Synthesis of Ammonium‐ and 4‐Dimethylaminopyridinium Amidofluorophosphates and Crystal Structure of [DMAPH][PO 2 F(NH 2 )]

NH 4 [PO 2 F(NH 2 )] has been prepared by the reaction of a betaine py·PO 2 F with excess ammonia in acetonitrile solution, while the ammonolysis of DMAP·PO 2 F with a stoichiometric amount of NH 3 yields [DMAPH][PO 2 F(NH 2 )]. The crystal structure of the latter was determined by single‐crystal X‐ray diffraction, which revealed that the anions [PO 2 F(NH 2 )] — are linked to infinite chains by double N—H···O bridges. Additional strong N—H···O bridging bonds connect each anion with its [DMAPH] + counterion. The formation of a new betaine NH 3 ·PO 2 F in the solution of py·PO 2 F in liquid ammonia was proved by 31 P NMR spectroscopy and by identification of its hydrolysis products.