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

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

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.

Revisiting the photophysical properties and excited singlet-state dipole moments of several coumarin derivatives

2011 ◽  
Vol 79 (3) ◽  
pp. 428-436 ◽  
Author(s):  
Lamine Cisse ◽  
Abdoulaye Djande ◽  
Martine Capo-Chichi ◽  
François Delatre ◽  
Adama Saba ◽  
...  
Keyword(s):  
Singlet State ◽  
Dipole Moments ◽  
Photophysical Properties ◽  
Excited Singlet State ◽  
Coumarin Derivatives ◽  
Excited Singlet

The structure, photochemical reactivity, and photophysical properties of adamantyl X-substituted aryl ethers and a comparison with the alkyl groups, methyl, tert-butyl, and allyl

2005 ◽  
Vol 83 (9) ◽  
pp. 1237-1252 ◽  
Author(s):  
A L Pincock ◽  
J A Pincock
Keyword(s):  
Excited State ◽  
Rate Constants ◽  
Singlet State ◽  
Bond Cleavage ◽  
Photophysical Properties ◽  
Excited Singlet State ◽  
Quantum Yields ◽  
Aryl Ether ◽  
Excited Singlet ◽  
Aryl Ethers

The structure, photophysical properties, and photochemistry of the adamantyl aryl ethers 1 in both methanol and cyclohexane have been examined. UV absorption spectra, 13C NMR chemical shifts, X-ray structures, and Gaussian calculations (B3LYP/6-31G(d)) indicate that these ethers adopt a 90° conformer in the ground state. In contrast, fluorescence spectra, excited singlet state lifetimes, and calculations (TDDFT) indicated a 0° conformer is preferred in the first excited singlet state S1. Irradiation in either solvent results in the formation of adamantane and the corresponding phenol as the major products, both derived from radical intermediates generated by homolytic cleavage of the ether bond. The 4-cyano substituted ether 1j was the only one to form the ion-derived product, 1-methoxyadamantane (16% yield), on irradiation in methanol. Rate constants of bond cleavage for these ethers from S1 were estimated by two different methods by comparison with the unreactive anisoles 2, but the effect of substituents was too small to determine structure–reactivity correlations. The temperature dependence of the quantum yields of the fluorescence of the unsub stituted, 4-methoxy and 4-cyano derivatives of 1 and 2 were also determined. These results indicated that the activated process for 1 was mainly bond cleavage for the 4-cyano substrate whereas for 2, it was internal conversion and intersystem crossing. Key words: aryl ether photochemistry, fluorescence, excited-state rate constants, excited-state temperature effects.

Control of the Photophysical Properties of Polyatomic Molecules by Substitution and Solvation:  The Second Excited Singlet State of Azulene

1999 ◽  
Vol 103 (15) ◽  
pp. 2524-2531 ◽  
Author(s):  
Nicolas Tétreault ◽  
Rajeev S. Muthyala ◽  
Robert S. H. Liu ◽  
Ronald P. Steer
Keyword(s):  
Singlet State ◽  
Photophysical Properties ◽  
Polyatomic Molecules ◽  
Excited Singlet State ◽  
Excited Singlet

Photophysical Properties of Conformationally Distorted Metal-Free Porphyrins. Investigation into the Deactivation Mechanisms of the Lowest Excited Singlet State

1994 ◽  
Vol 116 (16) ◽  
pp. 7363-7368 ◽  
Author(s):  
Steve Gentemann ◽  
Craig J. Medforth ◽  
Timothy P. Forsyth ◽  
Daniel J. Nurco ◽  
Kevin M. Smith ◽  
...  
Keyword(s):  
Singlet State ◽  
Photophysical Properties ◽  
Excited Singlet State ◽  
Excited Singlet ◽  
Metal Free
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