Figure 1 High-resolution ESI-MS/MS of
[M –OTf]+: (a ) 1 ,
(b ) 2 , (c ) 3 and (d )4 .
Scheme 3 Proposed fragmentation patterns of
[M –OTf]+: (a ) 1 ,
(b ) 2 , (c ) 3 and (d )4 .
When we examined diaryliodonium salt 4 with introduction of a
nitro group into Ar2, We not only observed fragment
ions consistent with the processes outlined in Scheme 3 but
also identified novel types of fragment ions:
[t Bu-C6H4O]+at m/z 149 and
[p -NO-C6H4I]+•at m/z 233 in the ESI-MS/MS of
[(p -t Bu-C6H4)-I+-(p -NO2-C6H4)]
at m/z 382 (Figure 1d and Scheme 3 ). These
findings strongly suggested the involvement of a gas-phase O-atom
transfer reaction from the nitro group to the aryl moiety in the
ESI-MS/MS of
[(p -t Bu-C6H4)-I+-(p -NO2-C6H4)].
It could be attributed to the presence of a nitro group in
Ar2 of the diaryliodonium cations.