CHARACTERIZATION OF OLIGOMERS OF 3,3,3-TRIFLUORO-1-PHENYLPROPYNE AND 1-PHENYLPROPYNE BY MASS-SPECTROMETRY

Oligomers of Ph-C=C-CF3 and of Ph-C=C-CH3 have been prepared by heating the alkynes with dibenzoyl peroxide as an initiator. The degree of oligomerization, the average molecular weights and the nature of the end groups were determined using a combination of mass spectrometric techniques including desorption electron impact, fast atom bombardment, field desorption and MS/MS. The contrasting end-group patterns have been interpreted in terms of relative rates and HOMO/SOMO energy gaps.