Nitrogen-15 nuclear magnetic resonance spectroscopic study of compounds with nitrogen—nitrogen bonds

Abstract

The 15N NMR spectra of several substances with nitrogen—nitrogen bonds have been obtained at the natural-abundance level by high-resolution NMR spectroscopy. Azo (—N═N—) nitrogens are 300–500 ppm deshielded compared with hydrazo (—NH—NH—) nitrogens. The sensitivity of the ^(15)N shifts in these types of substances to substituent changes are reported, along with ^(15)N–^1H spin–spin couplings for some hydrazo compounds. Hydrogen-bonding effects arising from solvent changes on the ^(15)N shifts of azoxybenzene are different for its two kinds of nitrogen. The ^(15)N NMR spectrum of N,N'-dinitrosopiperazine in dimethyl sulfoxide at room temperature is consistent with the presence of two different conformations about the N—NO bonds.

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