ISSN:
0570-0833
Keywords:
Mass spectrometry
;
Analytical methods
;
Mass spectrometry
;
Chemistry
;
General Chemistry
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
The diluted gas phase within a mass spectrometer is ideally suited for performing collision experiments of fast moving ions with thermalized target atoms. One important reaction which can be brought about with a given cation is its selective reduction, i. e. its neutralization. This allows the synthesis in tailored experiments of a variety of unusual chemical species, which because of intermolecular processes cannot be prepared or studied in solution or in a matrix. Among the molecules which have been generated in this way are hypervalent species (Rydberg radicals) like H3⊙, van der Waals complexes like He2, mono- or disubstituted acetylene derivatives XC≡CY (X = H, Y = OH, NH2; X = Y = OH, NH2), and elusive compounds like carbonic acid (H2CO3) or carbamic acid (NH2CO2H). Collision experiments can also be used advantageously for the structural analysis of the neutral molecule N generated in unimolecular dissociation reactions of the type m1⊕ → m2⊕+N. The dissociation of ionized aniline for example yields, besides C5H6⊙⊕ cations, neutral isocyanic acid, HNC, and not cyanic acid, HCN. The technique of Neutralization Reionization Mass Spectrometry (NRMS) is performed in the diluted gas phase, a medium where intermolecular interactions are entirely absent. The method may therefore increasingly be applied to the study of molecular species whose reactivity precludes their characterization in matrices. Molecules in specific excited states and fragments of organometallic compounds with unsaturated valencies are two examples of systems which could fruitfully be studied.
Additional Material:
5 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/anie.198708053
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