Halide Functionality Dependent Formation of Molecular Receptors and Their Ion Recognition Properties

The halide functionality on *bridged tripodal receptors has shown a distinct behavior on their self-assembly structures and binding ability toward HgCl2 and ClO4- anions. The receptors containing fluoro, chloro, and iodo groups crystallized to form hemicarcerands in the solid state, whereas the receptor with a bromo group forms a molecular capsule via C-H center dot center dot center dot Br and C-H center dot center dot center dot pi interactions. The cavity of the molecular capsule is tunable and is capable of reversible encapsulating-releasing the guest molecules by pH modulation.