Spectroscopy Worksheet by parpar

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									                                      Spectroscopy Worksheet

Part I
Given the molecular formula, calculate the degree of unsaturation for the following compounds. Suggest at least
three possible structures consistent with the degree of unsaturation for each compound.
1) C7H14O2
2) C4H10O
3) C9H10O
4) C8H9NO3 (Special case: a nitro group, –NO2, has a degree of unsaturation of 1)
5) C4H6O2
6) C7H10Cl2
Part II
Nine compounds are drawn below. The NMR spectrum for each is among the nine spectra on the following 3
pages.
1) Match each compound with its NMR.
2) Draw the structure above the corresponding spectrum and show clearly which NMR peak corresponds to
   which proton(s) in the molecule.
3) Write down one or two bands which you would look for in the IR spectrum of the compound to verify your
   assignment.
                             Br
                                             CH3CH2OH                         CH2Br
                      2-bromobutane             ethanol               1-bromobutane




                                                                          O
                                                    CH2CH3


                        1-pentene            ethylbenzene               2-butanone



                        O                                                       O
                                                                                C
                                            CH3CH2CO2H                               H
                       2-pentanone           propanoic acid              pentanal
                            3

            1
        2




                                        3




                2
1
                        2       2




                                    3




    5

                    2
                                            3




        2                       2   2

1




                            3

                                        3




                        2
    1




                3

                    2


                                    3



            2
                                3



    2




                2   2




            3




                        3


        2




                                    3




                            2


1
Part III
The structures of ethyl butanoate and propyl butanoate are drawn below. Note how each has an ethyl group and a
propyl group; the only difference is how they are orientated around the ester functional group. The NMRs for
these two compounds are on the next page.
1) Match each compound with its NMR.
2) Draw the structure above the spectrum and indicate clearly which proton(s) correspond to which NMR peak.
                                        O                            O

                           H3CH2CH2C        OCH2CH3         H3CH2C       OCH2CH2CH3

                                 ethyl butanoate                propyl propanoate

Note: Esters are named from their parent carboxylic acid. For example, ethyl butanoate is derived from butanoic
acid and propyl propanoate is derived from propanoic acid.
                                                   O                     O

                                  H3CH2CH2C            OH     H3CH2C         OH

                                      butanoic acid            propanoic acid
                    3
                            3




2       2

                2




                    3   3



2

    2
            2
Part IV
The eight spectra on the following pages represent mono, di, and trisubstituted aromatic compounds. An example
of each type of disubstituted compounds is represented: ortho, meta, and para subsituted. The structures of the
compounds which correspond to the eight spectra are drawn below.
1) Match each compound with its NMR. (You probably will not be able to tell an ortho from a meta subsituted
   compound; you will not be marked off if you have these wrong. You will be marked off if you mix up a para
   with an ortho or meta substituted compound.)
2) Draw the structure above the spectrum and indicate which proton(s) correspond to which NMR peak. You do
   not have to assign each proton on the aromatic ring to a specific peak in the NMR aromatic region—simply
   indicate that they are “somewhere” in the aromatic grouping of NMR peaks.

                               NH2                         CH3                       CH2CH2CH2CH3


                         aniline                     toluene                       butylbenzene



                           CH3                H 3C

                               OCH3                            OCH3         H 3C                  OCH3


                     2-methylanisole           3-methylanisole                  4-methylanisole




                                                                             CH2CH3
                                         Cl
                                                                                   NH2
                              Cl              CHO
                                                                             CH2CH3

                            2,4-dichlorobenzaldehyde                  2,6-diethylaniline
                                                  3



                                                                                3




4




7.0       6.5       6.0   5.5   5.0   4.5   4.0           3.5   3.0       2.5       ppm




                                                      3
      1




                5




                                                                      2
                                                             3




      5




                                                  3



                                                                        3

 4




7.0       6.5   6.0   5.5   5.0       4.5   4.0       3.5   3.0   2.5       ppm



                                                                   6




                                                  4

 3


                                  2
                                                                          3

5




                                                  2

                                                              2   2




                                              3



                                                                      3

     4




    7.0   6.5   6.0   5.5   5.0   4.5   4.0       3.5   3.0       2.5         ppm

								
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