Construction of regulated nanospace around a porphyrin core

A series of 1,3,5-phenylene-based rigid dendritic porphyrins were synthesized by Suzuki coupling between a porphyrin core and dendron units. The intramolecular energy transfer was studied by absorption and fluorescence spectroscopies. The encapsulation of the porphyrin core within the 1,3,5-phenylene dendron units was found to provide highly efficient energy transfer from the dendron units to the porphyrin core. The dendritic wedge structure affected the energy transfer efficiency. The 1,3,5-phenylene-based rigid dendron units act as highly efficient light-harvesting antennae. These dendritic porphyrins have also been examined as C₆₀ hosts and substrate-selective oxidation catalysts. The attachment of the second generation of 1,3,5-phenylene-based dendron units with the porphyrin core enabled a stable inclusion of C₆₀ in toluene. Furthermore, the size and shape of the nanospace in the rigid dendritic porphyrins were found to affect the selectivity of substrates in the catalytic olefin oxidations.