Photostability and Spectral Properties of Fluorinated Fluoresceins and their Biarsenical Derivatives: A Combined Experimental and Theoretical Study

CARLA C. SPAGNUOLO, WALTER MASSAD, SANDRA MISKOSKI, GUILLERMO O. MENENDEZ, NORMAN A. GARCıA AND ELIZABETH A. JARES-ERIJMAN

PHOTOCHEMISTRY AND PHOTOBIOLOGY

Wiley/Blackwell

Lugar: New Jersey; Año: 2009 vol. 85 p. 1082 - 1088

0031-8655

New fluorinated biarsenical derivatives with improved opticalproperties based on highly photostable analogs of fluoresceinwere recently introduced. The photophysical parameters of thetriplet excited states as well as photosensitized oxidationreactions of these dyes were determined in order to investigatethe influence of molecular structure on the exceptional photostabilityof these fluorophores. The lack of correspondencebetween triplet quantum yields and lifetimes with the photobleachingrates of some of the fluorophores of the series suggeststhat differential reactivities of the excited states with groundstate oxygen accounts for the different photodegradation resistances.The UV?visible absorption and emission spectra of thefluorinated fluoresceins and their biarsenical derivatives wereevaluated using a TD-DFT ⁄ BP86 ⁄ 6-31G** approach, takingbulk solvent effects into account by means of the polarizablecontinuum model. The calculated properties are in good agreementwith experimental data. The S0 fi S1 vertical excitationenergies in the gas phase and in water were obtained with theoptimized geometries of the excited states. This type ofcalculation could be used in the rational design of new dyes.