Chapter 14, Problem 77CP

Interpretation Introduction

Interpretation: The reasonable structure and mechanism of formation for the ion consistent with a peak at $\text{m/z}\text{=}\text{113}$ has to be determined.

Concept Introduction:

Mass spectrometry:

• It is a technique used to find out the molecular weight of the compounds and thus providing the structure and chemical properties of different molecules.
• The sample ion is converted into gaseous ions with or without fragmentation and are characterized by their charge to mass ratios and relative abundances.
• Mass spectrum is a plot of the relative abundance of the generated ions as a function of the charge to mass ratio.

Nitrogen rule:

• If the molecular weight is odd, then it indicates the odd number of nitrogen atoms in the compound.
• If the molecular weight is even, then it indicates the absence of nitrogen or an even number of nitrogen atoms.

McLafferty rearrangement:

• It is the fragmentation involves in ketones and aldehydes.
• A hydrogen atom has to be present at the gamma position in aldehydes and ketones in-order to undergo the fragmentation known as McLafferty rearrangement.
• The rearrangement results in the loss of a neutral alkene fragment.