Metastable ion study of organosilicon compounds part II—hexamethyldisiloxane

✍ Scribed by Seiji Tobita; Susumu Tajima; Fumio Okada; Shigeru Mori; Eiichi Tabei; Mitsuo Umemura

• Publisher: John Wiley and Sons
• Year: 1990
• Tongue: English
• Weight: 375 KB
• Volume: 25
• Category: Article
• ISSN: 1076-5174
• DOI: 10.1002/oms.1210250109

✦ Synopsis

Unimolecular reactions of the metastable silicenium ion (CH,),SiOSi(CH,), + generated by dissociative ionization of hexamethyldisiloxane were investigated by mass-analysed ion kinetic energy (MIKE) spectrometry. The characteristic fragmentations observed were losses of CH, and (CH,),Si=O molecules. Complete scrambling of all methyl groups prior to these reactions was found by investigating the MIKE spectra of deuterium labelled analogues (CD,),SiOSi(CH&* and (CH,),SiOSi(CD,),+. The loss of methane was accompanied by a large kinetic energy release (To.5 = 482 meV). Tbe MIKE spectra of silicenium ions were compared with those of their carbon analogues. The most predominant reaction of metastable (CH,),COC(CH,), + ion was the loss of CH,=C(CH,), leading to protonated acetone. Significant differences between the ion fragmentation characteristics of silicon and carbon compounds were found.