Poly[(3, 5-di-tert-butyl-4-hydroxyphenly)-acetylene]: formation of a conjugated stable polyradical

A description is given of the synthesis of poly[(3,5-di-tert-butyl-4-hydroxyphenyl)acetylene] (1) and the formation of its polyradical. Experimental data shows that the absorption intensity of the oxidized 1 solution suggests formation of the phenoxy radical of 1 in high concentration and stays constant upon standing at room temperature over a day. This radical formation of 1 is in contrast to the radical formation of the corresponding low molecular phenols, e.g. 3,5-di-tert-butyl-4-hydroxycinnamate; the latter had been reported to give bisquinone methides irreversibly. The sterically crowded structure of 1 probably suppresses bond formation between unpaired electrons.