Research

Anionic Transition Metal Compounds with Metals in Low Oxidation States: In this exploratory project, we investigate organometallic complexes that can be used as sources of "M^x-"- and "CpM^x-" synthons (M = transition metal, Cp = cyclopentadienyl ligand) for the synthesis of unusual new compounds and in catalysis. Transition metal anions of this type have scarcely been applied due to the limited availability of suitable synthesis equivalents. Starting with anionic synthons, we synthesize new metal clusters, "functionalized" transition metal anions with an interesting subsequent chemistry, and novel multimetallic complexes. The catalytic properties of the anions investigated in this project are being studied as well. Our investigations focus on iron, which is of particular interest for catalytic processes as an abundant, non-toxic, and environmentally friendly metal.

Cooperative Reactivity of Metal Atoms in Polynuclear Transition Metal Hydrides: This project explores the cooperative reactivity of novel mono- and multinuclear polyhydrido complexes. The ability of oligonuclear hydrides to activate C-H and C-C bonds through a multimetallic mechanism and their catalytic activity lie at the heart of our investigations. Another focus lies on metal-ligand cooperativity in NHC ruthenium complexes (NHC = N-heterocyclic carbene) in catalytic reactions.

Selective Oxyfunctionalization via Coupled Redox Photocatalysis: The selective oxidation of alkenes and aliphatic hydrocarbons represents a major challenge in modern chemistry. In nature, these oxidations are performed successfully under mild conditions by metalloenzymes such as cytochrome P450 and non-heme based oxygenases. In the lab, a plethora of successful transition metal-based catalysts have been developed. However, only few catalysts are able to use atmospheric oxygen as the terminal oxidant, and these rare examples still show poor selectivities. Moreover, few examples for photocatalytic oxyfunctionalizations have been described to date.

In this project, we develop new photocatalytic methods for the selective oxyfunctionalization of hydrocarbons. Preferably, atmospheric oxygen is used as the oxidant. The investigations are conducted in the framework of the research training group "Chemical Photocatalysis" (GRK 1626).