Guest-induced misfolding of a crown-ether-functionalized ortho-phenylene

A crown-ether-functionalized o-phenylene tetramer has been synthesized and co-assembled with monotopic and ditopic, achiral and chiral secondary ammonium ion guests. NMR spectroscopy shows that the o-phenylene forms both 1:1 and 1:2 complexes with monotopic guests while remaining well-folded. Binding of an elongated ditopic guest, however, forces the o-phenylene to misfold by pulling the terminal rings apart. A chiral ditopic guest biases the o-phenylene twist sense.