Electron-capture-induced dissociation of protoporphyrin IX ions.
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.
Bernigaud
Virgile
V
Centre de Recherche sur les Ions, les Matériaux et la Photonique, Caen Cedex 5, France.
Drenck
Kasper
K
Huber
Bernd A
BA
Hvelplund
Preben
P
Jabot
Tristan
T
Kadhane
Umesh
U
Kirketerp
Maj-Britt Suhr
MB
Liu
Bo
B
Lykkegaard
Morten Køcks
MK
Manil
Bruno
B
Nielsen
Steen Brøndsted
SB
D003198:Computer Simulation; D004583:Electrons; D007477:Ions; D013058:Mass Spectrometry / Q000379:methods*; D008956:Models, Chemical; D008958:Models, Molecular; D008968:Molecular Conformation / Q000528:radiation effects; D011524:Protoporphyrins / Q000737:chemistry* / Q000528:radiation effects
D007477:Ions; D011524:Protoporphyrins; C028025:protoporphyrin IX