Open-Resonance-Assisted Hydrogen Bonds and Competing Quasiaromaticity

J Org Chem. 2018 Sep 7;83(17):9850-9857. doi: 10.1021/acs.joc.8b01331. Epub 2018 Aug 6.

Abstract

The delocalization of electron density upon tautomerization of a proton across a conjugated bridge can alter the strength of hydrogen bonds. This effect has been dubbed resonance-assisted hydrogen bonding (RAHB) and plays a major role in the energetics of the tautomeric equilibrium. The goal of this work was to investigate the role that π-delocalization plays in the stability of RAHBs by engaging other isomerization processes. Similarly, acid-base chemistry has received little experimental attention in studies of RAHB, and we address the role that acid-base effects play in the tautomeric equilibrium. We find that π-delocalization and the disruption of adjacent aromatic rings is the dominant effect in determining the stability of a RAHB.

Publication types

  • Research Support, Non-U.S. Gov't