Nmr Flashcards
What are the two types of NMR
13C
1H
For each carbon environment how many peaks
Just one peak
For 1,4 (R group)Benzene how many peaks would there be
Two peaks
For 1,2(R group) benzene how many peaks would there be
3 peaks
For a 1,3 (R group ) benzene how many peaks would there be
4 peaks
How is the integration value written
In a ratio
What is the rule for the integration value
The integration value is proportional to the amount of hydrogen present
E.g 6:1:2:3
Means there are 6 hydrogens which share the same type of environment
1 hydrogen with abouther type of environment
2 carbons in another environment
What types of solvents are used in HNMR
inert solvents which don’t contain any hydrogens
Why are inert solvents used
So they don’t produce any hydrogen peaks
What are tow solvents used
CCl4 - for non polar organic molecules
CDCl3- for polar organic compounds
What is used to calibrate the spectrum
TMS (tetramethylsilane)
Why is TMS used to calibrate
It give one signal
The signal is away from other H signals
Is inert
Non toxic
Low boiling point so can be removed from the sample easily
What is chemical shift
How much the field has shifted away from the field for TMS
What determines the splitting of peak ion HNMR
Number of Hs on neighbouring carbon atom +1
What is the rule if hydrogen is bonded to oxygen or nitrogen
It doesn’t count as a hydrogen
So the hydrogen would be a singlet
