Textbook Question
Label each set of chemically equivalent protons, using a for the set that will be at the lowest frequency in the 1H NMR spectrum, b for the next lowest, and so on. Indicate the multiplicity of each signal.
c.
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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 47b(2)
How many signals are produced by each of the following compounds in its
b. 13C NMR spectrum?
2. 
Verified step by step guidance1
Analyze the structure of the compound. The molecule consists of a benzene ring with a methyl group attached to one position, a ketone group attached to another position, and an ethoxy group attached to the ketone.
Determine the symmetry of the benzene ring. The methyl group creates asymmetry, meaning the carbons in the benzene ring are not equivalent. Each carbon in the benzene ring will produce a unique signal in the 13C NMR spectrum.
Consider the methyl group attached to the benzene ring. The carbon in the methyl group is unique and will produce its own signal.
Examine the ketone group. The carbonyl carbon (C=O) is distinct and will produce a separate signal in the 13C NMR spectrum.
Analyze the ethoxy group. The ethoxy group contains two unique carbons: the carbon directly attached to the oxygen and the terminal carbon in the ethyl chain. Each of these carbons will produce separate signals in the 13C NMR spectrum.
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Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Nuclear Magnetic Resonance (NMR) Spectroscopy
NMR spectroscopy is a powerful analytical technique used to determine the structure of organic compounds. It relies on the magnetic properties of certain nuclei, such as carbon-13 (13C), to provide information about the environment surrounding these nuclei. In 13C NMR, different carbon environments produce distinct signals, allowing chemists to infer the number and types of carbon atoms in a molecule.
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General NMR Features
Chemical Shifts
Chemical shifts in NMR spectroscopy refer to the variation in resonance frequency of a nucleus due to its electronic environment. In 13C NMR, the chemical shift is influenced by factors such as electronegativity of nearby atoms and hybridization. This shift helps in distinguishing between different types of carbon atoms, such as those in aliphatic, aromatic, or functional groups, which is crucial for interpreting the spectrum.
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11:441H NMR Chemical Shifts
Signal Multiplicity and Integration
In NMR spectroscopy, the multiplicity of a signal indicates the number of neighboring hydrogen atoms (or other nuclei) that influence the resonance of a particular carbon atom. While 13C NMR typically shows singlets for each unique carbon environment, understanding the integration of these signals can provide insights into the number of equivalent carbons present. This concept is essential for accurately determining the number of signals in the spectrum.
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06:461H NMR Integration
Related Practice
Textbook Question
What does cross peak X in Figure 14.34 tell you?
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Textbook Question
How many signals are produced by each of the following compounds in its
a. 1H NMR spectrum?
4.
5.
6.
1011
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Textbook Question
Label each set of chemically equivalent protons, using a for the set that will be at the lowest frequency in the 1H NMR spectrum, b for the next lowest, and so on. Indicate the multiplicity of each signal.
a.
1552
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Textbook Question
How many signals are produced by each of the following compounds in its
b. 13C NMR spectrum?
1.
1249
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Textbook Question
Identify pairs of coupled protons in the compound whose COSY spectrum is shown below.
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106
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