Indolocarbazole-Based Foldamers Capable of Binding Halides in Water
摘要:
A series of indolocarbazole-based foldamers have been prepared which can fold into a helical array with an internal cavity encircled by multiple indole NHs, thus allowing for binding anions by hydrogen bonds. The helical folding has been confirmed by computer modeling, 1H NMR spectroscopy, 2D ROESY experiments, and binding studies. A water-soluble derivative binds small, hydrophilic anions in the order Cl- > F- > Br- but negligibly with large, diffuse anions such as I- and ClO4-. Interestingly, the relative binding affinities of the fluoride and chloride ions in water are opposite to each other in an organic medium 4:1 (v/v) DMSO/MeOH, possibly due to the difference in the competing solvation energy.
were revealed by (1)H NMR and fluorescence spectroscopy. The oligoindoles exist in an extended conformation, but adopt a compact helical structure in the presence of an anion. The anion is entrapped inside the tubular cavity of the helical strand, comprising four aryl units per turn, by multiplehydrogenbonds with the indole NHs. These structural features were confirmed by (1)H NMR and fluorescence
Indolocarbazole-Based Foldamers Capable of Binding Halides in Water
作者:Jae-min Suk、Kyu-Sung Jeong
DOI:10.1021/ja804845m
日期:2008.9.10
A series of indolocarbazole-based foldamers have been prepared which can fold into a helical array with an internal cavity encircled by multiple indole NHs, thus allowing for binding anions by hydrogen bonds. The helical folding has been confirmed by computer modeling, 1H NMR spectroscopy, 2D ROESY experiments, and binding studies. A water-soluble derivative binds small, hydrophilic anions in the order Cl- > F- > Br- but negligibly with large, diffuse anions such as I- and ClO4-. Interestingly, the relative binding affinities of the fluoride and chloride ions in water are opposite to each other in an organic medium 4:1 (v/v) DMSO/MeOH, possibly due to the difference in the competing solvation energy.