Interplay between intramolecular resonance-assisted hydrogen bonding and aromaticity in o-hydroxyaryl aldehydes

J Org Chem. 2006 Jul 7;71(14):5241-8. doi: 10.1021/jo060591x.

Abstract

In this work, we analyze a series of o-hydroxyaryl aldehydes to discuss the interrelation between the resonance-assisted hydrogen bond (RAHB) formation and the aromaticity of the adjacent aromatic rings. As compared to the nonaromatic reference species (malonaldehyde), the studied compounds can be separated into two groups: first, the set of systems that have a stronger RAHB than that of the reference species, for which there is a Kekulé structure with a localized double CC bond linking substituted carbon atoms; and second, the systems having a weaker RAHB than that of the reference species, for which only pi-electrons coming from a localized Clar pi-sextet can be involved in the RAHB. As to aromaticity, there is a clear reduction of aromaticity in the substituted ipso ring for the former group of systems due to the formation of the RAHB, while for the latter group of species only a slight change of local aromaticity is observed in the substituted ipso ring.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aldehydes / chemistry*
  • Anthracenes / chemistry
  • Hydrogen Bonding
  • Molecular Structure
  • Naphthalenes / chemistry
  • Phenanthrenes / chemistry

Substances

  • Aldehydes
  • Anthracenes
  • Naphthalenes
  • Phenanthrenes