C 3 ‐symmetrical self‐assembled structures investigated by vibrational circular dichroism

• Published in: Chirality (New York, N.Y.) Vol. 20; no. 9; pp. 1016 - 1022
• Main Authors: Smulders, Maarten M. J., Buffeteau, Thierry, Cavagnat, Dominique, Wolffs, Martin, Schenning, Albertus P. H. J., Meijer, E. W.
• Format: Journal Article
• Language: English
• Published: 01-10-2008
• ISSN: 0899-0042; 1520-636X
• DOI: 10.1002/chir.20568

Abstract
We demonstrate by using vibrational circular dichroism (VCD) spectroscopy that it is possible to investigate the chirality of a supramolecular polymeric system in relatively dilute solutions. Chiral C
3
‐symmetrical discotic molecules, based on a trialkylbenzene‐1,3,5‐carboxamide, form supramolecular columnar stacks with a right‐handed helical structure in solution due to intermolecular hydrogen bonds. The handedness of the supramolecular chirality is determined using electronic spectroscopy measurements. Under dilute conditions (at 10
−3
M concentrations), it was also possible to probe the hydrogen bonding moieties with IR and VCD spectroscopy on these self‐assembled structures. In combination with density functional theory (DFT) calculations, we could verify the preference for a right‐handed chirality in the helical stacks and the nonplanar orientation of the carbonyl groups present in the molecule. This chiral arrangement is in agreement with the structure determined for a related benzene‐1,3,5‐tricarboxamide by X‐ray diffraction. Chirality, 2008. © 2008 Wiley‐Liss, Inc.