Hierarchical Organization of Spherical Assembly with Reversibly Photocontrollable Cross-Links

A ternary photocontrollable assembly was hierarchically constructed by the orthogonal host guest interaction of different types of cyclodextrins toward the porphyrin and azobenzene. Spectroscopic titrations and microscopic investigations demonstrate that the inclusion complex of azobenzene modified water-soluble porphyrin (1) with phthalocyanine-grafted permethyl beta-cyclodextrins (2) could be reversibly cross-linked to relatively larger nanospheres with naphthyl bridged bis(alpha-cyclodextrin)s (3). Moreover, the large-sized spheres (1.2.3) could be disassembled and switched to small-sized complex (1.2) upon the photoinduced isomerization of an azophenyl group.