Synthesis, Characterization, and Application of pH-Sensitive Monoazo Heterocyclic Disperse Dyes: A Study of Solvatochromism, DFT Analysis, and Biological Activity
摘要
In the present work, five monoazo heterocyclic disperse dyes PY1–PY5 were synthesized in good yield. A 2-amino-3-hydroxypyridine was used as a coupling component with five distinct heterocyclic diazonium salts. All the dyes are new except the dye PY4. The obtained colorants were characterized by melting point, 1H-NMR, FT-IR, UV–Vis, FAB-LRMS, and FAB-HRMS. The main skeletons of the dyes PY1, PY3, and PY4 were further confirmed by 13C-NMR (BB), 1H–1H COSY, 1H–13C HSQC, and 1H–13C HMBC. The effect of pH variation on the λmax of these colorants was assessed in methanol and DMSO. Their solvatochromism analyses were performed in various organic solvents, e.g., acetic acid, methanol, acetone, acetonitrile, dimethyl sulfoxide, and dimethyl formamide. The geometries of the dyes were optimized at the B3LYP/6-311G (d,p) level, and their electronic excitation properties were determined using time-dependent density functional theory. The computed data were in good agreement with the experimental data. These colorants were applied to polyester fabric as disperse dyes and evaluated for build-up study along with complete observation of their fastness to water, washing, sublimation, rubbing, perspiration, and light. The antimicrobial exploration of these dyes was performed in detail against human pathogenic fungi including Aspergillus fumigatus, Candida glabrata, Candida albicans and Trichophyton rubrum. The dye PY5 was found to have promising inhibition against all the human pathogenic fungi used.
Graphical Abstract