Signs of 19F1H and 19F13C spin–spin coupling constants mainly transmitted through space

The details of two‐dimensional 13C1H correlated spectra have provided information about the relative signs of J(C, F) and J(F, H) for several molecules in which C, F and H are mutually coupled. Unlike signs are found for J(C, F) and J(F, H) when the coupling pathways lie approximately in the plane, but serious deviations from planarity can bring about changes in sign of J(F, H) and J(C, F).