Dependence of the long‐range phosphorus–hydrogen coupling constant n J P–H ( n = 3,6,7) on the bond order between phosphorus and its substituents: preparation and spectroscopic characterization of several phosphoramidates

The examination of spectra of a selected series of phosphoramidates showed that, in addition to a double bond, whenever there are one or two partial multiple bonds in the molecule the long‐range coupling constant, such as 6 J P–H , 7 J P–H and 3 J P–H , either disappears or at least reduces. In particular, the experimental data indicate the unexpected effect of a partial multiple bond between phosphorus and fluorine in 7 J P–H and 3 J P–H . The preparation of the compounds p ‐CH 3 C 6 H 4 NHP(O)Cl 2 (II), p ‐CH 3 C 6 H 4 NHP(O)(Cl)OC 6 H 4 CH 3 ‐ p (XIV), m ‐CH 3 C 6 H 4 NHP(O)(Cl)OC 6 H 4 CH 3 ‐ p (XV), m ‐CH 3 C 6 H 4 NHP(O)(Cl)OC 6 H 4 CH 3 ‐ m (XVI) and the rigid molecule CH 3 C 6 H 3 (NH) 2 P(O)Cl (XVII) are described and they are characterized by 1 H, 13 C, 31 P NMR, IR spectroscopy and elemental analysis. Copyright © 2001 John Wiley & Sons, Ltd.