Colorimetric chemosensors designed to provide high sensitivity for Hg~(2+) in aqueous solutions

摘要

The specific colorimetric detection of Hg~(2+) in the context of interference from coexisting metal ions in aqueous solutions is a challenge. Therefore, a series of easy-to-make Hg~(2+) colorimetric chemosensors S1~S3, bearing thiourea moiety as binding site and nitrophenyl moiety as signal group, were designed and synthesized. Among these sensors, S3 showed excellent colorimetric specific selectivity and high sensitivity for Hg~(2+) in DMSO and DMSO/H2O binary solutions. When Hg~(2+) was added to the solution of S3, a dramatic color change from brown to colorless was observed, while the cations Ca~(2+), Mg~(2+), Cd~(2+), Fe~(3+), Co~(2+), Ni~(2+), Cu~(2+), Zn~(2+), Pb~(2+), Ag~+ and Cr~(3+) did not interfere with the recognition process for Hg~(2+). The detection limits were 5.0 x 10~6 and 1.0 x 10~(-7) M of Hg~(2+) using the visual color changes and UV-vis changes respectively.