Y13 NMR Flashcards
What does the number of peaks in a carbon-13 spectrum represent?
Number of different carbon environments
What do the chemical shifts in a carbon-13 spectrum represent?
Types of carbon atom present
If 2 carbons are positioned symmetrically within a molecule, what are they?
Equivalent - have the same carbon environment
Which peak would be shown on a carbon-13 spectrum when COOH is present (each carbon is only shown once)?
The peak which appears in the range further to the left so C=O
In which direction will environments affected by electronegative atoms or π electrons shift?
Left - could mean peaks are outside of stated ranges
What does the number of peaks in a proton spectrum represent?
Number of different proton environments
What do the chemical shifts in a proton spectrum represent?
Types of proton present
What do relative peak areas/integration trace/peak intensity/relative intensity show on a proton spectrum?
Relative number of protons in each environment
What does the splitting pattern on a proton spectrum show?
Number of non-equivalent hydrogen carbons on the adjacent carbon
What rule/formula is used to determine splitting patterns?
n + 1 where n = number of protons on adjacent carbon
What are the 5 types of splitting pattern?
- Singlet (no adjacent carbon or adjacent carbon has no protons)
- Doublet (adjacent carbon has 1 proton)
- Triplet (adjacent carbon has 2 protons)
- Quartet (adjacent carbon has 3 protons)
- Multiplet (adjacent carbons with protons on both sides)
What does a relative intensity of 9 protons in the same environment show?
3 CH3 groups bonded to the same carbon
What does a relative intensity of 6 protons in the same environment show?
2 CH3 groups bonded to the same carbon
Why are D2O and CDCl3 used in NMR?
D2O: Used to identify O-H or N-H protons
CDCl3: Used as a solvent
