Optical rotation of noncovalent aggregates

J Am Chem Soc. 2003 Dec 24;125(51):15696-7. doi: 10.1021/ja0376893.

Abstract

Dilute solutions of (R)-(-)-pantolactone in CCl4 were studied by polarimetry in conjunction with theoretical calculations of [alpha]D. Our data demonstrate that the self-association of a chiral solute results in a change in [alpha]D that can be accounted for by the presence of hydrogen-bonded dimeric species. The theoretical analysis predicts a concentration-dependent specific rotation in good agreement with experiment. Further exploration of monomer and dimer [alpha]D differences, through atomic map analysis, reveals large contributions to [alpha]D from the hydrogen-bonded hydroxyl groups in the tightly-coupled dimer. This study extends the computation of chiroptical properties to the accurate concentration-dependent prediction of [alpha]D for noncovalently interacting self-associating species.

Publication types

  • Research Support, U.S. Gov't, Non-P.H.S.
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • 4-Butyrolactone / analogs & derivatives*
  • 4-Butyrolactone / chemistry*
  • Dimerization
  • Hydrogen Bonding
  • Kinetics
  • Models, Molecular
  • Molecular Conformation
  • Stereoisomerism
  • Thermodynamics

Substances

  • pantolactone
  • 4-Butyrolactone