Ni‐catalyzed dehalogenation polycondensation of dihaloaromatic compounds with NaH

Ni‐catalyzed dehalogenation polycondensation of p‐dichlorobenzene, 2,5‐dichloropyridine, and 1,4‐dialkoxy‐2,5‐dichlorobenzene in the presence of NaH affords corresponding π‐conjugated poly(arylene)s in high yields. In this polymerization system, Ni(II)‐compounds used as the catalyst are considered to be reduced to Ni(0)‐complexes by NaH, and the Ni(0)‐complexes are regarded to be responsible for the polycondensation. The π‐conjugated poly(arylene)s obtained have well‐defined linkages between the monomer units as revealed by NMR spectroscopy. Poly(2,5‐diethoxybenzene‐1,4‐diyl) (PEOP) and poly(2,5‐dibutoxybenzene‐1,4‐diyl) (PBOP) have number‐average molecular weights (Mn) of 4300 and 11 000 as determined by GPC (vs. polystyrene), respectively. The chemical and electrochemical properties of resulting polymers are discussed in comparison with those of corresponding poly(arylene)s reported previously.