The research activity of the group has traditionally been centered on fullerene chemistry for applications in materials science and biology, and from this core area branches into dendrimers, luminescent transition metal complexes, porphyrins, macrocyclic compounds and π-conjugated systems. Our research is highly synthesis-driven and at the frontier between different fields of the chemical sciences (organic chemistry, supramolecular chemistry, coordination chemistry, macromolecular chemistry, bio-organic chemistry and physical organic chemistry).
Fullerenes combining three-dimensionality with unique electronic properties are extremely promising nanostructures for the preparation of new advanced materials or biologically active molecules. In this general context, the expertise of the Nierengarten group ranges from the development of versatile easy to functionalize fullerene building blocks to the preparation of fullerene derivatives having the required design features for their applications in materials science or biology.
Among the large number of molecular subunits used for dendrimer chemistry, fullerene has proven to be a versatile building block. fullerene itself is a convenient core for dendrimer chemistry.We have shown that specific advantages are brought about by the encapsulation of a fullerene moiety in the middle of a dendritic structure. On the other hand, dendritic structures with fullerene units at their surface or with fullerene spheres in the dendritic branches have been also prepared.
As part of our research directed towards the synthesis of complex nanomolecules that exhibit specific properties, we have recently extended our work on hexa-substituted fullerenes to scaffolds based on a pillararene core. Pillararenes are unique tubular-shaped macrocyclic compounds made of 1,4-disubstituted hydroquinone subunits linked by methylene bridges in their 2,5-positions. They are usually prepared from 1,4-dialkoxybenzene derivatives and paraformaldehyde in the presence of a Lewis acid catalyst.
During the photophysical studies carried out on dyads combining fullerene with coordination compounds possessing low-lying MLCT excited states, we have also systematically investigated the electronic properties of the corresponding model compounds and thus became progressively involved in the field of phosphorescent metal complexes. In particular, we have developed strongly luminescent Cu(I) complexes and have been among the first to show the potential of such compounds for light emitting applications.