ٍٍSynthesis, Spectral Characterization and Fluorescent Assessment of 1,3,5-Triazoline Derivatives: Experimental and Theoretical Studies

Abstract Two new pyrazoline derivatives, namely 5-(4- bromophenyl)-3-(5-chlorothiophen-2-yl)-1-phenyl-4,5- dihydro-1H-pyrazole (3) and 5-(4-bromophenyl)-3-(2,5- dichlorothiophen-3-yl)-1-phenyl-4,5-dihydro-1H-pyrazole (4) have been synthesized and characterized based on their spectral (IR, 1 H and 13C NMR and MS) data and microanalysis. The fluorescence properties of 3 and 4 were studied by UV?Vis and emission spectroscopy. For compound 3, a fluorescence emission was observed in the blue region of the visible spectrum. The effect of different solvents on fluorescence was also investigated. Density Functional Theory calculations have also been performed to gain insight into geometric, electronic and spectroscopic properties of the pyrazoline derivatives. Both structures are analysed and compared in order to rationalize the different behaviour in 3 and 4.