Does the ipso‐carbon chemical shift tell us anything about the structure of phenylated phosphorus compounds?

The nuclear magnetic resonance signals exhibited by the ipso‐carbon atoms of a variety of phenylated phosphorus compounds were found to span over the remarkably wide range of + 162 to + 117 ppm. Nevertheless, these changes in chemical shifts have little diagnostic value. They are tentatively attributed to a charge‐mediated contraction and expansion of the C,P σ‐bond orbital on one hand and to a σ‐bond induced deformation of the aromatic π‐electron cloud on the other.