A novel triphyrin was unexpectedly formed as a major by-product in the synthesis of mesoaryl-substituted dibenzo-5,10,15-triazaporphyrin from meso-aryl-substituted 1,9-dibromodipyrromethene and 5,6-diaryl-substituted 1,3-diiminoisoindoline in the presence of N,N-dimethylaminoethanol (DMAE). X-ray single crystal diffraction analysis elucidated that the terminal α-positions of this triphyrin were bridged by an N-methylaminoethoxy chain, which plausibly originated from DMAE during the reaction. The same compound was also obtained as a major product in the reaction of DMAE and meso-arylsubstituted 1,9-dibromodipyrromethene. Its unique properties, such as conformational fexibility of the bridging moiety and broad absorption in the visible region, were also revealed by1H NMR and UV-vis absorption spectroscopies.
- Contracted porphyrin analog
- Thermal conformational equilibrium
- UV-vis absorption
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