Intramolecular fluorescence quenching in aminocoumarines. Identification of an excited state with full charge separation

1985 ◽  
Vol 63 (7) ◽  
pp. 1649-1653 ◽  
Author(s):  
Wolfgang Rettig ◽  
André Klock
Keyword(s):  
Dipole Moment ◽  
Excited State ◽  
Charge Transfer ◽  
Fluorescence Quenching ◽  
Charge Separation ◽  
Intramolecular Charge Transfer ◽  
Stokes Shift ◽  
Twisted Intramolecular Charge Transfer ◽  
Full Charge

The fluorescence of 6-aminocoumarine (A6C) is very weak and anomalously redshifted as compared to its 7-substituted analogues 4-methyl-7-aminocoumarine (A7C) and 4-methyl-7-diethylaminocoumarine (DEA7C). The solvatochromic redshift in homologous alcohols is much stronger for A6C, pointing to an increased dipole moment of the emitting state. A twisted intramolecular charge transfer (TICT) state with full charge separation is made responsible for this emission. This is rationalized by molecules-in-molecules calculations. The strong Stokes shift in n-hexane and in ethanol glass at 77 K suggests that A6C emits from a TICT state even under these conditions.

Spectroscopic Studies of Dimethylamino Derivatives of Fluorene

2000 ◽  
Vol 55 (11-12) ◽  
pp. 902-908 ◽  
Author(s):  
J. Heldt ◽  
J. R. Heldt ◽  
T. Redzimski ◽  
H. Diehl ◽  
P. Schultz
Keyword(s):  
Dipole Moment ◽  
Excited State ◽  
Charge Transfer ◽  
Fluorescence Spectra ◽  
Intramolecular Charge Transfer ◽  
Stokes Shift ◽  
Spectroscopic Studies ◽  
Polar Solvents ◽  
Derivatives Of ◽  
Transfer State

Abstract 2-dimethylamino-9-fluorenol and 2-dimethylamino-9(4'dimethylamino)phenyl-9-fiuorenol in polar solvents in the excited state undergo conformation changes in which two fluorescent isomers are created. The isomers (in the local excited (LE) and charge transfer (CT) configuration) possess separate fluorescence bands, one appearing from the S1 (LE) state and the second from the intramolecular charge transfer state S1 (CT) of the neutral, aromatic molecule. Both bands show a solvatochromic effect. Using the method of the solvent induced Stokes shift of the absorption and fluorescence spectra the permanent dipole moment of the excited state of fluorene and its two derivatives have been determined. The dipole moment of the ground state and the Onsager cavity radius of the studied molecules were calculated with the Auestion Model 1 (AM1) program.

Dynamic adjustment of emission from both singlets and triplets: the role of excited state conformation relaxation and charge transfer in phenothiazine derivates

2021 ◽  
Author(s):  
Weidong Qiu ◽  
Xinyi Cai ◽  
Mengke Li ◽  
Liangying Wang ◽  
Yanmei He ◽  
...  
Keyword(s):  
Excited State ◽  
Charge Transfer ◽  
Intramolecular Charge Transfer ◽  
Dynamic Adjustment ◽  
Twisted Intramolecular Charge Transfer

Dynamic adjustment of emission behaviours by controlling the extent of twisted intramolecular charge transfer character in excited state.

Improving the fluorescence brightness of distyryl Bodipys by inhibiting the twisted intramolecular charge transfer excited state

2021 ◽  
Vol 57 (76) ◽  
pp. 9744-9747
Author(s):  
Xin Lv ◽  
Taihe Han ◽  
Yi Wu ◽  
Boran Zhang ◽  
Wei Guo
Keyword(s):  
Excited State ◽  
Charge Transfer ◽  
Quaternary Ammonium ◽  
Intramolecular Charge Transfer ◽  
Twisted Intramolecular Charge Transfer

The fluorescence brightness of distyryl Bodipys was substantially improved by employing sulfone- and quaternary ammonium-modified piperidines as auxochromes instead of conventional dialkylamino auxochromes.

Sign in / Sign up

Export Citation Format

Share Document