HELVETICA CHIMICA ACTA-Vol. 59, Fasc. 2 (1976)-Nr. 42-43 379 are NI= 119.3 and 128.0 ppm; Na= 301.5 and 295.7 ppm for X= C1 and NO2 respectively [ll]. Thus we see that the hydrazine nitrogen N1 appears at much higher field than the nitrogen resonances in our complexes by> 100 ppm suggesting that the azo-form 3 dominates in these molecules. We conclude that 15N-NMR. can be a powerful tool in the elucidation of molecular structure ...