447463-65-2Relevant articles and documents
Fluorescent Dyes with Large Stokes Shifts Based on Benzo[1,2-d:4,5-d']bis([1,3]dithiole) (“S4-DBD Dyes”)
Freyse, Daniel,Kelling, Alexandra,Schuster, David,Wessig, Pablo
, (2020/03/13)
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 S4-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.
Trityl Radicals with a Combination of the Orthogonal Functional Groups Ethyne and Carboxyl: Synthesis without a Statistical Step and EPR Characterization
Hintz, Henrik,Vanas, Agathe,Klose, Daniel,Jeschke, Gunnar,Godt, Adelheid
, p. 3304 - 3320 (2019/03/11)
Finland trityl radical (FTR) shows very attractive EPR spectroscopic properties for a manifold of applications. For most of its applications only one chemically reactive functional group is needed. The presence of three equally reactive carboxyl groups leads to FTR modifications through reactions which give statistical mixtures of 1-fold-, 2-fold-, and 3-fold-modified and unmodified FTR. To avoid the side effects of such a statistical reaction - limited yields and separation challenges - we took a route to FTR-type trityl radicals with scaffold assembly by addition of an aryllithium with one type of substituent to a diarylketone with another type of substituent. This gave the two FTR-type trityl radicals 1 and 2 which carry a combination of the chemically orthogonal groups, carboxyl and triisopropylsilylethynyl. Standard column chromatography was sufficient for product isolation on all stages, whereby polar tagging helped. The EPR spectroscopic properties of the trityl radicals 1 and 2 in ethanol were determined in X and W bands. Their g anisotropy and T1 and T2 relaxation times make them spin labels as good as the benchmark FTR. This paper discloses also details on the synthesis of building blocks used for FTR preparation and improved access to the bare FTR scaffold.
TRIARYLMETHYL RADICALS
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Page/Page column 11, (2014/02/15)
New radical compounds, useful in the field of MRI imaging of formula (I). The radical compounds are in particular new triarylmethyl ("trityl") radicals which can be used as polarizing agents for polarizing a molecule in the DNP process.
