Facile synthesis of heat-resistant and photoluminescent poly(N-aryleneindole ether)s via catalyst-free CN/CO coupling reaction

ABSTRACT We present here a novel programmable polymerization route for the synthesis of new indole‐based polymers via a catalyst‐free nucleophilic substitution reaction. The polycondensation of 4‐hydroxyindole with different activated difluoro monomers undergoes in N‐methylpyrrolidinone, affording soluble poly(N‐aryleneindole ether)s (PEINs) with high molecular weights (Mw up to 486,000) in high yields (up to 96%). The structures of the polymers are characterized by means of FT‐IR, 1H NMR spectroscopy and elemental analysis, the results show good agreement with the proposed structures. The resulting polymers are processable and enjoy high glass transition temperatures (Tgs > 180 °C) and thermal stability (Tds > 420 °C). Thin films of PEINs show great mechanical behaviors with high tensile strength up to 104 Mpa, and good optical transparency. In addition, due to the indole moieties in the main chains, all these PEINs are endowed with significantly strong photonic luminescence in chloroform and display highly solvent‐dependent emission bands. Especially, the polymer PEIN‐3 carrying sulfonyl units, shows outstanding blue‐light emission with high quantum yields (45.2%, determined against quinine sulfate). The results obtained by cyclic voltammetry suggest that PEINs possess good electroactivity. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014, 52, 313–320 Soluble and high‐thermal stability poly(N‐aryleneindole ether)s (PEINs) are synthesized by a catalyst‐free nucleophilic substitution polycondensation reaction, exhibiting a promising film‐forming ability, outstanding photonic luminescence properties, and electroactivity.