10.6084/m9.figshare.3503852.v1 Ajit Kumar Mahapatra Ajit Kumar Mahapatra Rajkishor Maji Rajkishor Maji Kalipada Maiti Kalipada Maiti Sanchita Mondal Sanchita Mondal Syed Samim Ali Syed Samim Ali Saikat Kumar Manna Saikat Kumar Manna Prithidipa Sahoo Prithidipa Sahoo Carbazole-driven ratiometric fluorescence turn on for dual ion recognition of Zn<sup>2+</sup> and Hg<sup>2+</sup> by thiophene-pyridyl conjugate in HEPES buffer medium: spectroscopy, computational, microscopy and cellular studies Taylor & Francis Group 2016 Ratiometric fluorescent probe zinc and mercury ions single-crystal X-ray diffraction chemoensembles living cells 2016-07-28 08:28:27 Journal contribution https://tandf.figshare.com/articles/journal_contribution/Carbazole-driven_ratiometric_fluorescence_turn_on_for_dual_ion_recognition_of_Zn_sup_2_sup_and_Hg_sup_2_sup_by_thiophene-pyridyl_conjugate_in_HEPES_buffer_medium_spectroscopy_computational_microscopy_and_cellular_studies/3503852 <p>Carbazole-based thiophene-pyridyl conjugate (<b>L</b>) was synthesised and characterised. The complexation between <b>L</b> with Zn<sup>2+</sup> and Hg<sup>2+</sup> was studied in HEPES buffer medium by fluorescence, absorption and visual colour change with the detection limit of ~3.7 and ~4.8 μM, respectively. The <b>L</b> detects Zn<sup>2+</sup> by bringing ratiometric change in the fluorescence signals at 418 and 515 nm, but in the case of Hg<sup>2+</sup>, the signals are observed at 418 and 365 nm, while no new band is observed at 515 nm. The structure of <b>L</b> has been established by single-crystal XRD and that of complexes <b>[ZnL]</b> and <b>[HgL]</b> by density functional theory calculations. TDDFT calculations were performed in order to demonstrate the electronic properties of receptors and their zinc and mercury complexes. The isolated fluorescent complexes <b>[ZnL]</b> and <b>[HgL]</b> were found to be sensitive and selective towards phosphate-bearing ions and sulfide ions, respectively, among the other anions studied. The nanostructural features such as shape and size obtained using atomic force microscopy distinguish <b>L</b> from its complexes formed between <b>L</b> and Zn<sup>2+</sup> from that formed with Hg<sup>2+</sup>. Moreover, the utility of the conjugate <b>L</b> in showing the zinc recognition in live cells has also been demonstrated using RAW cells as monitored by fluorescence imaging.</p>