Heat On, Heat Off: A Synthesis of Polyacetylene Revisited
A New Synthesis of Poly(acetylene).
15 February 2019 (online)
Polyacetylene (6) is the simplest organic conducting polymer and was pivotal to the development of the field organic electronics, an impact that was recognized with a Nobel prize in 2000. Sensitivity to atmospheric conditions stymied early efforts towards the investigation and application of this material. Edwards and Feast provided a method for the casting and controlled formation of trans-polyacetylene using a creative ROMP and thermal cycloreversion of polymer 5.
Monomer 4 was prepared by the cycloisomerization of cyclooctatetraene (1) and subsequent Diels–Alder reaction with perfluorobutyne (3). Ring-opening metathesis of 4 with a titanium tetrachloride/trimethylaluminum catalyst, stereoselectively provides polymer 5. At room temperature, this polymer decomposed to provide trans-polyacetylene (6) and 1,2-bistrifluoromethyl benzene (7) over several days. Heating under vacuum accelerates this process, providing 6in three hours.