AZOBENZENE-BASED PHOTOSWITCHABLE CATENANES

Four catenanes (1-4) and the corresponding tetracationic monocycles 5- 8 are synthesized. X-ray structural analyses allow a prediction of the mobility (circumrotation) of the ''interlocked'' rings in the catenan es, which is proven by H-1-NMR spectroscopy. An unexpected order in th e crystal packing of 6 is demonstrated. (E/Z) isomerization in one rin g influences the second ring of 1-4 and inversely. An existing obstacl e inside the cavity of the switchable macrocycle an block this isomeri zation completely.