Hydrogen bonding causes distinct downfield shifts in nuclear magnetic resonance spectra

The retrieved literature discusses how hydrogen bonding interactions directly influence nuclear magnetic resonance (NMR) parameters, specifically noting the traditional and well-documented occurrence of downfield chemical shifts (deshielding) upon hydrogen bond formation (e.g., in papers [3], [5], and [9]). While paper [3] notes rare exceptions involving blue-shifting hydrogen bonds that display shielding, the overwhelming spectroscopic consensus and baseline principle confirmed across the evidence is that hydrogen bonding correlates with downfield shifts.