Synthesis and spectral characterization of new homologous 1,3,5-triaryl-2-pyrazolines: Influence of alkyloxy chain length on fluorescence
摘要:
Twelve new homologous 1,3,5-triaryl-2-pyrazolines (1c-12c) have been synthesized and characterized on the basis of their spectral (IR, H-1 and C-13 NMR and MS) data and microanalysis. The influence of alkyloxy chain length on absorption and fluorescence properties of lc-12c was studied by UV-Vis and emission spectroscopy. For all the compounds, fluorescence was observed in the blue region of the visible spectrum. Furthermore, a strong influence of alkyloxy chain length was found on the emission intensity of 1,3,5-triaryl-2-pyrazolines, without causing any major blue- or red-shift in the emission wavelength (lambda(em)(max)). The absorption and emission maxima (lambda(abs)(max) and lambda(em)(max))for all the compounds were observed in the range of 408-416 nm and 471-476 nm, respectively. The effect of chloro-substituent present on the conjugated backbone of 1,3,5-triaryl-2-pyrazoline moiety is also discussed. (C) 2014 Elsevier &V. All rights reserved.