Cyclo[4]carbazole, an Iodide Anion Macrocyclic Receptor.

A novel preorganized and rigid iodide anion macrocyclic receptor, cyclo[4]carbazole (Cy[4]C), is reported here. The structure of Cy[4]C was confirmed by single-crystal X-ray analysis. The binding affinity of Cy[4]C for iodide anion was investigated by UV-vis and 1H NMR spectroscopic techniques. The crystal structure of the complex between Cy[4]C and chloroform also provided evidence for the recognition ability of Cy[4]C toward iodide anion. Furthermore, the 1:1 complexation stoichiometry between Cy[4]C and iodide anion was confirmed by high-resolution mass spectrometry and molecular modeling.