Polymer-supported calix[4]arenes for sensing and conversion of NO2/N2O4

The use of simple calix[4]arenes for NO2/N2O4 sensing and conversion is demonstrated, both in solution and in the solid state. Upon reacting with these gases, compounds encapsulate reactive NO+ cations within their cavities with the formation of deeply colored (λmax∼570 nm) charge-transfer complexes . Further functionalization of the calix[4]arene platform is reported for attachment to solid supports. Polymer-supported calixarene material was prepared, which reversibly traps NO2/N2O4 with the formation of nitrosonium storing polymer . Material was effectively used for nitrosation of amides.