Transition Metal Complexes with Chiral Pincer Ligands: Reactions, Catalyses, Mechanisms

本课题研究手性钳形配体作为立体定向配体在对映选择性催化中的配位化学。一个主要的目标将是评估这类配体在多大程度上也可以在不同范围的对映选择性转化中“特权”立体定向配体系统。计划研究的一个目的是分离和表征（高自旋）氢化物和硼原子衍生物的boxmi -锰，铁，钴和镍配合物，作为这些三维金属对映选择性催化还原的关键中间体，以及在化学计量学和催化还原的系统动力学研究中使用分离的配合物。此外，我们的目标是基于最近发现的Ni（I/II）催化的以O2为共底物的径向氧化，开发高效的氧化催化剂，并将继续对这些转化的机理进行更深入的研究。最后，我们计划研究boxmi -锰配合物作为酮类对映选择性α -酰基化反应的可能催化剂，及其反应机理，并确定所涉及的（电子开壳，顺磁性）配合物。

The research project concerns the coordination chemistry of such chiral pincer ligands as stereodirecting ligands in enantioselective catalysis. A main objective will be to assess to which extent this class of ligands may serve als "privileged" stereodirecting ligand systems in a diverse range of enantioselective transformations. An aim of the planned research will be the isolation and characterization of (high spin) hydrido and boranato-derivatives of Boxmi-manganese, iron, cobalt and nickel complexes as key intermediates of enantioselective catalytic reductions with these 3d metals as well as the use of the isolated complexes in systematic kinetic studies of the stoichiometric and catalytic reductions. Furthermore, we aim to develop efficient oxidation catalysts based on the recently discovered Ni(I/II) catalyzed radikal oxygenations with O2 as co-substrate, and ongoing mechanistic studies of these transformations will be continued and pursued to greater depth. Finally we plan to investigate Boxmi-manganese complexes as possible catalysts for the enantioselective alpha-acyloxylation of ketones, the reaction mechanism(s) and identify the (electronically open shell, paramagnetic) complexes involved.