Collection of Czechoslovak Chemical Communications - digital archive 

Abstract

¹³C and ¹⁵N NMR spectra of ten model azo dyes containing NH₂ or NHCOCH₃ group in ortho- or para-position to the phenylazo group on benzene, naphthalene and anthracene skeleton were measured. A negligible content of the hydrazone form in these compounds follows from the ¹³C and ¹⁵N chemical shifts and from a slight temperature dependence of the ¹⁵N chemical shifts and ¹J(¹⁵N¹⁵N) coupling constants. The ¹⁵N isotope effect Δδ (¹⁵N) = 0.1 ppm was observed and the values of ¹J(¹⁵N¹⁵N) = 15.6 ± 0.3 Hz were found with compounds double labelled by ¹⁵N.