Spectroscopic Analysis
* IR - The -N-H should be apparent. -NH one band, -NH2 two bands (symmetric and asymmetric)
Absorbance (cm-1) Interpretation
3500 - 3100 NH stretch
1350 - 1000 C-N stretch
* 1H NMR - The -N-H proton(s) tend to be broad peaks. N is less electronegative than O so it deshields less.
Resonance (ppm) Interpretation
0.5 - 5.0 (broad, exchangeable) -NH proton
1.5 - 3.0 CH2-NR2
* 13C NMR
C-N typically 35 - 50 ppm (deshielding due to N)
note: the deshielding is less than that observed in alcohols, C-O = 50 - 65 ppm)
* UV-VIS
maxima due to n®s* (190 nm)
o n electron from N lone pair
o s* antibonding C-N
* Mass Spectrometry
Peak for the molecular ion, M+, is usually apparent.
The nitrogen rule : compounds composed of only C, H, O have an even molecular weight.
If a compound contains an odd number of N atoms will have an odd molecular weight. (the Nitrogen rule).
Since N is very good at stabilising positive charge, cleavage at the b-carbon are common.
![](https://www.thevespiary.org/rhodium/Rhodium/hive/hiveboard/picproxie_docs/000540278-file_fyuk.gif)