Multiply Lewis-acidic and metallophilic receptor systems with trisilacyclohexane skeletons

特定的化学功能可以通过有目的地选择功能及其定义的空间定位来实现。这一原理在自然界中以多种方式实现，例如在酶中，化学家在设计分子催化剂时使用它。通常，使用供体功能或氢桥连单元，而路易斯酸受体的排列则不太常见。然而，这种方法为检测和络合阴离子或刘易斯碱并因此改变它们的性质和反应性提供了可能性。该项目的目的是合成和利用具有多个空间排列的路易斯酸或亲金属受体功能的新系统。在以前的工作中，我们已经表明，三硅环己烷框架取代三个炔基代表一类分子，具有所需的目标系统的建设的所有先决条件：良好的制备的可达性，没有竞争刘易斯碱功能和一些既定的反应容易官能化。在该项目中，几类三炔-三硅环己烷通过烷烃消除反应与金属烷基进行末端金属化，或者通过加氢金属化反应将金属官能团添加到炔基上。以这种方式，基团如R2 Al、Cl 2Ga和R2 Ga或电负性取代的硼基和甲硅烷基基团如BR 2和SiR 3（R = F、Cl、C2 F5、C6 F5、C6 F3（CF 3）2等）可以被取代。而且其它金属原子如金和汞也将连接到刚性框架上。前者通过刘易斯酸-碱相互作用构建具有底物识别可能性的分子骨架，后者利用分散驱动的d10-d10相互作用。目标是学习构建定制的受体，并将其用于选择性识别和修饰刘易斯碱性或亲金属底物的化学和物理性质。该化学的进一步应用方面涉及在受抑刘易斯对的化学中螯合刘易斯酸的检查，以及尝试设计具有其第13族元素的金字塔配位环境的金属-金刚烷化合物形式的超级刘易斯酸的新方法。

Specific chemical functionality can be achieved by purposeful selection of functions and their defined spatial positioning. This principle is realized in nature in many ways, for example in enzymes and chemists use it when designing molecular catalysts. Typically, donor functions or hydrogen bridging units are made use of, while the arrangement of Lewis-acidic receptors is much less common. However, such an approach opens up the possibility for detecting and complexing anions or Lewis bases and thus to change their properties and reactivities. The aim of this project is the synthesis and utilization of new systems with multiple spatially aligned Lewis-acidic or metallophilic receptor functions. In previous work we have shown that trisilacyclohexane frameworks substituted with three alkyne groups represent a class of molecules that possess all prerequisites for the construction of the desired target systems: good preparative accessibility, absence of competing Lewis base functionalities and facile functionalization by a number of established reactions. In this project several classes of trialkyne-trisilacyclohexanes are to be terminally metalated with metal alkyls via alkane elimination reactions, or metal functions are to be added via hydrometalation reactions to the alkyne groups. In this way, groups like R2Al, Cl2Ga and R2Ga or electronegatively substituted boryl and silyl groups such as BR2 and SiR3 (R = F, Cl, C2F5, C6F5, C6F3(CF3)2, etc.) but also other metal atoms such as gold and mercury will be attached to the rigid frameworks. The former serve to construct molecular skeletons with the possibility of substrate recognition via Lewis acid-base interactions, the latter make use of dispersive driven d10-d10 interactions. The goal is to learn constructing tailor-made receptors and to use them for selective recognition and modification of chemical and physical properties of Lewis basic or metallophilic substrates. Further application aspects of this chemistry concern the examination of chelating Lewis acids in the chemistry of frustrated Lewis pairs and to try a new approach in designing super-Lewis-acids in the form of metal-adadamantane compounds with pyramidal coordination environments of their Group 13 elements.