Some fluorescence properties of dimethylaminochalcone and its novel cyclic analogues

This paper demonstrates the basic character (polarity, solubility, colour, absorption and fluorescence quantum yield) of synthetic dimethylaminochalcone (1) and its cyclic analogues measured in toluene, chloroform, dimethylsulfoxide and ethanol, which have been studied by absorption and fluorescence spectroscopy. The biologically active dye 4′-dimethylaminochalcone (1b) and its less flexible analogues 4-dimethylaminoindanone (2b), -tetralone (3b), and -benzosuberone (4b) are lipophilic molecules that displayed the best solubility in toluene and chloroform. The highest fluorescence and quantum yields of compounds 1 and 2 have been obtained in DMSO and chloroform. Quenching effect of fluorescence compounds (1–4) has been studied in the mixture of the most polar organic solvents DMSO and water. In the presence of water, fluorescence of compound 1 has been quenched the best from all studied chalcones and emission maxima of molecules 1–4 have been shifted to the longer wavelengths. Quenching effect of fluorescence by water was in order 1 > 2 > 3 > 4.