Synthesis of n-Type Poly(benzotriazole)s Having p-Conducting and Polymerizable Carbazole Pendants

Abstract

Poly(benzotriazole)s, P(BTz)s, having an n-type benzotriazole-π-conjugated main chain and p-type and electrochemically polymerizable carbazole (CBz) pendant groups, −(CH2)m−CBz (m = 12 or 6) groups, were synthesized by Ni− (for homopolymers) and Pd-promoted (for a copolymer) organometallic polycondensations. The copolymer between benzotriazole with the −(CH2)12−CBz pendant and p-phenylene was soluble in organic solvents and showed a number-average molecular weight (Mn) of 27000 in the GPC analysis. The homopolymers (m = 12, 6) were less soluble, and about half of the polymer was soluble in CHCl3 in the case of m = 12; the soluble part gave an Mn value of 4700. The polymers were photoluminescent with quantum yields of 50−70%. Cyclic voltammograms of the polymers revealed that the polymers were active in electrochemical n-doping in accord with the electron-accepting nature of the benzotriazole main chain. Application of electrochemical oxidation potential to the polymer made the polymer insoluble due to occurrence of electrochemical polymerization of the CBz unit.