Influence of trimethoxy-substituted positions on fluorescence of heteroaryl chalcone derivatives

Abstract

AbstractThree series of heteroaryl chalcones, (E)-1-(2-pyridyl)-3-(X)prop-2-en-1-one (Ia-Ic), (E)-1-(2-thienyl)-3-(X)prop-2-en-1-one (IIa-IIc), and (E)-1-(2-furyl)-3-(X)prop-2-en-1-one (IIIa-IIIc), where X = 2,4,5-trimethoxyphenyl (for series a), X = 2,4,6-trimethoxyphenyl (for series b), and X = 3,4,5-trimethoxyphenyl (for series c) were synthesised using basic catalysed aldol condensation and characterised using 1H NMR and FT-IR spectroscopies. Compound IIa was also characterised by single crystal X-ray analysis. The absorption and fluorescence emission spectra of these compounds revealed that the absorption and fluorescence depended on the heterocycle rings and trimethoxysubstituted phenyl rings linked to the enone system. The position of methoxy groups substantially affected the fluorescent properties. Compounds Ia-IIIa containing the 2,4,5-trimethoxyphenyl moiety exhibited the red-shift phenomenon and strong emission fluorescence.