Lewis Acid Stabilized OPI 3 : Implications for the Nature of Free OPI 3

While reinvestigating the published synthesis of OPI 3 , it became evident from the experiments that phosphoryl triodide may only be formed as an intermediate and that the end products of the reaction of OPCl 3 with LiI are P V oxides, PI 3 , I 2 , and LiCl. This is also in agreement with MP2/TZVPP calculations, which assign Δ r H ° (Δ r G °) [Δ r G ° in CHCl 3 ] for the disproportionation of OPI 3 as −7 (−18) [−17 kJ mol −1 ] (assuming P 4 O 10 as the P V oxide). The first products of this reaction visible in a low‐temperature in situ 31 P NMR experiment are P 2 I 4 and PI 3 , as well as traces of a compound that may be OPCl 2 I. By contrast, it was possible to prepare and structurally characterize Lewis acid [A] stabilized [A]←OPX 3 adducts, where [A] is Al(OR F ) 3 for X=Br and Al(OR F ) 2 (μ‐F)Al(OR F ) 3 for X=I (R F =C(CF 3 ) 3 ). These adducts are formed on decomposition of PX 4 + [Al(OR F ) 4 ] − ; high yields of Br 3 PO→Al(OR F ) 3 ( δ ( 31 P)=−65) were obtained, while I 3 PO→Al(OR F ) 3 ( δ ( 31 P)=−337) and I 3 PO→Al(OR F ) 2 (μ‐F)Al(OR F ) 3 ( δ ( 31 P)=−332) are only formed as by‐products. The main product of the room‐temperature decomposition of PI 4 + [Al(OR F ) 4 ] − is PI 4 + [(R F O) 3 Al(μ‐F)Al(OR F ) 3 ] − , which was also characterized by X‐ray crystallography and was independently prepared from Ag + [(R F O) 3 Al(μ‐F)Al(OR F ) 3 ] − , PI 3 , and I 2 .