Soluble and processable conjugated polyazines with oligo(p-phenylene vinylene)s

An efficient polycondensation reaction between α,ω-diformyl functional aromatics, namely 2,5-diheptyloxy-1,4-diformylbenzene and side-chain substituted α,ω-diformyl oligo(p-phenylene vinylene) (OPV) with hydrazine afforded novel soluble and processable conjugated polymers, P1 and P2, respectively. The reaction conditions were investigated and structural analysis of the polymers was carried out by means of 1H, 13C, 15N NMR, indicating all-trans configured CN–NC linkages. The molecular weights Mn were observed at ∼1100–1400 g/mol for P1 and ∼8700–10,500 g/mol for P2. The optical properties showed absorption maxima at ∼455 nm and ∼487 nm for P1 and P2 (CHCl3 solutions), respectively, red shifted by 31–60 nm relative to the monomer aromatics due to conjugation through the azine linkage. The emission maxima are observed at ∼515 nm and ∼560 nm for P1 and P2 (CHCl3 solutions), respectively. Thin films of P2 readily undergo n-doping.