New BODIPY chromophores bound to polyhedral oligomeric silsesquioxanes (POSS) with improved thermo-and photostability

摘要

New hybrid dyes, analogs of the BODIPY laser dye PM567, with the chromophore group covalentlyudbound to a POSS T8 group, have been prepared and their photophysical properties in ethyl acetateudsolution and in poly(methyl methacrylate) (PMMA) thin film solution have been studied. In PMMAudsolution and under comparative conditions, the dyes show higher thermostability than the parent dyeudPM567, the related compound POSS(iBu)8, and the corresponding unbound model dyes, because theudfirst mass loss takes place at higher temperatures. In addition, their photostabilities in the same mediumudunder irradiation with 365 nm light are much higher than those of the dye PM567 or an equimolarudmixture of PM567 plus POSS(iBu)8 under the same conditions, indicating that the POSS moietyudphotostabilizes the bound BODIPY group. The different photostabilities could be a consequence ofuddifferent reactivities of the hybrid dyes with self-generated singlet oxygen, because they show lowerudreaction rate constant values than PM567, although the observed tendency of these values does notudcorrelate with that of the photodegradation quantum yield values. The new hybrid materials can beudemployed in applications where highly photostable and highly emissive dyes are required.