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Loss of methyl from ionized 2‐hydroxy‐1,3‐butadiene
Author(s) -
Turefček František,
Maquin Francis,
Hill Nicholas,
Stahl Daniel,
Gäumann Tino
Publication year - 1988
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.1210230206
Subject(s) - deuterium , chemistry , ion , hydrogen atom , metastability , hydrogen , methyl radical , medicinal chemistry , carbon fibers , radical , atomic physics , organic chemistry , materials science , physics , alkyl , composite number , composite material
The loss of methyl from unstable, metastable and collisionally activated [CH 2 CHC(OH)CH 2 ] + ˙ ions (1 + ˙) was examined by means of deuterium and 13 C labelling, appearance energy measurements and product identification. High‐energy, short‐lived 1 + ˙ lose methyl groups incorporating the original enolic methene (C(1)) and the hydroxyl hydrogen atom (H(0)). The eliminations of C(1)H(1)H(1)H(4) and C(4)H(4)H(4)H(0) are less frequent in high‐energy ions. Metastable 1 + ˙ eliminate mainly C(1)H(1)H(1)H(4), the elimination being accompanied by incomplete randomization of the five carbon‐bound hydrogen atoms. The resulting [C 3 H 3 O] + ions have been identified as the most stable CH 2 CHCO + species. The appearance energy for the loss of methyl from 1 was measured as AE [C 3 H 3 O] + = 10.47 ± 0.05 eV. The critical energy for 1 + ˙ → [C 3 H 3 O] + + CH 3 ˙ is assessed as E c ⩽ 173 kJ mol −1 . Reaction mechanisms are proposed and discussed.