键词: Polydentate; Lewis; Acid; Acceptor; Bowls

Supramolecular chemistry deals with the association of molecules to larger structures. These associations are not connected by covalent bonds, but by weaker, reversible interactions. Lewis acid-base interactions have already been studied in great detail, but mostly on complex scaffolds with several base functions that complex relatively simple acid particles (mostly cations). Selectivity is achieved by the spatial arrangement of the base functions. The inverse situation of poly-Lewis acids has only been very poorly investigated so far. The reasons for this lie in the high sensitivity of these compounds to air and water, the larger number of bonds at the Lewis acid centres and the larger changes in the receptor structure during the formation of Lewis acid-base complexes.However, the concept of poly-Lewis acids with defined spatial structure of the acid functions allows the recognition and complexation of anions and Lewis bases as well as the construction of supramolecular architectures. Properties and reactivity of the base fraction can thus be specifically influenced. The aim of this project is therefore to develop a series of new Lewis acid groups and to position them in a defined way on rigid molecular frameworks alongside known functions. In this way, we want to present systems for the optimal binding of Lewis-base substrates. New acid groups are those with strong electron withdrawing substituents (perchloro-catecholate, perfluoroalkyl and perfluoroaryl, possibly combined) at silicon or boron functions. Perfluoroarylboryl, dialkylaluminium and -gallium groups have already been tested. In the run-up to the project, these groups are to be classified systematically and quantitatively on the basis of simple model compounds with regard to their Lewis acid properties. As rigid donor-free and easy to functionalize frameworks, we want to use tribenzotriquinacene derivatives on the one hand, which allow three or six substituents to be attached on both sides in a bowl-like or chalice-like manner, which can then be functionalized with Lewis acids. The second subproject concerns the development of chalice-shaped tridentate Lewis acids by hydrometallation of planar precursors. We recently observed a reaction in which the hydrosilylation of hexadehydrotribenzo[12]annule, a planar ring-shaped molecule with three alkyne functions, leads to selective C3-symmetric triple addition with folding of all benzene rings to one side. The functionalization of the backbone and the spatial orientation of the new Lewis acid centers are therefore concerted. We want to test the chelating Lewis-acid systems with regard to their complexing properties and the selective recognition of multiple Lewis-based substrates. We will also try to build up larger cage-like associates with suitable bases.

超分子化学研究分子与更大结构的结合。这些缔合不是通过共价键连接的，而是通过较弱的可逆相互作用连接的。刘易斯酸碱相互作用已经被非常详细地研究过了，但大多是在具有几种碱功能的复杂支架上，这些碱功能复合相对简单的酸颗粒（主要是阳离子）。选择性是通过基函数的空间排列来实现的。到目前为止，对聚路易斯酸的逆情况的研究非常少。其原因在于这些化合物对空气和水的高度敏感性、在刘易斯酸中心处的大量键以及在形成刘易斯酸-碱络合物期间受体结构的较大变化。聚的概念，具有明确酸官能空间结构的刘易斯酸可以识别和络合阴离子和刘易斯碱，并构建超分子建筑因此，可以具体地影响基础馏分的性质和反应性。因此，该项目的目的是开发一系列新的刘易斯酸基团，并将它们以确定的方式定位在刚性分子框架上，与已知的功能一起。通过这种方式，我们希望提出用于路易斯碱底物的最佳结合的系统。新的酸基团是在硅或硼官能团上具有强吸电子取代基（全氯儿茶酚、全氟烷基和全氟芳基，可能组合）的那些。全氟芳基硼基、二烷基铝和-镓基团已经被测试过。在该项目的准备阶段，将根据简单的模型化合物，根据其刘易斯酸特性，对这些类别进行系统和定量的分类。作为刚性的无供体和易于官能化的框架，我们一方面希望使用三苯并三喹并苯衍生物，其允许三个或六个取代基以碗状或杯状方式连接在两侧，然后可以用刘易斯酸官能化。第二个子项目涉及通过平面前体的水金属化来开发杯形三齿刘易斯酸。我们最近观察到的反应中，氢化硅烷化的hexadehydrotribenzo[12]annule，一个平面的环状分子与三个炔功能，导致选择性的C3-对称的三重加成与折叠的所有苯环的一侧。因此，骨架的官能化和新的刘易斯酸中心的空间取向是一致的。我们想测试螯合路易斯酸系统的络合性能和多个路易斯基基板的选择性识别。我们也会尝试建立更大的笼状联盟与合适的基地。