Ch12/13 IR and NMR

Question 1

NMR Identification?

Answer 1

ethyl

Question 2

NMR Identification?

Answer 2

isopropyl (or similar)

Question 3

NMR Identification?

Answer 3

para-disubstituted aromatic

Question 4

NMR Identification?

Answer 4

vinyl hydrogens (monosubstituted alkene)

Question 5

What information from NMR?

Answer 5

1. # signals (# different environments for H
2. Position of signals (what environments)
3. Intensity of signals (relative amounts of environments - how many)
4. Spin-spin splitting (neighboring environments)

Question 6

What factors increase chemical shift?

Answer 6

1. ↑ Electronegativity of neighbors
2. Hybridization in the order sp2 > sp > sp3
3. Magnetic induction 0 sp2π reinforces Bo ↓ chem shift ; spπ opposes Bo ↑ chem shift

Question 7

What is B₀?

Answer 7

Applied Force (overall)

Question 8

What is B_p?

Answer 8

Magnetic field at proton (net field)

Question 9

What’s always massive chem shift?

Answer 9

Aldehydes & Acids

Question 10

Calculate actual Integration

Answer 10

Total integration / total # protons = units per proton

Question 11

IR Frequencies

Answer 11

Question 12

Energy Equation

Answer 12

Photon E = h𝜈 = hc/𝜆 = hcᜧ

h - Planck’s constant (in J s or kJ s mol^-1 or kcal s mol^-1)

c- 3.0 x 10⁸ (in m s^-1)

𝜈 - c/𝜆 (in s^-1 Hz)

ᜧ - 1/𝜆 (in cm^-1)