Authors: Y. Liu
Affilation: Lawrence Berkeley National Laboratory, United States
Pages: 206 - 209
Keywords: catenane, macrocycle, cyclodextrin, coordination
Here we describe our findings on the facile preparation of first catenanes from metal-ligand coordination macrocycles and b-CD ring. The catenane formation is illustrated in Figure 1. Coordination between a divalent ligand and Pd(II) spontaneously gives rise to a macrocycle. This macrocycle is able to interlock with b-CD as a result of the hydrophobic interaction between the divalent ligand and b-CD ring. The complexation between the two ring components undergoes dynamic equilibrium in solution. The catenane formation was illustrated by various 1H NMR spectroscopic methods and UV-vis spectroscopic methods. By changing the metal center from Pd(II) to Pt(II), the dynamic nature of the catenanes was altered to a “locked” one because the Pt(II)-pyridine coordination bond is irreversible (“locked”) under ordinary conditions in contrast to the reversible Pd(II)-pyridine bond. The reported method provides an extremely simple and highly efficient approach in generating catenanes from readily available starting materials. Such findings will be extended towards the development of higher order polymers and switchable devices with embedded b-CD units.