Polydentate Lewis Acid Acceptor Bowls and Chalices

超分子化学研究的是分子与较大结构的缔合。这些联系不是通过共价键联系在一起的，而是通过较弱的可逆相互作用而联系在一起的。刘易斯酸碱相互作用已经被非常详细地研究过，但主要是在具有几个碱功能的复杂支架上，这些支架使相对简单的酸粒子(主要是阳离子)复杂化。选择性是通过基本功能的空间排列实现的。到目前为止，多路易斯酸的相反情况还没有得到很好的研究。其原因在于这些化合物对空气和水的高度敏感性，Lewis酸中心的更多键，以及在Lewis酸碱络合物形成过程中受体结构的较大变化。然而，具有定义的酸功能空间结构的多Lewis酸的概念允许识别和络合阴离子和Lewis碱以及构建超分子结构。因此，碱组分的性质和反应性会受到特别的影响。因此，该项目的目的是开发一系列新的Lewis酸基，并以定义的方式将它们与已知功能一起定位在刚性分子框架上。通过这种方式，我们想要提出刘易斯碱底物的最佳结合系统。新的酸基是那些在硅或硼功能上具有强吸电子取代基(全氯儿茶酸盐、全氟烷基和全氟芳基，可能结合在一起)的基团。已经测试了全氟芳基硼基、二烷基铝和-镓基团。在项目的准备阶段，这些基团将根据其Lewis酸的性质，根据简单的模型化合物进行系统和定量的分类。作为刚性的、无给电子体的、易于功能化的骨架，一方面我们希望使用三苯并三苯并喹啉的衍生物，它允许三个或六个取代基以碗状或圣杯状的方式连接在两侧，然后用Lewis酸进行官能化。第二个分项目涉及通过平面前体的湿法金属化开发圣杯形三齿路易斯酸。我们最近观察到了一个反应，在这个反应中，六氢三苯并[12]环的硅氢化反应导致了选择性的C3对称三加成，所有苯环都折叠到一边。因此，主链的官能化和新的Lewis酸中心的空间取向是一致的。我们想测试络合路易斯酸系统的络合性能和对多个路易斯基底物的选择性识别。我们还将努力建立更大的笼状伙伴，并建立合适的基地。

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.