Chiral and non-chiral assemblies from lipidated serine-based pseudopeptidic molecules

Abstract

A series of lipidated molecules L-A1–L-A5 containing two serine units linked by a variety of aromatic spacers were designed and synthesized. Compound L-A1 containing a m-xylylene unit self-assembled into intertwined twisted-ribbons, while compound L-A2 containing a p-xylylene unit formed nano-sized twisted-ribbons. A racemic mixture of L-A1 and D-A1 showed tapes, while a racemate from L-A2 and D-A2 showed fibres. In contrast, compounds L-A3 and L-A4 containing a benzene-1,3-dicarbonyl spacer showed a fibrillar morphology. Control over self-assembly was achieved by the choice of aromatic spacers and N-terminal substituents. The need for molecular curvature for the formation of twisted ribbons was demonstrated by the inability of control compound L-A5 to form twisted-ribbons.