TY  - JOUR
A1  - Wessig, Pablo
A1  - Freyse, Daniel
A1  - Schuster, David
A1  - Kelling, Alexandra
T1  - Fluorescent dyes with large stokes shifts based on Benzo[1,2-d:4,5-d']bis([1,3]dithiole) (“S4-DBD Dyes”)
JF  - Europan journal of organic chemistry
N2  - We report on a further development of [1,3]-dioxolo[4.5-f]benzodioxole (DBD) fluorescent dyes by replacement of the four oxygen atoms of the heterocyclic core by sulfur atoms. This variation causes striking changes of the photophysical properties. Whereas absorption and emission significantly shifted to longer wavelength, the fluorescence lifetimes and quantum yields are diminished compared to DBD dyes. The latter effect is presumably caused by an enhanced intersystem crossing to the triplet state due to the sulfur atoms. The very large Stokes shifts of the S-4-DBD dyes ranging from 3000 cm(-1) to 7400 cm(-1) (67 nm to 191 nm) should be especially emphasized. By analogy with DBD dyes a broad variation of absorption and emission wavelength is possible by introducing different electron withdrawing substituents. Moreover, some derivatives for coupling with biomolecules were developed.
KW  - fluorescent dyes
KW  - sulfur
KW  - heterocycles
KW  - stokes shift
KW  - photophysics
Y1  - 2020
U6  - https://doi.org/10.1002/ejoc.202000093
SN  - 1434-193X
SN  - 1099-0690
VL  - 2020
IS  - 11
SP  - 1732
EP  - 1744
PB  - Wiley
CY  - Weinheim
ER  - 
TY  - JOUR
A1  - Wessig, Pablo
A1  - John, Leonard
A1  - Sperlich, Eric
A1  - Kelling, Alexandra
T1  - Sulfur tuning of [1,3]-dioxolo[4.5-f]benzodioxole (DBD) fluorescent dyes
JF  - European journal of organic chemistry
N2  - The replacement of oxygen by sulfur atoms of [1,3]-dioxolo[4.5-f]benzodioxole (DBD) fluorescent dyes is an efficient way to adjust the photophysical properties (sulfur tuning). While previously developed S-4-DBD dyes exhibit considerably red-shifted absorption and emission wavelength, the heavy atom effect of four sulfur atoms cause low fluorescence quantum yields and short fluorescence lifetimes. Herein, we demonstrate that the replacement of less than four sulfur atoms (S-1-DBD, 1,2-S-2-DBD, and 1,4-S-2-DBD dyes) permits a fine-tuning of the photophysical properties. In some cases, a similar influence on the wavelength without the detrimental effect on the quantum yields and lifetimes is observed. Furthermore, the synthetic accessibility of S-1- and S-2-DBD dyes is improved, compared with S-4-DBD dyes. For coupling with biomolecules a series of reactive derivatives of the new dyes were developed (azides, OSu esters, alkynes, maleimides).
KW  - fluorescent dyes
KW  - heterocycles
KW  - photophysics
KW  - stokes shift
KW  - sulfur
Y1  - 2020
U6  - https://doi.org/10.1002/ejoc.202001418
SN  - 1434-193X
SN  - 1099-0690
VL  - 2021
IS  - 3
SP  - 499
EP  - 511
PB  - Wiley-VCH
CY  - Weinheim
ER  -