Molecular Mechanism for the Radiationless Deactivation of the Intramolecular Charge-Transfer Excited Singlet State of Aminofluorenones through Hydrogen Bonds with Alcohols

1998 ◽  
Vol 102 (45) ◽  
pp. 8657-8663 ◽  
Author(s):  
Tomoyuki Yatsuhashi ◽  
Yuka Nakajima ◽  
Tetsuya Shimada ◽  
Hiroshi Tachibana ◽  
Haruo Inoue
Keyword(s):  
Charge Transfer ◽  
Hydrogen Bonds ◽  
Molecular Mechanism ◽  
Singlet State ◽  
Intramolecular Charge Transfer ◽  
Excited Singlet State ◽  
Excited Singlet

Photophysical Properties of Intramolecular Charge-Transfer Excited Singlet State of Aminofluorenone Derivatives

1998 ◽  
Vol 102 (18) ◽  
pp. 3018-3024 ◽  
Author(s):  
Tomoyuki Yatsuhashi ◽  
Yuka Nakajima ◽  
Tetsuya Shimada ◽  
Haruo Inoue
Keyword(s):  
Charge Transfer ◽  
Singlet State ◽  
Intramolecular Charge Transfer ◽  
Photophysical Properties ◽  
Excited Singlet State ◽  
Excited Singlet

Fluorescence of Trans-4-Cyano-4′-dimethylaminostilbene; No Evidence for a TICT State

1983 ◽  
Vol 38 (8) ◽  
pp. 928-936 ◽  
Author(s):  
Henry Gruen ◽  
Helmut Görner
Keyword(s):  
Charge Transfer ◽  
Double Bond ◽  
Relaxation Process ◽  
Singlet State ◽  
Intramolecular Charge Transfer ◽  
Solvent Polarity ◽  
Quantum Yields ◽  
Excited Singlet ◽  
Dual Emission ◽  
Fluorescence Maximum

AbstractThe fluorescence properties of trans-4-cyano-4′-dimethylaminostilbene (trans-1) and a rigid analogue, in which the dimethylaminophenyl group is replaced by an indoline ring, trans-l-(4-cyanophenyl)-2-(5-[2,3-dihydro]N-methylindolyl)ethylene (trans-2) were studied in 20 solvents. The quantum yields of fluorescence (Φf) and of trans→cis photoisomerization (Φt→c) as well as the fluorescence maximum (ν̃f) and the bandwidth (⊿ν̃f) were examined. The activation energies (range: 3.5-7.8 kcal/mol) obtained from <2>f and <£t_c measurements are nearly the same for 1 and 2 in a given solvent. Φf , ν̃f and ⊿ν̃f as a function of solvent polarity and temperature show similar trends for 1 and 2. No dual emission was observed for either of the cyanostilbenes. These findings indicate that a twisted intramolecular charge transfer (TICT) state is not involved in the relaxation process of the first excited trans singlet state (1t*). The main deactivation pathway of 1t* competing with fluorescence is trans→cis photoisomerization by twisting about the C = C double bond in the first excited singlet state for both.

Fluorescence of some simple umbelliferone derivatives

1979 ◽  
Vol 44 (2) ◽  
pp. 508-518 ◽  
Author(s):  
Vladimír Mikeš
Keyword(s):  
Excited State ◽  
Hydrogen Bonds ◽  
Fluorescence Spectra ◽  
Singlet State ◽  
Excited Singlet State ◽  
Absorption And Fluorescence Spectra ◽  
Excited Singlet ◽  
Nonpolar Medium ◽  
Phenolic Group

The absorption and fluorescence spectra of umbelliferone were studied; it was found that in the excited state the basicity of the α-pyrone part of the molecule increases to such an extent that it exceeds that of the phenolate oxygen of the molecule. This is responsible for the neutral nondissociated form of umbelliferone being only in nonpolar medium which prevents the dissociation of the phenolic group in the excited state. In nonpolar medium, umbelliferone behaves as a substance with closely lying π → π* and n → π* transitions. Hydrogen bonds affect the fluorescence of 7-methoxycoumarin so that the π → π* transition is preserved as the lowest excited singlet state.

The Gold Porphyrin First Excited Singlet State¶

2002 ◽  
Vol 76 (1) ◽  
pp. 47 ◽  
Author(s):  
Joakim Andréasson ◽  
Gerdenis Kodis ◽  
Su Lin ◽  
Ana L. Moore ◽  
Thomas A. Moore ◽  
...  
Keyword(s):  
Singlet State ◽  
Excited Singlet State ◽  
Excited Singlet
Sign in / Sign up

Export Citation Format

Share Document