New Conjugated Polymers with Donor−Acceptor Architectures: Synthesis and Photophysics of Carbazole−Quinoline and Phenothiazine−Quinoline Copolymers and Oligomers Exhibiting Large Intramolecular Charge Transfer

Alternating carbazole−quinoline and phenothiazine−quinoline donor−acceptor conjugated copolymers and a corresponding oligomer were synthesized, and their solution and solid-state photophysics were investigated. The new copolymers, poly(2,2‘-9-methyl-3,6-carbazolylene-6,6‘-bis(4-phenylquinoline)) and poly(2,2‘-10-methyl-3,7-phenothiazylene-6,6‘-bis(4-phenylquinoline)), had intrinsic viscosities of 11.2−22.0 dL/g, indicating very high molecular weights. The optical band gaps of the new copolymers were 2.35−2.64 eV, which are significantly smaller than the corresponding homopolymers. The absorption and emission spectra of the related donor−acceptor oligomers, 3,6-[bis(4-phenyl-2-quinolyl)]-9-methylcarbazole and 3,7-[bis(4-phenyl-2-quinolyl)]-10-methylphenothiazine, in solvents of varying polarity showed positive solvatochromism. An unusual dual fluorescence, with a blue emission band at 454 nm and an orange emission band at 584 nm, was observed in solid films of the carbazole-linked oligomer and related to i...