A pyrenyl-appended triazole-based ribose as a fluorescent sensor for Hg2+ ion

For the efficient detection of toxic trace metal ions, two pyrenyl-appended triazole-based d-ribose fluorescent chemosensors 6 and 7 were prepared and their fluoroionophoric properties toward transition metal ions were investigated. Chemosensors 6 and 7 exhibit highly selective recognition toward Hg2+ ion among a series of tested metal ions in CH2Cl2/MeOH solution. The association constants of 6 and 7 are calculated to be 1.73 × 105 M−1 and 4.44 × 105 M−1, respectively. Both 6 and 7 formed complexes with the Hg2+ ion at a 1:1 ligand-to-metal ratio with a detection limit of 10–15 μM Hg2+. Computational analysis demonstrated that the Hg2+ ion occupied the coordination center of 6 with N2 and N3 atoms in two triazole groups, thus separating and distorting the two parallel pyrenes away from each other.