Versatile reagent Ph3 As(OTf)2: one-pot synthesis of [P7(AsPh3)3][OTf]3 from PCl3

Compound Ph3 As(OTf)2 as a pentacoordinated As(V) Lewis acid readily forms dicationic Lewis acid/base adducts upon addition of various Lewis bases. It also represents a stronger chloride-abstracting agent than Me3 SiOTf and facilitates the reductive coupling of PCl3 in the presence of AsPh3 to the unprecedented cation [P7 (AsPh3 )3](3+) as triflate salt. This crystallographically characterized nortricyclane-type cation represents a P7 R3 -derivative with the most electron-withdrawing substituents, resulting in a pronounced effect on the structural parameters of the P7 core.