Trifluoromethyl Phosphoranide, erste Phosphoranide mit Csp3-P Bindungen: Synthese, Eigenschaften und Derivate

Abstract

The new tris(trifluoromethyl)fluorophosphoranide and tetrakis(trifluoromethyl)phosphoranide salts were synthesized. High relative stability of these derivatives allowed theirs full characterization including X-Ray analysis as well as comprehensive studying of theirs chemical properties. Thermal stability and fluxional behavior of the salts in solution in dependence on the nature of cation were investigated. Energy barriers to pseudorotation in trifluoromethyl phosphoranides were compared with those for trifluoromethyl phosphoranes. Ab-initio calculations of electronic and geometrical parameters as well as selected gas-phase acidities for phosphoranides were performed and close interrelationships of different parameters for each group of substituents (axial, equatorial) were established. A new class of compounds was discovered during studying the chemistry of phosphoranides. Mixed-valence species (l3s3P-l5s6P system) were unexpectedly obtained in the reactions of trifluoromethylphosphoranides with fluoride ion sources in monoglyme. These derivatives were characterized by NMR and MS spectral methods however, numerous attempts to grow single crystals applicable for X-Ray analysis failed compounds quickly decomposed in solution even at -40 Ã ?Ã ºC to give corresponding phosphate salts.Perphosphoranides were obtained in high yields in the reaction of corresponding trifluoromethyl phosphines with DFI. These compounds were fully described including X-Ray analysis.Syntheses of starting compounds (trifluoromethyl-phosphines, DFI, DFTMU) were optimized significantly and new convenient large-scale routes to ones were found.