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Effect of ortho substituents in the electron impact induced fragmentation of 2,2′‐disubstituted stilbenes
Author(s) -
Mintas M.,
Jakopčić K.,
Klasinc L.,
Güsten H.
Publication year - 1977
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.1210120904
Subject(s) - fragmentation (computing) , chemistry , metastability , ion , electron ionization , electron , medicinal chemistry , photochemistry , stereochemistry , computational chemistry , organic chemistry , physics , quantum mechanics , computer science , ionization , operating system
The effect of ortho substituents NH 2 , OCH 3 , CH 3 , Cl and NO 2 on the fragmentation of five symmetrically and five unsymmetrically 2,2′‐disubstituted stilbenes under electron impact was investigated. The fragmentation patterns deduced were supported by metastable transitions in the first and second field free regions and by exact mass measurements of prominent ions. In general, the fragmentation was found to be in accord with that of stilbene and the corresponding monosubstituted stilbenes. There are, however, some deviations from the general fragmentation scheme caused by direct through‐space interactions of the ortho , ortho ′ substituents with concomitant loss of neutral fragments. It is supposed that the formation of 7‐membered cyclic or heterocyclic ions is the result of such through‐space reactions.