Fluorophosphines reaction with

Although the direct reaction between alkyl- or aryldichlorophos-phines and h fdrogen fluoride only produces 10-15% yields of aryldi-fluorophosphines and no isolable alkyl derivatives 84), treatment of the intermediate products of the reaction with tertiary amines significantly increases the yields (30-35%, R = aryl 15-20%, R = alkyl). 

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). 

Complete displacement of CO from [Rh(CO)2Cl]2 is possible using fluorophosphines RPF2 the reaction with trifluorophosphine affording [(PF3)2RhCl]2 (250). 

On heating with PCI3, the fluorine is replaced by chlorine and a mixed trihalide is produced. A mixed trihalide also results when a hydrogen halide is used. If dimethylamino difluorophosphine is treated with chlorine or bromine at low temperatures, a pentaphosphorane is produced, which will in turn react with sulphur dioxide to give dimethylamino fluorophosphine oxide. A 6-coordinated phosphoride anion is obtained in a reaction with KHF2 (7.107). 

It must be concluded, therefore, that fluorophosphines are strongly reducing, a fact which was confirmed in further attempts at their preparation, using different reagents in the fluorination of chlorophosphines. There was either no reaction at all under the experimental conditions—e.g., with alkali fluorides in benzene as a solvent—or the trivalent phosphorus in the starting chlorophosphine was readily converted to the quinquevalent state—e.g., when phenyldichlorophosphine reacted with sodium fluoride in the presence of an antimony trioxide catalyst in a polar solvent such as acetonitrile to give phenylphosphonic difluoride. Recent Russian work showed that phenyldichlorophosphine was converted into phenyltetrafluoro-phosphorane, C6H5PF4, when it reacted with antimony trifluoride (34),... 

Knowing all these facts, especially the difficult access to fluorophosphines and the poor donating abilities of phosphorus trifluoride (5, 6), we decided to use another approach, which readily led to a number of coordination compounds with fluorophosphine ligands—namely, the fluorination of chlorophosphines already coordinated to the transition metal, where the 3s electrons of phosphorus are blocked by the complex formation. There was no reaction between elemental nickel and phosphorus trifluoride, even under extreme conditions, whereas the exchange of carbon monoxide in nickel carbonyl upon interaction with phosphorus trifluoride proceeded very slowly and even after 100 hours interaction did not lead to a well defined product (5,6). 

In the course of a study of the formation of fluorophosphoranes from chloro-phosphines (22) we observed one exception in the compound chloromethyldi-chlorophosphine, which reacted smoothly with antimony trifluoride to give the flammable fluorophosphine, C1CH2PF2, under conditions where many other chloro-phosphines were invariably converted into fluorophosphoranes. As this fluorophosphine is readily available, its interaction with a metal carbonyl derivative was studied, and cycloheptatriene molybdenum tricarbonyl, obtained from the reaction of molybdenum hexacarbonyl with cycloheptatriene (I, 2), was chosen as a starting compound. 

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. 

The reaction is conducted in a 250-mL, three-necked flask, fitted with a mechanical stirrer, a thermometer reaching close to the bottom of the flask, and a 25-cm Vigreux column to which has been connected a distillation head with multiple receiver. tert-Butyldichlorophosphine (31.8 g, 0.2 mole) is added to a stirred suspension of NaF (25.2 g, 0.6 mole) in 100 mL of sulfolane over a period of 1 hour. A slow stream of nitrogen is passed through a T-tube connected to the outlet of the distillation apparatus. After the addition of the chloro-phosphine, the reaction mixture is heated as follows 45 minutes at 80°, 15 minutes at 100-180°, and 30 minutes at 180°. Distillation of the fluorophosphine commences at 80° and is complete at 180°. The product is collected in a receiver flask cooled in Dry Ice. fer -Butyldifluorophosphine is obtained as a colorless liquid of bp 41-44° the yield is 20-23 g (79-91%, based on tert-butyl-dichlorophosphine ). Anal. Calcd. for C4H9F2P P, 24.6 F, 30.2. Found P, 24.1 F, 29.0,... 

A theoretical study of the intermediates involved in the formation of phospha-propyne from pyrolysis of vinylphosphirane has led to a new route to phospha-alkynes. Thus, pyrolysis of trimethylsilyl(l-phosphiranyl)diazomethane has yielded MeaSiC = P, via an intermediate 1-phosphiranylmethylene . Regioselec-tivity in the [3 + 2] cycloaddition reaction between phosphaethyne and diazomethane has been studied by theoretical techniques , and further examples of reactions of this type described . Cycloaddition of phospha-alkynes with silylenes has also been reported. The primary phosphine 324 has been isolated from the addition of diethylphosphite to t-butylphosphaethyne. The chemistry of phospha-alkyne cyclotetramer systems has been reviewed and the first examples of platinum(II) complexes of such cage systems described. Aspects of the reactivity of coordinated phospha-alkynes have received further study, and a remarkable metal-mediated double reduction of t-butylphosphaethyne to the complexed fluorophosphine 325 described Phosphorus-carbon-aluminium cage structures have been isolated from the reactions of kinetically stable phospha-alkynes with trialkylaluminium compounds and new phosphaborane systems have been obtained from the reactions of phospha-alkynes with polyhedral boranes . Further studies of wo-phospha-alkyne coordination chemistry have appeared . The reactivity of the ion 326 has been explored. ... 

Although PBrCIF cannot be isolated in the pure state from the above reactions, Clune and Cohn (64) have very recently obtained the un-symmetrical fluorophosphine Me2NPFBr by reacting cyanogen bromide with dimethylaminodifluorophosphine. The formula of the compound... 

Mixed halogenofluorophosphoranes PFs X may be obtained by controlled reactions between the appropriate fluorophosphines with a halogen. 

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... 

Preparation. - Fluorophosphines have been obtained from the reactions of the related chlorophosphines with trimethyl tin fluoride. Phenyl(isopropyl)-fluorophosphine has been resolved via a chiral amine-palladium(II) complex, providing the first example of the resolution of a free fluorophosphine chiral at phosphorus. This compound racemises at 20 °C in benzene solution over six hours. The neat compound rapidly decomposes by redox disproportionation. The same approach has been used for the resolution of the related chloro-phosphine, but the optically active compound could not be liberated unchanged from the crystallised diastereoisomeric palladium complex. The dihalo-genophosphines... 

Observations have been made which support coordination of the dialkyl-amino fluorophosphine ligands to the transition metal through phosphorus, rather than through nitrogen, whereas in the reaction of (CH )2NPp2 with some boron acceptor molecules coordination both through phosphorus or nitrogen was observed (1). 

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