15: Carbon NMR Flashcards
What do the number of peaks on a carbon NMR spectrum show?
How many different carbon environments there are in a particular molecule
Why do carbons closer to more electronegative atoms have a higher chemical shift?
They are less shielded.
Name the solvent used in carbon NMR.
Tetramethylsilane
Give the formula for tetramethylsilane.
Si(CH3)4
Why do we use tetremetylsilane as the solvent in carbon NMR?
Its peak will form much further away from other molecules being analysed so does not interfere with the spectra
In proton NMR, what does the relative area under peaks represent?
The number of hydrogen atoms in each environment.
What is spin spin coupling?
Where clusters form on the spectrum rather than a single peak.
Help us identify the number of hydrogens on the neighbouring carbons.
What rule is spin spin coupling also known as?
n + 1
If a singlet is seen on a proton NMR spectrum, how many hydrogens would be seen on the adjacent carbons?
0
If a doublet is seen on a proton NMR spectrum, how many hydrogens would be seen on the adjacent carbons?
1
If a triplet is seen on a proton NMR spectrum, how many hydrogens would be seen on the adjacent carbons?
2
If a quartet is seen on a proton NMR spectrum, how many hydrogens would be seen on the adjacent carbons?
3
Why are proton free solvents needed in proton NMR?
So protons dont interfere with the spectrum.
What is another name for a proton free solvent?
Deuterated
Name 2 solvents that could be used in proton NMR.
CCl4 or Deuterium
