Metal-induced conversion of a ‘closed’ receptor to an ‘open’ receptor on a p-tert-butylcalix[4]arene diamide derivative; fluorescence detection of a molecular recognition process

Molecular receptors, which change from a ‘closed’ form with intramolecular hydrogen bonds to an ‘open’ form with intermolecular hydrogen bonds with a pteridine guest upon Na+-binding designed on a calix[4]arene platform are described; the conversion process is monitored easily by a fluorescence change in a flavin guest.