Fragmentation and rearrangement processes in the mass spectra of perhalogenoaromatic compounds. Part II. Pentafluorophenyl derivatives of GroupIV

Abstract

The mass spectra of compounds of the type (C₆F₅)₄M (M = Si, Ge, Sn, and Pb) have been studied. Bond forming rearrangements were detected, involving fluorine abstraction by the central atom, forming perfluorophenylene ions and neutral metal fluoride species. The heavier metals give simpler spectra and fragmentation schemes. The bulk of the ion current is carried by fluorocarbon ions for the silicon derivative and by organometallic or metal fluoride ions in the other three cases, SnF⁺ and PbF⁺ forming the base peaks in their spectra. When M is carbon in the compounds (C₆F₅)₃COH and (C₆F₅)₂CO, there is little evidence for rearrangements and transfer of fluorine to the central carbon atom.