15N 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. (March 2018)

• Record Type: Journal Article
• Authors: Lyčka, Antonín
• Is Part Of: Dyes and pigments. Volume 150(2018)
• Page Start: 181
• Page End: 184
• Publication Date: 2018-03
• Subjects: Azo dyes -- 15N NMR -- Azo-hydrazo tautomerism -- E/Z isomerism; Dyes and dyeing -- Periodicals; Pigments -- Periodicals; 667.2
• DOI: 10.1016/j.dyepig.2017.10.023
• Languages: English
• ISSNs: 0143-7208

Abstract

Abstract: The one- and two-dimensional 15 N NMR spectra of ( E )- and ( Z )-2-(2-(2-hydroxy-4-nitrophenyl)hydrazono)-1-phenylbutane-1, 3-diones (1) were measured and analysed and 15 N chemical shifts and 1 J ( 15 N, 1 H) 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 15 N NMR spectroscopy application in determination of acidic proton positions and azo-hydrazo content determination are discussed. We would like to propose the application of 15 N NMR data measured at the natural abundance level of 15 N 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=Nβ double bond. Graphical abstract: