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).
Carbon rich nanostructures have been a major hot topic in chemical research over the past two decades. In particular, 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 (for a recent review, see: Chem. Rec. 2015, 15, 31).
The unique electronic properties of C60 have generated significant research activities focused on its use as an electron and/or energy acceptor in photochemical molecular devices. Our group has significantly contributed to this field and various series of donor-fullerene arrays have been developed. In the particular case of covalent systems combining the carbon sphere with π-conjugated oligomers, we have been the first to show that such compounds can be incorporated into photovoltaic devices (Chem. Commun. 1999, 617). Coordination compounds possessing low-lying metal-to-ligand charge transfer (MLCT) excited states with marked reducing character are also excellent partners for C60 in photoactive multicomponent hybrid systems. We have prepared a large number of dyads in which C60 is coupled with photoactive coordination compounds of Ru(II), Re(I), Ir(III) and Cu(I). During the photophysical studies carried out on these dyads, 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 (Adv. Mater. 2006, 18, 1313). More recently, the group has shown its expertise in the synthesis of bioactive molecules. In particular fullerene-based glycoclusters have shown outstanding biological properties. Examples include the first significant multivalent effects for sugar-processing enzymes (Angew. Chem. Int. Ed. 2010, 49, 5753; Chem. Eur. J. 2012, 18, 641) and the inhibition of Ebola virus infection (Nature Chem. 2016, 8, 50).
As part of our research concerned with the design of versatile nanoscaffolds allowing for the grafting of one or more molecular entities to easily generate sophisticated nanomolecules, our efforts were mainly focused on fullerene-based scaffolds. More recently, we became also interested in the use of pillar[n]arene cores as scaffolds for the preparation of nanomaterials with a controlled distribution of functional groups on the macrocyclic framework. These building blocks have been already used for several applications. For example, the pillararene scaffold has been used as a multivalent core unit to prepare glycoconjugates to target specific bacterial lectins (Chem. Eur. J. 2016, 22, 2955). We have also reported the preparation of polycationic dendritic pillararene derivatives and shown their capability of interacting with DNA. Owing to their efficient ability to compact DNA, these compounds have been used for gene transfer experiments thus opening new research avenues in the field of biological applications with pillar[n]arene derivatives (Chem. Eur. J. 2013, 19, 17552).
For the most recent news about our research, follow us on Twitter or on our personal pages.