A novel [1,2,4]triazolo[1,5-a]pteridine framework: Synthesis, photophysical properties and material studies

The synthesis of novel [1,2,4]triazolo[1,5-a]pteridine (TPt) derivatives was carried out starting from [1,2,4]triazolo[1,5-a]pyrimidine-6,7-diamines and 1,2-dicarbonyl compounds. For obtained TPt DFT/TD-DFT calculations were performed with subsequent complex photophysical and electrochemical studies. The substituent in the pyrazine ring of TPt framework proved to have a higher effect on photophysical properties than that in the triazole ring. The fluorescence quantum yields of studied compounds were generally low (3–23%). However, it was shown that some of TPt was sensitive to trace amounts of organic peroxides (about 100 ppm), which will make it possible to create test systems based on them. On the other hand, low-lying HOMO energy levels and the energy gap values of TPt (2.63 eV < E_0-0 < 2.97 eV) as well as the electron mobility in solid-state films measured by the conventional CELIV technique (approximately 10⁻⁴ cm² V⁻¹ s⁻¹) make these materials promising for the further use in organic electronic devices.