Two new reversible naphthalimide-based fluorescent chemosensors for Hg(2.).

Naphthalimide-based fluorescent probes 1 and 2 were synthesized, and were designed to form probe-Hg complexes through Hg(2+) ions coordinated to the amide group and imidazole group. They showed high sensitivity and were selective 'naked-eye' chemosensors for Hg(2+) in phosphate buffer. The fluorescence of compounds 1 and 2 could be quenched up to 90% by the addition of Hg(2+) . Reversible probes can detect Hg(2+) ions over a wide pH range (7.0-10.0).