Synthesis, characterization, and iodine doping of a soluble polyazine: the propyl-methyl substituted derivative

Reaction of 2,3-hexanedione with 2,3-hexanedione dihydrazone leads to a polyazine that is soluble in organic solvents. This synthetic method gives a polymer with statistically alternating methyl and propyl substituents on the carbon atoms along the chain. Like the previously reported permethyl polyazine, IR spectra suggest that the propyl methyl polymer is a linear chain with double bonds in the E conformation and single bonds in the anti (or s-trans) conformation. IR, UV-vis, and NMR spectra all imply that extensive conjugation exists along the polymer backbone. The high-resolution 13C NMR spectrum shows the presence of two types of sequences of propyl and methyl groups along the polymer chain. Iodine doping of this polyazine leads to a charge-transfer product with no measurable electrical conductivity. An iodine titration of the polymer allows an estimate of the equilibrium constant for the charge-transfer reaction of 800 M−1.