Chapter 15, Problem 78CP

Interpretation Introduction

Interpretation: The chemical shift value and the multiplicity of each signal in the ${}^{\text{1}}\text{H}$ NMR spectrum of the compound have to be determined.

 Concept Introduction:

${}^{\text{1}}\text{H}$ NMR spectroscopy:

It is the study of the interaction between electromagnetic radiation and the nuclei of atoms and the variety of nuclei studied includes ${}^{\text{1}}\text{H,}{}^{\text{13}}\text{C,}{}^{\text{15}}\text{N,}{}^{\text{19}}\text{F}\text{and}{}^{\text{31}}\text{P}$

Chemical shift: The frequency of the proton signal in the spectrum with reference to the standard compound  which may be TMS (Tetramethylsilane) shows signal at 0 ppm(parts per million).

Multiplicity: The number of peaks on the each signal in NMR spectrum is defined as multiplicity; the multiplicity of each signal indicates the neighboring protons. It is generated by coupling of the subjected protons with the neighboring protons (both subjected and neighbor protons are to be chemically not equivalent) separated by either two or three sigma bonds.

Rule: Multiplicity of each signal is calculated using $\text{(n+1)}$ rule only when the neighboring protons are chemically equivalent to each other.

$\begin{array}{l}\text{(n+1)}\\ \text{where }\\ \text{n indicates number of neighboring protons}\end{array}$