Synthesis, characterization and photophysical properties of novel azole derivatives

This paper concerns the design, synthesis, structural characterization, thermal stability evaluation and fluorescence properties of novel triazolothiadiazole derivatives. The target compounds 6a-e were synthesized by condensing 4-amino-3-(4-methoxybenzyl)-1H-1,2,4-triazole-5 (4H)-thione (5) with biphenyl, naphthyl, p-terphenyl, pyrenyl and ferrocenyl carboxylic acid in the presence of phosphorous oxychloride. The structures of newly synthesized compounds were characterized by IR, (1)H NMR and (13)C NMR analysis. The photophysical properties of synthesized compounds were measured in a variety of organic solvents of variable polarities. Spectral properties of the compounds were highly dependent on the nature of the substituent and coupling components attached to the triazolothiadiazole skeleton as well as slightly affected by the solvent polarities. Correlation of the absorption spectra and fluorescence emission response of 6a-e with the substituent revealed that the fluorescent properties can easily be tuned by varying conjugation length of side coupled groups. The newly synthesized derivatives represent a new type of fluorescent materials with efficient visible absorption and surpassing brightness which could be a promising candidate for bioimaging, photonic applications, organic light emitting diodes and dye sensitized solar cells.