Chapter 32 (Structure Determination) Flashcards

1
Q

What factors influence choice of pathway?

A
  • Availability/cost of starting materials
  • Number of stages needed to convert target molecule
  • If more than one product formed/purification needed
  • Number and cost of separation
  • Percentage yield expected
  • Atom economy of overall process
  • Amount of waste generated
  • If toxic chemicals needed
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2
Q

Why is TMS used to calibrate spectra?

A
  • Gives one signal
  • Non-toxic and inert
  • Has low boiling point
  • Gives signal that is far to the right of signals of organic compounds
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3
Q

What is shown on a Proton NMR?

A
  • Number of signals: How many different sets of equivalent H atoms there are
  • Positions of the signals: Suggests environment that H atom is found
  • Relative intensity: How many H atoms are found in that environment
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4
Q

What affects the chemical shift of the absorbance in H NMR?

A
  • The closer the H is to electronegative atoms, the greater the shift
  • The more electronegative atoms the greater the shift
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5
Q

What does splitting in H NMR show?

A

Provides information about the number of H atoms on the adjacent carbon.

singlet = no H on next carbon

doublet = 1 H on next carbon

triplet = 2 H on next carbon

quartet = 3 H on next carbon

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6
Q

How is absorbance strength found for H NMR?

A

Area under each peak

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