Photoionisation of the tropyl radical

• Kathrin H. Fischer,
• Patrick Hemberger,
• Andras Bodi and
• Ingo Fischer

Beilstein J. Org. Chem. 2013, 9, 681–688, doi:10.3762/bjoc.9.77

• are reassigned to the C–C stretch mode ν16+ and to a combination of ν16+ with the ring breathing mode ν2+. Above 10.55 eV dissociative photoionisation of tropyl is observed, leading to the formation of C5H5+ and C2H2. Keywords: dissociative photoionisation; gas phase; reactive intermediates

• precursor 3. Already at around the same energy a signal at m/z = 91 appears. Since there is no pyrolysis, the signal has to originate from dissociative photoionisation of bitropyl. Hence, in the mass spectrum recorded at 8.7 eV (centre trace of Figure 2) the observed masses are m/z = 91, 92 and 182, which

• correspond to a tropyl fragment, its 13C isotopologue and the bitropyl precursor. Above a photon energy of 8.9 eV, the m/z = 104 and 167 peaks appear in addition. They are products from higher energy dissociative photoionisation channels and are probably formed through the loss of benzene or a methyl group