Arnaud-Pierre Schaffner

Porous 3-D honeycomb architecture by self-assembly of helical H-bonded molecular tapes

Enantiopure dipeptide-derived 1,3,5-triazepan-2,6-diones and form H-bonded 3(1) helical molecular tapes with P chirality in the solid state; in the case of , these columnar tapes self-assemble through aromatic-aromatic interactions to give hollow tubular structures.

A Short-Range Interaction of the cis-trans Urea Motif in Ureapeptides

The urea motif is known to promote particular structures, such as β-like sheets, in which the chains exchange multiple intermolecular H-bonds between all-trans urea groups [1]. Preliminary studies in CHC13 on the α-acylamino ureas Boc-gXaa-CO-NHR 1, where gXaa denotes a gem-diamino residue, have revealed a structure folded by the NH… H-bond closing an 8-membered cycle, in which the urea fragment adopts the cis-trans conformation, and that we name a urea-turn [2]. Investigations have been extended to the urea-containing dipeptides 2, 2′, 3 and 4 by considering the N-H and C=0 stretching frequencies, the NH proton solvent-accessibility and the NOE data.