RESUMO
Three novel iminocoumarin derivatives with high quantum yield are synthesized from 3-benzimidazole substituted coumarin and different aromatic aldehydes. The photophysical behavior of the synthesized compounds was studied using UV-visible and fluorescence spectroscopy in polar and non-polar solvents. The compounds show absorption maxima at around 450 nm and emission maxima at around 500 nm. The quantum yields of compounds in dichloromethane and chloroform are more than 0.90. The absorption, emission and quantum yield of compounds are dependent on the polarity of solvents. Along with an intense absorption, these compounds show shoulder absorption peak in the studied solvents. The solvent polarity plots revealed the charge transfer process in the synthesized molecules from donor to acceptor. Density Functional Theory and Time Dependent Density Functional Theory computations have been used to have more understanding of the structural, molecular, electronic and photophysical parameters of the dyes. The dyes were characterized by FT-IR, (1)H NMR, (13)C NMR and mass spectral analysis.
RESUMO
Novel fluorescent 2-[4-(4,5-diphenyl-1H-imidazol-2-yl) phenyl]-2H-naphtho [1,2-d] [1,2,3] triazolyl derivatives were synthesized from 4-(4,5-diphenyl-1H-imidazol-2-yl) aniline and substituted naphthalen-2-amine. The photophysical properties of the three new fluorophores were evaluated in acetonitrile, methanol, dimethylsulfoxide and N,N-dimethylformamide solvents and were compared with the reported analogs. The compounds show the absorption in the ultraviolet region and the emission in the blue region. The thermal stabilities of these compounds was evaluated by thermogravimetric analysis. The solvatochromism data are used for ground and excited state dipole moment determination of the synthesized triazoles using Bakhshiev and Bilot-Kawski correlations. The experimental absorption and emission were compared with the theoretical data obtained by DFT and TD-DFT computations and they are well in agreement with each other.
