抄録
We have explored the electronic natures of representative expanded porphyrins, [26]- and [28]-hexaphyrins, to investigate the interplay between the aromaticity and antiaromaticity that is brought by two electron oxidation/reduction processes. The excited singlet and triplet states of [26]hexaphyrin in solution exhibit lifetimes of 125 ps and 1.8 μs, respectively, as revealed by various time-resolved spectroscopic measurements. On the other hand, [28]hexaphyrin shows faster singlet and triplet lifetimes than those of [26]hexaphyrin, which is largely in accordance with the perturbation of aromaticity due to the π electron formulation of [4n] in [28]hexaphyrins. The two-photon absorption cross-section values at 1200 nm for [26]hexaphyrins show ca. 9890 GM which is > 102 larger than those of porphyrins. The reduced TPA values of 2600 and 810 GM of [28]hexaphyrin and perfluorinated [28]hexaphyrin, respectively, match well with their relatively short excited-state lifetimes. Overall, the enhanced excited-state lifetimes for various hexaphyrins go in line with the increased TPA cross-section values and the ring planarity.
本文言語 | 英語 |
---|---|
ページ(範囲) | 12856-12861 |
ページ数 | 6 |
ジャーナル | Journal of the American Chemical Society |
巻 | 127 |
号 | 37 |
DOI | |
出版ステータス | 出版済み - 9 21 2005 |
外部発表 | はい |
All Science Journal Classification (ASJC) codes
- Catalysis
- Chemistry(all)
- Biochemistry
- Colloid and Surface Chemistry