Topic 22: 1H-NMR: Integration

22.1What is integration in the context of NMR spectroscopy (and in mathematics), and why is it valuable?
 
22.2What do we mean when we say that the numbers given for integration are relative numbers?
 
22.3How are integration values in 1H NMR useful?
 

Topic 23: 1H-NMR: Splitting

23.1How does proton coupling lead to observable splitting of NMR signals?
 
23.2Where does the rule that a set of n equivalent protons splits the signal of a nearby nonequivalent proton into n + 1 peaks arise from? What if the n protons are not equivalent?
 
23.3Can you fix this statement: When two sets of adjacent protons are different from each other (n protons on one adjacent carbon and m protons on the other), the number of peaks in an NMR signal equals (n + 1)(m + 1) by changing just one word?
 
23.4How many lines are there in an HMR signal when a proton is split with a coupling constant of 8 Hz by one proton a coupling of 4 Hz by two others? [Answer: 5 lines. But why? That‘s not (1+1)(2+1).] Can you show that their relative areas within the split signal will be in the ratios 1:2:2:2:1?
 
23.5Why do the two methylene (CH2) group hydrogens of phenylsuccinic acid (shown below) split each other and also have different coupling constants with the adjacent methine (CH) hydrogen?


 
23.6 What is special about OH protons in 1H NMR spectra (three things)?
 
23.7What is the simple NMR experiment that can be done see whether an NMR signal is due to an OH or a CH?
 
10 questions
364 questions for Organic I

364 Questions for Organic I

Dearest Student. This web page is a set of questions I call Detailed Intended Learning Outcomes For Organic Chemistry (Part I). Some time ago I asked myself, "Bob, what do you think are the key questions that you hope students will be able to answer after taking Chemistry 247 at St. Olaf College?" So here you have them. Some are very simple; some require more thought. All are good questions to be thinking about as you read, discuss, and master the practical aspects of organic chemistry. They are discussion starters and review tips. There are no answers here (though there are some clues). The questions are here to help you focus on what's important (to me, at least!) and organize your learning process. The questions are grouped into topics. Bite-size chunks. Take them a few at a time. Don't feast on them all at one sitting!

(preliminary version 2021.01.15 feeback: Bob Hanson)