4 CONCLUSIONS
In summary, a total of 54 diaryliodonium cations were subjected to a
comprehensive study using high-resolution ESI-MS/MS, and their
fragmentation patterns were elucidated based on the accurate mass
measurements of the resulting fragment ions. Our investigations unveiled
that the incorporation of the nitro group into Ar2 of
[Ar1-I+-Ar2]
could lead to an unexpected type of fragment ion
[Ar1O]+ through an O-atom
transfer process from the nitro group to Ar1 in their
ESI-MS/MS. The particular case was the nitro group positioned in theortho -position of Ar2 moiety of the
diaryliodonium salt. The theoretical calculations provided mechanistic
insights into the O-atom transfer rearrangements ofortho- nitro-substituted diaryliodonium cations which supported
the occurring of gas-phase Smiles rearrangement of
[Ar1-I+-(o -NO2-Ar2)]
to the intermediate
[Ar1-O-(o -NOAr2I)]+,
finally giving the product ions
[Ar1O]+ or
[o -NO- Ar2I]+•.
This work would be useful for the structural characterization of
diaryliodonium cations by mass spectrometry, and the gas-phase Smiles
rearrangement of
[Ar1-I+-(o -NO2-Ar2)]
might offer valuable insights for organic chemists for the design of new
types of organic reactions involving diaryliodonium salts.