Rational Design of New Conjugated Polymers with Main Chain Chirality for Efficient Optoelectronic Devices: Carbo[6]Helicene and Indacenodithiophene Copolymers as Model Compounds.

The unique properties of conjugated polymers (CPs) in various optoelectronic applications are mainly attributed to their different self-assembly processes and superstructures. Various methods are utilized to tune and control CP structure and properties with less attention paid to the use of chirality. CPs with main chain chirality are rare and their microscopic and macroscopic properties are still unknown.

From Quinoxaline, Pyrido[2,3-]pyrazine and Pyrido[3,4-]pyrazine to Pyrazino-Fused Carbazoles and Carbolines.

2,3-Diphenylated quinoxaline, pyrido[2,3-]pyrazine and 8-bromopyrido[3,4-]pyrazine were halogenated in deprotometalation-trapping reactions using mixed 2,2,6,6-tetramethyl piperidino-based lithium-zinc combinations in tetrahydrofuran. The 2,3-diphenylated 5-iodo- quinoxaline, 8-iodopyrido[2,3-]pyrazine and 8-bromo-7-iodopyrido[3,4-]pyrazine thus obtained were subjected to palladium-catalyzed couplings with arylboronic acids or anilines, and possible subsequent cyclizations to afford the corresponding pyrazino[2,3-]carbazole, pyrazino[2',3':5,6] pyrido[4,3-]indole and pyrazino[2',3':4,5]pyrido[2,3-]indole, respectively. 8-Iodopyrido[2,3-] pyrazine was subjected either to a copper-catalyzed C-N bond formation with azoles, or to direct substitution to introduce alkylamino, benzylamino, hydrazine and aryloxy groups at the 8 position.