Cyclams bearing diametrically disubstituted pyrenes as Cu²⁺- and Hg²⁺-selective fluoroionophores

(Chemical Equation Presented) New cyclam derivatives having diametrically disubstituted pyrene fluorophores were prepared and their fluoroionophoric properties toward transition metal ions were investigated. The compounds exhibited significant selectivity toward Hg²⁺ and Cu²⁺ ions in switching-off type responses in aqueous methanol or acetonitrile solution. Dipyrene-diamide derivative 3, having extra binding sites of the amide function, exhibited more pronounced chemosensing behavior toward Hg ²⁺ and Cu²⁺ ions than its parent, dipyrene derivative 2. Detection limits for the analysis of Hg²⁺ and Cu²⁺ ions of dipyrene-diamide derivative 3 were 1.45 × 10^-6 and 1.30 × 10^-6 M, respectively. The diametrically disubstituted dipyrene-cyclam 2 may be utilized as a new starting platform for the design of other supramolecular fluorescent signaling systems having switching or chemosensing behaviors toward transition metal ions.