3.8 Nitrogen Compounds
65
3.8 Nitrogen Compounds
3.8.1 Amines
Assignment
Range
Comments
al C–N
25–70 ppm
Shift with respect to C–H ≈+20 ppm
al C–(C–N)
10–60 ppm
Shift with respect to C–(C–CH 3 ) ≈+2 ppm
al C–(C–C–N)
10–60 ppm
Shift with respect to C–(C–C–CH 3 ) ≈-2 ppm
(C)=C–N
120–170 ppm
Shift with respect to (C)=C–C ≈+20 ppm
C=(C–N)
75–125 ppm
Shift with respect to C=(C–C) ≈-25 ppm
ar C–N
130–150 ppm
Shift with respect to C–H ≈+20 ppm
ar C–(C–N)
100–130 ppm
Shift with respect to C–(C–H):
ortho ≈-15 ppm
meta ≈+1 ppm
para ≈-10 ppm
HN–C al
HN–C ar
0.5–4.0 ppm
2.5–5.0 ppm
HN + –C al or ar 6.0–9.0 ppm
Often broad
CH 3 –N
CH 2 –N
2.3–3.1 ppm
2.5–3.5 ppm
Singlet
CH–N
CH–N +
3.0–3.7 ppm
3.2–4.0 ppm
ar CH–C–N
6.0–7.5 ppm
Shift with respect to CH–(C–H):
ortho ≈-0.8 ppm
meta ≈-0.2 ppm
para ≈-0.7 ppm
ar CH–C–N +
7.5–8.0 ppm
Shift with respect to CH–(C–H):
ortho ≈+0.7 ppm
meta ≈+0.4 ppm
para ≈+0.3 ppm
N–H st
3500–3200 cm -1 Position and shape depend on the degree of
association. Often different bands for Hbonded and free NH. For NH 2 , always at
least two bands
N + –H st
3000–2000 cm -1 Broad, similar to COOH but more structured
N–H δ
1650–1550 cm -1 Weak or absent
N + –H δ
1600–1460 cm -1 Often weak
H–C(–N) st
2850–2750 cm -1 For CH 3 –N and CH 2 –N in amines; similar
range for corresponding ethers
13 C
1 H
IR