NMR - Nuclear Magnetic Resonance Flashcards
What are uses of NMR?
MRI scanners
airport securtiy
How do we get NMR spectra?
atoms with an external magnetic field absorb radiowave energy to flip their nuclear spin - gives spectra
What are the drawbacks to using chemical shift data?
a peak can mean more than one group
always start form the left hand side of the spectrum
What does each peak of the NMR spectrum show?
A different carbon environment
What does the integration peak area tell you?
number of equivalent protons in that environment - simplest ratio
Why is trichloromethane CDCl3 used in NMR?
doesn’t produce a NMR peak
polar - will dissolve other polar substances easily
strong C-Cl bonds - unreative
What is hydrogen/deuterium exchange?
D replaces H on OH/NH so this proton peak disappears
What does the chemical shift show?
type of proton environment
What is splitting in NMR?
number of adjacent protons
What is the the name for different numbers of peaks and the number of adjacent H?
1 - singlet - 0 adjacent
2 - double - 1 adjacent
3 - triplet - 2 adjacent
4 - quartet - 3 adjacent
5 - quintet - 4 adjacent
6 - sextet - 4 adjacent
7 - septet - 6 adjacent
Why are sextets rare?
no symmetry - triplet of quartet
