title: A chelation enhanced selective fluorescence sensing of Hg2+ by a simple quinoline substituted tripodal amide receptor.
abstract: Two tris(2-aminoethyl)amine (tren) based tripodal amide fluoroionophores, 1 and 2, functionalized with quinoline (chelating fluorophore) and naphthalene (non-chelating fluorophore) respectively, are synthesized in good yields. Fluoroionophore 1 shows a selective UV-Vis spectral shift in the case of Hg(2+) in acetonitrile among different metal ions like Li(+), Na(+), Ca(2+), Mg(2+), Cr(2+), Mn(2+), Fe(2+), Co(2+), Ni(2+), Cu(2+), Zn(2+), Cd(2+), Hg(2+), Pb(2+), and Ag(+). On the other hand, fluoroionophore 2 shows no selectivity towards any of the above metal ions in the UV-Vis study. Furthermore, 1 shows a selective chelation induced fluorescence enhancement in the presence of Hg(2+) whereas 2 shows the enhancement of fluorescence with most of the metal ions via a photoinduced charge transfer mechanism. The naked eye detection of Hg(2+) in an acetonitrile solution of 1 shows a greenish fluorescence upon UV light irradiation. The isolated Hg(2+) complex of 1, 3, shows a similar UV-Vis and fluorescence spectral output as observed from in situ spectroscopic studies of 1 in the presence of Hg(2+). Infra-red (IR) and (1)H- NMR studies also reveal the interaction of Hg(2+) with the quinoline nitrogen atoms as well as with the amide functionality.
authors: Department of Inorganic Chemistry, Indian Association for the Cultivation of Science, Kolkata, 700 032, India.
authors: B Nisar
authors: BN
authors: Ahamed
authors: Pradyut
authors: P
authors: Ghosh
mesh_terms: D000097:Acetonitriles / Q000737:chemistry; D000577:Amides / Q000737:chemistry*; D002614:Chelating Agents / Q000737:chemistry*; D056831:Coordination Complexes / Q000737:chemistry; D005456:Fluorescent Dyes / Q000737:chemistry*; D008628:Mercury / Q000032:analysis*; D009281:Naphthalenes / Q000737:chemistry; D011804:Quinolines / Q000737:chemistry; D013056:Spectrophotometry, Ultraviolet
chemical_list: D000097:Acetonitriles; D000577:Amides; D002614:Chelating Agents; D056831:Coordination Complexes; D005456:Fluorescent Dyes; D009281:Naphthalenes; D011804:Quinolines; C031721:naphthalene; C037219:quinoline; D008628:Mercury; C032159:acetonitrile