L38 - NMR And MRI: Interpreting NMR Data
No description yet. This curated deck is ready for daily study.
Card preview (11)
What are the 3 kinds of data which are considered for 1H NMR?
• chemical shift data - types of protons • integrals - ratio of each kind of proton • 1H-1H coupling - protons near proton in interest
What is chemical shift equivalent?
If there is an element of symmetry in the molecule = symmetric atoms are chemically equivalent
What does topicity describe?
Sterochemical relationship of 2 or more atoms is a molecule
What are the different types of topicity?
• homotopic • enantiotopic • distereotopic • heterotopic
What are homotopic and enantiotopics protons like?
Resonate at the same frequency
What are diastereotopic and heterotopic protons like?
Resonate at different frequencies
How do diasterotopic and heterotopics appear?
At different ppm values, experience a difficult chemical environment
How do you compare the strucutres to determine relationship for any two protons?
• identical - protons are homotopic • enantiomers - protons are enantiotropic • diastereomers - diastereotopic • structural isomers - heterotopic
What are integrals?
height - proprotional to intensity = ratio for each kind of proton
What is 1H-1H coupling?
• neighbouring protons orient with/against magnetic field of NMR instrument • HB reinforces HA = stronger field • HB opposes HA = weaker field • = 2 signals = doublet • more lines when more protons
What are the spiltting patterns of neighbouring protons?
• 1 - singlet • 1 1 - doublet • 1 2 1 - triplet • 1 3 3 1 - quartet • 1 4 6 4 1 - pentet • 1 5 10 10 5 1 - sextet • 1 6 15 20 15 6 1 - septet