NMR Spectroscopy

1H Chemical Shift Calculations for Substituted Alkenes


dH = 5.25 + dgem + dcis + dtrans
Substituent (R) dgem dcis dtrans
-alkyl 0.44 -0.26 -0.29
-alkyl (ring) 0.69 -0.25 -0.28
-CH2OR 0.67 -0.02 -0.07
-CH2NR2 0.58 -0.10 -0.08
-CH2X 0.70  0.11 -0.04
-C=C 1.00 -0.09 -0.23
-C6H5 1.35  0.37 -0.10
-CHO 1.02  0.95  1.17
-C(O)R 1.10  1.13  0.81
-CO2H 1.00  1.35  0.56
-CO2R 0.84  1.15  0.56
-CN 0.23  0.78  0.58
-OR 1.18 -1.06 -1.28
-OC(O)R 2.09 -0.40 -0.67
-NR2 0.69 -1.19 -0.31
-NO2 1.87  1.30  0.62
-F 1.54 -0.40 -1.02
-Cl 1.00  0.19  0.03
-Br 1.04  0.40  0.55
-I 1.14  0.81  0.88
-SiR3 0.90  0.90  0.60
-SR 1.11 -0.29 -0.13
-SO2R 1.55  1.16  0.93


Example 1:

dH1 = 5.25 - 0.67 = 4.58 ppm
Observed: 4.55 ppm
dH2 = 5.25 + 2.09 = 7.34 ppm
Observed: 7.25 ppm
dH3 = 5.25 - 0.40 = 4.85 ppm
Observed: 4.85 ppm

Example 2:

dH1 = 5.25 + 0.56 = 5.81 ppm
Observed: 5.82 ppm
dH2 = 5.25 + 0.84 = 6.09 ppm
Observed: 6.14 ppm
dH3 = 5.25 + 1.15 = 6.40 ppm
Observed: 6.42 ppm


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