Comparative sp and spd SCF-INDO-FPT calculations of PC and PP nuclear spin-coupling constants of phosphorins and diphosphines

Abstract

Comparative SCF-INDO-FPT calculations have been carried out for the n J(PC) couplings of phosphorins and the 1 J(PP) couplings of phosphines with the sp and spd basis sets and taking into account the Fermi contact, orbital-dipole, and spin-dipole interaction terms. The couplings obtained with both basis sets correlate satisfactorily with observation, account for the angular dependence of the 1 J(PP) coupling, and provide the same elucidation of the electronic origin of the various couplings. These results indicate therefore that the restricted sp basis set can be confidently used to investigate the couplings of compounds containing di- and tricoordinated phosphorous. The importance of all three interaction mechanisms for interpreting the n J(PX) couplings is stressed.