Fluorescent calixarene hosts

Calixarenes, cyclic oligomers of p-tert-butyl phenol and formaldehyde, are among the most investigated macrocyclic scaffolds for molecular recognition. Owing to their well-defined calix cavity, derivatization of upper and lower rims, and conformational preferences, calixarenes and their derivatives are versatile hosts for numerous guest species, including cations, anions, and other analytes. Among the various calixarene derivatives, fluorescent hosts containing different fluorophores are especially important for the sensitive and selective detection of guest molecules. The selectivity pattern of these receptors toward guest molecules depends on the type of ligating sites and on the conformation of the calixarene. This chapter summarizes the recent developments of fluorogenic calix[4]arene hosts and their various applications.