Sample NMR Problems

1. You have three unlabeled vials each containing a trichlorobenzene isomer. In order to correctly identify each compound and properly label its container you have taken their 13C nmr spectra. Match the spectrum characteristics given below with a compound from the following group:
1,2,3-trichlorobenzene
1,2,4-trichlorobenzene
1,3,5-trichlorobenzene

13C NMR:
(i)
Two peaks between δ125 and 140 ppm
1,2,3-trichlorobenzene
1,2,4-trichlorobenzene
1,3,5-trichlorobenzene
(ii) Six peaks between δ125 and 140 ppm
1,2,3-trichlorobenzene
1,2,4-trichlorobenzene
1,3,5-trichlorobenzene
(iii) Four peaks between δ125 and 140 ppm
1,2,3-trichlorobenzene
1,2,4-trichlorobenzene
1,3,5-trichlorobenzene


2. You have three unlabeled vials each containing a tetrachlorobenzene isomer. In order to correctly identify each compound and properly label its container you have taken their 13C nmr spectra. Match the spectrum characteristics given below with a compound from the following group:
1,2,3,4-tetrachlorobenzene
1,2,3,5-tetrachlorobenzene
1,2,4,5-tetrachlorobenzene

13C NMR:
(i)
Two peaks between δ125 and 140 ppm
1,2,3,4-tetrachlorobenzene
1,2,3,5-tetrachlorobenzene
1,2,4,5-tetrachlorobenzene
(ii) Three peaks between δ125 and 140 ppm
1,2,3,4-tetrachlorobenzene
1,2,3,5-tetrachlorobenzene
1,2,4,5-tetrachlorobenzene
(iii) Four peaks between δ125 and 140 ppm
1,2,3,4-tetrachlorobenzene
1,2,3,5-tetrachlorobenzene
1,2,4,5-tetrachlorobenzene




3. You have four unlabeled vials each containing a different dichloropropane isomer. In order to correctly identify each compound and properly label its container you have taken their 13C nmr and 1H nmr spectra. Match the spectrum characteristics given below with a compound from the following group:
1,1-dichloropropane         2,2-dichloropropane
1,2-dichloropropane         1,3-dichloropropane

(i) 13C NMR:
Three signals between δ0 and 60 ppm
1H NMR:
Three signals between δ0 and 5 ppm
(the lowest field signal is a sextet)
1,1-dichloropropane
2,2-dichloropropane
1,2-dichloropropane
1,3-dichloropropane

(ii) 13C NMR:
Two signals between δ0 and 70 ppm
1H NMR:
One signal, a singlet at δ1.2 ppm
1,1-dichloropropane
2,2-dichloropropane
1,2-dichloropropane
1,3-dichloropropane

(iii) 13C NMR:
Two signals between δ0 and 70 ppm
1H NMR:
Two signals between δ0 and 5 ppm
(the lowest field signal is a triplet)
1,1-dichloropropane
2,2-dichloropropane
1,2-dichloropropane
1,3-dichloropropane

(iv) (iv) 13C NMR:
Three signals between δ0 and 70 ppm
1H NMR:
Three signals between δ0 and 5 ppm
(the lowest field signal is a triplet)
1,1-dichloropropane
2,2-dichloropropane
1,2-dichloropropane
1,3-dichloropropane


This script written by William Reusch, Dept. of Chemistry, Michigan State University. Please send comments and corrections to whreusch@pilot.msu.edu.