Ion-molecule reactions of transition-metal ions with nitriles in the gas phase: competitive formation of both "end-on" and "side-on" coordination

First field-free region B/E linked scan studies of metastable and particularly collision-induced dissociations show that two competitive coordination processes ("end-on" and "side-on") exist in the complexation of metal ions (Ni + , Co + , Fe + , and Mn + ) with alkanenitriles in the FAB source of an E/B configuration mass spectrometer. Analysis of the B/E linked scan CA spectra gives approximate percentages of the end-on coordination mode in the reactive complexes. An unusual β-methyl migration, involved in the elimination of CH 4 from end-on complexes, may be in competition with β-H migration/elimination of H 2 and β-CC bond cleavage/elimination of alkene. For the side-on complexes, the metal ions can insert into various CC bonds followed by β-H transfer/competitive elimination of alkene and alkane or by a direct CM + bond cleavage to give an alkyl radical. Key words: FAB mass spectroscopy, metal-ion/nitrile reactions, collisional activation, coordination modes, ion-molecule reactions.