Two dibenzobarrelene‐incorporated 1,3‐pentadienes and a 5‐sila derivative have been synthesized by intramolecular cycloaddition reactions between (9‐anthryl)methyl, (9‐anthryl)hydroxymethyl, or (9‐anthryl)dimethylsilyl groups and a phenylethynyl group linked by an ethene moiety with a cis conformation. The three compounds exhibit blue luminescence (λem = 432–445 nm) in CH2Cl2 with high quantum yields (ΦF = 0.83–0.92). In the solid state, the methylene and dimethylsilyl derivatives luminesce (λem = 442 and 438 nm, respectively) with narrow full‐width at half‐maxima (FWHM, 40 and 37 nm, respectively), whereas the hydroxymethylene compound shows a broad and slightly redshifted emission (λem = 488 nm, FWHM = 112 nm) due to intermolecular hydrogen bonding. The fluorescence intensity of the dimethylsilyl compound was decreased by desilylation with Bu4NF. The structures of the compounds were characterized unambiguously by NMR spectroscopy and X‐ray crystallography, and their photophysical properties were elucidated both experimentally as well as by TD‐DFT calculations.

Contents:(1) S0 of ketone 6Transition state (TS) from (E)-10 to Oxathiirane 19 ••• S37

An abbreviated synthesis of hexafluorocyclopentane-annulated 2,5-diarylfurans has been developed. 1,2-Dichloro-3,3,4,4,5,5-hexafluorocyclopentene was converted to corresponding polyfluorinated 1,2-diaroylalkenes, treatment of which with P(OEt) 3 afforded the polyfluorinated 2,5-diarylfurans. Solid-state photo-luminescence of the furan derivatives exhibited remarkable red-shifts compared to fluorescence emissions in solution, probably because of intermolecular interactions in the solid state. Comparisons of the optical and electrochemical data of the fluorinated furan derivatives with those of a non-fluorinated 2,5-diarylfuran suggest that the perfluorocycloalkane-annulation effectively enhances the electron-accepting ability of the 2,5-diarylfuran framework.

1,2,5‐Triphenylpentadienyl cation fused with a dibenzobarrelene skeleton was synthesized. The pentadienyl cation was persistent in the solution and characterized by 1H and 13C NMR spectroscopies. The cation abstracts a hydride from Et2O at the 5‐position to give the 5‐H derivative together with acetaldehyde and ethene. The reaction with H2O provided the 5‐OH derivative and not the 1‐OH precursor. The hydride reduction of the pentadienyl cation with silanes or NaBH4 occurred at the 3‐ and 5‐positions, and the ratio was dependent on the bulkiness of reducing reagents. The cation in dichloromethane exhibited long‐wavelength absorptions at 678, 523, and 443 nm and an emission maximum at 729 nm with the emission quantum yield of 0.175, which are longer and larger than those of the referenced 1,5‐diphenylpentadienyl cation. TD‐DFT calculations show that the absorptions are due to the π‐π* excitations on 1,2,5‐triphenylpentadienyl and dibenzobarrelene benzene rings.