title: Synthesis, characterization and Cu(2+) triggered selective fluorescence quenching of Bis-calix[4]arene tetra-triazole macrocycle.
abstract: A novel fluorescent bis-calix[4]arene macrocycle 9 incorporating metal-binding pockets was successfully prepared. The structure of macrocycle 9 and its precursors were characterized via EI-MS, MALDI-TOF-MS, ESI-MS, (1)H NMR, (13)CNMR, 2D NMR, and X-ray crystallography. The macrocycle 9 displayed selective fluorescence quenching after interacting with Cu(2+) in the presence competing metal cations including Mg(2+), Ca(2+), Ba(2+), Ag(+), Zn(2+), Ti(4+),Cd(2+), Hg(2+), Pb(2+), In(3+), La(3+), Cr(3+), Ni(2+), Sb(3+), V(5+), Fe(3+), Co(2+), Sn(2+), Sn(2+), and Tl(+). The Cu(2+) limit of detection was found to be 40 nM much lower than its threshold level (∼ 20 μM) in drinking water permitted by the U.S Environmental Protection Agency (EPA). Furthermore, drinking water samples from Karachi University (Pakistan) spiked with Cu(2+) were analysed with the sensing system and the results showed an excellent agreement with the fluorescence quenching phenomenon of macrocycle 9 examined in deionized water. Importantly, the chemosensor 9 could be used to detect Cu(2+) in living cells.
authors.affiliation: H.E.J. Research Institute of Chemistry, International Center for Chemical and Biological Sciences, University of Karachi, Karachi 75270, Pakistan.
authors.forename: Burhan
authors.initials: B
authors.lastname: Khan
authors.affiliation: H.E.J. Research Institute of Chemistry, International Center for Chemical and Biological Sciences, University of Karachi, Karachi 75270, Pakistan. Electronic address: raza.shah@iccs.edu.
authors.forename: Muhammad Raza
authors.initials: MR
authors.lastname: Shah
authors.affiliation: H.E.J. Research Institute of Chemistry, International Center for Chemical and Biological Sciences, University of Karachi, Karachi 75270, Pakistan.
authors.forename: Dania
authors.initials: D
authors.lastname: Ahmed
authors.affiliation: H.E.J. Research Institute of Chemistry, International Center for Chemical and Biological Sciences, University of Karachi, Karachi 75270, Pakistan.
authors.forename: Muhammad
authors.initials: M
authors.lastname: Rabnawaz
authors.affiliation: Department of Chemistry, University of Karachi, Karachi75270, Pakistan.
authors.forename: Itrat
authors.initials: I
authors.lastname: Anis
authors.affiliation: Dr.Panjwani Center For Molecular Medicine And Drug Research, International Center for Chemical and Biological Sciences, University of Karachi, Karachi 75270, Pakistan.
authors.forename: Saifullah
authors.initials: S
authors.lastname: Afridi
authors.affiliation: Dr.Panjwani Center For Molecular Medicine And Drug Research, International Center for Chemical and Biological Sciences, University of Karachi, Karachi 75270, Pakistan.
authors.forename: Talat
authors.initials: T
authors.lastname: Makhmoor
authors.affiliation: Department of Physics, University of Sargodha, Sargodha, Pakistan.
authors.forename: Muhammad Nawaz
authors.initials: MN
authors.lastname: Tahir
keywords: Atomic force microscopy; Bis-calix[4]arene; Fluorescence; Macrocycle; Supramolecular