Phosphoranides contain a tetracoordinated, formally negatively charged phosphorus atom. This type of compound with three phosphorus–carbon bonds, i.e., triorganylphosphoranides, is rare. Mira Keßler, University of Bielefeld, Germany, and colleagues have used phosphanes with electron-withdrawing pentafluoroethyl (C2F5) groups to synthesize new phosphoranides of this type.
The team obtained silver fluorotris(pentafluoroethyl)phosphoranide, Ag[P(C2F5)3F], via a reaction of tris(pentafluoroethyl)phosphane, P(C2F5)3, with silver fluoride (pictured below). The addition of chelating 2,2′-bipyridine to Ag[P(C2F5)3F] then gave the isolable silver complex [Ag(bipy){P(C2F5)3F}], which was characterized using X-ray diffraction analysis.
The researchers also found that treatment of cyanobis(pentafluoroethyl)phosphane, P(C2F5)2(CN), with [K(18-crown-6)]F gave the respective cyanofluorobis(pentafluoroethyl)phosphoranide salt [K(18-crown-6)][P(C2F5)2(CN)F] (pictured below). The team was able to structurally characterize this [P(C2F5)2(CN)F]− salt despite its tendency to undergo an exchange of substituents, which results in a mixture of the corresponding [P(C2F5)2F2]− and [P(C2F5)2(CN)2]− salts.
- Triorganylphosphoranides: Realization of an Unusual Structural Motif Utilizing Electron Withdrawing Pentafluoroethyl Groups,
Mira Keßler, Michael Kapiza, Hans‐Georg Stammler, Beate Neumann, Gerd‐Volker Röschenthaler, Berthold Hoge,
ChemPlusChem 2023.
https://doi.org/10.1002/cplu.202200436
