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明确的空间定位来实现。这一原理在自然界中以多种方式实现，例如在酶和化学家设计分子催化剂时使用它。通常，使用供体功能或氢桥接单元，而刘易斯酸受体的排列则不太常见。然而，这种方法开辟了检测和络合阴离子或路易斯碱的可能性，从而改变它们的性质和反应性。该项目的目的是合成和利用具有多个空间排列的刘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，用三个炔基取代的三硅环己烷框架代表了一类具有构建所需目标体系的所有先决条件的分子：良好的制备可及性，缺乏竞争的路易斯碱官能团和易于通过许多已建立的反应实现功能化。在本项目中，几类三炔-三硅环己烷通过烷烃消去反应与金属烷基端金属化，或通过金属氢化反应在炔基上添加金属官能团。这样，像R2Al， Cl2Ga和R2Ga这样的基团或电负性取代的硼基和硅基，如BR2和SiR3 （R = F, Cl, C2F5, C6F5, C6F3(CF3)2等）以及其他金属原子，如金和汞，将附着在刚性框架上。前者通过Lewis酸碱相互作用构建具有底物识别可能性的分子骨架，后者利用色散驱动的d10-d10相互作用。目标是学习构建量身定制的受体，并使用它们选择性识别和修饰路易斯碱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是研究螯合路易斯酸在受挫的路易斯对化学中的作用，并尝试一种新的方法来设计具有13族元素金字塔配位环境的金属-金刚烷化合物形式的超级路易斯酸。

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.