Week 8: C13 Nuclear Magnetic Resonance (NMR) Spectroscopy Flashcards
(30 cards)
What does NMR stand for?
Why is 13C NMR less sensitive than 1H NMR?
What is the purpose of proton decoupling in 13C NMR?
What is the typical range of chemical shifts for 13C NMR?
Explain the concept of chemical shift in 13C NMR.
How many signals would you expect in the 13C NMR spectrum of benzene?
A compound shows a signal at 200 ppm in its 13C NMR spectrum. What functional group is likely present?
Explain the difference between upfield and downfield shifts in 13C NMR.
How can you distinguish between primary, secondary, and tertiary carbons in a 13C NMR spectrum?
A compound with the molecular formula C4H8O shows two signals in its 13C NMR spectrum. Draw a possible structure.
Predict the number of signals in the 13C NMR spectrum of ethanol.
Draw the structure of a compound that would show four signals in its 13C NMR spectrum.
Predict the chemical shift range for the carbonyl carbon in an aldehyde.
How would you expect the chemical shift of a carbon atom to change if a nearby electronegative atom is introduced?
Predict the splitting pattern for a carbon atom that is directly bonded to three hydrogen atoms.
A compound with the molecular formula C5H10O shows three signals in its 13C NMR spectrum. Draw a possible structure.
A compound with the molecular formula C6H12O2 shows six signals in its 13C NMR spectrum. Draw a possible structure.
A compound with the molecular formula C7H14O shows four signals in its 13C NMR spectrum. Draw a possible structure.
A compound with the molecular formula C8H16O2 shows five signals in its 13C NMR spectrum. Draw a possible structure.
A compound with the molecular formula C9H18O shows six signals in its 13C NMR spectrum. Draw a possible structure.
What is the difference between DEPT and off-resonance decoupling?
Explain the concept of coupling constants in 13C NMR
How can 13C NMR be used to determine the stereochemistry of a molecule?
What is the difference between 13C NMR and 1H NMR spectroscopy?
