1,3-Bis[4-(p-aminostyryl)-pyridinyl]-propane dibromide derivatives: Synthesis and spectroscopic investigation

The synthesis and basic spectroscopic properties of eight dichromophoric solvatochromic styrylpyridinium dyes are presented. The dyes were prepared by the condensation of propane 1,3-bis[4-methylpyridinium] dibromide with p-(N,N-dialkylamino)benzaldehydes. The synthesis of suitable substrates is presented as well. The dyes were characterized by 1H NMR spectroscopy and their purity with the use of thin-layer chromatography. The spectroscopic properties of the prepared dyes were determined in two organic solvents. The electronic absorption spectra of tested dyes demonstrate low sensitivity to the nature of the substituents introduced into the side aromatic rings. In contrast to this, the fluorescence band positions are affected by the structure of an electron donor and solvent polarity.