title: Selective sensing of Hg2+ by a proton-ionizable calix[4]arene fluoroionophore.
abstract: A fluorogenic derivative of a calix[4]arene with two proton-ionizable N-(phenyl)sulfonyl carboxamide-containing side arms in the 1,3-positions on the lower rim is employed for the selective sensing of Hg(2+) at low concentration levels in water/MeCN (1:1, v/v) solutions containing Pb(2+) and Cd(2+). All three metal ions quench the fluorescence of the ligand in pure MeCN. However, in water/MeCN mixed solvent, the recognition of such cations occurs differently as only Hg(2+) complexation quenches the fluorescence of the calixarene. Experiments carried out in the presence of an acid and a bulky non-complexing cation shows that the quenching of the calixarene fluorescence upon Hg(2+) addition is likely due to proton displacement from the proton-ionizable side arms of the ligand. The system may be employed as a simple tool for the selective and efficient mercury sensing in mixed water/organic solvent.
authors.affiliation: Dipartimento di Scienze Chimiche, Università degli Studi di Catania, Catania, Italy.
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Arena
authors.forename: Francesco
authors.initials: F
authors.lastname: Attanasio
authors.forename: Dongmei
authors.initials: D
authors.lastname: Zhang
authors.forename: Yanfei
authors.initials: Y
authors.lastname: Yang
authors.forename: Richard A
authors.initials: RA
authors.lastname: Bartsch
authors.forename: Carmelo
authors.initials: C
authors.lastname: Sgarlata
mesh_terms: D015374:Biosensing Techniques / Q000295:instrumentation / Q000379:methods*; D047250:Calixarenes / Q000737:chemistry*; D005456:Fluorescent Dyes / Q000737:chemistry*; D008628:Mercury / Q000032:analysis*; D011522:Protons; D014874:Water Pollutants, Chemical / Q000032:analysis*
chemical_list: D005456:Fluorescent Dyes; D011522:Protons; D014874:Water Pollutants, Chemical; D047250:Calixarenes; D008628:Mercury