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Molecules 2010, 15(12), 8915-8932; doi:10.3390/molecules15128915
Article

Influence of Polarity of Solvents on the Spectral Properties of Bichromophoric Coumarins

1
, 2,* , 2
 and 2
Received: 12 November 2010; in revised form: 1 December 2010 / Accepted: 6 December 2010 / Published: 7 December 2010
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Abstract: Absorption and fluorescence spectra of bichromophoric coumarins were investigated in different solvents and in polymer matrices. These bichromophoric coumarins were composed of a coumarin dimethylamino-substituted at position 7 or unsubstituted coumarin and phthalimide or a 1,8-naphthylimide linked with an iminomethyl bridge to the position 3 or 8 of the coumarin ring. Absorption spectra of 7-dimethylamino derivatives in position 3 of coumarin were quite similar, exhibiting broad bands around 430-440 nm like the parent compound 7-dimethylaminocoumarin-3-carbaldehyde. For coumarin derivatives substituted in position 8, the absorption maximum was shifted to shorter wavelength as for derivatives without position 7 dimethylamino substitution. The most intense fluorescence was observed for 7-(N,N-dimethylamino)-3-[(N-phtalimidoyl)iminomethyl]coumarin in polar solvent, while intense fluorescence was observed for 7-(N,N-dimethylamino)-3-[N-(1,3-dioxobenz[de]isoquinolinyl)iminomethyl]-coumarin in non polar solvent (chloroform), comparable with the fluorescence of 7-amino-4-methylcoumarin. Spectral measurements of bichromophoric coumarins in polymer matrices revealed that the maxima lies in between those for chloroform and methanol yielding more intense fluorescence then in solutions. Completely different solvent effects were observed for 7-(N,N-dimethylamino)-3-[N-(1,3-dioxobenz[de]isoquinolinyl)imino-methyl]coumarin and 7-(N,N-dimethylamino)-3-[(N-phtalimidoyl)iminomethyl]coumarin. With addition of polar methanol the intensity of fluorescence decreases, yielding a Stern-Volmer-like constant of 0.54 dm3 mol−1 for 7-(N,N-dimethylamino)-3-[N-(1,3-dioxo-benz[de]isoquinolinyl)iminomethyl]coumarin and an even higher one of 1.08 dm3 mol−1 for 7-dimethylaminocoumarin-3-carbaldehyde compared to the rather low one of 0.024 dm3 mol−1 for 7-amino-4-methylcoumarin. Contrary to this, addition of methanol under identical conditions brings about an increase in fluorescence intensity of 7-(N,N-dimethylamino)-3-[(N-phtalimidoyl)iminomethyl]coumarin (about 60-fold). The reasons for these different solvent effects are discussed.
Keywords: fluorescence; bichromophoric coumarins; solvent effect; polymer matrices fluorescence; bichromophoric coumarins; solvent effect; polymer matrices
This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

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MDPI and ACS Style

Hrdlovic, P.; Donovalova, J.; Stankovicova, H.; Gaplovsky, A. Influence of Polarity of Solvents on the Spectral Properties of Bichromophoric Coumarins. Molecules 2010, 15, 8915-8932.

AMA Style

Hrdlovic P, Donovalova J, Stankovicova H, Gaplovsky A. Influence of Polarity of Solvents on the Spectral Properties of Bichromophoric Coumarins. Molecules. 2010; 15(12):8915-8932.

Chicago/Turabian Style

Hrdlovic, Pavol; Donovalova, Jana; Stankovicova, Henrieta; Gaplovsky, Anton. 2010. "Influence of Polarity of Solvents on the Spectral Properties of Bichromophoric Coumarins." Molecules 15, no. 12: 8915-8932.



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