1. Chemical Shift

2. Carbon-13 Spectra How many C-13 signals? Which signals are further upfield? Can the compounds be differentiated?

3. Correlation Chart Same number of signals Occur in different areas of spectrum Predictable shifts

4. Chemical Shift Tables Complex vs simple Basics: – Alkane: 5-45ppm – C-Q: 40-70ppm – sp: 70-100ppm – sp 2 : 100-160 ppm – Carbonyl: 160- 220 ppm

5. Predict C-13 Chemical Shifts If carbon fits two categories, choose higher shift

6. More subtle points Inductive effects Additive effects More substituted sp 3 carbon is further downfield

7. More subtle points Carbonyls – Above 200ppm, ketone and aldehyde – Below 200ppm, O=C-Q – Explain by shielding and resonance

8. More subtle points Alkene vs Alkyne

9. Which Structure(s) Fit? CDCl 3 TMS absent

10. Which Structure Fits?

11. C3H8OC3H8O

12. Proton NMR Shifts

13. Basic Correlation Chart How many 1 H signals? Shift? Proton NMRChemical Shift (ppm) alkane CH 3 0.9 alkane CH 2 1.3 alkane CH1.7 X=C-C-H (Ph-C-H or O=C-C-H) 2-3 O-C-H X-C-H 3-4 (sp 2 ) C=C-H5-6 Ph-H7-8 O=C-H9-10 O=C-O-H10-12 O-H, N-H1-5

14. Common “exceptions” Phenyl protons give one “signal” even if nonequivalent

15. Common “exceptions” Exchangeable protons are broad and small Washed away with D 2 O