High-yield synthesis and reactivity of stable diiron complexes with bent-phosphinidene bridges

Reaction of [Fe2Cp2(mu-CO)(2)(CO)(PRH2)] (Cp = eta(5)-C5H5; R = Cy, Ph) with [FeCp2]BF4 gives the phosphide-bridged complexes [Fe2Cp2(mu-PRH)(mu-CO)(CO)(2)]BF4, which are deprotonated by M(OH) (M = Na, K) to give the phosphinidene derivatives [Fe2Cp2(mu-PR)(mu-CO)(CO)(2)] in high yield. The cyclohexylphosphinidene complex reacts at room temperature with MeI, O-2, S-8, or H2C=CHR' (R' = CO2Me) to give selectively [Fe2Cp2(mu-PCyMe)(mu-CO)(CO)(2)]I or neutral derivatives of the types [Fe2Cp2{mu-PCyMe)(mu-CO)(CO)(2)] (E = O, S) and [Fe2Cp2{mu-k(1):k(1), eta(1)-CyPCH2CHR'C(O)}(mu-CO)(CO)].