1. DEGREE OF UNSATURATION EXAMPLE A COMPOUND HAS THE FORMULA C 8 H 7 Br 1.WORK OUT THE DEGREE OF UNSATURATION 2.PROPOSE A STRUCTURE FOR THE COMPOUND D.U. = 5

2. NORMAL MODES OF VIBRATION EXAMPLES Symmetrical stretch Asymmetrical stretch Scissoring RockingWaggingTwisting

3. UV/VIS LECTURE EXERCISE SUGGEST ALL POSSIBLE TRANSITIONS (e.g. n   * ) FOR THE FOLLOWING COMPOUND: σ  σ*σ  σ* π  π*π  π* n  σ* n  π* d  d L  M charge transfer

4. UV/VIS LECTURE EXERCISE    * transitions of the corrin ring

5. UV-VIS LECTURE EXERCISE THE UV/VIS SPECTRUM OF A SOLUTION (conc. = 2.5 × 10 -5 M) HAS TWO PROMINENT PEAKS. THE FIRST AT 400 nm HAS AN ABSORBANCE OF 0.8, AND THE SECOND AT 550 nm HAS AN ABSORBANCE OF 0.1. THE MEASUREMENT WAS CONDUCTED IN A CUVETTE WITH A PATHLENGTH OF 0.02 m. CALCULATE THE EXTINCTION COEFFICIENT FOR BOTH PEAKS.

6. UV-VIS LECTURE EXERCISE cont. A = ε×b×c  ε = A/(c × b)  ε 400 = 0.8/(2.5 × 10 -5 mol ℓ -1 × 2 cm) = 16000 mol -1 ℓ cm -1  ε 550 = 2000 mol -1 ℓ cm -1

7. TYPICAL INSTRUMENT

9. Using only the peak integrals, assign which signals belong to which protons.

10. Using peak multiplicities, and prior knowledge about shielding, fully assign the 1 H spectrum below. A A B B C C D D

11. HOW IS J CALCULATED? THE MAGNITUDE OF J CAN BE CALCULATED BY × THE SEPARATION OF THE LINES IN δ (ppm) UNITS BY THE RESONANCE FREQUENCY OF THE SPECTROMETER IN MHz. J (Hz) = δ (ppm) × ν 0 (MHz)

12. a b J ba J ab IF H a AND H b ARE COUPLED, THEN THE SPACING BETWEEN THE LINES ARE EQUAL, AND J ab = J ba MORE ON J J ab = J ba = 6.0 Hz