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  • Essay / Enable/disable proton transfer based fluorescence...

    Detection capability of fluorescence based chemosensor: Indole7carboxaldehyde (I7C) for environmentally hazardous metal ions (Xn+ = Zn2+ , Pb2+, Co2+, Ni2+, Cr3+) was studied. Based on the excited state proton transfer (ESPT) phenomenon, the sensing ability of I7C is verified experimentally (UVVis, FTIR, NMR) and theoretically (DFT, TDDFT) in media aqueous. , electrophilicity () and electronic chemical potentials () confirm the selective reactivity of I7C (Nc and Nt conforms) in the presence of metal ions by formation of metal ion (1:1): I7C complex ( MX, MX*). MX, MX* display excellent detection capacity for Zn2+ and Pb2+ ions. The “TurnOn” response for Zn2+ is observed thanks to the appearance of a new enhanced fluorescence at ~ 430 nm. By a strong blue emission, I7C establishes its strong candidacy. as “blue transmitter”. A “TurnOff” response is observed for Pb2+ thanks to the quenching of the existing fluorescence peak. Keyword: chemosensor, fluorescence, chemical reactivity, Zn2+ ion, PTSD.*Corresponding author, Fax: +91 120 2400986E- mail: [email protected]. Introduction: The detection of metal ions dangerous for the environment is today one of the major challenges of sustainable development [1] of society, because metal ions play an important role in a wide range of biological, chemical processes and environmental. With the increase in terrorist activities, it has now become an absolute necessity to design accurate, reliable and real-time metal sensors for the detection of explosives, landmines and chemical warfare using metal ions as a component main [2]. In particular, sensors that induce color changes seem particularly attractive due to their easy detection...... middle of paper ...... , (1) where εLUMO and εHOMO are the LUMO and HOMO energies, respectively .  represents the tendency of an electron to escape from an equilibrium. A larger value of  represents greater responsiveness of the system because:, (2) The overall electrophilicity index () measures the stabilization energy of a specific complex.  can be calculated as [33]. (3) To correlate the components of the formed complexation, the binding energy for the complexation can be calculated as follows :(4)