Aromatic Oligoamide beta-Sheet Foldamers

Laure Sebaoun (1) , Victor Maurizot (1) , Thierry Granier (1) , Brice Kauffmann (2, 3) , Ivan Huc (1)

1 CBMN - Chimie et Biologie des Membranes et des Nanoobjets
2 Soutien à la Recherche de l'Institut Européen de Chimie Biologique
3 IECB - Institut Européen de Chimie et Biologie

A rational approach for the construction of multistranded artificial beta-sheets based not on hydrogen bonding, but on pi-pi aromatic stacking is presented. Using 4,6-dinitro,3,5-phenylenediamine units, rigid turns were designed that allow face-to-face pi-pi interactions between appended linear aromatic segments to be strong enough for folding in an organic solvent, but weak enough to prevent aggregation and precipitation. Solution and solid state studies on a series of turn units showed that the desired degree of rigidity, resulting from hindered bond rotation, could be fine tuned by the inclusion of additional methyl substituents on the aromatic rings. The high degree of preorganization afforded by these qualities further allowed the facile preparation of macrocyclic sheet structures from their non cyclic precursors. These macrocycles were shown to have slow internal dynamics and defined conforma-tional preferences. Using this background three and five-stranded artificial beta-sheets were synthesized and their folded conformations extensively characterized in solution by NMR. The solid state structures of the three and five-stranded sheets were also elucidated in the solid state by x-ray crystallography and confirmed intramolecular pi-pi aromatic stacking.

Mots clés: Foldamers; beta-Sheets; Macrocycle; Structural Investigation; X-ray Crystallography; NMR

Domaines: Chimie organique

Laure Sebaoun, Victor Maurizot, Thierry Granier, Brice Kauffmann, Ivan Huc. Aromatic Oligoamide beta-Sheet Foldamers. Journal of the American Chemical Society, 2014, 136 (5), pp.2168-2174. ⟨10.1021/ja412729s⟩. ⟨hal-01509462⟩