1329995-89-2Relevant articles and documents
Synthesis and photophysical properties of dimethoxybis(3,3,3- trifluoropropen-1-yl)benzenes: Compact chromophores exhibiting violet fluorescence in the solid state
Shimizu, Masaki,Takeda, Youhei,Higashi, Masahiro,Hiyama, Tamejiro
, p. 2536 - 2544 (2012/07/13)
Dimethoxybis(3,3,3-trifluo-ropropen-1-yl)benzenes were prepared through palladium-catalyzed double cross-coupling reactions of diiododimethoxybenzenes with CF3C=CZnCl, followed by reduction of CF3C=C groups with LiAlH4 or H2 in the presence of the Lindlar catalyst. The edges of the absorption spectra of 1,2-(MeO)2-4,5-(CF 3CHC=CH)2benzenes 1 and 1,3-(MeO)2-4,6-(CF 3CH=CH)2benzenes 2 in cyclohexane ranged from 348 to 360 nm, whereas the absorption spectra of 1,4-(MeO)2-2,5-[(E)-CF 3CH=CH]2 benzene ((E)-3) ended at 406 nm. These findings indicate that the effective conjugation length of (E)-3 was significantly larger than those of 1 and 2. Consistently, 1 and 2 in cyclohexane exhibited fluorescence with emission maxima in the UV region, whereas (E)-3 in cyclohexane emitted violet light with an emission maximum at 407 nm. All the fluorescence spectra of 1-3 in various solvents redshifted as the solvent polarity increased. The photoluminescence of 1-3 in the solid states was also observed with emission maxima in the violet region. It is important to note that the quantum yields of (E)-3 in a neat thin film and in a doped polymer film were 0.37 and 0.49, respectively. Density functional theory calculations suggested that the fluorine atoms contribute to a slight extension of both the HOMOs and the LUMOs, as well as narrowing of the HOMO-LUMO gaps when compared with the corresponding fluorine-free analogues. In the case of (E)-3, it is suggested that the HOMO-LUMO transition includes charge transfer from the ethereal oxygen atoms to the C(sp2)-CF3 moieties. Copyright
