Phenylazoindole dyes 2: The molecular structure characterizations of new phenylazo indoles derived from 1,2-dimethylindole

Photophysical and theoretical studies on newly synthesized N,N-diphenylamine based azo dye

“…As a result, a migration of electrons occurs from the diphenylamino functionality to the azonium ion and the absorption band is seen at a longer wavelength. This observation is in agreement with previous studies [41,42]. In addition, the appearance of two absorption maxima in chloroform is attributed to a mixture of azo-hydrazone tautomeric forms of the dye in this solvent.…”

“…This result shows that a ground-state equilibrium between neutral (DPA) and monoprotonated (DPA þ H þ ) species. DPAþH þ can be attributed as azonium tautomeric form [41,42]. In this form, the positive charge on b-nitrogen is completely delocalized, leading to the experimentally observed bathochromic shift of about 117 nm in comparison with neutral form.…”

Phenylazoindole dyes 3: Determination of azo-hydrazone tautomers of new phenylazoindole dyes in solution and solid state

“…Among the different methods, UV-vis and NMR spectroscopy are still the best methods for qualitative studies of tautomeric behavior in solutions. Also, the useful system for determination of the azo-hydrazone tautomerism is to use model compounds [16][17][18][19][20][21][22]36].…”

“…In our earlier studies, we have synthesized and determined the tautomeric behaviors of a number of aryl/heteroarylazo indole dyes in solution and solid state [16][17][18][19][20][21][22] Fig. 1.…”

Hetarylazopyrazolone Dyes Based on Benzothiazole and Benzimidazole Ring Systems: Synthesis, Spectroscopic Investigation, and Computational Study

“…Various experimental and theoretical studies on the structure, tautomeric behavior, dyeing properties, and vibrational analysis of azo dyes [10][11][12][13][14][15][16][17][18][19] and their metal complexes [20][21][22] have been done. Due to their chemical significance and spectroscopic properties, hetarylazo dyes were studied extensively by spectroscopic and theoretical methods.…”