Chapter 13, Problem 24P

Interpretation Introduction

Interpretation:

One aspect from each of two spectroscopic methods that would distinguish each compound in the given pair is to be described.

Concept introduction:

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

舧 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).

舧 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.

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

舧 Infrared spectroscopy is a simple, instrumental technique, which helps to determine the presence of various functional groups.

舧 It depends on the interactions of atoms or molecules with the electromagnetic radiation.

舧 Infrared spectroscopy is most commonly used in the identification of the structure of the compound.

舧 Infrared spectroscopy is the examination of the infrared light interacting with a molecule. The examination can be done in three ways, that is, by measuring absorption, emission, and reflection, and it can also measure the vibration of atoms.

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

舧 A compound containing protons or carbon-13, when placed under a strong magnetic field and treated with electromagnetic radiation of suitable frequency, the nuclei of the compound absorb energy through a process called magnetic resonance.

舧 Nuclear magnetic resonance spectroscopy is a graph showing characteristic energy absorption frequencies and intensities of a compound under magnetic field. The number of signals in the spectrum indicates the number of different proton environments present in the molecule.

舧 DEPT stands for distortionless enhancement by polarization transfer. DEPT ${}^{13}\text{C}-\text{NMR}$ is used to indicate the number of hydrogen atoms that are bonded to each carbon while providing the information of chemical shift in a broadband proton-decoupled ${}^{13}\text{C}-\text{NMR}$ spectrum. The carbon signals in a DEPT spectrum are classified as ${\text{CH}}_3,{\text{CH}}_2,\text{CH or C}$ >, accordingly.

舧 Mass spectrometry is a detection of ions on the basis of weight and charge, and their abundancy after formation of ions.

舧 Mass spectroscopy is a graph with mass ($m/z$) of ions on $x-\text{axis}$ where m is the mass of the ion and z is the charge of the ion and their abundancy on the $y-\text{axis}$ >.

舧 Molecular ions formed by EI mass spectrometry are high energy species. Fragmentation of molecular ion means that a complex molecule is broken into smaller molecules and these fragments can undergo more breaking.

舧 When infra-red (IR) radiation is passed through a sample, the energy of the IR radiation is absorbed by the particle. Unlike UV-Vis, the electrons don’t jump to higher orbitals instead there is a change in the vibrational energy of the covalent bond, within the molecule.

舧 IR spectroscopy is used to find the functional groups in the molecule.