An approach to helical tubular self-aggregation using C-2-symmetric self-complementary hydrogen-bonding cavity molecules

Summary, in English

In an approach to helical self-aggregation, C-2-symmetric cavity compounds based on the fusion of the bicyclo[3.3.1] nonane and indole framework and incorporating two 2-pyridone hydrogen-bonding motifs, compounds (-)-4 (pyrrole N-butyl) and (-)-5 (pyrrole N-decyl), have been synthesized. The 2-pyridone AD-DA hydrogen-bonding motif failed to operate in the solid state as demonstrated by X-ray diffraction analysis of (-)-4. Instead, the hydrogen- bonded (D-A) chains center dot center dot center dot O=C-N-H center dot center dot center dot O=C-N-H center dot center dot center dot O=C-N-H center dot center dot center dot, interconnecting columnar stacks, comprise helices of the right-handed (P) chirality motif. In solution, the aggregation of (-)-5 was studied by NMR, electronic, and CD spectroscopies, and VPO measurements. These investigations strongly suggest that (-)-5 associates to oligomers in CHCl3 and CH2Cl2 using the 2-pyridone motif, fitting the equal K model, and that pi-stacking can be ruled out as a mode of aggregation. We conclude that the so formed aggregates of (-)-5 have a helical structure, based on the fact that only helical tubular structures can result when enantiomerically pure 5 uses its 2-pyridone AD-DA hydrogenbonding motifs for aggregation.

• Author: Sigitas Stoncius; Edvinas Orentas; Eugenius Butkus; Lars Öhrstrom; Ola Wendt; Kenneth Wärnmark
• Department/s: Centre for Analysis and Synthesis
• Publishing year: 2006
• Language: English
• Pages: 8272-8285
• Publication/Series: Journal of the American Chemical Society
• Volume: 128
• Issue: 25
• Links: http://dx.doi.org/10.1021/ja061160z
• Document type: Journal article
• Publisher: The American Chemical Society (ACS)
• Topic: Organic Chemistry
• Status: Published
• ISBN/ISSN/Other: ISSN: 1520-5126