Beyond Deshielding: NMR Evidence of Shielding in Hydridic and Protonic Hydrogen Bonds.

ABSTRACT: The red shift of the X-H stretching frequency, with a significant increase in intensity of the corresponding spectral band and a downfield chemical shift of hydrogen (deshielding) in nuclear magnetic resonance (NMR) spectroscopy, has traditionally been used as a criterion for identifying X-H···Y hydrogen bonds (HBs) where X is the hydrogen donor and Y is the acceptor. However, over the past two decades, it has become evident that certain HBs can exhibit a blue shift in the X-H stretching frequency and may also show a decrease in IR intensity, diverging from classical expectations. In this study, we investigate a wide array of HBs, encompassing both red-shifted and blue-shifted systems, as well as protonic and hydridic HB systems. We focus on understanding the underlying electronic conditio

SUBMITTER: Manna D 

PROVIDER: S-EPMC12355688 | biostudies-literature | 2025 Aug

REPOSITORIES: biostudies-literature