Ab initio study of NMR spin-spin coupling constants of five- and six-membered heterocyclic compounds

Ab initio calculations of spin-spin coupling constants have been carried out for a series of five- and six-membered heterocyclic compounds using both equilibrium experimental X-ray structures and molecular mechanics optimised structures. The relationships between neighbouring atom electronegativities, net charges on the carbon atoms, bond orders and the magnitudes of 1Jch have been investigated. The 4-31G and 6-31G basis sets have been found to be adequate to reproduce the general trends in 1Jch. © 1995.