Self-Assembly of an Artificial Light-Harvesting Antenna: Energy Transfer from a Zinc Chlorin to a Bacteriochlorin in a Supramolecular Aggregate

摘要

In recent years many supramolecular assemblies with novel chemical and material properties have been shown to form by self-organization of identical or complementary building blocks. We have studied extensively the self-assembly of metallochlorins ((17,l8-dihydroporphyrinato)metal complexes) in nonpolar organic solvents and have demonstrated that these in vitro homoaggregates have the same structure as aggregates of bacteriochlorophyll c and d (Scheme 1) present in natural chlorosomes. These aggregates, the light-harvesting system of green bacteria, are notably the first photosynthetic antenna system known not to require a protein for the pigment organization. The understanding of the principles of the interactions (for example hydrogen bonding, vander Waals, pi-pi, and electrostatic interactions) responsible for the self-assembly of both in vitro and in vivo supramolecular aggregates of metallochlorins can now be exploited in various ways. One of the possibilities is to construct artificial photoactive devices capable of performing a useful task.