Acid-Base Chemistry of Short Hydrogen Bonds: A Tale of Schrodinger's Cat in Glutamine-Derived Crystals.

ABSTRACT: Short hydrogen bonds, defined by donor-acceptor distances of less than 2.5 Å, represent a distinct regime in acid-base chemistry where conventional models of hydrogen bonding break down. In an organic crystal formed via a temperature-induced chemical transformation of l-glutamine, we previously identified a short hydrogen bond featuring a double-well potential indicative of an activated proton transfer. Here, using path-integral ab initio molecular dynamics, we show that nuclear quantum effects completely eliminate the classical barrier leading to a symmetrization of the proton along the hydrogen bond. Classically, proton transfer is strongly coupled to the rocking motion of a neighboring ammonium ion; under quantum effects, this coupling is significantly reduced. Furthermore, exami

SUBMITTER: Qaisrani MN 

PROVIDER: S-EPMC12376103 | biostudies-literature | 2025 Aug

REPOSITORIES: biostudies-literature