meso‐3,5‐Bis(trifluoromethyl)phenyl‐Substituted Expanded Porphyrins: Synthesis,Characterization, and Optical,Electrochemical, and Photophysical Properties |
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| Authors: | Soonchul Kang Hironobu Hayashi Tomokazu Umeyama Dr. Yoshihiro Matano Prof. Nikolai V. Tkachenko Prof. Helge Lemmetyinen Prof. Hiroshi Imahori Prof. |
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| Affiliation: | 1. Department of Molecular Engineering, Graduate School of Engineering, Kyoto University, Nishikyo‐ku, Kyoto 615‐8510 (Japan), Fax: (+81)?75‐383‐2571;2. Institute of Materials Chemistry, Tampere University of Technology, P. O. Box 541, Korkeakoulunkatu 8, FIN‐33101, Tampere (Finland), Fax: (+358)?3‐3115‐2108;3. Institute for Integrated Cell‐Material Sciences (iCeMS), Kyoto University, Nishikyo‐ku, Kyoto 615‐8510 (Japan);4. Fukui Institute for Fundamental Chemistry, Kyoto University, 34‐4, Takano‐Nishihiraki‐cho, Sakyo‐ku, Kyoto 606‐8103 (Japan) |
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| Abstract: | ![]()
Trifluoroacetic acid‐catalyzed condensation of pyrrole with electron‐deficient and sterically hindered 3,5‐bis(trifluoromethyl)benzaldehyde results in the unexpected production of a series of meso‐3,5‐bis(trifluoromethyl)phenyl‐substituted expanded porphyrins including [22]sapphyrin 2 , N‐fused [22]pentaphyrin 3 , [26]hexaphyrin 4 , and intact [32]heptaphyrin 5 together with the conventional 5,10,15,20‐tetrakis(3,5‐bis(trifluoromethyl)phenyl)porphyrin 1 . These expanded porphyrins are characterized by mass spectrometry, 1H NMR spectroscopy, UV/Vis/NIR absorption spectroscopy, and fluorescence spectroscopy. The optical and electrochemical measurements reveal a decrease in the HOMO–LUMO gap with increasing size of the conjugated macrocycles, and in accordance with the trend, the deactivation of the excited singlet state to the ground state is enhanced. |
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| Keywords: | aromaticity electrochemistry macrocycles photophysics porphyrinoids |
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