Chapter 14, Problem 45P

Interpretation Introduction

Interpretation:

The number of peaks into which the $\text{P}$ signal is split is to be determined. The difference in chemical shift in hertz between the lowest and highest field peaks of the $\text{P}$ multiplet is to be determined.

Concept introduction:

Splitting of a proton signal is a result of coupling with an atom which has a nuclear spin of $\text{±}\frac{\text{1}}{\text{2}}$.

The number of peaks into which an NMR signal is split is equal to $\text{n+1}$, where n is the number of coupling atoms in vicinal (or geminal) position.

Naturally occurring phosphorus is monoisotopic, $\text{P}$, and has a nuclear spin of $\text{±}\frac{\text{1}}{\text{2}}$. As a result, phosphorus atom can also split the signal of a proton in a geminal or vicinal position.

The separation between adjacent peaks is equal to the coupling constant.

The signals of both coupled atoms are split by the same value.