Reactive polythiophenes with zincke salt structure: Synthesis,polymer reactions,and chemical properties

Polythiophenes with reactive Zincke salt structure, such as PThThPy⁺DNP(Cl^?)Th , were synthesized by the oxidation polymerization of 3′‐(4‐N‐(2,4‐dinitrophenyl)pyridinium chloride)‐2,2′:5′,2″‐terthiophene ( ThThPy⁺DNP(Cl^?)Th ) with iron(III) chloride or copper(II) trifluoromethanesulfonate. The reaction of PThThPy⁺DNP(Cl^?)Th with R‐NH₂ (R = n‐hexyl (Hex) and phenyl (Ph)) substituted the 2,4‐dinitrophenyl group into the R group with the elimination of 2,4‐dinitroaniline to yield PThThPy⁺R(Cl^?)Th . Similarly, model compounds, ThThPy⁺R(Cl^?)Th (R = Hex and Ph), were also synthesized. In contrast to the photoluminescent ThThPyTh and PThThPyTh , the compounds PThThPy⁺DNP(Cl^?)Th , PThThPy⁺R(Cl^?)Th , and ThThPy⁺R(Cl^?)Th showed no photoluminescence because their internal pyridinium rings acted as quenchers. Cyclic voltammetry measurements suggested that PThThPy⁺DNP(Cl^?)Th received an electrochemical reduction of the pyridinium and 2,4‐dinitrophenyl groups and oxidation of the polymer backbone. PThThPy⁺DNP(Cl^?)Th was electrically conductive (ρ = 2.0 × 10^?6 S cm^?1) in the non‐doped state. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012