Multinuclear NMR of Azo Dyestuffs

Publisher Summary This chapter discusses the multinuclear NMR of Azo dyestuffs. Azo dyes of the common formula X–N=N–Y represent a very important class of dyestuffs, with more than 50% of commercial dyestuffs based on this type of compound. Nuclear magnetic resonance (NMR) spectroscopy—especially in its multinuclear form—is a powerful technique for the characterization of such compounds and for the description of azo-hydrazone tautomerism, a property indivisibly linked with this group of dyes. This chapter discusses high-resolution 1 H, I3 C, 14 N, 15 N, I7 O, 19 F, and 31 P NMR spectra of azo dyestuffs measured in solutions and describes the properties of the nuclei used in this study pertinent to the NMR experiments. The simplest azo dyes include the substituted azobenzenes of type 1 and 2.