Cloppa RPA-AM1 analysis of the anisotropy of NMR1J(XY) coupling tensors in Me3XY compounds (X =13C,29Si,119Sn,207Pb; Y =19F,35Cl)

Abstract

In this work, the CLOPPA approach is extended to allow the bond‐contribution analysis of the anisotropic part, ΔJ, of the indirect nuclear spin‐spin coupling tensor, J. As an example this method is applied to study the role played by the X‐Y bond, its antibonding orbital, and the Y lone pairs in determining the Fermi contact‐spin dipolar cross contribution to Δ1J(XY) in compounds of type Me3X(SINGLE BOND)Y (X = C, Si, Sn, Pb; Y = F, Cl). That contribution is found to be the main one, except for X = Pb, in this series of compounds. Calculations are carried out using semiempirical AM1 ground‐state wave functions. © 1997 John Wiley & Sons, Inc.