Chapter 16, Problem 16.61P

Interpretation Introduction

Interpretation:

The total number of protons coupled to the proton that gave rise to the signal shown is to be determined.

Concept introduction:

The nmr signal of a particular proton may be split into a number of peaks by nearby protons. These are typically protons that are present three bonds away from the proton of interest. If these (coupled) protons are structurally similar, then the number of peaks into which the signal is split equals $\text{n+1}$ where n is the number of coupled protons.

When a proton is coupled to more than one type of structurally distinct protons, the splitting pattern cannot be predicted by the $\text{n+1}$ rule. Each structurally distinct coupled proton independently splits the signal. In effect, the splitting by one type is superimposed on the splitting by the other.