Chapter 16, Problem 16.48P

Interpretation Introduction

Interpretation:

A compound generates two $\text{H}$ NMR signals. The frequency of the first is 450 Hz higher than that of the signal from TMS whereas the frequency of the second is 755 Hz higher than that of TMS. The signal corresponding to the protons that are shielded to a greater extent is to be determined. The reason for it is to be explained.

Concept introduction:

The chemical shift is calculated by

$\text{Chemical shift (ppm) = }\frac{{\text{ν}}_{\text{sample}}{\text{-ν}}_{\text{TMS}}}{{\text{ν}}_{\text{op}}}{\text{×10}}^{\text{6}}$

Here, ${\text{ν}}_{\text{sample}}$ is the frequency of the signal of interest; ${\text{ν}}_{\text{TMS}}$ is the frequency of the signal from the protons in TMS. Higher signal frequency corresponds to a larger chemical shift. A signal farther downfield corresponds to a proton that is more deshielded.