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    Öğe
    A new water-soluble naphthalene diimide as a highly selective fluorescent chemosensor for Cu(II) ion: Synthesis, DFT calculations, photophysical and electrochemical properties
    (Elsevier Science Sa, 2024) Abourajab, Arwa; Karsili, Pelin; Rashid, Rebwar; Dinleyici, Meltem; Pasaogullari, Nur; Altinisik, Sinem; Koyuncu, Sermet
    The highly selective, sensitive, and water-soluble fluorescent sensors are desideratum for optoelectronic, environmental, biological, and biomedical applications. An innovative fluorescence chemosensor, naphthalene diimide (3) with metal binding sites, was designed, synthesized and characterized. The chemosensor's optical, electrochemical, spectroelectrochemical, and morphological properties were investigated, and then the density functional theory (DFT) simulations were conducted. The selectivity of 3 for the metals Cu(II), Ag(I), Hg(II), Mg (II), Fe(III), Ca(II), Co(II), Zn(II), Pb(II) and Cd(II) were investigated through UV-visible and fluorescence spectroscopy techniques. 3 was highly selective and sensitive toward Cu(II) metal ions. The chemosensor can detect Cu(II) in water with a detection limit of 1.11 mu M, which is lower than the WHO standard and has good repeatability. Further investigations through the IR, DPV, AFM, UV-visible and fluorescence spectroscopies, SEM, EDX and TEM techniques confirmed the binding capabilities of the 3 with Cu(II).
  • [ X ]
    Öğe
    Synthesis, photophysical, electrochemical and morphological properties of a novel cross-linked chitosan-based fluorescent polymer: A fluorescence sensor for single-stranded DNA
    (Pergamon-Elsevier Science Ltd, 2023) Yucekan, Ilke; Dinleyici, Meltem; Temurlu, Selin; Rashid, Rebwar; Bodapati, Jagadeesh B.; Al-Khateeb, Basma; Abourajab, Arwa
    This report details the first-time use of the perylene-3,4,9,10-tetracarboxylic dianhydride as a cross-linker to synthesize a novel fluorescent, chitosan-based cross-linked polymer (3). The polymer has single-stranded DNA (ssDNA) binding properties that can be used in sensor production for detecting salmon sperm DNA. Chitosan polymer's solubility is poor and restricted to only acidic media. In contrast, this new fluorescent chitosan polymer was soluble in various organic solvents and aqueous solutions at different pHs. Its absorption, photo physical, electrochemical and morphological properties were investigated in detail. Gel permeation chromatography determined the weight average molecular mass (Mw) of polymer 3 as 21300 g/mol. Seventeen hydrophobic perylene units were determined in the cross-linked network. The energy levels of the highest occupied molecular orbitals and lowest unoccupied molecular orbitals of the new polymer 3 were calculated as-6.24 and-3.96 eV, corresponding to the band gap of 2.28 eV. Fluorescence and ultraviolet spectroscopy techniques were used to study the interaction between ssDNA and polymer 3. The interaction pointed to the intercalative mode, and the cross-linked chitosan can be used as a stable and sensitive platform for ssDNA detection. These results show a new class of organic biopolymers that could yield promising potential in many biomedical applications.