C-13 NMR

Question 1

Why does C NMR work with C-13?

Answer 1

Because nuclei possess “spin” due odd number of nucleons (6 protons, 7 neutrons)

Question 2

What does NMR spectrometer measure?

Answer 2

The amount of RADIO WAVE energy absorbed to resonate the nuclei (flip spin states in nuclei of atoms). Nuclei in different environments absorb slightly different amounts of energy to resonate

Question 3

Why are C13 NMR chemical shifts compared to TMS?

Answer 3

It is assigned a chemical shift value of 0 ppm and acts as a reference molecule

Question 4

What does the number of peaks in C 13 NMR tell you

Answer 4

Number of different carbon environments

Question 5

What does chemical shift/delta value tell you?

Answer 5

The type of carbon environment

Question 6

What solvent is the sample dissolved in?

Answer 6

CDCL3

Question 7

Why is CDCl3 used as a solvent?

Answer 7

One hydrogen has been swapped for deuterium isotope. It has an even number of nucleons (1 proton, 1 neutron) so does not give off a signal