Photo, proton and metal ion responsive wide-rim acridane substituted calix[4]arenes

Calix[4]arenes bearing acridinium and acridane substituents at the wide rim and a short glycol chain and two OH-groups at the narrow rim have been prepared. The interaction with alkali metal ions can be identified with the naked eye by the change in solution color arising from deprotonation of the OH-groups. Unlike the acridane calixarenes, the acridinium-substituted calixarene-crown-4 binds sodium ions. Due to the photoheterolysis of the acridane, calixarene sodium ions are picked up from the acetonitrile solution due to the formation of acridinium calixarene.