| Abstract
| - The selectivity and sensitivity of two colorimetric sensors based on the ruthenium complexesN719 [bis(2,2‘-bipyridyl-4,4‘-dicarboxylate)ruthenium(II) bis(tetrabutylammonium) bis(thiocyanate)] and N749[(2,2‘:6‘,2‘ ‘-terpyridine-4,4‘,4‘ ‘-tricarboxylate)ruthenium(II) tris(tetrabutylammonium) tris(isothiocyanate)] aredescribed. It was found that mercury ions coordinate reversibly to the sulfur atom of the dyes' NCS groups.This interaction induces a color change in the dyes at submicromolar concentrations of mercury. Furthermore,the color change of these dyes is selective for mercury(II) when compared with other ions such as lead(II),cadmium(II), zinc(II), or iron(II). The detection limit for mercury(II) ionsusing UV−vis spectroscopyinhomogeneous aqueous solutions is estimated to be ∼20 ppb for N719 and ∼150 ppb for N749. Moreover,the sensor molecules can be adsorbed onto high-surface-area mesoporous metal oxide films, allowingreversible heterogeneous sensing of mercury ions in aqueous solution. The results shown herein haveimportant implications in the development of new reversible colorimetric sensors for the fast, easy, andselective detection and monitoring of mercuric ions in aqueous solutions.
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