Ultramacrocyclization through Reversible Catenation

Extreme macrocyclization! An ultramacrocyclic structure with 238 non-hydrogen atoms in its backbone is obtained quantitatively through the reversible catenation of a double-loop compound that contains PdII-clipped coordination rings at both ends (see structure). The PdII ring can be regarded as a nanoscale reaction center that is available for connecting nanoscopic components without high entropy costs.