Four-membered heterocyclic Biradicaloids: Reagents for Bond Activation and Ligands for 3d Transition-metals

均相催化因其潜在的应用潜力而成为现代化学的主要研究领域。贵金属的分子络合物，如钯、铂和铑，主要用作催化剂。不幸的是，由于它们的丰度较低，它们对供应波动很敏感，贵金属及其络合物的成本通常非常高。此外，对环境的影响与它们复杂的采矿过程有关。因此，用较轻的同系物取代这些金属或使用主族化合物作为催化剂是一个持续的兴趣。拟议的项目涉及一类对这两种方法都有前景的化合物，即四元杂环双自由基化合物。这些化合物构成了开壳单重态物种的一个亚群，通常表现出较高的反应活性。Schulz和Grützmacher小组的初步工作包括激活二氢、氨和多键体系。这个项目的目的是进一步探索这类耐人寻味的化合物。因此，最终的目标是将所研究的反应性纳入催化循环。为了实现这一目标，将进一步研究已有体系的反应性，并将合成基于硅和砷的新的双自由基体系。此外，杂环双自由基化合物将被用作3D过渡金属的氧化还原活性夹心配体，以模拟贵金属在催化反应中的行为。

Homogeneous catalysis is a main research area in modern chemistry due to its enourmos application potential. Molecular complexes of precious metals like palladium, platinum and rhodium are predominantly used as catalysts. Unfortunately, because of their low abundance, they are sensitive towards supply fluctuations and the cost of the precious metals and complexes thereof are usually very high. In addition, environmental implications are associated with their complex mining processes. Therefore, there is an ongoing interest to replace those metals by their lighter congeners or to use main-group compounds as catalysts instead.The proposed project deals with a promising class of compounds for both approaches, namely four-membered heterocyclic biradicaloids. These compounds constitute a subgroup of open-shell singlet species which usually show a high reactivity. Preliminary work by the groups of Schulz and Grützmacher include the activation of dihydrogen, ammonia and multiple-bond systems. The aim of this project is the further exploration of this intriguing class of compounds. Thereby, the ultimate goal is the incorporation of the studied reactivity into catalytic cycles. To achieve this goal, the reactivity of known systems is going to be studied further and also, new biradicaloid systems based on silicon and arsenic will be synthesised. Additionally, the heterocyclic biradicaloids will be utilised as redox-active sandwich ligands for 3d transition-metals in order to mimic precious-metal behaviour in catalytic reactions.