Some fluorescence properties of dimethylaminochalcone and its novel cyclic analogues.

Abstract 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 .