Choice of exchange-correlation functional for computing NMR indirect spin–spin coupling constants

The choice of exchange-correlation functional for the determination of indirect nuclear spin–spin coupling constants in density-functional theory is considered. In an assessment of one-bond 1JCH couplings, the PBE functional was recently shown [S.N. Maximoff, J.E. Peralta, V. Barone, G.E. Scuseria, J. Chem. Theory Comput. 1 (2005) 541] to perform well, significantly outperforming B3LYP. For couplings involving N, O, and F atoms in simple molecules, we demonstrate that the opposite is observed; PBE is considerably less accurate than B3LYP. By contrast, the B97-2 and B97-3 semi-empirical functionals provide good, consistent quality couplings for all these atom types in an extensive assessment.