Tetrameric and Hexameric Porphyrin Nanorings: Template Synthesis and Photophysical Properties.

Hexameric and tetrameric porphyrin nanorings, · and ·, were synthesized in 53% and 14% yields, respectively, by the Sonogashira-type self-oligomerization of porphyrin monomer using hexadentate template and tetrapyridylporphyrin template . Template-free nanorings and were also prepared. The femtosecond transient absorption measurements revealed fast excitation energy hopping (EEH) along these nanorings with hopping rates of 2-5 ps. Treatment of with chiral template gave · showing circular dichroism (CD) and circularly polarized luminescence (CPL) in the absorption and fluorescence regions of , respectively, which indicates chirality transfer from to .