Systematic investigations on fused π-system compounds of seven benzene rings prepared by photocyclization of diphenanthrylethenes

Shota Fujino, Minoru Yamaji, Hideki Okamoto, Toshiki Mutai, Isao Yoshikawa, Hirohiko Houjou, Fumito Tani

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15 Citations (Scopus)


We studied the photoproducts of 1-(n-phenanthryl)-2-(m-phenanthryl)ethenes (nEm; n, m = 1, 3 and 9) for understanding photocyclization patterns based on NMR spectroscopy. The crystal structures of the photoproducts were analyzed by X-ray crystallography, and the photophysical features of the photocyclized molecules were investigated based on emission and transient absorption measurements. Phenanthrene derivatives substituted at the 1- and 3-positions were prepared for synthesizing nEm by photocyclization of stilbene derivatives. We obtained four types of primary photoproducts (n@m) from the corresponding nEm. Two of them were found to have racemic molecular structures in the single crystal determined by X-ray crystallography. Besides the primary photoproducts, two types of secondary photoproducts (n@mPP) were isolated. Fluorescence quantum yields and lifetimes of the obtained photoproducts were determined in solution whereas the definite fluorescence quantum yields were obtained in the powder. Observation of the triplet-triplet absorption spectra in solution by laser photolysis techniques showed that intersystem crossing to the triplet state competes with the fluorescence process.

Original languageEnglish
Pages (from-to)925-934
Number of pages10
JournalPhotochemical and Photobiological Sciences
Issue number6
Publication statusPublished - 2017

All Science Journal Classification (ASJC) codes

  • Physical and Theoretical Chemistry


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