Proton NMR Flashcards
Why does proton NMR work with 1H?
Their nuclei possess spin, due to odd number of nucleons (1 proton, 0 neutrons)
What does NMR spectrometer measure in H NMR?
The amount of radio wave energy absorbed in order to resonate the nuclei (flip the spin states in the nuclei of atoms).
Nuclei in different environments absorb slightly different amounts of energy to resonate
What is the reference molecule in proton NMR?
TMS. It is assigned a chemical shift of 0 ppm
What is solvent used in proton NMR?
CDCL3. A hydrogen atom has been replaced by deuterium (1proton and 1 neutron) = no spin = no signal.
What do the number of peaks tell us in proton NMR?
The number of different proton environments
What does the chemical shift value of each peak tell us?
The type of proton environment
What does the peak area/intergration value tell us?
The relative numbers of each type of proton
What does the splitting pattern in proton NMR tell us?
The number of protons adjacent (within 3 bonds)
What is the n+1 rule?
n= no. adjacent H. n+1 = number of splits
(n= no. splits).
Singlet = H causing signal has no adjacent H.
1-1= 0 adjacent H
0 adjacent H + 1= 1 peak
Doublet = H causing signal adjacent to CH
1-1= 2
Triplet = H causing signal adjacent to CH2
What do O-H and N-H signals show up as in proton NMR?
Singlets
How are O-H and N-H signals removed?
By adding D2O to the sample. The D swaps with the H so they have no signal as D has no spin
