Gas phase ion chemistry of (CH3)3SiCF3 and (CH3)3SiC2F5, FTICR experiments and theory

The ion chemistry of the fluoroalkyltrimethylsilanes (CH3)3SiCF3 and (CH3)3SiC2F5 has been investigated in the gas phase with Fourier transform ion cyclotron resonance spectrometry. The formation of positive and negative ions was studied. Reaction pathways for primary ions with neutral molecules at different pressures for various trapping times were monitored. The major product ions were siliconate (SiX5−) and fluoronium ions like (CH3)6FSi2+. Siliconate ions were also generated by F−-transfer reactions with SF6− and SF5−. The results of the mass spectrometric investigations are supported by DFT-calculations.