Triazole-Based Functionalized Olygo(Arylene Ethynylene)s—Synthesis and Properties

Oligo(arylene ethynylene)s (OAEs) containing 4,5-(diethynylaryl)-1,2,3-triazoles with 3(OMe) and NR₂ substituents at the 5-position and bis-1,4-dialkoxybenzene moieties as spacers at the 4-position were obtained using the <i>retro</i>-Favorskii reaction as a key step. The most intense fluorescence was observed for OAEs with a trimethoxyphenyl substituent in THF solutions, with a quantum yield of up to 88%. Increasing the solvent polarity had minimal effect on the emission of trimethoxyphenyl substituted derivatives. A notable red shift in emission spectra was observed with increasing solvent polarity for OAEs <b>10a</b>,<b>g</b> containing para-dimethylaminophenyl group. Their emission spectra in aqueous organic solutions revealed that an increase in water fraction in THF/water mixtures led to a bathochromic shift in emission spectra maxima accompanied by a hypochromic effect. An increase in intensity was observed in aqueous acetonitrile and DMSO. The maximum intensity was observed in DMSO solutions containing 30% water, which is attributed to aggregate-induced emission enhancement. Dynamic light scattering data also confirmed the formation of nanoscale aggregates in aqueous organic mixtures.