Premium
Site of protonation in the reaction of gaseous Brønsted acids with halobenzene derivatives
Author(s) -
Liauw Wie Giap,
Harrison Alex G.
Publication year - 1981
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.1210160905
Subject(s) - protonation , fluorobenzene , chemistry , chlorobenzene , reagent , ring (chemistry) , photochemistry , medicinal chemistry , deuterium , ion , catalysis , organic chemistry , benzene , physics , quantum mechanics
The site of protonation in the reaction of gaseous Brønsted acids with chlorobenzene and fluorobenzene derivatives has been examined using deuterium labelling of chlorobenzene and deuterated reagent gases (D 2 and N 2 /D 2 ). In the protonation of chlorobenzene by [H 3 ] + ∼30% of the [MHHCl] + fragment ions arise from a chlorine‐protonated species while ∼70% arise from a ring‐protonated species in which complete hydrogen scrambling has occurred. In the reaction of [N 2 H] + with chlorobenzene ∼75% of the fragment ions arise from the chlorine‐protonated form with ∼25% arising from the ring‐protonated form of [MH] + . By contrast fluorobenzene fragments almost entirely from the fluorine‐protonated form. Similar results are obtained for dihalobenzenes. The mechanistic implications are discussed.