No abstract

The interaction between POCl(3) or POBr(3) and pyridine or DMAP has been reinvestigated to clarify the discrepancies between previously published results concerning the Lewis acidity of phosphoryl halides and their behavior toward pyridine bases. The obtained results show that POCl(3) virtually does not react with pyridine, while it does with 4-(dimethylamino)pyridine (DMAP), even in SO(2) solution, to yield an ionic compound [(DMAP)(2)PO(2)]Cl.3SO(2) (1.3SO(2)). Its recrystallization from acetonitrile gives [(DMAP)(2)PO(2)]Cl.CH(3)CN (1.CH(3)CN). The POBr(3) reacts readily with both DMAP and pyridine forming the analogous tribromides, [(DMAP)(2)PO(2)]Br(3) (2) and [(py)(2)PO(2)]Br(3) (3), respectively. Treatment of 3 with Me(3)SiOSO(2)CF(3) in acetonitrile solution led to [(py)(2)PO(2)][CF(3)SO(3)].CH(3)CN (4), while the reaction between 1.CH(3)CN and Me(3)SiOPOF(2) gave [(DMAP)(2)PO(2)][PO(2)F(2)] (5). The crystal structures of 1.CH(3)CN, 1.3SO(2), 2, and 4 revealed that all four compounds are ionic containing the distorted tetrahedral cations [(DMAP)(2)PO(2)](+) and [(py)(2)PO(2)](+). Both ions represent a donor-stabilized form of the so far unknown cation [PO(2)](+). The geometry of [(DMAP)(2)PO(2)](+), optimized by density functional calculations at the B3LYP/6-31G(d,p) level, is in good agreement with X-ray structural data. The NBO analysis of natural atomic charges shows an extensive delocalization of the [PO(2)](+) intrinsic positive charge and indicates a contribution of the electrostatic attraction to the formation of N-P donor-acceptor bonds. According to a (31)P NMR study, the reactions of both phosphoryl halides with DMAP proceed via successive formation of the intermediates [(DMAP)POX(2)](+) and (DMAP)PO(2)X to give an equimolar mixture of [(DMAP)(2)PO(2)](+) and PX(5) (X = Cl, Br) as the end products. The NMR spectroscopic identification of the cations [(DMAP)POX(2)](+) and [(DMAP)(2)PO(2)](+) was supported by ab initio calculations of their chemical shifts.

A simple procedure for the preparation of phosphoryl chlorofluorides, POFCl 2 and POF 2 Cl, by chlorination of the appropriate potassium fluorophosphates, K 2 PO 3 F and KPO 2 F 2 , respectively, with PCl 5 is described. The analogous bromination with PBr 5 gives POFBr 2 and POF 2 Br. However, due to low yields and high content of impurities, this method is not suitable for the synthesis of the former compound. Both chlorofluorides were crystallized from the melt at low temperatures and their crystal structures were determined by X-ray diffraction at Ϫ153°C. Distorted

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 )] Ϫ are linked to infinite chains by double NϪH···O bridges. Additional strong NϪH···O Synthese von Ammonium-und 4-Dimethylaminopyridinium-Amidofluorophosphaten und die Kristallstruktur von [DMAPH][PO 2 F(NH 2 )]Inhaltsübersicht. NH 4 [PO 2 F(NH 2 )] wurde durch Umsetzung des Betains py·PO 2 F in acetonitrilischer Lösung mit überschüssigem NH 3 dargestellt, während bei der Ammonolyse von DMAP·PO 2 F mit einer stöchiometrischen Menge von Ammoniak [DMAPH]-[PO 2 F(NH 2 )] entsteht. In der Kristallstruktur von [DMAPH]-[PO 2 F(NH 2 )] sind die Anionen durch doppelte Wasserstoff-Brü-* Dr. Miloš Č erník

Key indicatorsSingle-crystal X-ray study T = 120 K Mean '(C±C) = 0.005 A Ê R factor = 0.045 wR factor = 0.142 Data-to-parameter ratio = 12.9For details of how these key indicators were automatically derived from the article, see