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C13 NMR

The first type of NMR we shall look at is 13C NMR. This is slightly more simple than 1H NMR.

<sup>13</sup>C spectra

13C spectra

  • We can work out the different 13C environments from the 13C spectra.
    • In the spectra, different chemical shifts represent 13Cs in different environments.
  • Remember it is only the isotope 13C that this NMR works for, NOT the more common 12C.
    • 13C's abundance is only 1.1%.
Tetramethylsilane

Tetramethylsilane

  • Tetramethylsilane (TMS) is used during the 13C spectrum readings as a reference.
  • This is used because the chemical shifts along the x-axis are relative to the shift of TMS.
  • TMS is a good reference since it only produces one peak at 0ppm because each 13C is in the same environment.
    • For this reason, lots of spectra will have a single peak at 0ppm. Remember this is just your reference peak.
<sup>13</sup>C example

13C example

  • 13C NMR of ethanal. You need to look at a data table to determine the carbon environments represented by the peaks in the spectrum.
    • The peak at 200 ppm represents the carbon in the C=O bond.
    • The peak at 31 ppm represents the carbon in the C-C bond.
    • The peak at 0 ppm is the reference peak from TMS.
Diagram
Diagram
Jump to other topics
1

Structure - Models of the Particulate of Matter

2

Structure - Models of Bonding & Structure

3

Structure - Classification of Matter

3.1

The Periodic Table: Classification of Elements

3.2

Periodic Trends

3.3

Group 1 Alkali Metals

3.4

Halogens

3.5

Noble gases, group 18

3.6

Functional Groups: Classification of Organic

3.7

Functional Group Chemistry

3.8

Alkanes

3.9

Alcohols

3.10

Halogenoalkanes

4

Reactivity - What Drives Chemical Reaction?

5

Reactivity - How Much, How Fast & How Far?

6

Reactivity - The Mechanisms of Chemical Change

7

Measurement, Data Processing & Analysis

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