Poly{arylene-alt-[bis(1-methylpyrrolylene)]}s .1. Synthesis and electrochemical polymerization of terarenes

Novel alternating conjugated copolymers were prepared by electrochemical polymerization of defined bis(1-methylpyrrol-2-yl)arenes. The comonomers were synthesized by the nickel-catalyzed coupling reaction (Kumada synthesis) of 1-methylpyrrol-2-yl anion with various dibromoarenes. The monomers were characterized via common techniques, such as ultraviolet/visible (UV/Vis), proton nuclear magnetic resonance (H-1 NMR), C-13 NMR, infrared (IR) and mass spectroscopy (MS). All monomers show irreversible electrochemical behavior and could therefore be polymerized to conducting polymers. The resulting copolymers reveal a conductivity in the range of 10(-2) S/cm to less than 10(6) S/cm. The conductivity mainly depends on steric hindrance between the aromatic rings. A high decoupling of the conjugated systems could be observed in case of the anthracene/bis(1-methylpyrrole) copolymer, which is due to the highest torsion angle between the rings of the series. Additionally, in the case of the furan derivative a soluble copolymer is formed under certain conditions in the reduced state.