Diazonium hexafluorophosphates, aryl fluorides from

The diazonium hexafluorophosphates, prepared similarly from the appropriate diazonium chloride solution and hexafluorophosphoric acid, may in general be used instead of the fluoroborates with advantage. The thermal decomposition of diazonium hexafluorophosphates to aryl fluorides generally proceeds smoothly and in better yield.29... 

Difluorotris(perfluoroalkyl)-25-phosphancs (Rf)3PF2 give stable salts with cesium fluoride, potassium fluoride, sodium fluoride or arenediazonium fluorides, i.e. Cat + [(RF)3PF3] , where Cal+ = Cs +. K+, Na +, ArN2+. The last are difficult to dissolve and they decompose at much lower temperatures (60-90 C) than tetrafluoroborates and hexafluorophosphates. which allows more complete precipitation of diazonium salts from water solutions and their conversion into aryl fluorides 6 without tar formation.6... 

Fluorine can also be introduced onto aromatic rings via diazonium ions. One procedure is to isolate aryl diazonium tetrafluoroborates. These thermally decompose to give aryl fluorides presumably by formation of the aryl cation which abstracts fluoride from the anion.Hexafluorophosphate salts behave similarly.The... 

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