Slow anion exchange, conformational equilibria, and fluorescent sensing in venus flytrap aminopyridinium-based anion hosts

Wallace, K.J.; Belcher, W.J.; Turner, D.R.; Syed, K.F.; Steed, J.W.

Abstract

The synthesis, anion binding, and conformational properties of a series of 3-aminopyridinium-based, tripodal, tricationic hosts for anions are described. Slow anion and conformational exchange on the 1H NMR time scale at low temperature, coupled with NMR titration, results in a high level of understanding of the anion-binding properties of the compounds, particularly with respect to significant conformational change resulting from induced fit complexation. Peak selectivity for halides, particularly Cl-, is observed. The approach has been extended to dipodal and tripodal podands based on 3-aminopyridinium "arms" containing photoactive anthracenyl moieties. The 1,3,5-tripodal host shows a remarkable selectivity for acetate over other anions, in contrast to the analogous unsubstituted tris(3-aminopyridinium) analogue, despite the fact that low-temperature 1H NMR experiments reveal a total of four acetate-binding conformations. Photodimerization of anthracene units results in the formation of potential fluorescent anion sensors.

Citation

Wallace, K., Belcher, W., Turner, D., Syed, K., & Steed, J. (2003). Slow anion exchange, conformational equilibria, and fluorescent sensing in venus flytrap aminopyridinium-based anion hosts. Journal of the American Chemical Society, 125(32), 9699-9715. https://doi.org/10.1021/ja034921w

• Journal Article Type: Article
• Publication Date: Jul 1, 2003
• Deposit Date: May 10, 2007
• Journal: Journal of the American Chemical Society
• Print ISSN: 0002-7863
• Electronic ISSN: 1520-5126
• Publisher: American Chemical Society
• Peer Reviewed: Peer Reviewed
• Volume: 125
• Issue: 32
• Pages: 9699-9715
• DOI: https://doi.org/10.1021/ja034921w