Highly selective fluorescence sensor based on azido pyrazole-chalcone conjugates for rapid detection of iodide ion

Abstract

Present study disclosed the synthesis of iodide (I−) ion fluorescence sensor based on azido pyrazole-chalcone derivatives for selective detection of iodide ion in pure form. The azido pyrazole-chalcone derivatives were obtained from condensation reaction of 5-azido-3-methyl-1-phenyl-1H-pyrazole-4-carbaldehyde and various acetophenones under alkaline methanol. The developed fluorescence sensor compound 4A shown selective fluorospectrometric recognition of I− via fluorescence TURN-OFF mechanism, while the various competitive anions (N3−, BrO3−, OH−, SO3−, CN−, Br−, NO3−, CO3−2, HPO4−, CH3COO−, SCN− and NO2−) did not led to any noticeable interference. The iodide ion showed linear correlation with fluorescence intensity of developed fluorescence sensor over the concentration range 7.5 to 37.5 mM. The correlation coefficient value of the method is 0.9906 with 2.5 mM detection limit of iodide ion. Further, azido pyrazole-chalcone 4A as sensor showed high Stokes shift and selectivity towards iodide anion. The decay study of 4A showed decreased lifetime in the presence of iodide ion which indicates dynamic quenching mechanism. The synthesized compound 4A was also capable to detect iodide ion in catalyst like KI and TBAI. The outcomes of the method showed that synthesized fluorescence sensor (4A) was selective and sensitive detector of iodide ion in aqueous solution.