N
X
C
O
N
S
Hal
Solvents
Natural
Products
P Si
C
C
C C
C
C
116
4 13 C NMR
Estimation of 13 C Chemical Shifts of Linear Perfluoroalkanes
(δ in ppm) [3]
F 3 C
CF 2 CF 2
CF 3
F
F
CH 2 F
CHF 2
CF 3
N
F
N
F
N
F
91.0; 1 J CF 170.6
163.3; 1 J CF 245.1
137.0; 2 J CF 16.5
134.4; 2 J CF 22.2
131.0; 2 J CF 36.6
168.7; 1 J CF 261.8
32.8; 2 J CF 19.0
115.5; 2 J CF 21.0
127.8; 3 J CF 6.1
125.5; 3 J CF 5.6
125.3; 3 J CF 3.7
111.8; 2 J CF 16.1
23.6; 3 J CF 7.6
130.1; 3 J CF 7.8
124.5; 3 J CF 4.3
121.2; 4 J CF 4.2
159.8; 1 J CF 255.1
109.7; 2 J CF 37.6
163.7; 1 J CF 236.3
141.3; 3 J CF 7.5
122.7; 2 J CF 17.7
145.9; 4 J CF 3.7
147.8; 3 J CF 14.9
138.3; 2 J CF 22.5
128.9; 4 J CF 1
128.6
128.8; 4 J CF 1
152.5; 3 J CF 6.4
25.3; 4 J CF 1.5
124.1; 4 J CF 3.2
129.0; 5 J CF 3
130.7
131.8; 5 J CF ≈ 0
84.9; 1 J CF 166.0
114.8; 1 J CF 238.6
124.5; 1 J CF 272.2
Increments Z i for the CF 2 or CF 3 substituent in position:
α
β
γ
-8.6
1.8
0.5
Example: Estimation of the chemical shifts in perfluorobutane
CF 3 base value
124.8
CF 2 base value
124.8
1 α-CF 2
-8.6
1 α-CF 3
-8.6
1 β-CF 2
1.8
1 α-CF 2
-8.6
1 γ-CF 3
0.5
1 β-CF 3
1.8
estimated
118.5
estimated
109.4
exp
118.5
exp
109.3
δ = 124.8 + ∑ Z i