title: Photophysical characterization of new 3-amino and 3-acetamido BODIPY dyes with solvent sensitive properties.
abstract: The structural, electronic and photophysical properties of three new asymmetric, highly fluorescent difluoroborondipyrromethene (BODIPY) dyes, bearing an amino or an acetamido group at position 3 of the chromophoric core, have been studied in different apolar, polar and polar/protic solvents. The presence of the 3-amido group extents the delocalization of the pi-system, leading to bathochromic shifts in the absorption and fluorescence bands, as predicted by quantum mechanic calculations. The 3-amino dye shows photophysical properties highly dependent on the solvent polarity and acidity, and is characterized by a hypsochromic shift of its absorption band, with regard to the corresponding acetylated dye, as well as a low fluorescence quantum yield in acid media with proton concentration lower than 4 x 10(-4) M. In media with higher proton concentration, the BF(2) bridge group of the 3-amino dye is removed, yielding the corresponding non-fluorescent dipyrromethene precursor. These results suggest that the 3-amino dye could be used as a fluorescence probe for the study of the acidity of different environments.
authors.affiliation: Departamento de Química Física, Universidad del País Vasco-EHU, Apartado 644, 48080, Bilbao, Spain.
authors.forename: J
authors.initials: J
authors.lastname: Bañuelos
authors.forename: F
authors.initials: F
authors.lastname: López Arbeloa
authors.forename: T
authors.initials: T
authors.lastname: Arbeloa
authors.forename: S
authors.initials: S
authors.lastname: Salleres
authors.forename: J L
authors.initials: JL
authors.lastname: Vilas
authors.forename: F
authors.initials: F
authors.lastname: Amat-Guerri
authors.forename: M
authors.initials: M
authors.lastname: Liras
authors.forename: I
authors.initials: I
authors.lastname: López Arbeloa