Problem Set 5

A compound contains only carbon and hydrogen.

  1. Which of the following are not possiblities for this compound?

    an alkane, an alkene, an alkyl chloride, an alkyne, an aromatic

  2. Examine the proton-decoupled carbon-13 spectrum below and speculate about the origin of the peaks at about 76 and 82 ppm.

  3. Next take a look at the non-decoupled carbon-13 spectrum. Remember that what you are seeing here is primarily carbon-13 coupled to directly attached hydrogens. For example, if a peak appears as a doublet in the non-decoupled spectrum it indicates that the carbon is attached to one hydrogen. What can you conclude about the carbon that gives rise to the peak at 76 ppm?
  4. Notice that the peak at 82 ppm is also a doublet, but with a much smaller separation. This is due to coupling to a hydrogen that is not directly attached, but two bonds removed. Given then that there must be two carbons attached to one another, one of which has one attached proton and the other has no attached proton, what functional group must be present?

  5. Finally, take a look at the proton spectrum to see if there are another groups, and produce a structural formula for the compound.