Porphyrin supramolecules by self-complementary coordination

The supramolecular organization of porphyrins using self-complementary coordination is reviewed. Complementarity affords large stability constants for coordination organization, and as a result various structural variations of porphyrin supramolecules were obtained. Dimeric porphyrins are of special interest as they mimic the special pair of the photosynthetic reaction centers. A very stable slipped cofacial dimer was obtained and the dimer effect on photoinduced charge separation is discussed. Macrocyclic porphyrin supramolecules were prepared as photosynthetic antenna models and rapid energy transfer rates among the components were estimated. Three-dimensional organization represents another type of approach to light-harvesting antenna systems. One- and two-dimensional arrays of porphyrins have also been prepared using this methodology. Energy and electron transfers along the array provide the basis for photonic and electronic applications. Introduction of molecular polarization in the array leads to the development of nonlinear optics materials. Photocurrent generation is enhanced by array formation on electrode surfaces.