Successful Synthesis of Wholly Aromatic Polyketones via Nickel-Mediated Aromatic Coupling Polymerization

Novel aromatic polyketones (<BO>8a</BO>, <BO>8b</BO>) without ether linkage in the main chain were successfully synthesized via nickel-mediated aromatic coupling polymerization of bis(chlorobenzoyl)dimethoxybiphenyls (<BO>3a</BO>,<BO> 3b</BO>). The polymers affording flexible films were obtained in the reaction where an excess amount of bipyridyl and a stoichiometric amount of the nickel(II) bromide were present. The resulting polyketones (<BO>8a</BO>, <BO>8b</BO>) have sufficiently high molecular weight (inherent viscosity:  0.59 dL/g for polyketone <BO>8a</BO>; 0.35 dL/g for polyketone<BO> 8b</BO>) and a highly amorphous nature with a rather high glass transition temperature:  218 °C for polyketone<BO> 8a</BO>; 192 °C for polyketone<BO> 8b</BO>.