Fluorination of dimethylaminopentachlorocyclotriphosphazene

Abstract

Reaction of dimethylaminopentachlorocyclotriphosphazene (I) with KSO₂F under reduced pressure yields a series of partially fluorinated compounds, P₃N₃F_nCl_{5 –n}NMe₂(n= 1–4). For n= 1 and 3, cis and trans isomers are formed. The reaction is shown to follow a geminal replacement scheme with preferential attack at the PCl₂ group. Reaction of (I) with KSO₂F in MeNO₂ yields mainly P₃N₃F₅NMe₂ while with NaF in MeCN solution the major product is P₃N₃F₄ClNMe₂. A second monofluoride, P₃N₃FCl₄NMe₂, in which the fluorine is attached to the amine substituted phosphorus atom is obtained by reacting (I) with SbF₃ in the presence of SbCl₅. Structures are proposed on the basis of ¹H and ¹⁹F n.m.r. spectroscopy. Important features from i.r. spectroscopy and mass spectrometry are also discussed.