Metastable ion study of organosilicon compounds. Part IX. CH 3COOSi(CH 3) 3 and CF 3COOSi(CH 3) 3

Abstract

The unimolecular metastable dissociation of trimethylsilyl acetate, CH 3COOSi(CH 3) 3 ( 1), and its fluorine analogue, trimethylsilyl trifluoroacetate, CF 3COOSi(CH 3) 3 ( 2), upon electron impact have been investigated by means of a B/E linked scan, high resolution data, and D-labeling. The results are compared with those of the carbon analogue, tert-butyl acetate, CH 3COOC(CH 3) 3 ( 3). No molecular ion of any of these compounds can be observed, but loss of CH 3 occurs exclusively from the trimethylsilyl or tert-butyl groups. The fragmentation of 1 + is slightly different from that of 3 +, and quite different from that of 2 +, In the case of 3 +, (CH 3) 2CO is eliminated from [3-CH 3] +, giving rise to the peak at m z 43 , but the loss of (CH 3) 2SiO does not occur from [ 1-CH 3] +. In the case of 2 +·, an interesting fluorine atom (F) migration is observed.