13C NMR Interpretation
13C NMR Shift Values
Question 1
• A compound has a molecular formula of C5H8O2 and exhibits the following 13C NMR spectrum; �; 199.83, 197.54, 29.22, 23.70, 6.95. Which of the compounds listed below would be consistent with this structure?
• Hint #1: Count the number of peaks– 5 peaks
Question 1 Answer Set
Step 1: Narrow the list of possibilities with the number of possible peaks
Question 1 Answer Set
3 peaks
3 peaks
Question 1 Answer Set
Step 2: What should the 13C NMR spectrum look like?
Choice 1
171.42
69.47
29.84
22.31
19.06
Choice 2
166.18
130.31
128.88
60.48
14.28
Choice 3
170.67
132.50
118.0965.19
20.81
Choice 4
27.72
197.21
106.85
163.49
57.54
Choice 5
171.48
141.42
97.34
27.33
8.80
Choice 6
199.83
197.54
23.70
29.22
6.95
Question 1 Answer Set
Final step: The choice looking most similar to expectations
Question 2
• A compound exhibits the following 13C NMR spectrum: �; 171.42, 69.47, 29.84, 22.31, 19.06Which of the compounds listed below would be consistent with this structure?
• Hint #1: Count the number of peaks– 5 peaks
Question 2 Answer Set
Step 1: Narrow the list of possibilities with the number of possible peaks
Question 2 Answer Set
4 peaks
4 peaks3 peaks
3 peaks
Reconfirm your choice with expectations
171.42
69.47
29.84
22.31
19.06
Question 2 Answer Set
Question 3
• A compound has a molecular formula of C8H10 and exhibits the following 13C NMR spectrum; �; 136.42, 129.63, 125.85, 19.66 . Which of the compounds listed below would be consistent with this structure?
• Hint #1: Count the number of peaks– 4 peaks
Question 3 Answer Set
Step 1: Narrow the list of possibilities with the number of possible peaks
Question 3 Answer Set
Step 1: Narrow the list of possibilities with the number of possible peaks
6 peaks
3 peaks5 peaks
Question 3 Choice 1
64.89
78.69
13.01
13.53
Mirror plane
Question 3 Choice 2
125.85
129.63
136.4219.66
Mirror plane
Question 3 Answer Set
Step 1: Narrow the list of possibilities with the number of possible peaks
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