Urea-functionalized Resorcinarenes: Preparation, Self-folding, and Their CD Phenomena Caused by Chiral Urea Termini through Intramolecular Hydrogen Bonding Interactions

Self-folding resorcinarenes bearing optically active urea moieties showed unique circular dichroism (CD) phenomena on the macrocyclic skeleton, which were caused by their chiral urea termini through intramolecular hydrogen bonding interactions in chloroform. These characteristic CD bands were disappeared upon complexation with anions such as chloride and bromide.