A macrocyclic aromatic thioether ketone: synthesis, structure and anionic ring-opening polymerisation

Nucleophilic polycondensation at high concentration between benzene-1,3-dithiol and 4,4′-difluorobenzophenone affords not only linear polymer1 but also a significant yield (ca. 8%) of cyclic oligomers, mainly the [2+2] cyclodimer 2. Under high-dilution conditions 2 becomes by far the major reaction product. Macrocycle 2 has been isolated, structurally characterised by single-crystal X-ray methods and found to undergo rapid anionic ring-opening polymerisation in the melt (330–360 °C), affording a linear, high molecular weight poly(arylthioether ketone).