Some INDO calculations of ¹<i>J</i>(PN) values

Abstract

Abstract Self consistent perturbation theory calculations of 1 J (PN) are performed using INDO parameters. The change in sign of the coupling upon passing from tri‐ to penta‐valent phosphorus arises from the influence of the phosphorus lone‐pair electrons. The observed coupling trends are reproduced by the variation in the contact contribution which, in turn, depends largely upon the s character of the lone‐pair electrons on the coupled nuclei. There appears to be no significant role played by the phosphorus d orbitals in the couplings considered.