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.