Week 8: C13 Nuclear Magnetic Resonance (NMR) Spectroscopy Flashcards

1
Q

What does NMR stand for?

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2
Q

Why is 13C NMR less sensitive than 1H NMR?

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3
Q

What is the purpose of proton decoupling in 13C NMR?

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4
Q

What is the typical range of chemical shifts for 13C NMR?

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5
Q

Explain the concept of chemical shift in 13C NMR.

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6
Q

How many signals would you expect in the 13C NMR spectrum of benzene?

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7
Q

A compound shows a signal at 200 ppm in its 13C NMR spectrum. What functional group is likely present?

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8
Q

Explain the difference between upfield and downfield shifts in 13C NMR.

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9
Q

How can you distinguish between primary, secondary, and tertiary carbons in a 13C NMR spectrum?

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10
Q

A compound with the molecular formula C4H8O shows two signals in its 13C NMR spectrum. Draw a possible structure.

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11
Q

Predict the number of signals in the 13C NMR spectrum of ethanol.

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12
Q

Draw the structure of a compound that would show four signals in its 13C NMR spectrum.

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13
Q

Predict the chemical shift range for the carbonyl carbon in an aldehyde.

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14
Q

How would you expect the chemical shift of a carbon atom to change if a nearby electronegative atom is introduced?

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15
Q

Predict the splitting pattern for a carbon atom that is directly bonded to three hydrogen atoms.

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16
Q

A compound with the molecular formula C5H10O shows three signals in its 13C NMR spectrum. Draw a possible structure.

17
Q

A compound with the molecular formula C6H12O2 shows six signals in its 13C NMR spectrum. Draw a possible structure.

18
Q

A compound with the molecular formula C7H14O shows four signals in its 13C NMR spectrum. Draw a possible structure.

19
Q

A compound with the molecular formula C8H16O2 shows five signals in its 13C NMR spectrum. Draw a possible structure.

20
Q

A compound with the molecular formula C9H18O shows six signals in its 13C NMR spectrum. Draw a possible structure.

21
Q

What is the difference between DEPT and off-resonance decoupling?

22
Q

Explain the concept of coupling constants in 13C NMR

23
Q

How can 13C NMR be used to determine the stereochemistry of a molecule?

24
Q

What is the difference between 13C NMR and 1H NMR spectroscopy?

25
Q

How can 13C NMR be used to study dynamic processes?

26
Q

How is 13C NMR used in the pharmaceutical industry?

27
Q

How is 13C NMR used in materials science?

28
Q

How is 13C NMR used in environmental chemistry?

29
Q

How is 13C NMR used in food science?

30
Q

How is 13C NMR used in the study of biological systems?