Chapter 14, Problem 42P

Interpretation Introduction

Interpretation:

The structure of the compound C in the given reactionis to be drawn and explanation of high degree of symmetry of compound D is to be suggestedby making structure.

Concept introduction:

According to Huckel’s rule, aromatic compounds contain a planar ringand havea conjugated pi system with $(4n+2)\pi$ $4n+2\pi$ electrons, where $n=0,1,2,3,\mathrm{...}$

The aromatic compound contains conjugated pi bonds.

All the atoms in the ring have an unhybridized $p$ orbital.

Antiaromatic compounds contain $(4n)\pi$ electrons. They are very unstable and are highly reactive.

The numerical proportion of signals generated in $\text{H}\text{ NMR}$ spectrum indicates the number of different chemical environments for protons.

Nuclear Magnetic Resonance (NMR) is one of the most capable analytical techniques used for determining the functional groups and how the atoms are structured and arranged in a molecule.

Few elements, such as ${}^{13}{\text{C and }}^1\text{H}$, have nuclei behaving as magnets about an axis. These elements are placed in magnetic field irradiated with electromagnetic energy of specific frequency and the nuclei tend to absorb energy via magnetic resonance. There is this graph that shows energy absorption frequencies and intensities of a sample kept in the magnetic field called nuclear magnetic resonance (NMR).

In $\text{NMR}$ spectroscopy, the proton nuclear magnetic resonance ${(}^{\text{1}}\text{H}\text{NMR)}$ is used to find out the structure of molecules with the help of ${}^{\text{1}}\text{H}$ atom within the molecules.

Induced magnetic field consists of electricity generated from movement in a magnetic field.

Any signal’s position on the X-axis in the $\text{NMR}$ spectrum is the chemical shift expressed in $\delta$ or ppm.

The number of signals in $\text{H}\text{ NMR}$ spectrum tells about the number of different chemical environments for the protons.

The area covered by the signal is proportional to the number of equivalent protons causing the signal.

The hydrogen atom on adjacent carbon atoms splits the peak into two or more peaks. One, two, and three hydrogen atoms split the peak into two, three and four peaks, which further, is referred to as doublet, triplet or quartet.

The decrease in the electron density around a proton deshields the signal downfield at a larger value of chemical shift.

The increase in electron density shields the signal upfield at a lower value of chemical shift.

${}^{13}\text{C}$ NMRis only used in the observation of isotopes of carbon atoms.

Cyclopentadiene, on treatment with sodium, loses a proton to form cyclopentadienyl anion