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Abstract We report attempts to create conjugated polymers consisting of alternating phenylene and heterocyclic rings separated by double bonds by means of condensations between terephthalaldehyde and dimethyl nitrogen bases. Because the products precipitated during their formation even at 180°C in N‐methyl‐2‐pyrrolidinone (NMP), only oligomers of up to ca. 30 rings (DP = 15) could be obtained; most of the adequately soluble products had DP between 4 and 8, and from these oligomers films on glass or quartz could be made. When the films were exposed to I 2 , NO 2 , or SbF 5 , most of them, initially very good insulators, showed an increase in electrical conductivity of up to 6 powers of 10; but the rapid reversal of this change when the reagent evaporated and the lack of any clear changes in the UV‐vis spectrum of the films showed that most likely true “doping” had not occurred. Extensive syntheses with a variety of quaternised bases also failed to yield oligomers oxidisable by electron‐acceptors. For reference purposes, especially for their spectra, a large number of pure “model” compounds of the distyrylpyridine and distyrylpyrazine type, and quaternised analogues of the former, were synthesised, many of them new compounds. These were also used as calibrants for a GPC column operating with NMP solutions. Several improvements were made in the synthetic techniques.
Nethsinghe et al. (Sun,) studied this question.