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Electron‐impact fragmentation of cyclocarbosiloxanes
Author(s) -
Orlov V. Yu.,
Nametkin N. S.,
Gusel'nikov L. E.,
Islamov T. H.
Publication year - 1970
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.1210040121
Subject(s) - electron ionization , fragmentation (computing) , ion , chemistry , metastability , mass spectrum , electron , molecule , analytical chemistry (journal) , physics , organic chemistry , ionization , quantum mechanics , computer science , operating system
The fragmentation of six and eight membered methyl substituted cyclocarbosiloxanes of general formula (CH 3 ) 6 Si 3 O 3 n (CH 2 ) n (n = 1 or 2) and (CH 3 ) 8 Si 4 O 4−n (CH 2 ) n (n = 1, 2 or 3) under electron‐impact (70 eV) is reported. The behaviour of these compounds under electron‐impact is intermediate between that of the corresponding cyclosiloxanes and cyclocarbosilanes. In every case the most intense singly and doubly charged ions correspond to the loss of one and two methyl groups respectively. In going from the cyclosiloxanes to the cyclocarbosilanes the intensity of the primary ions is reduced and the intensity of those fragment ions whose formation involves the rearrangement or breakdown of the cyclic framework of the molecule is increased. These ions are the [M CH 3 (CH 3 ) 4 Si] + ions in the eight membered and the [(CH 3 ) 3 Si] + ions in both cases. The data on doubly charged and metastable ions in the mass spectra of the cyclocarbosiloxanes are presented and discussed. The fragmentation of six and eight membered methyl substituted cyclocarbosiloxanes of general formula (CH 3 ) 6 Si 3 O 3 n (CH 2 ) n (n = 1 or 2) and (CH 3 ) 8 Si 4 O 4−n (CH 2 ) n (n = 1, 2 or 3) under electron‐impact (70 eV) is reported. The behaviour of these compounds under electron‐impact is intermediate between that of the corresponding cyclosiloxanes and cyclocarbosilanes. In every case the most intense singly and doubly charged ions correspond to the loss of one and two methyl groups respectively. In going from the cyclosiloxanes to the cyclocarbosilanes the intensity of the primary ions is reduced and the intensity of those fragment ions whose formation involves the rearrangement or breakdown of the cyclic framework of the molecule is increased. These ions are the [M CH 3 (CH 3 ) 4 Si] + ions in the eight membered and the [(CH 3 ) 3 Si] + ions in both cases. The data on doubly charged and metastable ions in the mass spectra of the cyclocarbosiloxanes are presented and discussed.