Multi-step synthesis, photophysical and physicochemical investigation of novel pyrazoline a heterocyclic D- π -A chromophore as a fluorescent chemosensor for the detection of Fe3+ metal ion

Abstract

The title compound has been 2-(1-(benzo[d]thiazol-2-yl)-5-(3,4-dimethoxyphenyl)-4,5-dihydro-1H-pyrazol-3-yl)phenol (BTDP) synthesized by reaction of (E)-3-(3,4-dimethoxyphenyl)-1-(2-hydroxyphenyl)prop-2-en-1-one (DMPO) with 2-Hydrazinylbenzo[d]thiazole. DMPO was synthesized by the reaction of 1-(2 hydroxyphenyl)ethan-1-one with 3,4-dimethoxybenzaldehyde. Structure of compound has been confirmed by the elemental analysis and spectroscopic techniques (FT-IR, 1H NMR and 13C NMR). Photophysical properties of the BTDP such as absorption, emission, stokes shift, transition dipole moments and fluorescence quantum yield have been studied in various solvents of different polarity and chromophore demonstrated positive solvatochromism. The chromophore undergoes micellization in two different micelles and its can be used as probe to determine the critical micelle concentration of surfactant such as CTAB and SDS. In addition, Pyrazoline derivative used as fluorescent chemosensor for metal ion selectively based on fluorometric detraction and pyrazoline displayed as on-off fluorescence chemosensor for the determination of Fe3+ ion in solution. Hildebrand, Stern-Volmer and job’s plot method has described quenching behavior of chromophore with Fe3+ ion.