Additivity Parameters for 13

C Chemical Shifts in Substituted Benzenes*

SubstituentIpso**OrthoMetaPara
H 0.0 0.0 0.0 0.0
CH3 8.9 0.7 -0.1 -2.9
C2H5 15.6 -0.4 0.0 -2.6
i -C3H7 20.2 -2.5 0.1 -2.4
t -C4H9 22.0 -3.4 -0.4 -3.1
CH=CH2 9.5 -2.0 0.2 -0.5
C6H5 13.1 -1.1 0.4 -0.2
CF3 2.6 -3.3 -0.3 3.2
OH 26.9 -12.7 1.4 -7.3
OCH3 31.4 -14.4 1.0 -7.7
OC2H5 31.0 -13.7 1.1 -7.9
SCH3 10.2 -1.8 0.4 -3.6
C(O)H 9.0 1.2 1.2 6.0
SubstituentIpso**OrthoMetaPara
C(O)OH 2.1 1.5 0.0 5.1
C(O)CH3 9.1 0.1 0.0 4.2
CN -15.4 3.6 0.6 3.9
NH2 18.0 -13.3 0.9 -9.8
NHC(O)CH3 11.1 -9.9 0.2 -5.6
N(CH3)2 22.6 -15.6 1.0 -11.5
NO2 20.0 -4.8 0.9 5.8
F 34.8 -12.9 1.4 -4.5
Cl 6.2 0.4 1.3 -1.9
Br -5.5 3.4 1.7 -1.6
I -32.0 10.2 2.9 1.0
Si(CH3)3 13.4 4.4 -1.1 -1.1
Sn(CH3)3 13.1 7.2 -0.4 -0.4

* Ppm relative to internal benzene. In CCl4, except for CH=CH2 (neat), N(CH3)2 (neat), Si(CH3)3 (neat), and Sn(CH3)3 (neat). Chemical shift of benzene: 128.5 ppm relative to TMS.

** Ipso refers to the carbon atom bearing the substituent.

Reference: Levy, Lichter and Nelson, pps. 111-112; Breitmaier and Voelter, pps. 256-258.