The proton spin–spin coupling surface in methane. A test of the J(H,H)=(γH/γD)J(H,D) rule for geminal protons

Abstract

Calculation shows that the proton–proton spin–spin coupling in methane is very sensitive to the interbond angle involving thecoupled protons, a result which leads to the prediction of primary isotope effects on ²J(H,H) in agreement with experimental results for geminal deuterium isotope effects in related compounds.