18 November
What NMR tells us
Chemical shift δ
Integration
Spin spin splitting
Signal splitting – defining H atom neighbors
NMR spectra usually complex (not only singlets)
Number of peaks = n + 1
n = # of H attached to C next to that group
Protons bound to a carbon that has a carbon with other protons are affected by the other
protons (spin spin splitting)
Practical Aspect of Signal Splitting: How Many & Sizes
N + 1 Rule
H-C signal splits into n + 1 peaks (n = # H’s on adjacent C’s)
Signal Splitting – Structural Complexities
If adjacent H’s are not all equivalent (chemically equal), situation can be more complicated (split
signals may be split individually)
Recommended Order of Determination
List signals to assign, and δ to match up with
Begin with easiest peaks
Such as CH next to O
