Synthesis of Bithiazole-Based Poly(arylenevinylene)s via Co-Catalyzed Hydroarylation Polyaddition and Tuning of Their Optical Properties by N-Methylation and N-Oxidation

Bithiazole-based poly(arylenevinylene) is synthesized via the Co-catalyzed hydroarylation polyaddition of N,N,N′,N′-tetrahexyl-(2,2′-bithiazole)-4,4′-dicarboxamide with 2,7-diethynyl-9,9-bis(2-ethylhexyl)fluorene in a regioselective manner. The introduction of the 2,2′-bithiazole unit deepens the highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) energy levels of the polymer compared to the analogous bithiophene-based poly(arylenevinylene). N-Methylation and N-oxidation of the thiazole moiety further deepen the HOMO and LUMO energy levels of the polymer, which is attributed to the enhanced electron-withdrawing effect. The N-oxidized polymer exhibits a high photoluminescence quantum yield and serves as an emitting material in an organic light-emitting diode, and its deep HOMO energy level efficiently restrains the trapping of holes in the host poly(vinylcarbazole) matrix.