Photophysical properties of coumarin compounds in neat and binary solvent mixtures: evaluation and correlation between solvatochromism and solvent polarity parameters

Journal of the Brazilian Chemical Society

Leonardo M. Moreira²  Mirian M. De Melo¹  Priscila A. Martins¹  Juliana P. Lyon¹  Ana Paula Romani¹  Lúcia Codognoto¹  Sandra C. Dos Santos¹  Hueder P. M. De Oliveira¹ 

[1] ,Universidade Federal de São João Del Rei Departamento de Zootecnia São João del Rei MG ,Brazil

关键词: coumarin;    fluorescence;    solvatochromic properties;    emission spectra;    excitation spectra;   

DOI  :  10.5935/0103-5053.20140051

来源: SciELO

【 摘 要 】

This work studied the fluorescent and solvatochromic properties of coumarin and its derivatives aiming to contribute in the elucidation of the excited state behavior of the molecule in solvent mixtures. This approach has been developed through a set of measurements involving different solvent ratios, which present distinct dielectric constants. The excitation and fluorescence maxima were largely blue-shifted with increasing participation of the organic solvent and the Stokes shifts were unusually low in mixtures with lower solvent polarity parameter, Δf. The emission intensity of coumarin was extremely sensitive to the polarity and the different structural conformations of solvents. These results influenced the spectroscopic behavior and explain the deviation from the linearity of the Lippert-Mataga relationship. The use of fluorescence spectroscopy makes the understanding of the behavior of the systems studied when in the presence of different environments being extremely important for the identification and characterization of coumarin in different pharmaceutical formulations.

【 授权许可】

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