الخطوط العريضة للقسم

  • Learning Goals: Understand that 13C spectra don't show C-C coupling because of the low natural abundance of C, and are collected using "proton decoupling" so that they don't show C-H coupling either.  Integrations are untrustworthy, but quaternary carbons show up at about 1/4 the size of carbons with H attached.  Various DEPT experiments can distinguish primary, secondary and tertiary carbons (know what these are).  Know what kinds of peaks occur in 0-100 ppm range, in 100-165 ppm range, and 165-230 ppm range (you can look these up on the chart on p. 2 of the chemical shift prediction handout)

    Reading: Soderberg section on carbon NMR.

    Notes: The first page of the pencast is "6 things to know about 13C NMR" and the second page shows a sketch of the 13C NMR (regular, + DEPT 90 + DEPT 135) for ethylbenzoate and shows how the spectrum can be analyzed for consistency with the structure of the molecule.  (*-Audio from old pencasts does not work.  Ignore the warning about needing to update to latest Adobe Reader - see note in first topic).