π‐conjugated polymers prepared by organometallic polycondensation and metal complexes of the polymers

Abstract

Organometallic dehalogenative polycondensation of dihaloaromatic compounds produces various π-conjugated polymers. π-Conjugated polymers with nitrogen in the aromatic ring form metal complexes, and regioregular π-conjugated polymers such as head-to-tail poly(3-hexylthiophene-2,5-diyl) (HT-P3HexTh), form a stacked structure. New examples are given in this paper. Poly(1,5-naphthyridine-2,6-diyl) (P(2,6-Nap)) formed a complex with Ru(bpy)22+ (bpy = 2,2′-bipyridine). The molar ratio between the monomeric unit and Ru(bpy)22+ in the formed complex was about 1 : 1, and the complex showed overlapped absorption bands in the region 370–460 nm. Dehalogenative polycondensation of a porphyrinatozinc(II) complex having two 5-bromo-2-thienyl units at the 5,15-positions gave a new porphyrinatozinc(II) polymer. The polymer exhibited a strong B absorption band at 416 nm and two weak Q bands at 546 and 584 nm. The polymer emitted light at the onset position of the Q bands (591 nm) when irradiated with 424 nm UV light; this result indicated occurrence of a transfer of energy absorbed at the B band to an excited state concerned with the Q bands. A cast polymer film was electrochemically active both in the oxidation and reduction regions. Electrochemically p-doped HT-P3HexTh formed a stacked structure, similar to neutral HT-P3HexTh. The p-doped HT-P3HexTh (dopant BF4– showed an electrical conductivity of 7.3 × 10−3 S cm−1 at room temperature. Copyright © 2000 John Wiley & Sons, Ltd.