Self-Consistent Perturbation Theory of Nuclear Spin-Coupling Constants: Application to Couplings Involving Carbon and Fluorine

A self-consistent perturbation theory is presented which permits efficient calculation of the contact, orbital, and dipolar contributions to nuclear spin coupling. The theory is applied with the INDO molecular orbital method to a number of couplings involving carbon and fluorine. The usually neglected orbital and dipolar terms are found to be very important in FF and CF coupling, and the orbital interaction plays a significant role in certain CC couplings. Generally good agreement is obtained between theory and experiment with the exception that the incorrect sign is obtained for cis JFF. The value of JCF in difluoroacetic acid is predicted to be − 235 Hz.