Solid state 15N NMR and theoretical studies of primary and secondary geometric H/D isotope effects on low-barrier NHN-hydrogen bonds

A study was conducted to analyze the H/D isotope effects on nitrogen-hydron distances and 15N chemical shielding tensors of hydrogen bonded-bisiscoyanide salts. The effects of the low-barrier hydrogen bond of polycrystalline was also examined in the study. Results indicated the chemical shielding of the nuclei in the hydrogen bridge was a qualitative probe for primary and secondary geometric isotope effects.