Fluorophosphines complexes

CjHj(,). These compounds react with anhydrous HX (X = Cl or Br) to yield the halogenated-fluorophosphine complexes e.g ... 

Fluorophosphates, 16 183 Fluorophosphine complexes with borane, 13 439-444 coordination, 13 41CM14 bonding, in, 13 410-414 with nontransition metal halides, 13 445-447... 

In our study of the fluorination of coordinated chlorophosphine ligands (23), we started out with tetrakis(trichlorophosphine)nickel-(0), which could previously be converted into tetrakis(trifluorophosphine)nickel-(0) by displacement of the coordinated phosphorus trichloride with excess phosphorus trifluoride in a sealed tube (32). The limitations of this method, requiring the use of phosphorus trifluoride, a low boiling gas, under pressure, and involving the mechanical separation of the fluorophosphine complex from phosphorus trichloride, are obvious, and the yield was low. A straightforward method for the synthesis of this interesting compound was found in the fluorination of the coordinated phosphorus trichloride with potassium fluorosulfinate ... 

The chemical and thermal stability of the fluorophosphine complexes is markedly increased in every case over the chlorophosphine complexes, none of the latter being volatile. The stability of the fluorophophine complexes as compared with the parent carbonyl is also noteworthy. While nickel carbonyl is distillable only with considerable decomposition, tetrakis(trifluorophosphine)nickel-(0) is far more stable on distillation at atmospheric pressure, and can also conveniently be handled in a high-vacuum system. 

Oxidation of trifluorophosphine by halogens is well known (282) and although corresponding reactions with alkyl or aryl fluorophosphines have received only little attention, it has become apparent that oxidation to the pentavalent phosphorus fluorides can be brought about by a wide variety of reagents. In certain cases the reducing property of the fluoro-phosphine has been utilized in the synthesis of zero-valent transition metal fluorophosphine complexes (Section IX). 

The ease of substitution of metal-fluorophosphine complexes has also been related to the a-donor and 7r-acceptor characteristics of the substituting ligand (152), since only ligands of high 7T-acceptor ability (e.g., CO, phosphites) can completely displace the coordinated fluorophos-phines, whereas tertiary amines, phosphines, arsines, and stibines usually form partially substituted products (see Section IX, 6). 

Trifluorophosphine complexes of nickel, palladium, and platinum have been obtained by direct reaction of PF3 with the metal at elevated temperatures and pressures (172). Similarly several fluorophosphine complexes of zero-valent nickel can be made under very mild conditions (60°C) using metallic nickel formed by decarboxylation of nickel oxalate... 

The strong reducing properties of certain fluorophosphines can, in certain cases, lead directly to fluorophosphine complexes of the metal in its zero-valent state (173, 234, 247), for example. 

Mixed phosphine-fluorophosphine (160, 247, 164, 173, 174), phos-phite-fluorophosphine (174), tertiary amine-fluorophosphine (174), carbonyl-fluorophosphine (160, 173, 56, 58, 59), tertiary arsine-fluoro-phosphine (174,175), and stibine-fluorophosphine complexes are readily formed directly from the appropriate fluorophosphine-metal complex. Only in the case of carbon monoxide, chlorophosphines, and phosphites is it possible to completely displace all the fluorophosphine ligands from the metal. Some typical examples are quoted below ... 

The infrared spectra of hydrido and perfluoroalkylcobalt carbonyl-fluorophosphine complexes RCo(CO),j(PF3)4 3. (R = H, CFg, C2F5, C3F7) have also been interpreted in terms of the presence of nonisolable isomers 320). This contrasts with a report 159) that pure HCo(CO)(PF3)3 can be obtained directly from dicobalt octacarbonyl. As discussed in Section XI,D, there is convincing evidence from F NMR studies of stereochemical nonrigidity in CF3Co(PFg)(CO)3. 

Fewer data are available on fluorophosphine complexes of metals in higher oxidation states. In Pt(II) complexes 241, 242) Sp occurs at higher field than the free ligand, whereas the behavior in Rh(I) complexes 242, 250) is more variable. 

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