Design principles of fluorescent molecular sensors for cation recognition

The main classes of fluorescent molecular sensors for cation recognition are presented: they differ by the nature of the cation-controlled photoinduced processes: photoinduced electron transfer, photoinduced charge transfer, excimer formation or disappearance. In each class, distinction is made according to the structure of the complexing moiety: chelators, podands, coronands (crown ethers), cryptands, calixarenes. The most representative examples are presented in each subclass with special attention given to selectivity.