Nitrogen‐Based Lewis Acids Derived from Phosphonium Diazo Cations

Reaction of PPh 3 and [( p ‐ClC 6 H 4 )N 2 ][BF 4 ] affords [( p ‐ClC 6 H 4 )N(PPh 3 )N(PPh 3 )][BF 4 ] 1 , while reaction with (Ph 2 PCH 2 ) 2 gave [( p ‐ClC 6 H 4 )(NPh 2 PCH 2 ) 2 )][BF 4 ] 2 . These species confirm the Lewis acidity of [( p ‐ClC 6 H 4 )N 2 (PR 3 )][BF 4 ] cations at N. In contrast, use of bulky phosphines afford the species [ArN 2 (PR 3 )][BF 4 ] (R= t Bu 3 , Mes 4 ). Compound  3 undergoes one electron reduction to give the stable radical [( p ‐ClC 6 H 4 )N 2 (P t Bu 3 )] . 5 . Combination of 3 and P t Bu 3 acts as an FLP to effect (SPh) 2 cleavage, generating [PhSP t Bu 3 ] + and the radical [ArN 2 (PR 3 )] . . Collectively, these data affirm the ability of the cations [ArN 2 (PR 3 )] + to behave as one or two electron acceptors.