N-2-Aryl-1,2,3-Triazoles: A novel class of blue–green emitting fluorophores-synthesis, photophysical properties study and dft computations

Three novel 2-{2-[4-( N,N -diethylamino)–2–hydroxyphenyl]–1 H –benzo[ d ]imidazol–6–yl}–2 H –naphtho [1,2 -d ] [1,2,3] fluorescent triazole derivatives were synthesized from 2-(5-amino-1H-benzimidazol-2-yl)-5-( N,N -diethylamino)phenol and amino substituted naphthylsulphonic acids. The absorption, emission, quantum yields and dipole moments of these compounds were evaluated in methanol, acetonitrile, N,N -dimethylformamide and dimethylsulfoxide. The compounds 8a and 8c absorb in the near visible region, while compound 8b shows two absorption peaks, short wavelength peak is in the near visible region and long wavelength absorption in the visible region. Compounds are fluorescent in solution and emit in blue and green region. The photophysical properties of the 8a – 8c were compared with structural analogs reported till date. The experimental absorption and emission properties were compared with the theoretical data obtained by DFT and TD-DFT computations with TD–B3LYP and CAM–B3LYP functional with 6–31G (d) and 6–311G (d) basis sets. Theoretical results obtained by TD-B3LYP functional are well in line with the experimental results. The compounds are thermally stable up to 300 °C. New compounds were characterized by spectral techniques.