- Photophysical Properties of Silyl-Substituted Stilbene Derivatives
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The effects of silyl groups on the structural, absorption, fluorescence, and photoisomerization properties of stilbenes were investigated. In comparison to that of the parent stilbene (1), fluorescence quantum yields (Φf) of Me3Si-substituted stilbenes 2–4 and 6 in solution were higher. Derivative 5, in which Me3Si groups are present at all ortho positions of the arene moieties, did not fluoresce at room temperature. The absorption and fluorescence wavelength maxima of Me3SiMe2Si-substituted stilbene 7 occurred at longer wavelengths compared to those of the Me3Si analog 2. The results of theoretical calculations showed that this difference is a consequence of an increase in the HOMO energy of 7 caused by orbital interaction between π-system and the σ(Si–Si) orbital. Stilbene 14, with two Me3Si-C≡C groups at both para positions, had a high Φf (0.95). The calculated transition dipole moment (μ) was well correlated with Φf. Derivative 21, which contains Ph2N and Me3SiC≡C groups exhibited solvatofluorochromism because it possesses a twisted intramolecular charge transfer (TICT) excited state in which the Ph2N group and the aromatic ring are orthogonal.
- Maeda, Hajime,Horikoshi, Ryo,Yamaji, Minoru,Furuyama, Taniyuki,Segi, Masahito
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supporting information
p. 3410 - 3422
(2020/06/17)
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- Palladium-Catalysed Desulfitative Heck Reaction Tolerant to Aryl Carbon-Halogen Bonds for Access to (Poly)halo-Substituted Stilbene or Cinnamate Derivatives
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The palladium-catalysed desulfitative Heck type reaction of (poly)halo-substituted benzenesulfonyl chlorides with alkenes was investigated. Styrene or acrylates in the presence of bromo- or iodobenzenesulfonyl chlorides and a phosphine-free palladium catalyst were found to afford the expected β-arylated Heck type products with complete regio- and stereoselectivities. The reaction tolerates a variety of substituents on the halobenzenesulfonyl chloride. Moreover, no cleavage of the C-Br and C-I bonds was observed in the course of these reactions, allowing further transformations. Using 4-bromobenzenesulfonyl chloride as the central unit, consecutive desulfitative Heck type reaction followed by palladium-catalysed direct arylation allowed to prepare heteroarylated stilbene derivatives in only two steps.
- Skhiri, Aymen,Salem, Ridha Ben,Soulé, Jean-Francois,Doucet, Henri
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p. 3097 - 3106
(2016/09/09)
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- Bimodal fluorescence signaling based on control of the excited-state conformational twisting and the ground-state protonation processes
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Amino-based fluoroionophores 1 and 2 can selectively sense alkaline earth metal ions in MeCN under both neutral and acidic conditions by different signaling mechanisms. The fluoroionophoric behavior for the neutral probes is characterized by an 'off-on' photoinduced electron transfer (PET)-like fluorescence intensity response due to a switching from a twisted internal charge transfer (TICT) to a planar internal charge transfer (PICT) state. For the protonated probes (i.e., 1/H+ and 2/H+), the fluorescing species is the localized stilbene fluorophores, but dual fluorescence is induced upon metal-ion recognition through a deprotonation process.
- Yang, Jye-Shane,Hwang, Chung-Yu,Chen, Mon-Yao
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p. 3097 - 3102
(2008/02/02)
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- Design of ??-conjugated organic materials for one-dimensional energy transport in nanochannels
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Various end-substituted distyrylbenzenes have been synthesized to serve as guest molecules in inclusion compounds to promote efficient energy transport along one-dimensional channels. Their optical and photophysical properties have been characterized at b
- Sancho-Garciì?a, Juan Carlos,Breì?das, Jean-Luc,Beljonne, David,Cornil, Jeì?roì?me,Martiì?nez-Aì?lvarez, Roberto,Hanack, Michael,Poulsen, Lars,Gierschner, Johannes,Mack, Hans-Georg,Egelhaaf, Hans-Joachim,Oelkrug, Dieter
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p. 4872 - 4880
(2008/03/14)
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- Spectroscopic Correlations between Supermolecules and Molecules. Anatomy of the Ion-Modulated Electronic Properties of the Nitrogen Donor in Monoazacrown-Derived Intrinsic Fluoroionophores
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The synthesis, absorption and emission spectra, fluorescence quantum yields, and fluorescence lifetimes of three compound series of trans-4,4′-disubstituted aminostilbenes (1-3) are reported. The chromo-/fluoroionophoric behavior of the monoaza-15-crown-5
- Yang, Jye-Shane,Hwang, Chung-Yu,Hsieh, Chia-Chun,Chiou, Shih-Yi
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p. 719 - 726
(2007/10/03)
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