Theoretical Investigation of the Relationship between Proton NMR Chemical Shift and Hydrogen Bond Strength

Hartree−Fock, Møller−Plesset, and DFT (BLYP, B3LYP) calculations have been carried out using the 6-31+G(d,p) basis set to study the relationship between calculated 1H NMR chemical shifts and calculated hydrogen bond strengths in several model low-barrier hydrogen bond complexes. For both the formic acid-substituted formate anion and enol-substituted enolate anion model systems, we find an excellent linear correlation between calculated hydrogen bond strength and predicted 1H NMR chemical shift, with an average slope of 1.5 kcal/mol per ppm chemical shift.