Organic Chemistry Semester 1 LABORATORY MANUAL - Moravian ...

Nuclear Magnetic Resonance Appendix E15 Part V. Techniques and Theory
Tables 9 & 10 and Figures 4 & 5 on the next three pages, summarize the outcomes of our
discussions. They can be used along with tables in Padías and CGWW for NMR analysis of
organic molecules. Focus particularly on the “Comments “ column to see how effects interact.
Chemical Shift Tables:
Table 9: Characteristic 13 C Chemical Shifts
(See also CGWW pp. 61, 362, 375, 377)
Type of Carbon Structure 13 C δ Comments
saturated carbon
atoms
1 o R-CH 3
2 o R-CH 2 -R
3 o R 3 CH
0->40
10->50
15->50
Know that these chemical
shifts are 0->60 and
increase with carbon
substitution.
carbons attached to
Heteroatoms
C
C
C
C
Br
Cl
N
O
10->25
15->30
30->45
Shifted ~ 10-40 δ down
field from the
corresponding sat'd
hydrocarbon and the
extent of the shift
increases with the
electronegativity of the
heteroatom.
45->75
benzylic
allylic
C
C
C
~20->80
~20->80
Know that these are
similar and are shifted
~ 20 δ downfield from
sat'd compound
C
vinylic
C C
80 -> 145
Shifted ~ 80 δ down field
from sat'd carbon
aromatic
HC
HC
HC
CH
CH
CH
110-> 170
Shifted ~ 100 -> 110 δ
down field from sat'd
carbon
acetylenic C C 65->95 Shifted ~ 50 -> 60 δ down
field from sat'd carbon
carbonyl carbon
atoms of
esters and amides
O
N
O
C
O
C
~155 -> 185
~155 -> 185
Know that these are all
similar and are generally
>150 δ and 220 Know that these are
C
similar and are generally
>190 δ