N
X
C
Hal
O
N
S
P Si
Natural
Products
Solvents
C
C
C
C C
C
4.9 Nitrogen Compounds
129
13 C Chemical Shifts and 13 C- 14 N Couplings of Isonitriles (δ in ppm, |J|
in Hz)
Because of the symmetrical electron distribution around the nitrogen atom, the
13 C- 14 N coupling can be observed in the 13 C NMR spectra of isonitriles, leading to
triplets with intensities of 1:1:1 (spin quantum number of 14 N: I = 1, natural abundance, 99.6%).
4.9.9 Isocyanates, Thiocyanates, and Isothiocyanates
13 C Chemical Shifts (δ in ppm)
124.9
121.5
111.9
135.7
124.8
131.5
131.0
125.8
130.7
129.8
130.7
127.5
124.2
111.8
128.7
130.4
128.7
113.4
29.3
16.5
110.7
124.7
125 (broad)
131 (broad)
133.6
26.3
34.2
32.3
43.3
45.0
13.6
13.3
20.4
20.0
28.7
40.6
15.4
15.7
124.8
129.6
125.8
165.7; 1 J 5.2
126.7; 1 J 13.2
126.3; 2 J ≈ 0
129.9; 3 J ≈ 0
129.4; 4 J ≈ 0
2 J 7.5
26.8
1 J 5.8
158.2
1 J 5.3
156.8
1 J 5.0
165.7
36.4
2 J 6.5
119.4
2 J 11.7
3 J ≈ 0
15.3
3 J ≈ 0
120.6
CH 3 NC
NC
NC
NC
CH 3 NCO
NCO
NCO
NCO
SCN
CH 3 NCS
NCS
SCN
–
NH 4
+
SCN
CH 3 SCN
NCS
NCS