2020年5月28日
Photoinduced Reactivity in a Dispiro-1,2,4-trioxolane: Adamantane Ring Expansion and First Direct Observation of the Long-Lived Triplet Diradical Intermediates
Journal of Physical Chemistry A
- 巻
- 124
- 号
- 21
- 開始ページ
- 4202
- 終了ページ
- 4210
- 記述言語
- 掲載種別
- 研究論文(学術雑誌)
- DOI
- 10.1021/acs.jpca.0c01974
Dispiro-1,2,4-trioxolane, 1, an ozonide with efficient and broad antiparasitic activity, was synthesized and investigated using matrix isolation FTIR and EPR spectroscopies together with both B3LYP/6-311++G(3df,3dp) and M06-2X/6-311++G(3df,3dp) theoretical methods. Irradiations (λ ≥ 290 nm) of the matrix isolated 1 (Ar or N2) afforded exclusively 4-oxahomoadamantan-5-one, 4, and 1,4-cyclohexanedione, 5. These results suggested that the reaction proceeded via a dioxygen-centered diradical intermediate, formed upon homolytic cleavage of the labile peroxide bond, which regioselectively isomerized to form the more stable (secondary carbon-centered)/oxygen-centered diradical. In situ EPR measurements during the photolysis of 1 deposited in a MeTHF-matrix led to the detection of signals corresponding to two triplet species, one of which was short-lived while the other proved to be persistent at 10 K. These observations strongly support the proposed mechanism for the photogeneration of 4 and 5, which involves intramolecular rearrangement of the intermediate diradical species 2 to afford the triplet diradical 3.
- リンク情報
- ID情報
-
- DOI : 10.1021/acs.jpca.0c01974
- ISSN : 1089-5639
- eISSN : 1520-5215
- PubMed ID : 32375479
- SCOPUS ID : 85085586218