Novel colorimetric phosphorescent chemodosimeter for Hg2+ based iridium(III) complex with phosphonodithioate auxiliary ligand

A colorimetric phosphorescent iridium(III) complex chemodosimeter (Ir1) for Hg2+ has been prepared and confirmed by NMR, MS, and crystal data, which displays a high selectivity and antidisturbance for Hg2+ among relevant metal ions. The solution color changed from orange to light yellow as soon as 1 equiv of Hg2+ was added. Phosphorescent studies show that the luminescence intensity in 599 nm decreased to ca. 13%, while the luminescence intensity in 465 nm increased to ca. 217%. The ratio of Ir1 responding to Hg2+ was determined to be 1:1 by UV–vis absorption and phosphorescent emission measurements. Further study demonstrates the detection limit on phosphorescent response of the sensor to Hg2+ is down to 10−6 M range. The mechanism study shows that the interaction between the S atom of ancillary ligand and Hg2+ is responsible for the highly selective and sensitive phosphorescent senor for Hg2+.