Phosphorus trifluoride substitution compounds of iron pentacarbonyl

Article abstract of DOI:10.1021/ic50020a011

The reaction of Fe(CO)₅ and PF₃ at elevated temperatures and pressures results in the formation of mixtures of Fe(CO-)_5-x- (PF₃)_x compounds where x has values of 1-5. The degree of replacement of carbon monoxide by phosphorus trifluoride is dependent upon the temperature of reaction with the average x in the above formula being 1 at 170° and 3-4 at 280° under pressures of 200-500 p.s.i. Higher temperatures lead to decomposition. Ultraviolet irradiation of mixtures with an average x of about 3 in the presence of PF₃ gas produces higher substitution without the problem of decomposition. The compounds were separated and isolated by means of vapor phase chromatography. They are yellow liquids except Fe(PF₃)₅ which melts to a yellow liquid at 44°. Infrared spectra of these compounds suggest some interesting structure anomalies but it is obvious that the structures are not simple trigonal bipyramids.