Energy transfer among light-harvesting macrorings incorporated into a bilayer membrane.

Amphiphilic bis(imidazolyl)tris(porphyrinatozinc) complexes having omega-carboxyalkyl meso substituents were prepared. The barrel-type porphyrin macroring organized through their complementary coordination was incorporated into a liposomal bilayer membrane with orientation normal to the surface. Under the conditions concentrated in the membrane, introduction of a fullerotripyridyl ligand into the cavity of the macroring quenched fluorescence not only from the host ring itself but also from other surrounding macrorings. Energy transfer among antenna macrorings in the membrane mimics the assembly of a bacterial light-harvesting antenna system.