Collision induced dissociation experiments

The apparatus and techniques of ion cyclotron resonance spectroscopy have been described in detail elsewhere. Ions are formed, either by electron impact from a volatile precursor, or by laser evaporation and ionization of a solid metal target (14), and allowed to interact with neutral reactants. Freiser and co-workers have refined this experimental methodology with the use of elegant collision induced dissociation experiments for reactant preparation and the selective introduction of neutral reactants using pulsed gas valves (15). Irradiation of the ions with either lasers or conventional light sources during selected portions of the trapped ion cycle makes it possible to study ion photochemical processes... 

The reaction of bare metal ions with sulfur has received some attention. The reaction of metal ions with elemental sulfur (S8) was first studied by Freiser and his co-worker (110) in the study of Fe+ with S8. This reaction produced the ions [FeSJ+, where x = 1-10, which under collision-induced dissociation experiments were observed to undergo sequential loss of S2 units. It has been suggested that Fe(S2)5 + would result in the unreasonable oxidation state of Fe(XI) (9). The S2 unit is similar to the 02 molecule with two unpaired electrons and could act as a neutral ligand (not an anion S2 or dianion) and the oxidation state of Fe in the ion Fe(S2)5 + would be (I). Some similar ions have also been produced by the reaction of Fe+ with ethene sulfide, QH4S. The results for Fe+ have now been confirmed in a study of all the transition metals cations (except Tc+) reacting with gaseous sulfur (50, 150). The study shows that [MS4]+ was a common first major ion (some reac-... 

Ackloo, S. Z., Smith, R. W., Terlouw, J. K., and McCarry, B. E. (2000). Characterization of ginseng saponins using electrospray mass spectrometry and collision-induced dissociation experiments of metal-attachment ions. Analyst 125, 591-597. 

Data obtained from collision-induced dissociation experiments did not allow for a distinction of the isomeric metal-silene and-silylene species however, structure-specific ion-molecule reactions of the complexes with labeled ethene were used to clearly differentiate between the metal silene and the silylene. In this intriguing study, Jacobson and coworkers also bracketed the bond dissociation energies of the isomeric ions. 

Another benefit noted was the absence of common interfering species, including C10+, ArO+, Ar2+. Collision-induced dissociation experiments were... 

In Table 5 are also shown the 0 K stepwise Ag+—CO bond dissociation enthalpies of Ag(CO)4+ from Armentrout and his coworkers49. From their collision-induced dissociation experiments in a guided ion beam mass spectrometer, one finds a nonmonotonic change in ZJo[Ag(CO)n+—CO] as a function of n. That the dissociation energy increases from n = 0 to n = I has been explained in terms of 4s-3d[Pg.62]

Amicangelo, J.C. Armentrout, P.B. Absolute binding energies of alkali-metal cation complexes with benzene determined by threshold collision-induced dissociation experiments and ab initio theory. J. Phys. Chem., A 2000. 104. 11420-11432. 

Absolute binding energies of alkali-metal cation complexes with benzene determined by threshold collision-induced dissociation experiments and ab initio theory ... 

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