Polythiophene derivatives having crown-ethereal subunit prepared by dehalogenation polycondensation with Ni(0)-complex

Dehalogenation polycondensation of thiophene derivative having crown ethereal subunit(2,5-Cl2-CT5) with zero-valent nickel complex Ni(0)LM(e.g., a mixture of bis(1,5-cyclooctadiene)nickel(0) and bpy) affords corresponding polymer (PCT5) with well-defined bonding between the monomer units. Analytical, IR, and NMR data agree with the structure of the polymer. PCT5 is easily soluble in general organic solvents such CHCl3 and benzene. Light scattering measurement reveals that PCT5 has high molecular weight (Mw= 7.4 × 105). PCT5 gives electrochemical n-doping peak at −2.3 V (AgAg+) and n-undoping peak at much higher potential (+0.3 V (AgAg+)) in an NaClO4 solution of CH3CN. Na-doped PCT5 is more under dry air than Na-doped usual polythiophene derivatives. This stability of n-doped state is due to a strong interaction of Na+ dopant with the crown ethereal subunit.