Supramolecular Assembly of Metalloamphiphiles

A recent research strategy in the Besenius group involves the design of a new class of hybrid bioorganic Au(I)-peptide materials. The aim is to couple molecular Au(I)-complexes to small peptide building blocks, in order to prepare new metalloamphiphiles as supramolecular monomers. Structurally and functionally the aurophilic interaction between Au(I)-centres is at the heart of these systems. We have developed a facile synthetic route for the preparation of stable peptidic Au(I)-metalloamphiphiles equipped with stabilising phosphane ligands (Chem. Commun. 2015). Using a diphenylalanine derivative, we have shown that the Au(I)-metalloamphiphile self-assembles into luminescent micellar nanostructures in buffered aqueous environments of medium to high ionic strength. We have extended the ligation strategy for Diels-Alder conjugation and biotinylation of Au(I)-complexes (Chem. Eur. J. 2017). The attractive feature of the Au(I)-complexes, are their phosphorescent properties which depend on the tuneable distance between the gold centres, as wells as the long lifetimes of the excited states. This new class of bioinorganic hybrid materials hold great promise for chemo- and biosensors, and for the preparation of ultrathin and mechanosensitive luminescent nanowires. A spectacular finding which holds great promise for further efforts in the above-mentioned applications, is a recently discovered stepwise self-assembly of a AuI-metallopeptides in water. Here we achieved kinetic control of the supramolecular polymer morphology using a temperature-dependent assembly protocol, which yields low dispersity supramolecular polymers, a metastable state at low temperature or helical bundled nanorods, at higher temperatures (J. Am. Chem. Soc. 2018).

Members involved: Oliver Stach.