Circular dichroism as a probe of chiral solvent structure around chiral molecules

Abstract

Molecular dynamics simulations have been used to study solvent effects on the circular dichroism (CD) of the n-π* carbonyl transition in camphor and 9,10-dibromocamphor. It is found that achiral solvents may contribute as much as 10-20% of the CD intensity; this arises because the camphors induce solvation structure that is chiral even when the solvent molecules themselves are achiral. The magnitude of the solvent effect is found to depend strongly upon the nature of both the solute and the solvent. This has implications for enhancing the enantiomeric selectivity of chiral syntheses.