MASS SPECTRA OF SOME SUBSTITUTED POLYFLUOROBENZENES

The application of mass spectrometry, including precise mass measurements of molecular ions and selected fragment peaks, in determining the structure of various substituted polyfluorobenzenes is discussed. A high resolution mass spectrometer was used. It is shown that the nature of substituents, their size, position on the ring, and the completeness of fluorination are all vitally important in determining the fragmentation process. The rupture of the various carbon to halogens and carbon to hydrogen bonds are discussed. Interesting metastable peaks were found in some cases and their precursors were traced. For example, the following transition C6F5(+) to C5F3(+) + CF2 was found where the metastable peak appears at m/e 81.97.