Synthesis of low band gap polymers: Studies in polyisothianaphthene

PITN is an easily prepared low band-gap conjugated polymer, albeit very ins oluble. The best synthetic route is the condensation of phthalic anhydride derivatives with P4S10. We have found that the, often more convenient, phth alic acids or methyl esters can be used as readily in place of the anhydrid e. We have also looked at a range of new substituted PITN polymers, and copoly mers. No significant band gap reduction has been observed. This work was carried out as part of Technology Group 7 of the MoD Corporat e Research Programme.