Specific Optical Rotations and the Horeau Effect. Issue 3 (28th December 2015)

• Record Type: Journal Article
• Authors: Covington, Cody L.; Polavarapu, Prasad L.
• Is Part Of: Chirality. Volume 28:Issue 3(2016)
• Page Start: 181
• Page End: 185
• Publication Date: 2015-12-28
• Subjects: optical rotation -- specific rotation -- Horeau effect -- optical purity -- enantiomeric purity; Chirality -- Periodicals; Pharmaceutical chemistry -- Periodicals; 541.22
• DOI: 10.1002/chir.22565
• Languages: English
• ISSNs: 0899-0042

Abstract

Abstract: The observation of nonequivalence of optical and enantiomeric purities, referred to as the Horeau effect, is thought to arise from molecular aggregation in liquid solutions. Although this effect was first observed in 1969, the conditions under which this effect may, or may not, be observable are not established. Considering the formation of dimers as the simplest form of aggregation, the expressions for specific optical rotations in the presence of homochiral and heterochiral monomer–dimer equilibria are presented. Analysis of these equations indicates that the Horeau effect will not be observable even in the presence of aggregation under either of the following two situations: 1) The specific optical rotation of the monomeric species is equal to that of the dimeric species; 2) The heterochiral equilibrium constant is twice that of the homochiral equilibrium constant. Chirality 28:181–185, 2016 . © 2015 Wiley Periodicals, Inc. Abstract : ▪▪▪