High-Yield Synthesis and Reactivity of Stable Diiron Complexes with Bent-Phosphinidene Bridges

Reaction of [Fe2Cp2(μ-CO)2(CO)(PRH2)] (Cp
= η5-C5H5; R = Cy, Ph) with [FeCp2]BF4 gives the
phosphide-bridged complexes [Fe2Cp2(μ-PRH)(μ-CO)(CO)2]BF4, which are deprotonated by M(OH) (M = Na,
K) to give the phosphinidene derivatives [Fe2Cp2(μ-PR)(μ-CO)(CO)2] in high yield. The cyclohexylphosphinidene
complex reacts at room temperature with MeI, O2, S8,
or H2CCHR‘ (R‘ = CO2Me) to give selectively [Fe2Cp2(μ-PCyMe)(μ-CO)(CO)2]I or neutral derivatives of the
types [Fe2Cp2{μ-P(E)Cy}(μ-CO)(CO)2] (E = O, S) and
[Fe2Cp2{μ-κ1:κ1,η1-CyPCH2CHR‘C(O)}(μ-CO)(CO)].