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15) Fluorescence Quenching of two coumarin-3-carboxylic acids by trivalent Lanthanide ions

The effects of various trivalent lanthanide ions (acetates of Ce3+, Er3+, Eu3+, Nd3+) on the electronic absorption and fluorescence spectra of un-substituted coumarin-3- carboxylic acid (CCA) and 7-N,N-diethylamino-coumarin-3-carboxylic acid (DECCA) have been investigated in dimethylsulfoxide (DMSO) at room temperature. Depending on the lanthanide ion nature and concentration, significant spectral changes of absorption bands occurred for both coumarin derivatives. These spectral changes were attributed to the formation of ground-state complexes between the coumarin carboxylate derivatives and lanthanide ions. The fluorescence quenching of CCA and DECCA upon increasing the lanthanide ion concentration was studied. Different quantitative treatments, including the Stern-Volmer equation, the Perrin equation and a polynomial equation, were applied and compared in order to determine the nature of the quenching mechanisms for both coumarin derivatives. The results suggested the contribution of both dynamic and static quenching. Significant differences of CCA and DECCA fluorescence quenching efficiency were also observed, depending on the lanthanide ion. DECCA fluorescence lifetime measurements, performed in the absence and in the presence of Ln3+, confirmed a contribution of static quenching.

Auteur(s) : Lamine Cissé, Abdoulaye Djande, Martine Capo-Chichi, François Delattre, Adama Saba, Jean-Claude Brochon, Serguei Sanouski, Alphonse Tine, Jean-Jacques
Pages : 1-10
Année de publication : 2016
Revue : Jounal of Fluorescence
Type : Article
Mise en ligne par : CISSE Lamine