Hexakis porphyrinato benzenes. A new class of porphyrin arrays

A new type of porphyrin array has been synthesized by the coupling of six porphyrin moieties to a central benzene core via an ether linkage. The resulting porphryin supermolecule has a diameter up to 80 PI. and a mass of 8500 daltons. In solution, the six porphyrins around the central benzene ring arrange themselves into three sets of offset overlapping dimers, which are rapidly interconverting at room temperature. Solution UV-vis and fluorescence studies, however, indicate that there are no electronic interactions between the individual porphyrin molecules. Upon spreading a chloroform solution of these porphyrin molecules on a surface, they self-assemble Co form ring-shaped architectures on a micrometer scale. Near-field scanning optical microscopy studies reveal that the porphyrin moieties within the rings have an ordered arrangement with respect to their position in the ring after the sample has been annealed at 80 degrees C for 2 days.