Chapter 11- spectroscopy

Question 1

IR

Answer 1

• most useful for distinguishing double and triple bonds
• wavenumber = 1/ wavelength
• most important peaks:
  OH (broad around 3300)
  NH (sharp around 3300)
  C=O (sharp at 1750)

Question 2

UV spectroscopy

Answer 2

• the more the conjugation, the greater the wavelength if max absorbance (lower frequencies)
• the smaller the gap between HOMO and LUMO the more it can get excited (like doodle jump game)

Question 3

NMR

Answer 3

• MRI
• the more deshielding (by electronegative atoms) the more downfield the chemical shift
• the more shielding (less electronegative) the more upfield or to the right the chemical shift
• peaks by n+1 rule
• splitting (magnitude as J)
• C12 not useful bec no magnetic moment