Finally, the stabilization value Qs is roughly the same, which explains, why in the melted state there are no differences in dynamics. Thus, despite the difference in the DQCC value is always within +5 kHz, we can conclude, that the fully isotope substitution of the PIL's cation notably alters the EFG tensor on the ND fragment of the cation. Since the latter is strongly hydrogen bonded with the anions, we can speculate, that the full deuteration is decreasing the hydrogen bond strength. To our knowledge, this is the first experimental evidence on the isotope effect on the hydrogen bonding in PILs due to H/D exchange not involving the N-H proton.