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EI fragmentation of E,Z‐3‐iodo‐2‐alkenoic acids and methyl E,Z‐3‐iodo‐2‐alkenoates
Author(s) -
Herrera J. C.,
Urdaneta N. A.
Publication year - 1998
Publication title -
rapid communications in mass spectrometry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.528
H-Index - 136
eISSN - 1097-0231
pISSN - 0951-4198
DOI - 10.1002/(sici)1097-0231(19980731)12:14<955::aid-rcm267>3.0.co;2-7
Subject(s) - chemistry , heterolysis , fragmentation (computing) , ion , dissociation (chemistry) , electron ionization , polyatomic ion , mass spectrum , bond dissociation energy , medicinal chemistry , computational chemistry , stereochemistry , ionization , organic chemistry , catalysis , computer science , operating system
The electron ionization mass spectra of some E,Z‐3‐iodo‐2‐alkenoic acids and methyl E,Z‐3‐iodo‐2‐alkenoates were investigated. A semi‐empirical method was used to examine the thermochemical and molecular properties of the species. Two fragmentation paths of the molecular ions are determined by the geometry of the carbon–carbon double bond: (i) heterolytic loss of I · radical, and (ii) a rearrangement that produces [M − C n H 2n ] +· ions. The E‐compounds show less stabilized molecular ions, preference to lose I · , and little tendency for the rearrangement. A favourable critical energy (E o ), in the C–I bond dissociation of the E‐compounds, is required to observe the configuration effect. A mechanism for the formation of [M − C n H 2n ] +· ions is proposed. © 1998 John Wiley & Sons, Ltd.