Halogenated triazines and related systems
Trifluoro- and 5-chlorodifluoro-1,2,3-triazine were prepared from the vapour- phase fluorination of trichloro-1,2,3-triazine, and their reactions with several simple nucleophiles were investigated. A new reagent system for the polyfluoroalkylation of the reactive trichloro-1,2,3- and -1,3,5-triazines under very mild conditions was developed with Dr. T. Shepherd. This system was also used to fluorinate various perchloroheteroaromatics under mild conditions. The photolysis of both trifluoro- and perfluoro-4,6- bis-isopropyl-1,2,3-triazines, at liquid nitrogen temperatures, provided conclusive evidence for the direct observation of both trifluoro- and perfluoro-2,4-bisisopropyl- azetes and their respective dimers. Additionally, the transference photolysis of perfluoro-4,6-bis-isopropyl- 1,2,3-triazine provided clear evidence that the dimerisationof perfluoro-2,4-bis-isopropylazete is a thermal process. The static photolysis of trifluoro-1,2,3-triazine produced abrown polymer, which was identified as poly(trifluoroacrylonitrile). The transference photolysis of perfluoro-3,5-bisisopropylpyridazine was repeated, and the identities of two of the perfluoro- 3- isopropylazete dimers were confirmed.Some photolysis and pyrolysis reactions of both perfluoro-3,4,6-tris-isopropylpyridazine and perfluoro-4-(2' -methylpent- 2' -yl)pyridazine were also investigated. An improved synthetic route to hexachlorocinnoline wasdeveloped, but all attempts to produce fluorinated and perfluoroalkyl derivatives were unsuccessful.Studies of the negative ion mass spectra and (^13)C n.m.r. spectra of various series of halogenated and perfluoroalkyl substituted heteroaromatics were also conducted.