Synthesis and inclusion properties of pyridinophane-linked macrocycles

Abstract

The macrocyclic host molecules 1 and 2 have been synthesized in satisfactory yields. These cyclophane-linked structures produce electron-rich cavities because the lone pairs of 2,11-diaza[ 3.3 ](2,6)pyridinophane and pyridine rings converge into the cavities. Although compound 1 strongly binds guanidinium ion and urea, compound 2 showed weak complexation toward these guests. In the inclusion of guests by hydrogen bonds, the cooperation of the pyridinophane donor sites plays a very important role. Interestingly, l adsorbed water molecules in solution to give the hydrated compound 1·6H₂O.