Dependence of the long-range phosphorus–hydrogen coupling constant <SUP>n</SUP>J<INF>P–H</INF> (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 ⁶J<INF>P–H</INF>, ⁷J<INF>P–H</INF> and ³J<INF>P–H</INF>, 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 ⁷J<INF>P–H</INF> and ³J<INF>P–H</INF>. The preparation of the compounds p-CH<INF>3</INF>C<INF>6</INF>H<INF>4</INF>NHP(O)Cl<INF>2</INF> (II), p-CH<INF>3</INF>C<INF>6</INF>H<INF>4</INF>NHP(O)(Cl)OC<INF>6</INF>H<INF>4</INF>CH<INF>3</INF>-p (XIV), m-CH<INF>3</INF>C<INF>6</INF>H<INF>4</INF>NHP(O)(Cl)OC<INF>6</INF>H<INF>4</INF>CH<INF>3</INF>-p (XV), m-CH<INF>3</INF>C<INF>6</INF>H<INF>4</INF>NHP(O)(Cl)OC<INF>6</INF>H<INF>4</INF>CH<INF>3</INF>-m (XVI) and the rigid molecule CH<INF>3</INF>C<INF>6</INF>H<INF>3</INF>(NH)<INF>2</INF>P(O)Cl (XVII) are described and they are characterized by ¹H, ¹³C, ³¹P NMR, IR spectroscopy and elemental analysis. Copyright © 2001 John Wiley & Sons, Ltd.