Peak at mz 44 58 or72

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Unformatted text preview: 51 Mass spectra of some classes of compounds: rules and examples 34. hetero ­aromaEc compounds •  prominent molecular ion peak •  cleavage of β bonds is very common CHM3122 Interpreta$on of mass spectra 52 Summary Ionic Fragments Lost Fragments fragment m/z fragment m/z CnH2n+1 14n+1: 15, 29, 43, 57, 71… H2O 18 CnH2n 14, 28, 42, 56, 70 … CO 28 CnH2n ­1 13, 27, 41, 55, 69 …  ­CH3 15 C6H5+ 77  ­CH2 ­ 14 C7H7+ 91 CHO 29 31  ­OH 17 105 CO2H 45 NH3 17 NO2 46 NO 30 HS 33 +CH 2OH PhCO+ CHM3122 Interpreta$on of mass spectra 53 General Strategy 1.  Look for M+ molecular mass 2.  Analyse the isotopic peak presence of Br and/or Cl 3.  Nitrogen Rule # of N atoms 4.  Consult Appendix A Molecular Formula 5.  Calculate DHIndex unsatura$on 6.  Analyze fragmenta$on pagerns and consult Appendices B & C molecular structure 7.  IR/NMR confirm/amend your structure CHM3122 Interpreta$on of mass spectra 54...
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This note was uploaded on 11/10/2012 for the course SCIENCE 1, 2, 3 taught by Professor All during the Spring '12 term at University of Ottawa.

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