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.

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Page 15696 and page S-9 of Supporting Information. A sentence in the fifth paragraph on page 15696 should read, "The [R I ] and [R II ] values were calculated using frequency-invariant atomic orbitals (FIAOs) with Dunning's correlation-consistent valence double-(aug-cc-pVDZ) basis set in the time-dependent density functional theory (TD-DFT) response formalism implemented in Turbomole. 9 " The Supporting Information page S-9 contains the same error.