Abstract
Mass Spectrometry is a powerful tool for identification, of organic compounds. One of the most important fragmentation in mass spectrometry is the McLafferty rearrangement. Organosilicon compounds are widely used in synthetic chemistry, industry, and polymer science. Silyl groups in organic compounds may exert an α-, β-, or γ-effect in various reactions. We prepared a series of organosilicon compounds and systematic analysed their mass spectra. Electron impact induced fragmentation was performed in the gas phase on δ-silyl aldehydes, ketones, thioketones, carboxylic acids, and acetates. All of them show significant silyl migration through a seven-membered ring transition states. This silyl migration process may overwhelm the McLafferty rearrangement, with a six-membered ring transition state, for ketones and acetates.