Structural origin of the formation of odd-numbered carbon clusters from fullerene derivatives

We report the mass spectrometric investigation on fullerene derivatives C60 CH2, C60RH, C60R2(R = C6H5CO-) and C60On under the 308 nm laser ablation. I n the negative ion mass spectra of C60CH2 C60R2, and C60On, odd-numbered cl usters C-57(-),G(55)(-), C-53(-), C-51(-) are observed clearly in addition to the even-numbered fullerene fragment ions, while for the monoadduct C60R H, odd-numbered species can not he detected. In the positive ion channel, t he fragmentation patterns of the three derivatives are similar. A mechanism related to the structural characteristics of the derivatives is supposed f or the odd-numbered cluster formation. The 3-membered ring formed on the C- 60 cage is thought of to play a vital role for the formation of odd-numbere d carl,on clusters.