Bis- and tris(arylethynyl)pyrimidine oligomers: synthesis and light-emitting properties

In this contribution, we describe the synthesis of bis- and tris(arylethylnyl)pyrimidine oligomers using Sonogashira, Negishi and Suzuki cross-coupling reactions and starting from chloro or iodopyrimidines. When the arms of such banana-shaped and star-shaped molecules are substituted by electron-donating groups, interesting fluorescence properties were observed. The influence of the nature of the electron-donating groups was studied and a comparison with banana-shaped and star-shaped pyrimidine core molecules without ethynyl moities was carried out, showing that the triple bonds generally enable a red shift of the absorption and emission spectra and upgrade fluorescence properties in terms of quantum yield.