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|a Fluorescent chemosensors for the detection and measurement of metal ions, especially for cations environmental interest such as Fe3+, Co2+, Mn2+, Cu2+, and Zn2+ are actively investigated because it shows simplicity, high sensitivity and fast response. New benzenyl derivative bearing pyridine group has been synthesized and studied as fluorescent chemosensor for Zn2+ ion. Chemosensor N-{2-[(4-Dimethylamino-benzylidene)-amino]-ethyl}-N'-pyridin-2-ylmethylene-ethane-1,2-diamine was synthesized by condensation of p-dimethylaminobenzaldehyde, diethylenetriamine and o-pyridinecarbaldehyde and characterized by FT-IR, H-1-NMR and elemental analysis (CHN). FT-IR showed the appearance of peak azomethine (C=NH) at 1639.46 cm(-1), pyridine (C-N) at 1591 cm(-1) and disappearance of NH2 peak at 3278.78 cm(-1) after the condensation reaction in between aldehyde and amine. H-1-NMR signal at 8.19 ppm, 3.12 ppm and 8.08 ppm was assigned to C=NH, N(CH3)(2) and C-N respectively, confirmed the formation of N-{2-[(4-Dimethylamino-benzylidene)-amino]-ethyl}-N'-pyridin-2-ylmethylene-ethane-1,2-diamine. The elemental analysis was found closed to the theoretical value and the percent composition of A is 91.82%. Sensor A exhibits high selectivity and sensitivity towards Zn2+. Other metal ions such Cu2+, Fe3+, Co2+ and Ni2+ had no such significant effect on the fluorescence. The detection limit of N-{2-[(4-Dimethylaminobenzylidene)-amino]-ethyl}-N'-pyridin-2-ylmethylene-ethane-1,2-diamine for Zn2+ was 3.5 x 10(-5) M. M. This sensor exhibits a very good fluorescence sensing ability to Zn2+ over a wide range of pH. Therefore it is capable of being a practical system for the monitoring of Zn2+ concentrations in real water sample.
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