Microwave-Assisted Synthesis, Physicochemical, and Optical Properties of Extended Pi (л) Bond Pyrazoline Derivative

Abstract

The title compound 2-(3-(2,5-dimethylthiophen-3-yl)-5-(2,4,5-trimethoxyphenyl)-4,5-dihydro-1H-pyrazol-1-yl)benzo[d]thiazole (DTPH) was synthesized by the reaction of (E)-1-(2,5-dimethylthiophen-3-yl)-3-(2,4,5-trimethoxyphenyl)prop-2-en-1-one (DTPO) with 2-hydrazinyl benzothiazole under microwave irradiation. Chalcone was synthesized by the reaction of 1-(2,5-dimethylthiophen-3-yl)ethan-1-one with 2,4,5-trimethoxybenzaldehyde under same conditions. The structure of the DTPH was confirmed by the spectroscopic techniques (IR, 1H-NMR, 13 C-NMR, EI-MS) and elemental analysis. The physicochemical behavior of newly synthesized DTPH was determined in different solvents. As a result of the measurements, a large red shift in the fluorescence of the DTPH studied was observed, when the polarity of the solvents increases (n-Hexane to DMSO). Optical properties of DTPH such as dipole moment, oscillator strength, stokes shift, and fluorescence quantum yields were determined in different polarities of the solvents. The effect of cationic and anionic surfactant such as CTAB and SDS on DTPH dye was also studied to determine the critical micelle concentration of CTAB and SDS surfactants.