Calixarene-Based Fluorescent Molecular Sensors for Toxic Metals

There is an increasing interest in the early detection of toxic metals in the environment. In this context, fluorescence is a very attractive detection method because of its intrinsic sensitivity, its response time and the possibility of imaging via fluorescence microscopy. Of the various complexing units available for the detection of toxic metal ions (chelators, open-chain structures, crown-ethers, cryptands), calixarenes offer distinct advantages in term of selectivity and the easy incorporation of a fluorophore into the structure. In this microreview, after recalling the main classes of fluorescent molecular sensors based on cation-induced changes in excited-state processes (photoinduced electron- or charge-transfer, excimer formation, energy transfer), we present various calixarene-based sensors designed for the detection of caesium, mercury, lead and cadmium. ((C) Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)