The NMR spectra of azo dyes, 5-arylazobarbituric (5a-g), 5-arylazo-1,3-dimethylbarbituric(6a-g) and 5-arylazothiobarbituric acids (7a-g) were studied in DMSO-d6 in differentconcentrations. An intramolecular hydrogen bond was observed and indicating that thehydrazone forms is mostly predominant. The peak of the hydrazone proton was severelybroadened and its chemical shift appeared at down field ...

Crystallizing the cobalt(II) salt of the azo dye Orange G from water was found to give the solvent-separated ion-pair species hexa-aqua-cobalt(II) 7-oxo-8-(2-phenyl-hydrazin-1-ylidene)-7,8-dihydro-naphthalene-1,3-disulfonate tetra-hydrate, [Co(H(2)O)(6)](C(16)H(10)N(2)O(7)S(2))·4H(2)O. The asymmetric unit of the cobalt(II) salt contains three independent octa-hedral [Co(OH(2))(6)](2+) cations, ...

In the present study, nine bis-azo dyes based on 5-arylidene-2,4-thiazolidinone were obtained in two steps, using Knoevenagel condensation and azo coupling reactions. The structure of the dyes was confirmed on the basis of spectral data. Analysis of spectroscopic data shows that there is equilibrium between the azo and hydrazone tautomers for all dyes in solutions. Investigation of antioxidant ...

Abstract A series of novel substituted-azo dyes 8-(aryldiazenyl)quinolin-5-ol (5a-i) were synthesized by the coupling reaction 5-hydroxyquinoline with diazotized aniline derivatives in presence NaNO2 HCl/H2O mixture. The study spectroscopic and solvatochromic properties performed FT-IR, 1H 13C-NMR UV-Visible spectroscopies. tautomerism these was studied using deuteration technique measurements....

New 1,2,4-triazole colorants were obtained, in high yields, by coupling 3-ethylthio-5-cyanomethyl-4-phenyl-1,2,4-triazole (1) with diazotized aniline derivatives 2, 4 and 6. The azo dyes prepared in this work may exist in three tautomeric forms. We found that the tautomerism is influenced mainly by the nature of substituent at the para position of the aniline coupling component. This tautomeris...

In the title compound, C(13)H(11)N(3)O(4), the dioxane ring adopts an envelope conformation with the C atom bonded to the dimethyl group in the flap position [deviation = 0.613 (1) Å]. The nitrile group and the attached benzene ring are roughly coplanar [maximum deviation = 0.087 (1) Å]. An intra-molecular N-H⋯O hydrogen bond involving the hydrazinyl group generates an S(6) ring. The N-N and C-...