MoO-02
MASS SPECTROMETRY AS A TOOL FOR GENERATING UNUSUAL ANIONS AND NEUTRALS OF INTERSTELLAR SIGNIFICANCE
Stephen Blanksby, Suresh Dua, John Sheldon, Helmut Schwarz* and
John H. Bowie
Department of Chemistry, The University of Adelaide, South Australia 5005
*Institut fur Organische Chemie der Technischen Universitat Berlin, Strasse des 17. Juni, D-10623 Berlin, Germany
Radio-astronomy has revealed a rich chemistry within both interstellar and circumstellar clouds. Over one hundred different molecular species have so far been identified in these environments many of which have unusual molecular structures and in some cases have not been previously identified in the laboratory environment1. Numerous different methods of generating these species have been attempted with varying degrees of success and structural specificity2-4. We have been particularly concerned with the highly unsaturated hydrocarbon chains C3Hn and C5Hn (where n=1,2). Using the techniques of negative ion mass spectrometry we have been able to "synthesise" anionic analogues of these hydrocarbons. Our approach gives sufficient structural specificity to address the vast number of possible isomers which we have identified by ab initio calculations. We have also used the techniques of Charge Reversal (CR) and more particularly Neutralisation Reionisation Mass Spectrometry (NRMS) to generate the corresponding neutrals. The mechanistic pathways for generation of these unusual anionic species will be discussed along with the CR and NRMS spectra and also the possibilities for future work based on ab initio data.
1. E. Herbst, Angew. Chem. Int. Ed. Engl. 1990, 29, 595.
2. G. Maier, H.P. Reisenauer, W. Schwab, P. Carsky, B.A. Hess, L.J. Schaad, J. Am. Chem. Soc. 1987, 109, 5183.
3. P. Thaddeus, C.A. Gottlieb, R. Mollaaghababa, J.M. Vrtilek, J. Chem. Soc. Faraday Trans. 1993, 89(13), 2125.
4. N. Goldberg, D. Sulzle, H. Schwarz, Chem. Phys. Letters 1993, 213(5,6), 593.