Main-group element compounds possessing multiple reaction centers - Systems between cooperativity, synergy and emergence

催化是在环保且经济的工艺中将传统和替代资源转化为有价值的化学品的最有力的策略之一。目前的工业催化剂几乎完全包含贵金属和非贵金属过渡金属，这些金属稀缺（并且相应地昂贵）并且通常在（生态）毒性方面存在问题。因此，需要将丰富和更环保的主族元素作为活性位点的替代概念。然而，在过渡金属催化中起作用的机理方案迄今为止并不完全适用于主族元素化合物的催化。对于主族元素化合物，尚未实现氧化加成和还原消除的催化最相关顺序。因此，开发新的小分子活化和转化模式以及增强互补策略是值得追求的。该项目的核心是通过多核环境友好的主族元素化合物，结合铝、钙、镓、锗、镁、硅和锡，对小分子和惰性化学键进行活化和催化功能化。我们感兴趣的合作和出现的影响时，一个配体框架主机两个活性位点在附近。协同性或协同作用描述了多中心催化剂与单中心催化剂的等效混合物相比的增强的反应性。相反，突现效应是不可约的，即，所观察到的化学转化不能通过使用单位点催化剂来实现。我们并不一定要寻求建立过渡金属催化剂的直接替代品，而是要发展由主族元素化合物介导的键断裂和键合成的新概念。

Catalysis is one of the most powerful strategies to convert both conventional and alternative resources to valuable chemicals in environmentally friendly and economical processes. Current industrial catalysts almost exclusively incorporate precious and non-precious transition-metals, which are scarce (and correspondingly expensive) and often problematic with regard to (eco)toxicity. Thus, there is a need for alternative concepts that incorporate abundant and more environmentally friendly main-group elements as active sites. However, mechanistic scenarios operative in transition-metal catalysis are so far not fully applicable in catalysis by main-group element compounds. The catalytically most relevant sequence of oxidative addition and reductive elimination has not yet been achieved for main-group element compounds. Consequently, the development of new modes of small molecule activation and transformation as well as the enhancement of complementary strategies are worthy of pursuit. This project is centered around the activation and catalytic functionalisation of small molecules and inert chemical bonds by means of polynuclear environmentally benign main-group element compounds incorporating aluminium, calcium, gallium, germanium, magnesium, silicon and tin. We are interested in both the cooperative and the emergent effects that arise when a ligand frame hosts two active sites in close proximity. Cooperativity or synergism describes the enhanced reactivity of a multi-site catalyst compared to an equivalent mixture of single-site catalysts. In contrast, emergent effects are irreducible, i.e., the observed chemical transformations are not accessible by using single-site catalysts. We do not necessarily seek to establish immediate substitutes for transition-metal catalysts, but rather to develop new concepts for bond breaking and making mediated by main-group element compounds.