Phosphorus–fluorine compounds. Part XIII. Phosphorus and fluorine nuclear magnetic resonance spectra of aminobis(difluorophosphines), RN(PF2)2, XX′AA′X″X‴ spin systems

Abstract

The ³¹P and ¹⁹F n.m.r. spectra of alkyl- and aryl-aminobis(difluorophosphines) RN(PF₂)₂(R = Me, Et, Ph, or m-ClC₆H₄) have been analysed as examples of XX′AA′X″X‴ spin systems and coupling constants |¹J_PF′|, |³J_PF′|, |²J_PP′|, |⁴J_FF|(two types), and |²J_FF′| have been accurately evaluated. Unusually large geminal phosphorus–phosphorus coupling constants are found in all cases (370–446 c./sec.) which decrease in the order R = Me ∼ Et > Ph ∼m-ClC₆H₄.