N
X
C
Hal
O
N
S
P Si
Natural
Products
Solvents
C
C
C
C C
C
207
5.7 Halogen Compounds
207
1 H- 19 F-Coupling Constants (J in Hz) [1]
Geminal coupling constants
Saturated systems: Approximately +45 to +55. Increasing values with
electronegative substituents
Alkenes:
Approximately +70 to +90
Vicinal coupling constants
Saturated systems: Approximately 0 to + 50. The values depend on the conformation and on the electronegativity of subsituents in a similar
way as for 1 H- 1 H-couping constants (Chapter 5.1.2)
Alkenes:
cis: -5 to +20
trans: +10 to +55
Benzene derivatives: ≈10
Long-range-coupling constants
Saturated systems: 4 J: |J| < 1, for W-arrangement ≈ +5
Alkenes:
4 J cis : -4 to +3
4 J trans : -1 to +4
Benzene derivatives: 4 J: +5 to +10; 5 J: -2 to +2
CF 3
H
7.61
7.84
8.11
7.13
7.51
7.53
7.38
5 J aF 2.2
3 J aF 10.7
4 J bF 5.4
Couplings
with CH 3 :
4 J o 2.5
5 J m 0.0
6 J p 1.5
CH 3
F
a
a
b
F