Application of spectroscopic and theoretical methods in the studies of photoisomerization and photophysical properties of the push—pull styryl-benzimidazole dyes
The synthesis and spectroscopic properties of a series of substituted 1,3-dimethyl-2-aminostyrylbenzimidazolium iodides are described and discussed. The products were identified by NMR, IR and UV-Vis spectroscopy and elemental analysis. Their electronic absorption and fluorescence band positions are...
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Published in | Photochemical & photobiological sciences Vol. 15; no. 1; pp. 117 - 128 |
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Main Authors | , , |
Format | Journal Article |
Language | English |
Published |
Cham
Springer International Publishing
2016
Springer Nature |
Subjects | |
Online Access | Get full text |
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Summary: | The synthesis and spectroscopic properties of a series of substituted 1,3-dimethyl-2-aminostyrylbenzimidazolium iodides are described and discussed. The products were identified by NMR, IR and UV-Vis spectroscopy and elemental analysis. Their electronic absorption and fluorescence band positions are affected by the character of the substituent and by the solvent polarity. The fluorescence decay of the dyes shows two lifetimes interpreted in terms of emission from two forms of the dye in the excited state. Moreover, the photochemical
trans
→
cis
isomerization is reported for these compounds. It occurs from the first excited singlet state of the
trans
isomer to the
cis
isomer following a
trans
-S
0
→ S
1
excitation. The electron-donating character of the substituent in a styrene moiety is one of the crucial factors influencing the photoisomerization process. The structure of the
cis
isomer was established by
1
H and
15
N NMR. Experimental studies are supported by the results of quantum chemical calculations. |
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Bibliography: | ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 23 |
ISSN: | 1474-905X 1474-9092 |
DOI: | 10.1039/c5pp00361j |