Textbook Question
How many signals would you expect to see in the 1H NMR spectrum of each of the following compounds?
m.
n.
o.
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Ch. 14 - NMR Spectroscopy
Bruice8th EditionOrganic ChemistryISBN: 9780135213711
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Table of contents
- Ch. 1 - Remembering General Chemistry: Electronic Structure and Bonding (Part 1)31
- Ch. 1 - Remembering General Chemistry: Electronic Structure and Bonding (Part 2)65
- Ch. 2 - Acids and Bases: Central to Understanding Organic Chemistry84
- Ch. 3 - An Introduction to Organic Compounds:Nomenclature, Physical Properties, and Structure183
- Ch. 4 - Isomers: The Arrangement of Atoms in Space121
- Ch. 5 - Alkenes: Structure, Nomenclature, and an Introduction to Reactivity • Thermodynamics and Kinetics83
- Ch. 6 - The Reactions of Alkenes • The Stereochemistry of Addition Reactions175
- Ch. 7 - The Reactions of Alkynes • An Introduction to Multistep Synthesis119
- Ch. 8 - Delocalized Electrons: Their Effect on Stability, pKa, and the Products of a Reaction • Aromaticity and Electronic Effects: An Introduction to the Reactions of Benzene148
- Ch. 9 - Substitution and Elimination Reactions of Alkyl Halides212
- Ch. 10 - Reactions of Alcohols, Ethers, Epoxides, Amines, and Sulfur-Containing Compounds131
- Ch. 11 - Organometallic Compounds60
- Ch. 12 - Radicals90
- Ch. 13 - Mass Spectrometry; Infrared Spectroscopy; UV/Vis Spectroscopy62
- Ch. 14 - NMR Spectroscopy95
- Ch. 15 - Reactions of Carboxylic Acids and Carboxylic Acid Derivatives123
- Ch. 16 - Reactions of Aldehydes and Ketones • More Reactions of Carboxylic Acid Derivatives141
- Ch. 17 - Reactions at the Alpha-Carbon101
- Ch. 18 - Reactions of Benzene and Substituted Benzenes144
- Ch. 19 - More About Amines • Reactions of Heterocyclic Compounds49
- Ch. 20 - The Organic Chemistry of Carbohydrates80
- Ch. 21 - Amino Acids, Peptides, and Proteins57
- Ch. 22 - Catalysis in Organic Reactions and in Enzymatic Reactions35
- Ch. 23 - The Organic Chemistry of the Coenzymes—Compounds Derived from Vitamins1
- Ch. 28 - Pericyclic Reactions58
Chapter 15, Problem 4e,f
How many signals would you expect to see in the 1H NMR spectrum of each of the following compounds?
e. 
f. 
Verified step by step guidance1
Step 1: Analyze the molecular structure provided in the image. The compound contains a double bond (C=C) and several chlorine atoms attached to the carbon atoms. Additionally, there are two hydrogen atoms directly bonded to the carbons in the double bond.
Step 2: Determine the symmetry of the molecule. The molecule is symmetrical about the double bond, meaning the environment of the hydrogens on each side of the double bond is identical.
Step 3: Identify the unique hydrogen environments. In this molecule, there are only two hydrogens present, both attached to the carbons in the double bond. Due to the symmetry, these hydrogens are in the same chemical environment.
Step 4: Predict the number of signals in the 1H NMR spectrum. Since both hydrogens are in the same environment, they will produce a single signal in the 1H NMR spectrum.
Step 5: Conclude that the molecule will exhibit one signal in its 1H NMR spectrum due to the identical environment of the hydrogens.
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Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Chemical Shifts in NMR
In 1H NMR spectroscopy, the position of signals (chemical shifts) is influenced by the electronic environment surrounding hydrogen atoms. Electronegative atoms, such as chlorine, can deshield hydrogen atoms, causing them to resonate at different frequencies. Understanding how substituents affect chemical shifts is crucial for predicting the number of signals in a spectrum.
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11:44
1H NMR Chemical Shifts
Multiplicity of Signals
The multiplicity of NMR signals arises from spin-spin coupling between neighboring hydrogen atoms. This is described by the n+1 rule, where n is the number of adjacent protons. Recognizing how many neighboring protons each hydrogen has helps determine the splitting pattern and the total number of distinct signals observed in the spectrum.
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02:02Identifying Proton Signals
Symmetry and Equivalent Protons
In NMR, protons that are chemically equivalent will produce a single signal. Symmetry in a molecule can lead to multiple protons being equivalent, reducing the number of signals in the spectrum. Analyzing the structure for symmetry and identifying equivalent protons is essential for accurately predicting the number of signals in the 1H NMR spectrum.
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00:25Determining Chirality with Plane of Symmetry
Related Practice
Textbook Question
How many signals would you expect to see in the 1H NMR spectrum of each of the following compounds?
g.
h.
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Textbook Question
How many signals would you expect to see in the 1H NMR spectrum of each of the following compounds?
a. CH3CH2CH2CH3
b. BrCH2CH2Br
3
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Textbook Question
How many signals would you expect to see in the 1H NMR spectrum of each of the five compounds with molecular formula C6H14?
1
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Textbook Question
What strength magnetic field is required when a 500-MHz instrument is used for 1H NMR?
1
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Textbook Question
Draw an isomer of dichlorocyclopropane that gives an 1H NMR spectrum
c. with three signals
1
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