Oxazolidinone-containing pseudopeptides: Supramolecular materials, fibers, crystals, and gels

The formation of fibers through self-assembly is of particular interest, as fibrous proteins (such as collagen, keratin, actin, and so on) are involved in intra- and extracellular functions. To understand aggregation phenomena, oligopeptides may be designed and prepared either to mimic or to interfere with these processes. In this article, we will demonstrate that the introduction of the 4-methyl-5-carboxy-oxazolidin-2-one (Oxd) moiety inside a peptide chain favors the formation of fiber-like materials organized either in β-sheets or in supramolecular helices, provided that it is combined with other factors, like π-stacking interactions and intermolecular NH•••OC bonds. The presence of the Oxd moiety is essential for the material formation: when Oxd is replaced with Pro, only liquids or amorphous solids are obtained. Remarkably, some of these molecules are low-molecular-weight gelators, as they induce the formation of both organogel and hydrogels that have been used for several applications.