Analysis of the selective sensing ability of a bifunctional crown ether-perylene fluoroionophore

The design of chemosensors able to selectively recognize and sense specific analytes has attracted considerable interests due to their importance in biological and environmental scenarios and stimulated the development of chromoionophores sensors for the detection of metal cations. Chromoionophores and fluoroionophores are chemical species based on the principle that a selective complexation of a cation by means of a crown ether compound can be rendered detectable by a colour effect initiated within the same molecule. This requires a chromophore attached close to the ligand moiety and an electronic coupling between the two parts of the molecule. As far as fluorogenic units are concerned, considerable attention has been recently devoted in literature to perylene based dyes, due to the effective combination of properties ranging from electro-optical and redox characteristics to thermal and migration stability which allow applications as fluorescence standards, thin film transistors, liquid crystals, light emitting diodes, and devices for photovoltaics. Intrigued by these preliminary considerations, we have carried out detailed studies aimed at exploring the cation fluorescence sensing properties of crown ethers covalently linked to a perylene chromophore (Pery-Crown5). For this purpose Pery-Crown5 was prepared and the sensing properties for various metal cations were investigated by means of absorption and emission spectroscopies.