Halogenotrifluoromethyl-phosphines and -phosphoranes

Halogenotrifluoromethyl-phosphines and -phosphoranes. The synthesis and stereochemistry of fluorophosphoranes RaPFj,-a (R = alkyl or aryl x — 1,2, or 3) have been extensively discussed, but comparatively little information is available on mixed halogenofluorophosphoranes of general formula 

Schmutzler, Halogen Chemistry , Academic Pres.s, New York, 1967, Vol. 2, p. 31 Angew. Chem. Internal. Edn, 1965, 4. 496. 

R PXyF6-(it+s() (X = halogen other than fluorine). This situation has been redressed somewhat by the synthesis of the mixed chlorofluorophosphoranes (41)— 

The bistrifluoromethyl compound (CF3)2PFCla has also been obtained as a by-product in the preparation of the fluorophosphine complex Pt[(CF3)aPF]i from potassium chloroplatinite and fluorobistrifluoromethylphosphine. Treatment of (43) with antimony trifluoride at room temperature converts it into the fluorophosphorane n-C3F7-PF4 similar fluorination of trichloro-bisheptafluoro-n-propylphosphorane yields (n-C3Fj)2PF3. The thermolysis of difluorotristrifluoromethylphosphorane (an established route to difluoro-carbene ) in the presence of the nitroso-compound CFaCl CFj-NO has been reported (see p. 113).  

Bistrifluoromethyl nitroxide combines with tristrifluoromethylphosphine to yield the phosphorane (CF8)sP[0-N(CF,)2]a, and has been likened to chlorine in this respect similarly, chlorobistrifluoromethylphosphine gives (CFa)2PCl[0 N(CF3)2]a. The trimethylsiloxyphosphorane (CFj)3-P(O SiMe3)3 is formed almost quantitatively when tristrifluoromethylphosphine oxide is left in contact with hexamethyldisiloxane at room temperature for several days thermal decomposition of the phosphorane yields principally the ester (CFalaPCOl O SiMej, another new compound which can also be prepared from (CFs)2P(0)Cl and MeaSi-O-SiMea.  

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