ZnII-induced conformational control of amphiphilic cavitands in Langmuir monolayers

The reversible switching from the C-4v-symmetric vase to the C-2v-symmetric kite conformation of an amphiphilic resorcin[4]arene cavitand was induced by Zn-II ion coordination. Langmuir monolayers were obtained of both conformers. with the area per molecule increasing dramatically from 120 Angstrom(2) for the vase to 270 Angstrom(2) for the kite form. H-1 NMR spectroscopy in chloroform solution supports the formation of a stoichiometric kite-cavitand(.)(ZnII)(2) complex, with the metal ions coordinating to pairs of neighbouring quinoxaline N-atoms.