Iron, trifluorophosphine complexes

The dihalogenotetrakis(trifluorophosphine)iron complexes can readily be obtained by direct oxidation of [Fe(PF3)5] with the appropriate halogen under mild conditions (method D). NMR studies establish that the halogens lie in cis-positions of the octahedron. 

Direct condensation of metal vapors with trifluorophosphine at -196°C provides a convenient alternative to the high-pressure route to metal-PF3 complexes. The reactions of Mo, Cr, Co, Ni, and Pd vapors with PF3 yield only one volatile product in each case, namely Mo(PF3)6 (132), Cr(PF3)6, Co2(PF3)g, Ni(PF3)4, and Pd(PF3)4 (128), respectively. The yields are good, 40-100% depending on the metal vapor used. Some defluorination of the PF3 accompanies the formation of Cr(PF3)6. No complex could be isolated from the manganese vapor-PF3 reaction, although some defluorination seems to have occurred. The reaction of iron and PF3 is complex,... 

A variety of synthetic routes to monoene and polyene tri-fluorophosphine-transition metal complexes have been devised. Direct photochemically induced reaction of a metal-PF3 complex with an activated alkene or diene (method A) has proved useful only for iron, the products being either [Fe(PF3)4(alkene)J or [Fe(PF3)3(diene)] (194). Mixed carbonyl-trifluorophosphine complexes of the type [Fe(PF3)x(CO)3 x(diene)] result from either thermal or photochemical reactions of dieneiron carbonyl complexes and PF3 (52, 53) (method B). The compounds are fluxional. 

A number of transition metals have been shown to react with trifluoro-phosphine [280]. Chromium, cobalt, nickel, palladium and iron all produced stable complexes. Manganese and copper also reacted at —196°C, but the products were unstable, and decomposed on warming. Nickel vapour has also been reacted with difluorochlorophosphine, yielding Ni(PF2Cl)2. Complexes produced by reaction with phosphine itself were unstable, decomposing on warming, although when a mixture of phosphine and trifluorophosphine was co-condensed with nickel vapour some mixed complexes were isolated. 

---