A Nontrigonal Tricoordinate Phosphorus Ligand Exhibiting Reversible “Nonspectator” L/X‐Switching

Abstract

© 2019 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim We report here a “nonspectator” behavior for an unsupported L-function σ3-P ligand (i.e. P{N[o-NMe-C6H4]2}, 1a) in complex with the cyclopentadienyliron dicarbonyl cation (Fp+). Treatment of 1a⋅Fp+ with [(Me2N)3S][Me3SiF2] results in fluoride addition to the P-center, giving the isolable crystalline fluorometallophosphorane 1aF⋅Fp that allows a crystallographic assessment of the variance in the Fe−P bond as a function of P-coordination number. The nonspectator reactivity of 1a⋅Fp+ is rationalized on the basis of electronic structure arguments and by comparison to trigonal analogue (Me2N)3P⋅Fp+ (i.e. 1b⋅Fp+), which is inert to fluoride addition. These observations establish a nonspectator L/X-switching in (σ3-P)–M complexes by reversible access to higher-coordinate phosphorus ligand fragments.