Chapter 10, Problem 63P

Interpretation Introduction

Interpretation:

It is better to use ${}^{\text{13}}\text{C NMR}$ or ${}^{\text{1}}\text{H NMR}$ to distinguish between the given compounds has to be explained.

Concept introduction:

The ${}^{\text{1}}\text{H NMR}$ spectrum of a compound provides some vital information that is required to predict the structure of the compound.  The chemical shift values can predict the groups that are present in the molecule.  The splitting of signals predicts the number of hydrogen or protons attached to the adjacent carbon in a carbon chain of a compound. By this information, the structure of the compound can be predicted.

The signals in the ${}^{\text{13}}\text{C NMR}$ spectrum of a compound are proportional to the number of carbons that are present in the different environment within the molecule.  The carbon which is present in the electron-rich environment shows a signal at a lower frequency and vice-versa.  Therefore, the carbons that are present nearest to the electron-withdrawing groups produce a high-frequency signal.