Copolyfluorenes containing polymethine dyes in the main chain: synthesis and photophysical properties

Abstract

The effect of polyfluorene main chain on both luminescence and pH-sensitivity of polymethine dyes incorporated covalently into the copolyfluorenes was studied. A series of fluorene-polymethine dye copolymers were synthesized by the Suzuki-Miyaura coupling polycondensation using cyanine, keto-cyanine, and squaraine comonomers, which exhibit fluorescence at ca. 500–700 nm. These polymers exhibit both green to red or near-infrared absorption and emission attributed to polymethine dyes, and absorption and emission bands corresponding to polyfluorene (at ca. 380 and 420−470 nm, respectively). The influence of pH on the UV-Vis absorption and luminescence spectra of the copolymers in solution was studied.