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Organic ions in the gas phase—XXI: Synthesis and mass spectra of deuteriothiophenes
Author(s) -
Meyerson Seymour,
Fields E. K.
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.1210020209
Subject(s) - mass spectrum , chemistry , deuterium , scrambling , ion , decomposition , spectral line , hydrogen , yield (engineering) , gas phase , hydrogen–deuterium exchange , analytical chemistry (journal) , atomic physics , physics , organic chemistry , mathematics , algorithm , astronomy , thermodynamics
Mass‐spectral and n.m.r. analysis of thiophenes labeled by exchange with deuteriosulfuric acid establishes that exchange at the 2 and 5 positions is essentially complete before any deuterium is incorporated at positions 3 and 4. Thus, such exchange is a satisfactory procedure for position‐specific labeling. Mass spectra of the labeled thiophenes show that about 60% of the [CHS] + ion yield is derived from molecular ions that have not undergone prior rearrangement. The remaining 40% arises by a path or paths in which the four hydrogen atoms lose position identity. Other decomposition paths contributing to the mass spectrum are characterized by more nearly complete scrambling of hydrogens.