Effective Chirogenesis in a Bis(metallosalphen) Complex through Host–Guest Binding with Carboxylic Acids

Strong host-guest complexation of chiral carboxylic acids results in the amplification of one of the chiral conformers of a bis[Zn²⁺(salphen)] complex, which can racemize by axis rotation (see picture). The complexation leads to a CD signal for which the sign of the first Cotton effect directly relates to the absolute configuration of the substrate and the amplitude depends on the size and nature of the substituents.