Complementary information on these compounds has been obtained from lH, 13C, and l g F n.m.r., including double and triple resonance experiments. The coupling constant, ,J(PNP), covers the range -23.9 to 731.9 Hz, and its magnitude and sign can be related to the proportion of molecules in which the local symmetry of the P-N-P skeleton is C,, rather than C,. Diphosphinoamine conformers of the latter type have been clearly identified for the first time both in solution (for R = Et or Pr', X = Ph, and R = But or CH,But, X = CI) and also in the solid phase.X-Ray analysis of Ph,PN(Pr') PPh,, based on 1 269 diffractometric intensities refined to R = 0.035, shows that the symmetry of the P-N-P skeleton is close to C, in the solid, with P-N = 1.706(4) and 1.71 l ( 4 ) A, and PNP = 122.8(3)".
140.8