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Chem-805 Identification of organic and inorganic compounds by spectroscopy

Chem-805 Identification of organic and inorganic compounds by spectroscopy. Mass Spectrometry Fragmentation-2 NMR Infrared. Index. MS. MS-fragmentation-1. Aromatic Ketones. Aromatic Ketones. 105. 77. Aromatic Ketone with Chlorine. Aliphatic Ketones.

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Chem-805 Identification of organic and inorganic compounds by spectroscopy

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  1. Chem-805Identification of organic and inorganic compounds by spectroscopy Mass Spectrometry Fragmentation-2 NMR Infrared Index MS MS-fragmentation-1

  2. Aromatic Ketones

  3. Aromatic Ketones 105 77

  4. Aromatic Ketone with Chlorine

  5. Aliphatic Ketones Longer Alkyl chain : McLafferty Rearrangement -R3-CH=CHR2 Major peak If R is a longer chain : the ion can rearrange again

  6. Aliphatic Ketones

  7. 43 113

  8. Aldehydes Straight Chain : M – 18 (H2O loss) • M – 28 => Loss of CH2=CH2 • M – 43 => Loss of CH2=CH-O Long Chain : Hydrocarbon Pattern m/z 29, 43, 57, 71 …. Aromatic : Large M .+ Large (M – 1) [-C≡O ]+

  9. Aromatic Aldehyde Large (M – 1)

  10. Aldehydes

  11. Aldehydes

  12. Long Chain Aldehyde

  13. CH3—CH2—CH2—CH2—CH2—C—OH O Acid McLafferty rearrangement (often Base peak) – (stronger for a branch) m/z 60, 74, 88 … Aso cleavage next to C=O 71 29 43 57 • Charge on Oxygen • Charge on Alkyl 87 73 59 45

  14. Aromatic Acid M+ is large (M – 17) loss of OH (M – 45) loss of COOH With ortho substituant  rearrangement - ZH Z  OH, OR, NH Y  CH2, O, NH Easy loss of Neutral Molecule (H2O, R-OH, NH3)

  15. Ortho-Aromatic Acid - H2O 120 B - COOH, H 138 92 M+

  16. para-Aromatic Acid 121 138 - OH M+ B

  17. Ester

  18. O C OR R m/z 74 Ester M-31 McLafferty m/z 74 Also cleavage next to C=O M – OR (if R=Me, M-31)

  19. Aliphatic Ester

  20. Aromatic Ester

  21. Aromatic Ether Molecular ion is prominent 1) Cleavage in b of aromatic ring - CO C5H5+ - R m/z 65 m/z 93 2) Rearrangement - CH2=CH2 m/z 94

  22. Primary Amines

  23. Secondary Amines

  24. M+. Odd, Cleavage next to heteroatom Fragmentation even

  25. M+. Odd, Cleavage next to heteroatom Fragmentation even Tertiary Amine

  26. Aromatic Amines

  27. Nitro

  28. Nitrile

  29. Nitrile McLafferty:

  30. Sulfide

  31. Sulfoxyde

  32. Isotope peaks in Halogen compounds

  33. Chlorine compound

  34. Bromine compound

  35. Iodine compound

  36. Halogen in alkyl chain Cleavage at C-X produce: [M-X]+. Weak [M]+.For linear chain

  37. Straight chain longer than C6 Have the following mechanism Halogen in alkyl chain Weak [M]+.For linear chain

  38. Halogens

  39. Chloro, Bromo alkyl

  40. Dichloromethane

  41. Dibromomethane Index MS MS-fragmentation-1 MS-Organometallic

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