In this study, four arylazobenzylidene dyes (a-d) were synthesized with excellent yields in two steps using Knoevenagel condensation and azo-coupling reactions. Absorption spectra of these dyes with different substituents were investigated in organic solvents as a function of solvent polarity. The spectral features of synthesized arylazobenzylidene dyes were described according to azo-hydrazone...

A series of five tetracyclic mono azo dyes based on the diazotization 1-amino-8-hydroxynaphthalene-3,6-disulphonic acid and subsequent coupling with substituted (un)sulphonated naphthalene derivatives have been synthesized. The chemical structures were established using UV–visible, IR, NMR as well mass spectrometry. Based number sulphonic other hydrophilic groups they contain, compounds showed ...

Acid Red 26 and 18 are two early synthetic dyes belonging to the monazo dye class. The molecular structure of this class is characterized by chromophoric azo group (NN) generally attached benzene or naphthalene derivatives containing electron withdrawing and/or donating groups as substituents. As both red have an OH in ortho- position respect group, they undergo azo-hydrazone tautomerism. In wo...

Abstract Seven novel azo dyes with 2-pyridone and dihydropyrimidinone moieties have been synthesized thoroughly characterized. The azo-hydrazone tautomerism has investigated by experimental theoretical approaches. optimizations of geometries performed density functional theory (DFT). vibrational NMR spectra were calculated correlated ones. Furthermore, quantum chemical descriptors MEP maps plot...

A novel lanthanide molecular cluster pair (MCP), displaying single molecule magnet behaviour, was assembled using the novel o-vanilloyl hydrazone ligand, versatile in terms of denticity, tautomerism and the rotatable C-C bond.

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 ...