title: Reaction of amines with 8-methylthioBODIPY: dramatic optical and laser response to amine substitution.
abstract: A thorough study of the photophysical and laser properties of 8-aminoboron dipyrromethene dyes was undertaken to determine the role of amine substitution and spatial disposition on the properties of the dyes. It was found that the fluorescent and laser response varied significantly. Although primary amines give rise to highly fluorescent products at the blue edge of the visible region, secondary amines yield nonfluorescent analogues in polar media. The crystal structures of two analogues are reported and described. Steric hindrance and the higher electron-releasing ability of the amine favor the formation of a quenching intramolecular charge-transfer state. Accordingly, boron dipyrromethene derivatives with primary amines exhibited laser emission with efficiencies of up to 44%. Besides, the more efficient derivative was also the most photostable, leading to a significant improvement in the lasing performance with regard to previously reported 8-aminoboron dipyrromethene derivatives. An increase in the solvent polarity, and mainly the presence of tertiary cyclic amines, led to a dramatic decrease or even the loss of the laser action.
authors: Departamento de Química Física, Universidad del País Vasco (UPV/EHU) aptdo. 644, 48080 Bilbao (Spain).
authors: Ixone
authors: I
authors: Esnal
authors: Arlette
authors: A
authors: Urías-Benavides
authors: C F Azael
authors: CF
authors: Gómez-Durán
authors: Carlos A
authors: CA
authors: Osorio-Martínez
authors: Inmaculada
authors: I
authors: García-Moreno
authors: Angel
authors: A
authors: Costela
authors: Jorge
authors: J
authors: Bañuelos
authors: Nerea
authors: N
authors: Epelde
authors: Iñigo
authors: I
authors: López Arbeloa
authors: Rongrong
authors: R
authors: Hu
authors: Ben Zhong
authors: BZ
authors: Tang
authors: Eduardo
authors: E
authors: Peña-Cabrera
keywords: charge transfer; dyes/pigments; fluorescence; heterocycles; laser chemistry