N-15 NMR study of (E)- and (Z)-2-(2-(2-hydroxy-4-nitrophenyl)hydrazono)-1-phenylbutane-1,3-diones. A suitable method for analysis of hydrazone isomers

作者：Lycka Antonin^*

来源：Dyes and Pigments, 2018, 150: 181-184.

DOI：10.1016/j.dyepig.2017.10.023

• Azo dyes
• N-15 NMR
• Azo-hydrazo tautomerism
• E/Z isomerism

The one- and two-dimensional N-15 NMR spectra of (E)- and (Z)-2-(2-(2-hydroxy-4-nitrophenyl)hydrazono)-1-phenylbutane-1,3-diones (1) were measured and analysed and N-15 chemical shifts and (1)J (N-15, H-1) coupling constants were used for characterization of these two compounds from the viewpoint of azo-hydrazo tautomerism. Both compounds exist completely in appropriate hydrazo forms in dimethyl sulfoxide.
Advantages of N-15 NMR spectroscopy application in determination of acidic proton positions and azo-hydrazo content determination are discussed. We would like to propose the application of 15N NMR data measured at the natural abundance level of N-15 as the "first glance" and strongest evidence method for the existence of hydrazo form in azo dyes and for differentiation of E- and Z-isomers around C = N-beta double bond.

• 出版日期2018-3