A novel, conjugated polymer containing fluorene, pyridine and unsymmetric carbazole moieties: Synthesis, protonation and electrochemical properties

An optically active, conjugated polymer bearing unsymmetric pendant carbazole chromophores was prepared via the Suzuki coupling of 9,9-dioctylfluorene-2,7-diboronic acid and a novel pyridine-containing compound. The polymer had a T_g of 192 °C and T_d10 at 437 °C under a nitrogen atmosphere and exhibited absorption bands at 320-400 nm and displayed an additional absorption bands at 380-480 nm after protonation with aq. HCl solution. The photoluminescence of the polymer shifted from 360-460 nm to 460-560 nm after protonation and the photoluminescence quantum yield of the polymer in THF solution was 0.88. The emission color of the polymer film changed from blue (439 nm) to yellow (551 nm) under an applied bias voltage of 2.5 V.