1. 111 CHEM 344 Organic Chemistry Lab June 18 th 2008 Spectroscopy of Organic Compounds Lecture 3 –Infrared and Mass Spec Nick Hill

3. 3 1703 cm -1

4. 1716 cm -1 2800 - 2600 cm -1

5. 2260 cm -1

6. Molecular Fragments Molecule Molecular Ion EI

7. Mass Spectrum of methanol CH 3 OH 32 31 29 15 [CH 2 OH] + [CHO] + [CH 3 ] + [CH 3 OH] +.

8. Cation stability more important than radical stability Molecular Ion A + B CationRadical X X A + B CationRadical

9. 85 71 57 43 29 114 C 6 H 13 + C 5 H 11 + C4H9+C4H9+ C3H7+C3H7+ C2H5+C2H5+ Mass Spectrum of octane

10. Mass Spectrum of 2,2,4-trimethylpentane 57 43

11. Mass Spectrum of 1-butanol 5631 43 29 via loss of H 2 O Resonance stabilized

12. Mass Spectrum of 2-methyl-2-butanol 59 55 73 70 43 31

14. Mass Spectrum of 2-octanone 113 43 58 via  - cleavage

15. m/z = 43 m/z = 113 Molecular ion m/z = 128  -cleavage at a C=O group

16. Mass Spectrum of 2-octanone 113 43 58 via  - cleavage McLafferty rearragement

17. McLafferty rearrangement of a ketone 1-pentene McLafferty rearrangement of a carboxylic acid ethene

18. Mass Spectrum of Benzamide 105 77 44 121

19. 19 Mass Spectrum of Toluene 92 91 Loss of H Benzyl cation???

20. Tropylium cation m/z = 91 Toluene radical cation m/z = 92 m/z = 91 common to all alkyl benzenes

21. Mass Spectrum of 3-methyl-1-butanamine 30 via  - cleavage