Photoactive Azobenzene-Containing Supramolecular Complexes and Related Interlocked Molecular Compounds

The reversible decomplexation/complexation of azobenzene-containing guests by cyclobis(paraquat-p-phenylene) has been realized by the photoisomerization of the azobenzene unit embedded within the guests. The reversible photoisomerization of the azobenzene units incorporated within the π-electron-rich components of a [2]catenane and a [2]rotaxane has also been achieved (see figure). By contrast, in two azobenzene-containing [2]catenanes, the trans→cis photoisomerization of the azobenzene unit is quenched because of electronic effects and/or prevented by geometrical constraints.