title: Fluorescence Quenching of Two Coumarin-3-carboxylic Acids by Trivalent Lanthanide Ions.
abstract: 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.
authors.affiliation: Laboratoire de Photochimie et d'Analyse, Faculté des Sciences et Techniques, Université Cheikh Anta DIOP, Dakar, Sénégal, France.
authors.forename: Lamine
authors.initials: L
authors.lastname: Cisse
authors.affiliation: Laboratoire de Chimie Moléculaire et de Matériaux Equipe de Chimie Organique et de Phytochimie, Université Ouaga 1Pr Joseph Ki-Zerbo, Ouaga dougou, Burkina Faso.
authors.forename: Abdoulaye
authors.initials: A
authors.lastname: Djande
authors.affiliation: Laboratoire de Physique des Matériaux Divisés et Interfaces, CNRS-UMR 810, Université Paris-Est Marne-la-Vallée, Champs-sur-Marne, 77454, Marne-la-Vallée Cedex 2, France.
authors.forename: Martine
authors.initials: M
authors.lastname: Capo-Chichi
authors.affiliation: Unité de Chimie Environnementale et Interactions sur le Vivant (UCEIV) ULCO, BP 59140, Dunkerque, France.
authors.forename: François
authors.initials: F
authors.lastname: Delattre
authors.affiliation: Laboratoire de Chimie Moléculaire et de Matériaux Equipe de Chimie Organique et de Phytochimie, Université Ouaga 1Pr Joseph Ki-Zerbo, Ouaga dougou, Burkina Faso.
authors.forename: Adama
authors.initials: A
authors.lastname: Saba
authors.affiliation: Laboratoire de Biologie et de Pharmacologie Appliquée, CNRS-UMR 8113, ENS Cachan, 61 Av. Président Wilson, 94235, Cachan, France.
authors.forename: Jean-Claude
authors.initials: JC
authors.lastname: Brochon
authors.affiliation: Laboratoire de Biologie et de Pharmacologie Appliquée, CNRS-UMR 8113, ENS Cachan, 61 Av. Président Wilson, 94235, Cachan, France.
authors.forename: Serguei
authors.initials: S
authors.lastname: Sanouski
authors.affiliation: Laboratoire de Photochimie et d'Analyse, Faculté des Sciences et Techniques, Université Cheikh Anta DIOP, Dakar, Sénégal, France.
authors.forename: Alphonse
authors.initials: A
authors.lastname: Tine
authors.affiliation: Laboratoire Géomatériaux et Environnement (LGE), Université Paris-Est Marne-la-Vallée, 5 boulevard Descartes, Champs-sur-Marne, 77454, Marne-la-Vallée Cedex 2, France. jeanjacquesaaron@yahoo.fr.
authors.forename: Jean-Jacques
authors.initials: JJ
authors.lastname: Aaron
keywords: 7-N,N-diethylamino-coumarin-3-carboxylic acid; Absorption and fluorescence spectra; Coumarin-3-carboxylic acid; Fluorescence quenching; Lanthanide acetates