Hybrid Cavitand Capsule with Hydrogen Bonds and Metal-Ligand Coordination Bonds: Guest Encapsulation with Anion Assistance

Multifunctionalized C-zv -Cavitand 1 was synthesized in six steps from a tetrabromo cavitand. A 1:1 mixture of 1 and 2 in CDCl3 or CD2Cl2 quantitatively self-assemble into a supramolecular hybrid capsule 3 through hydrogen bond and metal-ligand coordination bond. The cavity of the capsule 3 is filled with triflate ion and penetrated alkyl groups of ureides. Capsule 3 encapsulates a neutral guest molecule such as 4, 4' -diiodobiphenyl (4) with the assistance of an anion.The encapsulation complex was identified by an NMR technique. The kinetics of guest exchange is controllable by the amounts and/or types of anions or other influences such as the polarity of the solvent.