Topological Polymerization of tert-Butylcalix[4]arenes Containing Diynes

Abstract

The new 25,26,27,28-tetra(8-hydroxylocta-2,4-diynyl)-tert-butylcalix[4]arene was synthesized in good yield from copper-catalyzed coupling reaction of 25,26,27,28-tetra(2-propynyl)-tert-butylcalix[4]arene with 5-iodo-4-pentynol in pyrrolidine. The hydroxyl end groups were converted to urethane groups through addition to alkyl or phenyl isocyanate. Di- and trisubstituted tert-butylcalix[4]arene analogs were also synthesized through the same approach. The solid-state photopolymerization study revealed that only the calix[4]arene derivatives containing four diyne units with alkyl urethane groups were substantially polymerized upon exposure to UV or gamma irradiation to give polydiacetylenes containing calix[4]arene. The visible absorption band at 350−600 nm and the Raman signals around 1500 and 2100 cm-1 characterized the ene−yne conjugation formed through the topological 1,4-addition polymerization of the diyne units.