Synthesis and luminescence of poly(phenylacetylene)s with pendant iridium complexes and carbazole groups

Poly(phenylacetylene)s containing pendant phosphorescent iridium complexes have been synthesized and their electrochemical, photo-and electroluminescent properties studied. The polymers have been synthesized by rhodium-catalyzed copolymerization of 9-(4-ethynylphenyl)carbazole (CzPA) and phenylacetylenes (C∧N)₂Ir(κ²-O,O'-MeC(O)CHC(O)C₆H ₄C≡CH-4) (C∧N = κ²-N,C¹-2- (pyridin-2-yl)phenyl (Ir^ppyPA) or κ²-N,C ¹-2-(isoquinolin-1-yl)phenyl (Ir^piqPA)). In addition, organic poly(phenylacetylene)s with pendant carbazole groups have been synthesized by rhodium-catalyzed copolymerization of CzPA and 1-ethynyl-4-pentylbenzene. Complex (C∧N)₂Ir(κ²- O,O'-MeC(O)CHC(O)Ph) (Ir^piqPh; C∧N = 2-(isoquinolin-1-yl)phenyl- κ²-N,C¹) was prepared and characterized. While the copolymers of the Ir^ppy series were weakly phosphorescent, those of the Ir^piq series displayed at room temperature intense emissions from the carbazole (fluorescence) and iridium (phosphorescence) emitters, being the latter dominant when the spectra were recorded using polymer films. Triple layer OLED devices employing copolymers of the Ir^piq series or the model complex Ir^piqPh yielded electroluminescence with an emission spectra originating from the iridium complex and maximum external quantum efficiencies of 0.46% and 2.99%, respectively.