The significance of induced circular dichroism.

[reaction: see text] Achiral molecules or ions can display induced circular dichroism (ICD) within their absorption bands on association with chiral inducing molecules. The reverse process is equally important, although less appreciated: chiral inducing molecules, such as tartrates, can show significantly differing CD bands in different achiral environments. Therefore true ICD due to achiral molecules can only be demonstrated in the spectral region outside the absorption bands of the chiral inducing molecules. The case of tartrate-trisimidazoline helical assembly in aqueous solvent is discussed.