title: Reversible colorimetric probes for mercury sensing.
abstract: The selectivity and sensitivity of two colorimetric sensors based on the ruthenium complexes N719 [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)] are described. 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) ions--using UV-vis spectroscopy--in homogeneous aqueous solutions is estimated to be approximately 20 ppb for N719 and approximately 150 ppb for N749. Moreover, the sensor molecules can be adsorbed onto high-surface-area mesoporous metal oxide films, allowing reversible heterogeneous sensing of mercury ions in aqueous solution. The results shown herein have important implications in the development of new reversible colorimetric sensors for the fast, easy, and selective detection and monitoring of mercuric ions in aqueous solutions.
authors.affiliation: Institut de Ciencia Molecular (IcMol), Universitat de Valencia, 46100-Burjassot, Valencia, Spain.
authors.forename: Eugenio
authors.initials: E
authors.lastname: Coronado
authors.forename: José R
authors.initials: JR
authors.lastname: Galán-Mascarós
authors.forename: Carlos
authors.initials: C
authors.lastname: Martí-Gastaldo
authors.forename: Emilio
authors.initials: E
authors.lastname: Palomares
authors.forename: James R
authors.initials: JR
authors.lastname: Durrant
authors.forename: Ramón
authors.initials: R
authors.lastname: Vilar
authors.forename: M
authors.initials: M
authors.lastname: Gratzel
authors.forename: Md K
authors.initials: MK
authors.lastname: Nazeeruddin
mesh_terms: D015374:Biosensing Techniques / Q000379:methods*; D002104:Cadmium / Q000737:chemistry; D003124:Colorimetry / Q000379:methods; D004396:Coloring Agents / Q000737:chemistry; D007477:Ions; D007501:Iron / Q000737:chemistry; D017879:Isothiocyanates / Q000737:chemistry*; D007854:Lead / Q000737:chemistry; D008628:Mercury / Q000737:chemistry*; D015394:Molecular Structure; D009942:Organometallic Compounds / Q000737:chemistry*; D017975:Ruthenium Compounds / Q000737:chemistry*; D012680:Sensitivity and Specificity; D013056:Spectrophotometry, Ultraviolet; D013861:Thiocyanates / Q000737:chemistry*; D014025:Titanium / Q000737:chemistry; D015032:Zinc / Q000737:chemistry
chemical_list: C506094:(2,2':6',2' '-terpyridine-4,4',4' '-tricarboxylate)ruthenium(II) tris(tetrabutylammonium) tris(isothiocyanate); D004396:Coloring Agents; D007477:Ions; D017879:Isothiocyanates; D009942:Organometallic Compounds; D017975:Ruthenium Compounds; D013861:Thiocyanates; C506095:bis(2,2'-bipyridyl-4,4'-dicarboxylate)ruthenium(II) bis(tetrabutylammonium) bis(thiocyanate); D002104:Cadmium; C009495:titanium dioxide; D007854:Lead; D014025:Titanium; D007501:Iron; D008628:Mercury; D015032:Zinc