New interlocked molecules generated from a podand containing urea units and imidazolium salts using an anion template

A podand containing urea units (L) was found to form interlocked structures with 2,5-dihexylamide imidazolium salts (3(.)X), 2.5-dihexyl imidazolium salts (4(.)X), and 2,5-dihexyl benzoimidazolium salts (5(.)X), where X = Cl- , Br-, and PF6- using anions as templates. The binding ability of L and guest molecules was evaluated by H-1 NMR titrations in CDCl3 . It was found that L could form complexes with guest molecules in the following order, 3(.)X > 5(.)X > 4(.)X. Stabilities of the complexes also depended on shape of the templated anions: Cl- > Br(-)much greater than PF6-. Hydrogen bonding and pi-pi stacking interactions played an important role in the self-assembling of these interlocked molecules. (C) 2003 Elsevier Ltd. All rights reserved.