1. The electromagnetic spectrum covers a continuous range of wavelengths and frequencies, from radio waves at the low-frequency end to gamma (  ) rays at the high-frequency end 10.5Spectroscopy and the Electromagnetic Spectrum

2. Infrared (IR) region Ranges from 7.8 x 10 -7 m to 10 -4 m 2.5 x 10 -6 m to 2.5 x 10 -5 m used by organic chemists Wavelengths given in micrometers (1  m = 10 -6 m) Frequencies given in wavenumbers Wavenumber Reciprocal of wavelength in centimeters Expressed in units of cm -1 10.6 Infrared Spectroscopy

3. Molecules stretch or bend at specific frequencies Energy is absorbed if the frequency of the radiation matches the frequency of the vibration IR spectrum → What molecular motions? → What functional groups? Infrared Spectroscopy

4. Most functional groups have characteristic IR absorption bands that don’t change from one compound to another 10.7 Interpreting Infrared Spectra

5. Interpreting Infrared Spectra

6. Fig. 13-5, p. 509

7. Fig. 13-6, p. 510

8. Fig. 13-7, p. 510

9. Fig. 13-9, p. 512

10. Fig. 13-10, p. 513

11. Fig. 13-11, p. 513

12. Fig. 13-12, p. 514

13. Fig. 13-13, p. 515

14. Table 13-2, p. 522

15. Fig. 13-8, p. 511

16. Fig. 13-15, p. 523

17. Fig. 13-18, p. 526

18. Fig. 13-19, p. 527

19. Fig. 13-20, p. 528

20. Characteristic aldehyde and ketone IR absorptions Infrared Spectra of Some Common Functional Groups

21. Characteristic ester IR absorptions

22. Fig. 13-22, p. 529