Syntheses and Reactions of the Fluorinated Cyclic Thionylphosphazene NSO(Ar)[NPF2]2 (Ar = 4-t-BuC6H4−) with Difunctional Reagents

The S−aryl substituted thionylphosphazene (Cl2PN)2[4-t-BuC6H4(O)SN] (1) was prepared by Friedel−Craft's reaction of NSOCl(NPCl2)2 with tert-butylbenzene. When it reacted with excess KSO2F at 110 °C, the P−Cl bonds of 1 were fluorinated, yielding the tetrafluorothionylphosphazene, (F2PN)2[4-t-BuC6H4(O)SN] (2). An equimolar reaction of 2 with dilithiated 1,3-propanediol in THF at −78 °C resulted in the formation of the ansa-substituted compound CH2(CH2O)2[FPN]2[4-t-BuC6H4(O)SN] (3). The crystal structures of 2 and 3 were determined. In 3 the ansa ring is trans on the PNS heterocycle with respect to the aryl group. Reaction of 2 with the disiloxane (CF2CH2OSiMe3)2, in the presence of catalytic amounts of CsF in THF at 90 °C, resulted in the formation of the dispiro compound [(CF2CH2O)2PN]2[4-t-BuC6H4(O)SN] (4). Compounds 14 were characterized by IR, NMR (1H, 13C, 19F, 31P), mass spectral, and elemental analyses.