Synthesis of Ammonium‐ and 4‐Dimethylaminopyridinium Amidofluorophosphates and Crystal Structure of [DMAPH][PO2F(NH2)]

NH₄PO₂F(NH₂)] has been prepared by the reaction of a betaine py·PO₂F with excess ammonia in acetonitrile solution, while the ammonolysis of DMAP·PO₂F with a stoichiometric amount of NH₃ yields DMAPH]PO₂F(NH₂)]. The crystal structure of the latter was determined by single‐crystal X‐ray diffraction, which revealed that the anions PO₂F(NH₂)]^— 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 NH₃·PO₂F in the solution of py·PO₂F in liquid ammonia was proved by ³¹P NMR spectroscopy and by identification of its hydrolysis products.