Dipolar 3-methoxychromones as bright and highly solvatochromic fluorescent dyes.
Fiche publication
Date publication
février 2012
Auteurs
Membres identifiés du Cancéropôle Est :
Pr MELY Yves, Dr KLYMCHENKO Andrey, Dr RICHERT Ludovic
Tous les auteurs :
Kucherak OA, Richert L, Mely Y, Klymchenko AS
Lien Pubmed
Résumé
Herein, three environment-sensitive (solvatochromic) fluorescent dyes presenting a strong electron acceptor 3-methoxychromone unit and varied electron donor 2-aryl were developed. All three dyes showed remarkable polarity-dependent shifts of the emission maximum, which increase with extension of the dye conjugation. For the 3-methoxychromone bearing a 7-(diethylamino)-9,9-dimethylfluoren-2-yl donor group the difference between the excited and the ground state dipole moments, estimated from the Lippert-Mataga expression, reached 20 D, which is among the largest reported for neutral dipolar fluorophores. Moreover, the new dyes are characterized by significant two-photon absorption cross-section (up to 450 GM) and large fluorescence quantum yields. The strong decrease in the fluorescence quantum yields of the dyes in polar protic solvents was observed together with the increase in the non-radiative deactivation rates, which can originate from twisted intramolecular charge transfer and intermolecular proton transfer phenomena. In comparison to the parent 3-hydroxychromone derivatives, the new dyes presented significantly improved photostability, which confirms that photodegradation of 3-hydroxychromones occurs from a product of the excited-state intramolecular proton transfer (phototautomer). Finally, an application of the new dyes for probing local binding site polarity of serum albumin was shown. This new class of fluorescent dyes may serve as attractive building blocks for future molecular sensors utilizing environment-sensitive fluorophores.
Référence
Phys Chem Chem Phys. 2012 Feb 21;14(7):2292-300