| Abstract: | The synthesis and cation binding properties of a folded ditopic crown receptor, 3, are described. Intramolecular hydrogen-bonding interactions preorganize ditopic crown 3 into a helical conformation that positions the crown moieties in a manner that favors the formation of an intramolecular sandwich cation complex. Alkali-metal picrate extraction studies demonstrate that ditopic crown 3 exhibits a significantly different cation selectivity than mono-crown congener 2. A crystal structure of 3?2KClO4 indicates that two molecules of the complex are assembled into a molecular square in the solid state. |
