Chapter 15.10, Problem 24PTS

Interpretation Introduction

Interpretation: The structure of the compound to be identified for the given molecular formula ${\text{C}}_{\text{10}}{\text{H}}_{\text{10}}{\text{O}}_{\text{4}}$ and using the details of ${}^{\text{1}}\text{H}\text{NMR}$ spectrum.

Concept Introduction:

HDI calculation:

$\begin{array}{l}\text{HDI = }\frac{\text{(2C+2+N-H-X)}}{2}\\ \text{Where}\\ \text{C represent number of carbons}\text{.}\\ \text{N represent number of nitrogens}\text{.}\\ \text{H}\text{represent number of hydrogens}\text{.}\\ \text{X}\text{represent number of halogens}\text{.}\end{array}$

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.

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

Integration value (I): The integration value at the bottom of the ${}^{\text{1}}\text{H}\text{NMR}$ spectrum represents the number of protons giving rise to the signal.