Electron-impact induced fragmentation of some 5,10-di- hydrophenazastannines

• Published in: Journal of organometallic chemistry Vol. 42; no. 1; pp. 95 - 106
• Main Authors: Lengyel, István, Aaronson, Michael J.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 16.08.1972
• ISSN: 0022-328X; 1872-8561
• DOI: 10.1016/S0022-328X(00)81835-5

The electron-impact induced fragmentation of four 5,10-dihydrophenazastannides [(I)-(IV)] was studied by low and high resolution mass spectrometry. Two of the compounds contain tin in the spiro position. To identify energetically favorable reaction paths, low electron-energy scans (12 eV) were taken along with 70 eV ones. The molecular ions fragment by consecutive ejection of the 10-substituents or, alternatively, by loss of R 2Sn. Subsequent fragmentation is accompanied by complex skeletal rearrangements and hydrogen migrations. An example of SnBr bond formation has been discovered. Ions of the phenanthridine type (m/e 179, C 13H 9N) are formed via enlargement of the center heterocyclic ring and rearomatization. Tentative mechanistic pathways are derived for all major fragmentation sequences on the basis of computer-aided correlation of metastable peaks, accurate mass measurements (elemental composition) and shifts resulting from specific deuterium labelling.