The triazine-based azo–azomethine dyes; spectroscopy, solvatochromism and biological properties of 2,2′-((2,2′-(6-methoxy-1,3,5-triazine-2,4-diyl) bis(oxy)bis(2,1-phenylene))bis(azan-1-yl-1-ylidene)bis(methan-1-yl-1-ylidene))bis(4-phenyldiazenyl)phenol

Synthesis, structural characterization, X-ray, solvatochromism and biological properties of 7-hydroxy-2-(2-hydroxy-5-(phenyldiazenyl)benzylidene)amino)-4-phenyl-4H-chromene-3-carbonitrile

“…These chemical shifts propose that azo-azomethine compounds undergo a keto-enol tautomerism that is in agreement with the results obtained from other similar azo Schiff bases [23][24][25][26][27][28][38][39][40]. The 13 C NMR spectra of 3a-e exhibits three signals for the CN-C=C-O, CH=N and C-OH in the ranges of 163.…”

“…The UV-Vis absorption spectra of 3a-e in these solvents indicate one band at 340-363 nm due to π→π* transition of the aromatic ring involving the π electrons of the azomethine groups and a red shift similar to the same spectra of azo-Schiff bases [23][24][25][26][27][28][38][39]. In addition, the electronic absorption spectra of 3a-e in DMF…”

“…7 solvent shows another broad band in the range of 447-453nm that can be assigned to an n→π* electronic transition of azo-aromatic chromophore and intramolecular charge transfer interaction like the other dyes [23][24][25][26][27][28][38][39][40].The intramolecular charge transfer bands can be assigned to the existence of enol-keto equilibrium originating from hydrogen transferred form hydroxyl group to imine or azo nitrogen. The absorption bands at 447-453 nm in DMF show bathochromic shift with polarity change of solvent (Fig.…”

“…It shows that enolimine-keto-amine equilibrium is dependent on the pH (Scheme S1). The results indicated that solvatochromism as well as hydrogen bonding and dipole moment of azo-azomethine dyes depends on the nature of substitutions, solvent environment, temperature and acidity of media [23][24][25][26][27][28][38][39][40]. showed lower antibacterial activity than the others.…”

“…S1). It shows that the positive solvatochromism may be due to the effect of other causes such as dipole moment changes and the hydrogen bonding strength in polar solvents [23][24][25][26][27][28]. The absorption curves of 3a-e in DMF solvent are shown in Fig.…”