Electron-Capture–Induced Dissociation of Protoporphyrin IX Ions

Virgile Bernigaud (1) , K. Drenck (2) , B.A. Huber (1) , P. Hvelplund (2) , T. Jabot (2) , U. Kadhane (2) , M.-B. Suhr Kirketerp (2) , Bo Liu (3) , M. Kocks Lykkegaard (2) , Bruno Manil (1) , S. Brondsted Nielsen (2)

1 CIMAP - UMR 6252 - Centre de recherche sur les Ions, les MAtériaux et la Photonique
2 Department of Physics and Astronomy [Aarhus]
3 Institute of Photo-biophysics

Electron-capture induced dissociation of protoporphyrin cations and anions has been studied. The cations captured two electrons in two successive collisions and were converted to the corresponding even-electron anions. About one fifth of the ions lost a hydrogen atom to become radical anions but otherwise very little fragmentation was observed. The anions captured an electron to become dianions. No hydrogen loss occurred, and the only fragmentation channel observed was loss of CO2H, to give a doubly charged carbanion. Our results indicate that protoporphyrin ions are very efficient in accommodating one or even two electrons in the lowest unoccupied molecular orbital of the porphyrin macrocycle, and that electron capture induces only limited dissociation. (J Am Soc Mass Spectrom 2008, 19, 809–813)

Domains: Atomic Physics [physics.atom-ph]

Virgile Bernigaud, K. Drenck, B.A. Huber, P. Hvelplund, T. Jabot, et al.. Electron-Capture–Induced Dissociation of Protoporphyrin IX Ions. Journal of The American Society for Mass Spectrometry, 2008, 19, pp.809-813. ⟨cea-00306468⟩