1JCH Correlates with alcohol hydrogen bond strength

The strength of the H-bond donation by alcohols is reflected in the carbon−hydrogen bond of the H−C−O−H functional group. The one-bond 13C−1H spin−spin coupling constant of hexafluoroisopropanol (HFIP) correlates with the strength of the H-bond in various HFIP−amine complexes with a slope of ∼ −0.2 Hz in 1JCH per ∼1 kJ mol-1 increase in the H-bond enthalpy. The decrease in 1JCH is attributed to an increased overlap of the H-bonding σ orbital with the antibonding σ* orbitals of the vicinal C−H bonds.