Photoinduced processes in interlocked structures containing porphyrins

The recent literature on photoactive interlocked structures containing porphyrins is reviewed. Catenanes and rotaxanes studied both in the author's laboratory and by other groups, displaying either photoinduced energy or electron transfer processes are reported. In addition to porphyrins, the examined structures contain photo or electroactive components as C-60, paraquat, ferrocene, aromatic amines. Both metal catenanes/rotaxanes and free catenanes/rotaxanes are discussed and the differences in their behavior is outlined with respect to structural rigidity and electronic coupling properties. The role of different conformations and their effect on photophysical properties is examined. In spite of their uncommon topology, these arrays behave similarly to covalently or self-assembled photoactive multi-component architectures and display fast energy/electron transfer rates and high charge separation efficiency. A rationale for this behavior is provided.