Naphthalene Bis(4,8-Diamino-1,5-Dicarboxyl)Amide Building Block For Semiconducting Polymers

We report a new naphthalene bis(4,8-diamino-1,5-dicarboxyl)amide (NBA) building block for polymeric semiconductors. Computational modeling suggests that regio-connectivity at the 2,6- or 3,7-NBA positions strongly modulates polymer backbone torsion and, therefore, intramolecular pi-conjugation and aggregation. Optical, electrochemical, and X-ray diffraction characterization of 3,7- and 2,6-dithienyl-substituted NBA molecules and, corresponding isomeric NBA, bithiophene copolymers P1 and P2, respectively, reveals the key role of regio-connectivity. Charge transport measurements demonstrate that while the twisted 3,7-NDA-based P1 is a poor semiconductor, the planar 2,6-functionalized NBA polymers (P2-P4) exhibit ambipolarity, with mu(e) and mu(h) of up to 0.39 and 0.32 cm(2)/(V.s), respectively.