Skip to main content
Ch. 15 - Structural Identification II: Nuclear Magnetic Resonance Spectroscopy
Mullins - Organic Chemistry: A Learner Centered Approach 1st Edition
Mullins1st EditionOrganic Chemistry: A Learner Centered ApproachISBN: 9780137566471Not the one you use?Change textbook
All textbooksMullins 1st EditionCh. 15 - Structural Identification II: Nuclear Magnetic Resonance SpectroscopyProblem 35c
Chapter 14, Problem 35c

Draw a spectrum for each of the following molecules, being sure to indicate the multiplicity, integration, and chemical shift of each peak. Label each signal based on the set of equivalent hydrogens to which it corresponds.
(c) Chemical structure of isopropyl iodide, showing a central carbon bonded to two methyl groups and an iodine atom.

Verified step by step guidance
1
Identify the molecule structure and determine the number of unique hydrogen environments. Equivalent hydrogens will give rise to the same NMR signal.
For each set of equivalent hydrogens, determine the chemical shift. Consider factors such as electronegativity of nearby atoms, hybridization, and aromaticity. Use reference tables or known chemical shift ranges for guidance.
Determine the multiplicity of each signal using the n+1 rule, where n is the number of neighboring hydrogens. This will help you identify if the signal is a singlet, doublet, triplet, etc.
Calculate the integration of each signal, which corresponds to the number of hydrogens in each equivalent set. This is typically represented as the area under the peak in the spectrum.
Draw the spectrum, labeling each peak with its chemical shift, multiplicity, and integration. Ensure that each signal is clearly associated with the corresponding set of equivalent hydrogens in the molecule.

Verified video answer for a similar problem:

This video solution was recommended by our tutors as helpful for the problem above.
Video duration:
2m
Was this helpful?

Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

NMR Spectroscopy

Nuclear Magnetic Resonance (NMR) Spectroscopy is a technique used to determine the structure of organic compounds by observing the behavior of nuclei in a magnetic field. It provides information about the number of chemically distinct hydrogen environments (protons) in a molecule, their chemical shifts, multiplicity, and integration, which are crucial for identifying molecular structure.
Recommended video:
Guided course
10:06
General NMR Features

Chemical Shift

Chemical shift in NMR refers to the resonant frequency of a nucleus relative to a standard in a magnetic field. It is measured in parts per million (ppm) and provides insight into the electronic environment surrounding a nucleus. Different functional groups and bonding environments cause shifts in the resonance frequency, allowing for the identification of different types of hydrogen atoms in a molecule.
Recommended video:
Guided course
11:44
1H NMR Chemical Shifts

Multiplicity and Integration

Multiplicity in NMR describes the splitting pattern of a signal, which results from spin-spin coupling between non-equivalent neighboring protons. It follows the n+1 rule, where n is the number of adjacent protons. Integration refers to the area under each NMR signal, which is proportional to the number of protons contributing to that signal, helping to determine the relative number of equivalent protons in different environments.
Recommended video:
Guided course
06:46
1H NMR Integration
Related Practice
Textbook Question

Draw a spectrum for each of the following molecules, being sure to indicate the multiplicity, integration, and chemical shift of each peak. Label each signal based on the set of equivalent hydrogens to which it corresponds.

(b)

1047
views
Textbook Question

A chemist made what was thought to be compound A or B. How could coupling constants between Ha and Hb be used to distinguish between the two isomers? [Hint: Draw a chair conformation of each.]

1114
views
Textbook Question

Being able to recognize patterns of integration and multiplicity for common functional groups makes structure identification more efficient. Draw the pattern of integration and multiplicity you'd expect to see for each common alkyl group.

(d)

1235
views
Textbook Question

Alkene hydrogens usually appear at similar chemical shifts between 5 and 6 ppm. The alkene hydrogens in the structure shown are very different. Rationalize the difference in chemical shifts between Hₐ and H₆ in the structure shown.

1090
views
Textbook Question

Being able to recognize patterns of integration and multiplicity for common functional groups makes structure identification more efficient. Draw the pattern of integration and multiplicity you'd expect to see for each common alkyl group.

(c)

1468
views
Textbook Question

What coupling constant would you expect between Hₐ and H₆ in cyclopent-2-en-1-one?

1057
views