Synthesis and Characterization of Solution Processable Poly(pyrazolines)

Abstract

Solution‐processable poly(dibenzalacetone) and poly(dibenzalcyclohexanone) are prepared by the condensation of 1,4‐dialkoxy‐bisbenzaldehyde and acetone/cyclohexanone using classic Claisen–Schmidt condensation. The prepared polymers are readily soluble in common organic solvents due to the presence of alkoxy chains present on the aromatic ring. The availability of α,β‐unsaturated ketone on the backbone is readily functionalized with hydrazine hydrate to obtain poly(pyrazoline acetate), a nonconjugated polymer on the backbone, which shows enhanced emission characteristics on comparison with the pristine polymer and small molecule analogues. The highest occupied molecular orbital–lowest unoccupied molecular orbital (HOMO–LUMO) of levels of poly(pyrazolines) has a band gap of 1.54 eV as calculated from cyclic voltammetry and UV–vis studies. Uniform thin film is obtained by spin casting as 1% solution on chlorobenzene and annealing under vacuum. Atomic force microscopy analysis shows fine morphology of the thin film. I–V characterization of the film shows low turn‐on voltage of 5.3 V. HOMO–LUMO is calculated by density functional theory and the result suggests that these molecules have great potential toward polymer organic light‐emitting diode applications.

Polychalcones based on triphenylamine and carbazole building blocks via Claisen–Schmidt route

“…Poly(chalcone)s are prepared in tetrahydrofuran (THF) by polycondensation in the presence of aqueous base by reacting equimolar amounts of A 2 type monomer that contains two arylmethylketone (M 1 monomer in Figure 1) and B 2 type monomer that contain two arylaldehyde groups (M 2 and M 3 monomers in Figure 1). We chose sodium hydroxide in aqueous THF as a relatively less expensive and convenient route for the polymerization 39 …”