A Selective and Sensitive Phenanthroimidazole‐Based “Reactive” Ratiometric Sensor for Recognition of Hg 2+ Ions in Aqueous Solution

Based on specific reactivity of the vinyloxy group to Hg 2+ ions, a new ratiometric phenanthroimidazole‐based fluorescent sensor, 2‐(2‐(vinyloxy)phenyl)‐1  H ‐phenanthro[9,10‐ d ]imidazole, is prepared. The selectivity of the probe toward Hg 2+ ions is very high, and shows minimal interference from other commonly coexistent metal ions. The reactive stoichiometry of the probe with Hg 2+ ion is 2:1. Its detection limit is evaluated and Hg 2+ ions can be detected down to a lower limit of 2.5×10 −8   M . Moreover, the Hg 2+ ‐promoted selective hydrolysis of a vinyloxy group of the probe is further confirmed by 1 H NMR spectroscopy and mass spectrometry.