Research

The Schäfer group is interested in molecular organometallic chemistry of the main group elements with an emphasis on cyclopentadienyl compounds like metallocenes and metallocenophanes.
In particular, the focus lies on coordination chemistry of these compounds, as well as their application in homogeneous catalysis and the preparation of new metal-containing polymers.
A key motivation in our work is the aspect of Green Chemistry, which is well-represented by our research emphasis in magnesium catalysis and dehydrocoupling reactions, as well as small molecule activation and the synthesis of iron-containing metallopolymers.

 

Cyclopentadienyl Complexes of Main-Group Elements

The group 14 metallocenes (tetrelocenes) have been known for several decades. Nevertheless their coordination chemistry and the related metallocenophanes (tetrelocenophanes) are only poorly explored.
Our group was able to structurally characterize the first carbene complexes of this class of compounds, as well as obtain phosphanyl-functionalized Lewis-amphiphilic derivatives. The former are indicative of the central atom possessing Lewis-acidic character, the latter are being applied as ligands to different transition metal fragments.
Furthermore, we investigate related half-sandwich complexes and were able to obtain the first half-sandwich tetrylenes.

Heavier N-heterocyclic half-sandwich tetrylenes

Main-Group Metallocenophanes

Carbene Complexes of Stannocenes

Diphosphanylmetallocenes of Main-Group Elements

 

 

s-Block Catalysis

Metal catalysis has always played a pivotal role in chemistry, both at laboratory scale as well as at an industrial scale in technical chemistry. One of the biggest challenges in this area is finding viable substitutes for expensive and sometimes toxic transition metals, which are cheaper and possess a high biocompatibility. In this regard, s-block metals are of particular interest.
Our group develops new magnesium catalysts for a variety of different applications, such as dehydrocoupling and hydroelementation reactions.

Cross-Dehydrocoupling of Amines and Silanes Catalyzed by Magnesocenophanes

Magnesocenophane Catalyzed Amine Borane Dehydrocoupling

 

Polymetallocenylmethylenes

Metallopolymers are an important class of compounds at the frontier between organometallic and materials chemistry. Due to the metal centers incorporated in the polymer, the material can possess stimuli-responsive characteristics and promissess a variety of different applications. Within this group, the class of metallocene-based polymers play an especially important role. In particular, ferrocene groups exhibit good chemical and thermal stability and at the same time possess redox active properties.
Amoung other things, our group investigates the relatively unknown polyferrocenylmethylene (PFM), a polymer with ferrocene units in the main-chain, which are interlinked by methylene groups.

Rings and Chains: Synthesis and Characterization of Polyferrocenylmethylene

Ferrocene and Related Metallocene Polymers