A sugar-aza-crown ether (SAC)-based fluorescent sensor 4 was prepared. It contains a pyrene as the fluorophore and its fluoroionophoric properties toward transition metal ions were investigated. Chemosensor 4 exhibits highly selective recognition toward Cu2+ and Hg2+ ions among a series of tested metal ions in methanol solution. The association constants for 4*Cu2+ and 4*Hg2+ in methanol solution were calculated to be 7.4 × 101 M−1 and 4.4 × 103 M−1, respectively. Chemosensor 4 formed complexes with the Cu2+ or Hg2+ ion at a 1:1 ligand-to-metal ratio with a detection limit of 1.3 × 10−4 M Cu2+ and 1.26 × 10−5 M Hg2+, respectively.
