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Charge localization in molecule‐ions upon electron‐impact. Mass spectra of some substituted 1‐carbamoyl‐ and 1‐thiocarbamoyl‐2‐pyrazolines and related compounds
Author(s) -
Tam S. W.
Publication year - 1969
Publication title -
organic mass spectrometry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.475
H-Index - 121
eISSN - 1096-9888
pISSN - 0030-493X
DOI - 10.1002/oms.1210020707
Subject(s) - fragmentation (computing) , chemistry , electron ionization , mass spectrum , ion , molecule , polyatomic ion , ionization , isothiocyanate , computational chemistry , mass spectrometry , spectral line , diradical , photochemistry , electron , organic chemistry , atomic physics , physics , chromatography , astronomy , computer science , operating system , quantum mechanics , singlet state , excited state
The mass spectra of some substituted 2‐pyrazolines and a pyrazolidine are discussed. With the exception of III which favours McLafferty rearrangements prior to fragmentation, I, IV and V fragment to give isocyanate or isothiocyanate radicals and ions with structures corresponding to their heterocyclic molecular compounds. These results which can be explained in the light of the concept of charge localization at preferential sites, are in good agreement with the ionization potential studies on substituted ureas and thioureas. 5 Other compounds show simple straight‐forward fragmentations upon electron‐impact.