N
X
C
Hal
O
N
S
P Si
Natural
Products
Solvents
C
C
C
C C
C
4.7 Halogen Compounds
115
4.7 Halogen Compounds
The additivity rules for estimating the 13 C chemical shifts of various skeletons can
be applied to those haloalkanes that do not have more than one halogen atom at a
given carbon atom. In all other cases, the simple linear models fail but correction
terms for non-additivity are available for halomethanes and derivatives (see [1, 2]).
4.7.1 Fluoro Compounds
19 F (natural abundance, 100%) has a spin quantum number I of 1/2. The signals of
carbon atoms up to a distance of about four bonds are split by coupling to 19 F.
13 C Chemical Shifts and 19 F- 13 C Coupling Constants
(δ in ppm, |J| in Hz)
F 3 C CF 3
F 3 C
OH
O
F 2 HC
OH
O
FH 2 C
OH
O
F
F
CH 3 F
CH 2 F 2
CHF 3
CF 4
71.6
1 J CF 161.9
109.0
1 J CF 234.8
2 J CF 19.5
23.6
2 J CF 18.3
30.6
2 J CF 24.8
88.5
1 J CF 177
78.9
1 J CF 239
108.1
1 J CF 283.2
115.0
4 J CF ≈ 0
29.3
28.3
14.1 31.9
116.2
29.3
22.7
93.5
2 J CF 22.4
23.0
2 J CF 21.1
16.4
85.2
1 J CF 163.3
9.2
3 J CF 6.7
84.2
1 J CF 164.8
173.5
2 J CF 22
167.2
2 J CF 28
163.0
2 J CF 43.6
87.8
1 J CF 162.1
83.7
1 J CF 160.1
1 J CF 271
2 J CF 48.1
25.3
3 J CF 6.2
147.7
1 J CF 267.2
116.4
1 J CF 274.3
118.5
1 J CF 259.2
F
F
F
F